Thursday, June 3, 2010
the due date epidemic
As stated above, the average length of gestation for a human female is approximately 38 weeks (266 days) from the date of conception. However, since most women do not know the day they conceived, health care providers measure the length of pregnancy from the date of the last menstrual period, which works out to 40 weeks (the two extra weeks come from the fact that the average woman ovulates around 14 days after the first day of her last period, and this is when she is assumed to have conceived).
Because pregnancy is so long, and completely unpredictable, the medical community has latched on to the concept of a due date. Of course, the estimated due date is just that: an estimate, give or take a few days or weeks. However, doctors seem to have forgotten that the estimated due date is not to be relied upon as the actual day of birth. Doctors are increasingly relying on the estimated due date as a date on which to start planning inductions, and even threatening cesareans, for going 'overdue.'
But what does this mean for the woman whose menstrual cycle is not the standard 28-day cycle? This means that her estimated due date will actually be off by as much as one to two weeks in either direction. And if she has a doctor who likes to consider induction or cesarean after the estimated due date, he may be wrong by as much as two weeks early. For this reason, there is absolutely no justification for considering induction of a healthy pregnant woman before 42 weeks of gestation. Unless the woman herself knows either the day she ovulated, or the day she conceived, her due date may be off by as much as two weeks in either direction. Two weeks is too much of a margin of error to consider taking a baby early.
For the vast majority of women, induction increases risks for them and for their babies. Induction literally leads to a cascade of interventions, meaning that once intervention begins, another intervention is followed by another, which is followed by yet another, in a repetitive cycle of intervention. Having labor induced will medicalize a mother's birth experience. Once labor is augmented, a woman will need an IV and continuous electronic fetal monitoring which will confine her to a bed for the duration of her labor. Contractions will probably be more painful, often making pain medication unavoidable. If an epidural is administered, it will help eliminate the magnified pain, but it also introduces a long list of potential problems of its own. And with nearly 50% of woman whose labors are medically induced end up having a cesarean birth, a whole new set of complications are added to the cascade, with major abdominal surgery, pain, and increased recovery time.
However, each and every day the baby spends inside his mother's uterus is valuable to his development and ability to survive of the outside of the womb. Even during late pregnancy, the baby continues to grow, his brain develops, his little body stores more fat, and his little lungs grow stronger with the passing time. A mother's body also prepares for labor by dilating a few centimeters before labor even begins. If a woman goes beyond her estimated due date, it does not mean the baby is 'overdue.' This 'post-date' pregnancy should, however, be considered beneficial for the baby--an added opportunity for the baby to grow and develop.
At the end of pregnancy, if the pregnant woman is really tired and uncomfortable, and the idea of inducing seems welcome to her, and she is truly worried about going 'overdue,' there are better ways to know what is happening in her body than simply kicking the baby out. The baby's heart rate and movements can easily be monitored by the mother and the mother should pay attention to her body's signals. There is no need to cause an emergency situation when there is not one yet. Let the mother's body and the baby tell when it’s time. When the baby is fully developed and ready to live outside the womb, labor will assuredly start on its own.
If you are interested in reading more about pregnancies that extend beyond 40 weeks, I recommend In their own sweet time: A journey into post-date pregnancy. For ideas on how to carry on after your due date, try Surviving an Overdue Pregnancy.