Trust placentas?

Do you trust placentas? Whether you realize it or not, if you “trust birth,” that is precisely what you are doing.

Simply put, in order to “trust birth,” a woman must trust that her baby will fit, that her baby will survive labor, and that her baby will survive the serious challenges of the transition from life in utero to life outside.

Trusting that the baby will fit may be foolish, but it is usually not dangerous. There are many factors that determine whether a specific baby in a specific position will fit through a specific pelvis (Why won’t my baby’s head fit?). All the wishing, hoping and “trusting” in the world make no difference, but enduring many hours of fruitless labor is usually not harmful, and eventually it will become crystal clear that the baby does not fit.

Trusting newborns to make the transition is more problematic. Can a newborn be trusted to master breathing difficulties, circulatory problems and infections? As I wrote earlier this month, the signs of serious newborn illness are subtle can often can be diagnosed only by a medical professional. Therefore, “trusting” newborns to let us know when they have been overwhelmed by Group B strep bacteria, for example, is a recipe for disaster.

How about trusting placentas? That is what you are trusting when you “trust” that your baby will survive labor.

The placenta is the interface between the circulation of the mother, which provides oxygen and nutrients, and the circulation of the baby, which distributes oxygen and nutrients throughout the baby’s body. While most placentae function well, the placenta can be compromised by a variety of conditions. Moreover, the function of the placenta declines with age and as the due date passes, the placenta may become incapable of keeping up with the baby’s needs.

NCB and homebirth advocates who insist that “babies aren’t library books; they don’t have a due date” are implicitly trusting not merely that placental function will not decline, which is foolhardy since it is well known that placental function declines, but that it will not decline enough to suffocate the baby. Stillbirths rise in late pregnancy as the due date approaches and passes specifically because the placenta was not trustworthy.

“Trusting” birth means, in large part, trusting the placenta to provide the baby will a large enough reserve to tolerate contractions. During contractions, blood flow to the uterus (and therefore the placenta) is cut off. During each contraction, the baby is, in essence, holding its breath. Most babies tolerate this pretty well, because between contractions the placenta is providing so much oxygen that the baby has a reserve to draw upon during the contractions.

But what happens if the placenta is not functioning optimally? In that case, the baby develops fetal distress. Of course otherwise healthy babies can tolerate a fair amount of fetal distress. That’s why C-sections done in the early phases of fetal distress produce very healthy, apparently undistressed babies.

It’s like drowning. When someone who can’t swim falls into the water, they initially bob around for awhile. The sink, resurface and gulp air, and sink again. Eventually they fail to resurface. In the early phases, if you pluck the person out of the water, he or she will be perfectly fine, but that doesn’t mean they would have survived if you had refused to pluck them out.

It can take a long time for a baby to die of oxygen deprivation in labor, because the baby is usually getting some oxygen, albeit not enough. The typical pattern on the fetal monitor is known as “late decelerations.” The baby’s heart rate is completely normal between contractions, but toward the end of a contraction, the heart rate will drop and slowly recover. If that continues, the baby may develop bradycardias, periods of low heart rate that persist between contractions. Ultimately, the baby may develop a sustained bradycardia and the heart rate fails to come up; then the baby dies.

The bottom line is that NCB and homebirth advocates who claim they are trusting “birth” are actually trusting the placenta.

Is the placenta worthy of that trust?

That depends on a variety of factors:

Has the placenta been compromised before labor begins, either by a maternal condition like high blood pressure, or by the natural deterioration that occurs as the due date approaches and is passed?

Does the placenta provide the baby with an adequate oxygen reserve enabling the baby to tolerate “holding its breath” during contractions? That has to evaluated on an ongoing basis. Even when the oxygen reserve is inadequate, the baby can do well for quite some time, just like the drowning person flailing and bobbing for air. Eventually, though, the baby will not be able to tolerate any more and will die.

“Trusting birth” sounds sweetly spiritual. Trusting the placenta, not so much. That’s because the placenta is an organ, capable of being damaged, diseased, or failing altogether.

NCB and homebirth advocates need to ask themselves whether they “trust” a specific placenta to support a specific baby through a specific length of labor. And they need to be quite confident that they are right, because the baby’s life is literally depending on it.