Homebirth and natural childbirth advocates can’t make up their mind about the placenta.
They all agree that human placenta has magical traits, but they can’t agree what those magical traits are:
It resuscitates the baby! Really? If the baby is born distressed because the placenta couldn’t provide enough oxygen inside the mother’s body, why would it suddenly provide adequate oxygen outside it?
You should leave the placenta attached to the baby! Really? Is there any animal that leaves the placenta attached to the baby? No, of course not.
You should detach the placenta so you can eat it! Really? Which ancient or indigenous cultures consumed the placenta? Oh, right, none.
It’s the baby’s spiritual twin! Really? Really??!!
Eating the placenta is stupid for a whole host of reasons, but the most important reason is this: the removal of the placenta, and the hormones that it produces, is the trigger for breastmilk production.
How does breastmilk production work? According to Physiology and Endocrine Changes Underlying Human Lactogenesis II:
The evidence is summarized that progesterone withdrawal at parturition provides the trigger for lactogenesis in the presence of high plasma concentrations of prolactin and adequate plasma concentrations of cortisol.
Breastmilk production is divided into two stages: preparation for production, which occurs during pregnancy, as is known as lactogenesis I; and actual production of breastmilk after the birth of the baby, known as lactogenesis II.
As the levels of progesterone, prolactin and placental lactogen rise, the terminal ductal lobular units [the part of the breast that makes the milk] undergo a remarkable expansion so that each lobule comes to resemble a large bunch of grapes. During mid-pregnancy, secretory differentiation begins with a rise in mRNA for many milk proteins and enzymes important to milk formation. Fat droplets begin to increase in size in the mammary cells, becoming a major cell component at the end of pregnancy. This switch to secretory differentiation is called stage I lactogenesis. The gland remains quiescent but poised to initiate copious milk secretion around parturition.
But it is birth, specifically the expulsion of the placenta, that triggers milk production:
This period of quiescence depends on the presence of high levels of circulating progesterone; when this hormone falls around the time of birth, stage II lactogenesis or the onset of copious milk secretion ensues…
How does it happen?
It has long been known that abrupt changes in the plasma concentrations of the hormones of pregnancy set lactogenesis in motion … It is clear that a developed mammary epithelium, the continuing presence of levels of prolactin near 200 ng/mL and a fall in progesterone are necessary for the onset of copious milk secretion after parturition. That the fall in progesterone is the lactogenic trigger is supported by evidence from many species… In humans removal of the placenta, the source of progesterone during pregnancy in this species, has long been known to be necessary for the initiation of milk secretion. Furthermore, retained placental fragments with the potential to secrete progesterone have been reported to delay lactogenesis in humans. Thus, without a fall in progesterone, lactogenesis does not occur.
It’s an elegant system. The progesterone synthesized by the placenta to support the pregnancy, inhibits the production of breastmilk. When the baby is born and the placenta is expelled, the level of progesterone drops dramatically and this is the chemical trigger for production of copious breastmilk. This drop in progesterone is so critical to breastmilk production that even small fragments of the placenta left behind in the uterus can interfere with lactogenesis.
That’s how “unhindered” breast milk production is supposed to work. Eating the placenta, therefore, is an intervention, an intervention that interferes with the exquisitely coordinated rise and fall of various hormones in the postpartum period.
Eating the placenta is an excellent example of the profound ignorance of human physiology that undergirds most of homebirth and natural childbirth advocacy. Advocates have no clue how the actual physiologic processes of pregnancy, childbirth and the postpartum work. They create a fantasy physiology where profound complications are “variations of normal,” where birth in water (unknown in any primate species) is natural, and where eating the placental hormones that suppress breastmilk production are supposed to promote breastmilk production.
Only someone profoundly ignorant of human physiology would recommend consuming placenta and only a gullible fool would actually do it.