Why didn’t my baby’s head fit?


Did you have a C-section for “failure to progress”? It may have happened because the baby’s head did not fit through your pelvis, a condition known as cephalo-pelvic dysproportion (CPD).

CPD is far more common in humans than any other primates, because there are competing evolutionary pressures that have acted on the two most important parameters, the size of the mother’s pelvis (a big pelvis is good for childbirth, but bad for upright mobility) and the baby’s head (a big head is good for survival, but bad for childbirth).

Most people imagine that the pelvis is like a hoop that the baby’s head must pass through, and indeed doctors often talk about it that way. However, the reality is far more complicated. The pelvis is a bony passage with an inlet and an outlet having different dimensions and a multiple bony protuberances jutting out at various places and at multiple angles. The baby’s head does not pass through like a ball going through a hoop. The baby’s head must negotiate the bony tube that is the pelvis, twisting this way and that to make it through.


You can see what I mean in the illustration above (from Shoulder Dystocia Info.com). There are bony protuberances that jut into the pelvis from either side (the ischial spines) and the bottom of the sacrum and the coccyx, located in the back of the pelvis, jut forward. How does the baby negotiate these obstacles? During labor, the dimension of the baby’s head occupies the largest dimension of the mother’s pelvis. But because of the multiple obstacles, the largest part of the mother’s pelvis is different from top to middle to bottom. Therefore, the baby is forced to twist and turn its head in order to fit.

This illustration (from the textbook Human Labor & Birth) shows what happens. We are looking up from below and the fetal skull is passing through the mother’s pelvis. The lines on top of the skull demarcate the different bones of the fetal skull.


You can see that at the beginning of labor, the baby’s head is facing sideways; in the middle of labor, the head in facing toward the mother’s back; and after the head is born, it switches back to sideways and the shoulders come through the pelvis.

What does it mean when the baby’s head gets stuck? It can mean a number of different things. The pelvic inlet could be too small so the baby’s head never even drops into the pelvis. The ischial spines could stick too far into the pelvis and stop the head. The sacrum and coccyx could be angled too far forward and that could stop the head.

Clearly there is a great deal of potential for a mismatch between the size of the pelvis and the size of the baby’s head. Over time, babies have evolved so that the bones of the skull are not fused and can slide over each other, reducing the diameter of the head. This is called “molding” and accounts for the typical conehead of the newborn. But there is a limit to the amount of molding that the head can undergo and ultimately, the baby may not fit through.

The illustration above shows the baby’s head entering the pelvis in the optimal position, but babies don’t always cooperate. If the head is in anything other than the ideal position the fit will be even tighter. That’s why babies in the OP position (facing frontwards) and babies with asynclitic heads (the head titled to one side) are much more difficult to deliver vaginally. Their heads no longer in the smallest possible diameter. It’s like trying to put on a turtleneck face first of over your ear instead of starting from the back of your head. It’s much more difficult.

Although this is a more detailed explanation than that typically offered, it is still a simplified explanation. It does demonstrate, though, that many different variables are involved in whether a baby’s head will fit: the diameter of the pelvic inlet, the length and angle of the ischial spines, the angle of the coccyx, the position in which the fetal head enters the pelvis, the ability of the fetal head to mold to accommodate itself to the available dimensions.

Considering how many variables are involved, it’s not surprising that many babies simply do not fit. The real miracle is that most babies do fit. That was good enough to get the population to this point, despite the deaths of many babies and mothers childbirth. It’s no longer good enough, though because we want to save every baby and every mother. That’s why C-sections exist.


This piece first appeared in June 2010.

103 Responses to “Why didn’t my baby’s head fit?”

  1. Anna
    March 24, 2016 at 5:26 am #

    Very interesting article.Natural childbirth avocates seem to forget about something very obvious : us humains have evolved in a very different way than the animals they like to compare laboring women to.We are a unique species that needs particular care in order to stay healthy.
    Accepting this as a fact is the first step to choose a safe birth option : a hospital birth.
    We are women and we need qualified help from other human beings to give birth safety,it is a fact,it is the product of evolution therefore there is nothing more natural.

  2. Jennifer McGuire
    March 18, 2016 at 9:15 am #

    Both of my spawnlets were asynclitic (head tilted toward the shoulder in utero) and I never got far in labor – c-section both times, and we’d have been dead at the first go-round without one.

  3. Mishimoo
    March 17, 2016 at 8:09 am #

    This is a rather apt post for today as it’s the anniversary of the day I was rescued by a very caring, intelligent and stubborn Ob/Gyn when my head got thoroughly stuck in an android-type pelvis and the placenta partially abrupted. He made sure I came into the world kicking and screaming instead of quietly expiring and taking my mother out with me. So thank you, from my family and myself, to the Ob/Gyns who do their damnest to save lives.

    • The Bofa on the Sofa
      March 17, 2016 at 9:44 am #

      Happy birthday!

    • MI Dawn
      March 17, 2016 at 10:17 am #

      Happy remembrance of natal day! Good thing your mom had a great doctor to help her and you.

      • Mishimoo
        March 17, 2016 at 7:26 pm #

        Thanks! He is brilliant and only retired a few years ago. It’s just unfortunate that thanks to the woo, both of my parents still think it was an unnecessary caeserean.

    • Who?
      March 17, 2016 at 6:11 pm #

      Happy birthday-hope you’re enjoying the Festival of Mishimoo!

      • Mishimoo
        March 17, 2016 at 7:25 pm #

        Thanks! I wandered about the city with my dear husband and our youngest (the older two were at school). If you haven’t been to the medieval exhibit, I highly recommend going before it finishes. Seeing some of the reliquaries was a bit sad – it’s one thing to know that they held relics to be lent to women in childbirth, it’s quite another to actually see them.

        • Who?
          March 17, 2016 at 7:41 pm #

          Sounds like a lovely day.

          I haven’t been to see it, will try to get there.

    • Nick Sanders
      March 17, 2016 at 6:16 pm #

      Happy Birthday!

  4. Green Fish
    March 17, 2016 at 6:05 am #

    The antibiotics are kicking in and I’m slowly turning from a pain-filled slime monster back into a human.
    My OB isn’t completely happy with me though because I lost 3kg of weight due to this horrible cold/cough.
    She told me to be really, really nice to myself for the remainder of the pregnancy.
    Well, my due date is only one week away, so we’re nearly there.

    • Who?
      March 17, 2016 at 7:26 am #

      Good luck, take it easy!

      Be kind to yourself is very fine advice to all of us, particularly new and newish mums who tend to forget in the blur of caring for others.

    • Mishimoo
      March 17, 2016 at 8:02 am #

      Glad the antibiotics are working! Hope everything goes smoothly and take care of yourself!

    • MI Dawn
      March 17, 2016 at 10:15 am #

      Wow! That’s a lot of weight to lose. Be really nice to yourself, and make everyone who will be helping you be really, really nice. Take care!

  5. The Computer Ate My Nym
    March 17, 2016 at 3:48 am #

    More anecdata: I’m about average size for a US-American woman. My baby’s size was correctly estimated as 7-8 pounds, i.e. also pretty average. She was head down. I was healthy, no blood pressure problems, no diabetes, not even anemia. I ate a reasonably healthy vegetarian diet. I swam 40 laps the day before she was born. In short, apart from marginally old maternal age (just turned 35), I was in great shape. I also had no particular fear of childbirth. I was in NYC, going to deliver at a hospital with everything from an in-hospital birthing center with jacuzzi and birthing ball to an OR and NICU around the corner.

    None of it, from the size to the attitude made any difference. Small one’s head was in the wrong position and she was never going to come out my pelvis. Without a c-section we would have simply both died. And since it was probably happenstance, not the shape of my pelvis or anything particularly “wrong”, it wouldn’t even have improved the species. That’s nature for you: Sometimes crap just happens. I’m grateful for the enormous save roll that technology provides to us.

  6. seekingbalance
    March 17, 2016 at 2:15 am #

    slight correction: “baby’s have evolved” should read “babies” or “babies’ heads”

  7. rh1985
    March 17, 2016 at 1:08 am #

    I’m neither a big person nor a small person. I guess I’m rather average. My daughter was a very average 7lb8oz and probably couldn’t have been born vaginally. I was originally going to have a MRCS, it became an emergency CS due to pre-e, my OB noted “she probably wouldn’t have fit anyway” when she pulled her out. I asked her later what that meant and she said she wasn’t positioned very well. Yay for modern medicine! I suppose it’s good I wanted a CS anyway since that was probably going to be the end result no matter what. At least I didn’t torture myself with a failed induction first.

  8. H.
    March 16, 2016 at 9:33 pm #

    I honestly think that those people who feel that vaginal childbirth is possible for all women (i.e. the ‘no c-sections ever required, you were made to have babies,’) camp should spend a year or so in a mixed practice vet clinic. Animals don’t have any of the hangups about birth that we do; they don’t fret over breast vs bottle when they have poor supply or an infant can’t latch (the owners sure do but that’s another incredibly frustrating problem), they don’t debate the merits of pain control in labor, they don’t judge each other for how they birthed their babies. And yet, guess what? They still have c-sections.

    It’s the start of calving season in northern BC and I’ve done five c-sections in the last two weeks. In the last couple months we’ve had two dog and one cat c-section. While it’s easy to argue for this as a result of overbreeding and yes, one dog was a breed notorious for being unable to birth naturally anymore, the other was a plain old mutt bred to a plain old mutt. She had one big pup get stuck like a plug, leaving the five others. The owner felt that as an animal, she would be able to birth naturally no matter what. By the time we saw her all six of the pups were dead and she was damn sick. An emergency c-section, an OVH, and a ton of medical intervention later she was lucky to be alive. The cat was a similar situation, but seen much earlier. Three live kittens and one dead.

    Of the five calvings, two were too big to pass naturally despite being older experienced cows with spotless previous calving records and appropriately sized bulls. Two were badly tangled, breech with legs going every which way and in too much distress to risk untangling and pulling. One simply failed to progress, and despite oxytocin was never able to have effective contractions. Three of these calves lived, three more than if we hadn’t gone in to help. And you know what? None of these cows seemed overly concerned. All three bonded well, were up and nursing within a few minutes of the surgery being finished, and as of writing are doing great.

    Trusting birth is bullshit. If issues were caused by not trusting birth, then we would see every animal walk through our doors have a healthy, perfect, term labor with all live babies. And that’s just unrealistic.

    • CSN0116
      March 16, 2016 at 10:15 pm #

      One of the most eye-opening documentaries I ever watched was “Motherland Afghanistan”. It chronicles what it’s like to be pregnant and give birth in Afghanistan – a place with outrageously high maternal and infant mortality rates. Horrible things like fistulas, incontinence and still birth happen ALL THE TIME due to the inability to obtain a c-section. OMG – how any American birth junkies could see what the real “natural” looks like and still defend some bullshit 0-5% “necessary cesarean” rate is beyond me.

      • Deborah
        March 17, 2016 at 1:52 am #

        There’s also an on-line book you can download for free called “Veil of Tears” on the same subject. Heartbreaking and an absolute indictment on Western birth hobbyists.

        • demodocus
          March 17, 2016 at 8:20 am #

          God, my current due date group could really use this. They might be completely science minded about everything else, but they are *SO* caught in the vibe. Well, to be fair, it’s in most of the books, websites, and birth classes. Mostly, i talk to my origina due date group. Lots of woo there too, but at least i don’t get as many disagrees for every comment i make.

  9. Lurkerette
    March 16, 2016 at 9:28 pm #

    Oh, man, this hit close to home. Husband is a giant-headed, broad-shouldered guy. I’m of average height. My son had a 14 inch head that presented asynclitically. Eventually, the OB brought in forceps, and it’s astonishing still how fast he was born once his head was rotated. We just needed a little help. I’d felt useless at pushing (4 hours!) until I saw the giant bruise on kiddo’s head. Sorry, baby! Apparently trying to push you *through* the pubic bone wasn’t working!

    • meglo91
      March 17, 2016 at 10:20 am #

      Well, crap. I had a growth ultrasound a week ago at 34 weeks, and the baby’s head was already estimated at 12.5 inches (two weeks ahead). I do not remember my previous two kids’ head sizes, but I know that #1 was big. Hopefully I can push this sucker out.

      • TG
        March 18, 2016 at 4:38 am #

        my husband (2nd child) was born with a 14″ head and my mother-in-law said delivering it was no fun (but she managed apparently). she’s probably a bit broader than average. i’m probably a bit taller/broader than she is, and my husband is very tall. somehow, my daughter, also 2nd child, was also born with a 14″ head…and she shot right out (i literally barely pushed- the contractions pushed her out) and i only needed one stitch. so go figure.

  10. Deborah
    March 16, 2016 at 7:45 pm #

    There’s also the situation that occurs when a couple from different cultures have children. My Swedish dad (adoptive – I’m not Swedish) remarried a Phillipino woman and they had two boys. She labored for many hours without progress with the first before having a c/s and then had an elective for her second. Those kids were enormous and she was this tiny little woman. It was a foregone conclusion really. I guess NCBers and evolutionary theory would both concur that they weren’t really meant to live as, without modern obstetrics, none of them, stepmother included, would have.

    • Arnold Jones
      March 16, 2016 at 8:09 pm #

      Lol I relate to this – Dad Mexican – mom filipino – two c sections.

    • Young CC Prof
      March 16, 2016 at 8:29 pm #

      Shortly after I got pregnant, I read a study that found European/Asian couples in which the wife is Asian have a c-section rate twice as high as European/Asian couples in which the husband is. And I said, “Huh, probably won’t need one, then!” Then I discovered CPD is NOT the only thing that goes wrong.

      • CSN0116
        March 16, 2016 at 10:10 pm #

        My beloved grad school mentor is a super big guy – about 6’5″ and broad. He married a teeny tiny (cute as hell) Filipino woman who is 5′ if she’s lucky and 90 lbs soaking wet. She was completely unable to birth either of their two children, both girls. Her OB straight-up told her that cesareans are what happen when a Filipino woman gets pregnant by a (non-Filipino) man of that stature lol.

      • Roadstergal
        March 17, 2016 at 12:06 pm #

        I remember an odd moment about a year ago, when I was in the local salon getting my nails done (I live in an area with a very high Asian population), and a woman next to me started a conversation across the room with some women getting massages about everyone’s C-sections. They were all Asian and tiny.

    • Sue
      March 16, 2016 at 9:08 pm #

      Exactly. So much for “your body can’t grow a baby too big for your pelvis.” Of course it can – 50% of the genetic material is paternal.

    • Irène Delse
      March 17, 2016 at 5:28 am #

      Interesting. Though it can be awkward the other way round too. My paternal grandmother was French-Italian, barely 5 feet and slight-framed. She married a Filipino man who was rather tall. They had three kids, each time vaginal birth but the third baby was huge, a good 10 pounds if family lore can be trusted. Birth was long and harrowing, but this was at a place and time when the doctors only performed a CS if the mother’s life was immediately at risk. My grandmother survived and delivered a live, healthy child, but it was her last one. I never knew of she just didn’t want to risk a repeat of the ordeal, or if she was injured during the process.

    • worried
      March 17, 2016 at 12:14 pm #

      Unfortunately, the woo has even affected some ob-gyns. I tried telling my gynecologist that my husband is a foot taller than me and that’s part of why I’d like a recommendation of an obstetrician who is good at c-sections. She just smiled and said not to worry, that I could still have a vaginal birth. I don’t want a vaginal birth, but it seems no reason is good enough anymore. It makes me scared to get pregnant.

  11. cookiebaker
    March 16, 2016 at 7:44 pm #

    I was blessed with birthing hips and I’m forever grateful. Stage 2 goes very quickly, like 20 seconds quickly. Seriously. I also have small babies. My biggest baby was 7lbs, 4oz at 40+6, so I’m not sure how my hips would handle a big baby, but we’re not planning more, so we’ll never know.

    • Arnold Jones
      March 16, 2016 at 8:11 pm #

      Not sure blessed is the correct term… Like God proactively said “hmm that girl is going to have birthing hips *waves magic wand*”

  12. Christy
    March 16, 2016 at 7:31 pm #

    Oh man, this post is a little too soon for me. My now 5 week old had decels with contractions, then I had a heck of a time making any progress with pushing. My OB called in extra people because she was worried about shoulder dystocia. She eventually gave me a time limit to get him out or she was going to break out the vacuum, I felt like I wasn’t pushing hard enough or correctly or something but it turns out he was asynclitic. My OB is quite competent and we did get him out without interventions. I woudn’t exactly say I was traumatized but I do think that the maternal request c section I wanted would have had a lot less drama.

  13. Dr Kitty
    March 16, 2016 at 5:52 pm #

    My pelvis has a couple of extra bones and several screws and plates stuck onto the sacrum. I’m 5′ tall, with UK size 2 feet and wear jeans from the kids’ section.
    My husband can’t wear the paper hats that come in Christmas crackers because his head is too big.
    My babies, while 9th centile for weight, both had head circumferences between 25th and 50th.

    It was therefore unsurprising that in my first pregnancy, even at 38weeks, my daughter’s head was still high and free. At which point my OB predicted that our chances of a vaginal delivery were slim, and we opted for an elective CS on the basis that a baby that can’t get into a pelvis probably isn’t going to get out of it without help.

    My son was also high and free and gently spinning between OA and OP at 38 weeks, although I had already decided VBAC wasn’t for me long before then.

    No regrets here.

  14. mostlyclueless
    March 16, 2016 at 4:20 pm #

    My first baby (7 pounds, normal-sized head) never rotated from OT to OA and I had to have a c-section. Does anyone know what can cause that or if there’s any way to help the second baby become positioned correctly?

    • Allie
      March 17, 2016 at 1:03 am #

      One of the doulas at my only slightly woo-ish birth group (they were very proud of a c-sec rate of about 22% and recommended induction at 40 weeks for me due to the fact I was 42 years old) swore by Polynesian dancing in the later stages of pregnancy to ensure the baby was in a good position. There was a class on it about 2 to 3 weeks before we were all due. Not sure if it works, but I don’t think it could do any harm. Unfortunately, I missed that part of the class due to a family event. Perhaps that’s why I ended up pushing for 5 hours : /

      • Sue
        March 17, 2016 at 3:09 am #

        Polynesian DANCING?

        Do Polynesian babies tend to be positioned better than others?

        • Dr Kitty
          March 17, 2016 at 4:40 am #

          Have you seen the Samoan and Fijian rugby teams? Big, big people.
          I don’t think it is the dancing that enables Polynesian women to have huge babies with ease.

      • Inmara
        March 17, 2016 at 4:12 am #

        Hahaha, belly dancing is supposed to do all things good for your reproductive system and improve birth process and ouutcome. My teacher with more than a decade of belly dancing under her belt had a baby by emergency CS because her water broke but contractions never even started.

  15. Jessica
    March 16, 2016 at 3:57 pm #

    One of the things that drives me batty on birth boards is when women repeat the lie that your body won’t grow a baby that’s too big, or worse, spout off the anecdotes of their friend or sister who was teeny-tiny and delivered a 10/11/12 pound baby without any issue. This is usually in response to a poster whose doctor has cautioned her that the baby is big, her pelvis is small, and is trying to prepare her for the possibility of a C-Section. I acknowledge that doctors aren’t always right (as indicated by my recent experience), but they do have a lot of experience delivering babies and are trying to spare women long, difficult, or impossible deliveries.

    **My recent experience: suspected LGA baby, -2 station, no dilation and only 70% effacement at 39w5d. Although I had delivered vaginally before, my doctor suspected CPD was a real possibility and wanted me to consider going straight to a C-section rather than an induction that was likely to fail. After discussing it, I opted for the induction with aggressive pain management (epidural early and often, haha), and in the end that second stage of labor was less than 10 minutes long (my OB guessed I would be pushing for 90 minutes). Baby was 8lbs 13oz with a 14″ head. Based on the birthing experiences of my maternal relatives, I think we were blessed with “roomy” pelvises.

    • rh1985
      March 17, 2016 at 1:11 am #

      Plus you can have a baby that could have fit through your pelvis if positioned ideally, but because of bad luck the baby was in a non ideal position. I’ve seen posts by moms who needed a CS for a small baby with bad positioning but later had a VBAC with a larger baby in a better position.

    • MI Dawn
      March 17, 2016 at 10:04 am #

      We used to tell our patients to ask how big they and their siblings were at birth and how big their spouses and their sibs were at birth. If the sizes were similar, we usually figured, given a normal pelvis, things would be OK. If mom was tiny and dad was big (birth NOT currently), we usually figured on problems. Vice-versa, no worries.

      It wasn’t foolproof, but it worked pretty well.

      • Megan
        March 17, 2016 at 10:27 am #

        This has held true for us. I was an average sized baby. Hubby was nearly 10 lbs. Both of our babies have been 7-7.5 lbs at 37 weeks and easily would’ve been 8-9+ lbs at full term. (No GDM on my part either.) With my oldest, I could not deliver vaginally after an induction (for my high blood pressure) because she was OP and asynclitic; she was 7 lbs 6 oz at 37w4d. Second one was repeat CS last week; she was 7 lbs 2 oz at 37w exactly.

  16. Laura
    March 16, 2016 at 3:14 pm #

    Question for the medical professionals here. Is it really true that pelvic size isn’t correlated with the general size of the woman/her hips? Obviously tiny women of all sizes have given birth to children of all sizes just fine and larger women have struggled. But is there really no relationship?

    • AirPlant
      March 16, 2016 at 3:26 pm #

      I have heard that too! As a woman of generous hip I feel a little bit cheated. I have looked matronly since the 7th grade, I could at least get an easy childbirth out of the deal.

      • Dr Kitty
        March 16, 2016 at 5:38 pm #

        “Hips” aren’t the same as “pelvis” though. Females store our fat in our bums, hips and thighs. Sometimes the underlying bones are small, but this is belied by the overlying fat and muscles.

        If you have small hands, wrists and feet, places where bones aren’t so padded, you’re more likely to have a proportionately small pelvis. But sometimes it isn’t the size of the pelvis, it is the shape. Women with android or anthropoid pelvis shapes have a harder time than women with a gynecoid pelvis.

        • Dr Kitty
          March 16, 2016 at 8:25 pm #

          Oh, and I forgot, if you are at the upper end of the BMI scale the fat around your internal organs and pelvic floor can press in and prevent a baby descending properly too.

        • Sue
          March 16, 2016 at 9:12 pm #

          Yep – and it’s also the SHAPE of the pelvis. What forms the bony contours of our “hips” (quite apart from padding) are the so-called “wings” and crests of the iliac bones, whereas the baby’s head has to pass through the inlet at the base.

        • Who?
          March 17, 2016 at 2:33 am #

          I have small hands, wrists and feet, and am not very tall, but had 2x 3.8kg babies (that’s 8’6″ in old money) the old fashioned way, small tear only with the first one. I have a very feminine shape and presumably a gynecoid pelvis.

          They were both long-55cm or so (about 20 inches), more than 1/3 of my body length, which was weirder as far as I was concerned. How were they packed?

          They are both now small-ish average sized adults.

    • Erin
      March 16, 2016 at 3:40 pm #

      Entirely anecdotal but both my Grandmothers are tiny, one 4 foot 11 and the other just over 5 foot. They have tiny hips to match their height. I’m five eight and have had to deal with “childbearing hips” jokes since puberty. My six pound nine ounce son could not navigate my pelvis even with help from forceps. My Grandmothers birthed a load of 10 pound babies easily.

    • BeatriceC
      March 16, 2016 at 3:41 pm #

      Anecdotally, of course:

      Me: 5’7″, built like a linebacker, nice, wide hips.
      My sister: 5’4″, rail skinny, 95 pounds soaking wet.

      Me: Struggled to give birth, first close to term baby got suck (SD), opted for c-sections afterward. Baby was 8 pounds, 8 ounces
      Sister: Thought she had moderate gas and had to poop. Had a baby instead. Baby was 8 pounds, 14 ounces.

      • Deborah
        March 16, 2016 at 7:26 pm #

        Incredible about your sister! You hear these stories about how people never knew they were pregnant and you just think, how?
        How could you not know? All the pregnancy changes, the weight gain, the moving and pummelling of the baby inside?
        And so different to your experience. You would be excused for feeling a little hard done by!

        • BeatriceC
          March 16, 2016 at 8:02 pm #

          Oh! I’m sorry. I wasn’t clear. She knew she was pregnant, just didn’t realize she was in labor. It was still a couple days before her due date and she never felt anything that could possibly be interpreted as labor pains. She’d had what she thought was moderately uncomfortable gas for the previous few hours and the baby just slid out effortlessly when she thought she just had to have a bowel movement.

          • Deborah
            March 16, 2016 at 8:22 pm #

            Oh I get it! Still incredible though not realising one is about to pop out a baby! 🙂

    • Shawna Mathieu
      March 16, 2016 at 8:12 pm #

      When I had my second kid, my doctor’s the one who told me the big hips = clear sailing for baby doesn’t always work.

    • fiftyfifty1
      March 16, 2016 at 9:10 pm #

      The complicating factor is that what matters is the size of the inside of the pelvis but what we see when looking at a woman is the outside size of her hips + any overlying tissue.

      • Guestll
        March 17, 2016 at 3:09 pm #

        Yes, this. My mother is 5’7″ with 34″ hips, gave birth to 4 children vaginally and easily and only one (me) was OP and gave her any hint of difficulty. I am an inch taller, same hip size, and I had a lot of trouble getting my one and only out – also OP, and also a big baby, like me. The difference is, my mother has a normal sized pelvis. I don’t, per my gynecologist. You would never be able to tell the difference between us from the outside.

  17. guest
    March 16, 2016 at 2:45 pm #

    I’ve mentioned before that my mother’s coccyx broke during her labor with me (post-dates by three weeks [but who knows really given dating back in the day], large head circumference, first baby – forceps were used) and as a result she couldn’t sit down comfortably for a year. I was spared that by a combination of prematurity and a c-section, but large heads run in my family. I’m surprised there isn’t a family history of stuck babies, but there isn’t to my knowledge. And let me tell you, my big headed infants were pitifully funny as they tried to build the strength needed to lift their heads. It took them a while to master sitting up.

    • mabelcruet
      March 17, 2016 at 6:24 am #

      Your poor mum! I broke my coccyx falling down the stairs (one of my cats tried to assassinate me) and it was the most painful thing ever-I’ve had several surgeries and none of them came close to fractured coccyx pain. It definitely took a year or so until I could sit properly-even now sitting for more than half an hour is sore.

      We breed them big in my family-all the kids have enormous round heads, but luckily all the mothers have enormous wide hips to go with them. School photos always look a bit odd-it takes a while for bodies to catch up to head sizes!

      • guest
        March 17, 2016 at 7:57 am #

        Yes, at three mine still look top-heavy (although since it’s my family, I’m used to it – looks normal to me!). My daughter spent the first year of her life around the 15th percentile for height and weight and in the 95th for head circumference!

        Not being able to sit comfortably for so long would be so awful.

  18. MI Dawn
    March 16, 2016 at 2:21 pm #

    Both of my little darlings decided to try to come out OP…the back pain was awful. But at least a) both kids were preterm -37 and 36 weeks respectively and b) second labor was only about 5 hours (induced for pre-eclampsia). I also have a morbid fear of needles in my back, as I had kids when spinals were the C/S anesthesia of choice and epidurals weren’t as well done, and often lead to spinal headaches. So, demerol was the drug of choice for me during labor.

    • MI Dawn
      March 17, 2016 at 11:03 am #

      Need to add: both kids were also small….6-4 and 5-13 at birth, due to being early. I’m sure if they’d been term they would have probably been c/sections.

  19. Kelly
    March 16, 2016 at 1:39 pm #

    I did not realize that the tail bone could move. Is that why mine hurts every now and then after my third pregnancy? I also had pelvic pain that limited my mobility during my last pregnancy.

    • MI Dawn
      March 16, 2016 at 2:26 pm #

      Yep. The coccyx bones move and they can be broken. And you can have separation of the symphasis pubis (the place at the front of your pelvis where the left and right join – in Dr Amy’s pictures, it looks like a little darker area in the top middle) which I hear from those who’ve experienced it is excruciating, and really limits walking. Might be what you had, Kelly.

      • Kelly
        March 16, 2016 at 2:30 pm #

        Sounds about right. I also feel residual pain in my pubic bone as well especially if I sleep weird. It has gotten worse with each pregnancy. I am way out of shape than I used to be. Do you think lifting and getting my muscle tone might help with future pregnancies?

        • J.B.
          March 16, 2016 at 2:59 pm #

          You may want to see a physical therapist. My hip will pop out like there’s no tomorrow and I’m very slowly making progress towards less pain. And focus on strengthening your core before anything else.

          • Kelly
            March 16, 2016 at 11:41 pm #

            My core has been destroyed. I am slowly starting to work out. My postpartum depression reared its ugly head again and I am finally starting to feel better but I gained a lot of weight due stress eating and sitting on my butt. I will definitely be looking into physical therapy as I want at least one more kid but I want to be able to walk.

          • Inmara
            March 17, 2016 at 4:29 am #

            I started to work out too, 7 months postpartum (could do it earlier but, procrastination). My core is a mess, and what’s worse I just realized that lower and middle back pain which started during pregnancy may not be simply tight muscles but a turn for worse with my spondylosis (which was diagnosed almost a decade ago but kept under control by more or less regular exercise). I hope that strengthening core will improve something because I’m looking forward to have next baby in a few years but not with constant back pain.

          • Dr Kitty
            March 17, 2016 at 4:52 am #

            I started back at the gym a couple of weeks ago.
            I do Pilates, Yoga and a Les Mills BodyBalance class which all focus on core strength and stability.
            I’m pretty much back at all the basic options, but it’ll get better, and for those three hours I can get out of my head and into my body, which is always good.
            In the meantime, I just do planks and press ups on hands and knees…

          • nomofear
            March 17, 2016 at 9:42 pm #

            Check out Sahrmann core exercises. There are YouTube videos!

          • J.B.
            March 17, 2016 at 8:36 am #

            That sounds very difficult, I’m so sorry you went through that. I hope you’re in a good place and have the family support to take care of yourself now.

          • Kelly
            March 17, 2016 at 2:07 pm #

            I am. I was already on medicine so it was not as bad as it could have been but now that they have upped my meds, it is much much better. I have finally started therapy as well and with one session, I already feel like I am digging out of the hole. I now know that even with meds, I will probably continue to get postpartum depression every time I have a baby and will be even more proactive next time. Postpartum depression really really sucks. I hate feeling so foggy and dysfunctional. My kids suffer and I think that is what is the worst part. They then end up acting out to compensate and it is a very vicious cycle. I am just incredibly grateful for modern medicine so I can be functional.

          • nomofear
            March 17, 2016 at 9:20 pm #

            Look up Sahrmann exercises for your core. A lady physical therapist developed them just for postpartum core rebuilding.

        • FEDUP MD
          March 16, 2016 at 8:35 pm #

          I had a round of physical therapy and it was life changing. Went from significant frequent sacral/pubic pain to very rare mild twinges. Highly highly recommend. They strengthened my core (after I had umbilical hernia surgery, which also helped) and I feel pretty close to back to where I was before having kids (well, except for the extra 20 pounds, ugh).

      • Gatita
        March 16, 2016 at 4:39 pm #

        I had separation of the symphasis pubis and OMG the pain, the goddamned pain. It didn’t let up until I got the epidural in labor and luckily went away after birth.

      • mabelcruet
        March 17, 2016 at 6:26 am #

        There was a horrible obstetric scandal in Ireland a few years ago where mothers were subjected to a symphysiotomy during labour to forcibly open the pelvis.


        • Who?
          March 17, 2016 at 7:27 am #


        • MI Dawn
          March 17, 2016 at 9:59 am #

          Yeah, I remember that. They claimed it was better and safer than a c/section.

  20. Megan
    March 16, 2016 at 1:37 pm #

    OT update: Little lady and I are home. Her bili this morning was 13 this morning (even after ripping out her own IV yesterday!) and so she was deemed fit for discharge. I am so happy to be home. My older daughter has been upset and confused at our absence and asking both for “mama” and “baby.” Can’t wait to see her this afternoon after she gets home from daycare. Little lady is still breastfeeding for now and getting supplement and it’s working ok and we enjoy it at this point. I pumped a handful of times in the hospital when she was too sleepy to nurse but would prefer not to at home. We’ll see how things go. Thanks to everyone for all of your well wishes!

    • Kelly
      March 16, 2016 at 1:40 pm #

      I am so glad to hear. Although jaundice can be easy to control, it is still hard to deal with it.

    • LaMont
      March 16, 2016 at 2:17 pm #

      Oh my god your daughter asking for “baby” just melts my older-sib heart. I hope she gets a chance to play with her new best pal soon – best wishes to you and the little one! – a fellow jaundiced-preemie

    • Inmara
      March 16, 2016 at 3:54 pm #

      Glad to hear good news from you! Hopefully you’re on to the smooth sailing now (as smooth as it can be with a newborn!).

    • The Computer Ate My Nym
      March 17, 2016 at 3:36 am #

      Yay! Happy for you and little lady and older sister!

  21. Laura
    March 16, 2016 at 1:10 pm #

    Thank you for this. Fascinating and informative. And another risk I’m not going to take with my scheduled c-section. Thank god for that.

    • Daleth
      March 16, 2016 at 1:56 pm #

      Hello, fellow scheduled CS mama (or mama-to-be, rather)! Nice to see there’s a few of us here.

      • Laura
        March 16, 2016 at 1:59 pm #

        Hello! Mom-to-be and reading Choosing Cesaerean which I learned about from another comment on this blog. Has me more and more convinced it’s the right choice for me.

        • Daleth
          March 16, 2016 at 2:03 pm #

          That book is fantastic! It helped me make the decision too.

  22. Lisa
    March 16, 2016 at 12:44 pm #

    I had a combination of a narrow pelvis and a baby who had thrown his head back until he was leading with his face. He never descended past a +2. C-section saved both of us from an ugly, ugly vaginal delivery.

    • J.B.
      March 16, 2016 at 2:56 pm #

      Glad it was available to you and I hope you had a good recovery. I have the opposite problem of good birthing hips that are unstable meaning chronic misalignment.

    • Elisabetta Aurora
      March 17, 2016 at 7:28 am #

      Identical for me.

  23. March 16, 2016 at 12:43 pm #

    Anyone who thinks that a woman (or any animal) can’t grow a baby that is too big to be birthed needs to do some historical or comparative anatomy reading.

    A few years ago, we had a bull fail and replaced him with a bull we bought from another farm. We kept him in with mature cows who had had at least 2 calves previously (so we knew the cows had pelvises that could fit a calf through) and sold him three months later when we had a bull ready from our own farm.

    10-13 months later, we had a nightmare on our hands. The bull we had purchased bred for monstrously huge bull calves. Instead of 90-100 pound calves, his sons weighed 130-over 150 pounds. In humans, that would take you from a 7 pound baby to 11-14 pound babies. To make matters worse, the largest diameter on a calf is the rear hips. His bull calves had rear hips that were larger than their front shoulders leading to the dreaded “hiplock” scenario where the head and shoulders of the calf is born, but the back hips are trapped and the torso of the calf is blocking access to the hips.

    It was bad. Most of the bull calves died. Several of his heifer calves died. Worst of all, we had three cows die from complications after very hard deliveries.

    Remember, this happened in a situation where we had been breeding for calving ease for YEARS – and breeding to eliminate hiplock for decades. We can control cattle breeding in a way that is ragingly unethical in humans; the cows have no say in the sire of their offspring.

    Expecting good outcomes due to directed selection can fail miserably; expecting it due to evolution is foolish.

    • Suzi Screendoor
      March 16, 2016 at 3:59 pm #

      My parents have been breeding their cows for calving ease and good nursing for about 25 years. I don’t think they’ve had a c-section on the farm for years, and only had to pull a handful of calves.

      When I was a kid I got to help out with a late-night c-section. The vet drove 50 miles out to our farm only to find that his clippers were dead. I was dispatched back to the house at a run to get my dad’s beard-trimmer, which had to suffice for shaving the cow.

      The extra good part of having such a great herd these days is that my parents feel comfortable leaving the farm to look after my daughter when I “calve” next month, even though it’s the midst of calving season!

    • Deborah
      March 16, 2016 at 7:01 pm #

      Fascinating! The things we learn on this site! 🙂

  24. Roadstergal
    March 16, 2016 at 12:38 pm #

    Man, this is so simple and clear, especially in addressing the ‘we evolved to give birth’ meme. Why can’t a little pamphlet with this information be given out to newly pregnant women?

    • March 16, 2016 at 12:49 pm #

      The part that kills me is that we didn’t evolve to give birth. We evolved from people who managed to survive their own birthing process and from women who managed to birth children who survived.

      Notice those two things are not necessarily connected. An infant can survive a birthing process that kills the mother; a mother can survive a birthing process that kills an infant.

      Two of my great-grandfathers had 7 wives between them. Five of the wives died in or soon after childbirth based on gravestones with infants who died on or within a few days of birth. The two wives that survived married their husbands when he was an older widower and had two biological children of their own before he died.

      Net outcome: My direct maternal ancestors managed to both produce living children and die in childbirth. That fact alone makes me damn glad for hospital births.

      • Clorinda
        March 16, 2016 at 2:21 pm #

        I have one ancestor who, in her obituary, it said she was the mother of 10 children. From looking at the records and understanding how people reported things back then, it was 10 live births (miscarriages and stillbirths were VERY RARELY reported if at all and never in an obituary), but only 5 lived long enough to be given names that were recorded. Of those five, three survived to marry and have children of their own, and two survived their mother, the third died in childbirth or very shortly thereafter. At least one name was recycled by a younger child of the same sex after the previous bearer, born only 3 years previous, died. This was in the 1845-1860s.

        Another ancestor had three children that we know of, 1878, 1884, 1889. Who knows how many failed pregnancies occurred in between, and the middle child died at age 6 of scarlet fever.

        • Roadstergal
          March 16, 2016 at 2:52 pm #

          One of the striking bits I read in The Wordy Shipmates is how the midwife Anne Hutchinson had 15 live babies, and that wasn’t unusual. Fetuses died in utero, babies and moms died in childbirth, babies and toddlers died of diseases – you needed a huge brood of children just to be at replacement levels of reproduction! We just expect that our babies will be born healthy and live to adulthood, but I think it’s easy to forget how very recent it is for that to be a reasonable expectation.

          Also, tangentially, the magistrate sending people out to dig up the ‘monstrous’ fetus that Anne delivered in order to gloat over how it was a sign from God that he was right and Anne was wrong – that was quite a moment, too.

    • Sue
      March 16, 2016 at 11:48 pm #

      We haven’t even “evolved” to gestate a fertilised ovum – up to 20% of early pregnancies end in miscarriage.

      • Tigger_the_Wing
        March 17, 2016 at 6:33 pm #

        I don’t think we can even detect the rate of loss of eggs which were fertilised but failed to implant; only those which were lost after implantation.

        Even then, the figures vary from researcher to researcher – one study, using very sensitive tests designed to detect minute amounts of HcG around the expected time of implantation, found 22% were lost before any clinical signs of pregnancy would normally be detected. Of the pregnancies detected, 31% were lost overall.


Leave a Reply

You must be logged in to post a comment.