We have touched the topic of early labor on The Pulse from different perspectives, ranging from early labor signs to whether the shift from daylight savings to standard time might trigger premature labor. Normally, in such discussions, we take it for granted that early labor is undesirable, and therefore something to be prevented. There is good reason for this in that premature birth increases an infant’s risk of numerous health conditions, both in the short term and long time. Nevertheless, there are some mothers who wouldn’t mind the opportunity to deliver their child early –not extremely early, but maybe two or three weeks ahead of schedule, in order to lighten the load. After all, the last bit of pregnancy can be the most grueling as the womb and abdomen get squeezed to the max, the internal organs compressed to the max, and the lower back is put to the ultimate test.
To delve into this topic, we need perspective on the issues of premature birth. Babies born very prematurely must stay in the neonatal intensive care unit (NICU), to receive special management, as they are at risk for several life-threatening conditions in the near term. These conditions include respiratory distress, which requires mechanical ventilation, plus they include liver problems and bleeding disorders that can affect the brain. Sudden Infant Death Syndrome (SIDS) is another risk and premature infants also are at great risk for long-term difficulties, such as mental retardation, cerebral palsy, hearing and visual impairments, and failure to grow and develop normally. Evidence also suggests that infants born prematurely carry risk for brain conditions that are more subtle and difficult to recognize early, such as Attention Deficit-Hyperactivity Disorder (ADHD) and behavioral and learning disorders, leading to a need for intervention during school. Finally, when they grow up, such infants are more likely than others to develop heart disease, high blood pressure, diabetes, and other chronic conditions that constitute major causes of death in western countries.
We must consider also that premature delivery is something that happens more in the setting of negative phenomena, such as maternal use of alcohol, tobacco, and other drugs, infections, or a fetal anomaly. Delivering early also is an option that obstetricians will put on the table as a lesser of two evils when something is wrong in pregnancy –a condition called preeclampsia, for instance. If early delivery, though acceptable in some cases, is still lesser of two evils, this implies that you shouldn’t want it to happen, if your pregnancy is going well.
With all of the potential health problems getting more likely and severe the earlier a child is born, with premature delivery being the end point of a problematic pregnancy, why would anyone wish to deliver ahead of the 40 week milestone that marks the end of a full pregnancy?
Well, there is actually a little bit of wiggle room. Although 40 weeks marks the end of pregnancy on average, this is just the midpoint in a range that goes from roughly 39-41 weeks. Furthermore, if you give birth at 38 weeks, or later, obstetricians consider the infant full-term, and most obstetricians will also say that it is full term even at 37 weeks. But obstetricians and pediatricians start worrying when it becomes clear that a delivery is going to happen before 36 weeks into pregnancy. For a twin pregnancy, 36 weeks is actually normal, but that doesn’t necessarily mean good. Medically speaking, carrying twins is not the ideal situation. It’s merely tolerated, most of the time, when it happens, because there has been no strong evolutionary pressure for the capability to carry two fetuses at once to disappear from human ancestors. This is not to say that there has been no evolution away from twin pregnancy, or from multiple pregnancy. As their brains grew progressively bigger, the ancestors of humans evolved to carry mostly singleton pregnancies. Our close cousins, the great apes, and even our more distant cousins, monkeys, give birth mostly to one child at a time. That’s quite different from many other mammals, such as your dog, or your bunnies, giving birth to a litter.
Humans put up with twin pregnancies, but the cost is that the infants are born a little early, and there are consequences. Those consequences amplify in triplet pregnancies, where the labor typically occurs, even earlier, around 32 weeks. Natural selection has made triplet pregnancy exquisitely rare, but it’s more common than today than two generations ago, because of fertility treatments. The further back we go in gestational age, the more frequent are severe problems, and the lower the rate of survival.
In the 37 to 40 week interval, however, the risks are low enough that some mothers do ask their obstetrician if they could be induced early, closer to the 37-week mark. The obstetrician will almost always say no, and as a consequence you can find videos posted online on how to trigger early labor, accidentally-on-purpose. Some of the advice involves consuming particular foods, based on a multitude of urban myths, but evidence that is, at best, underwhelming. They also may advise you to try having sex, as this can really shake things up, possibly even breaking your water and, if the latter happens, that surely will put you into an early delivery situation. Still, not matter how uncomfortable things get, you should keep in mind that there are reasons why obstetricians don’t want to deliver your baby 3 weeks ahead of schedule when nothing is wrong. Even though the fetal lungs are perfectly mature enough to breath normally with no intervention, this last segment of pregnancy is a time when the fetus is putting on some extra mass, which is really to his or her advantage.