In order to keep an eye on the situation, your doctor will monitor you closely after the 40-week mark. You may have a weekly vaginal exam to determine whether your cervix is softening and dilating, and you'll be asked to perform daily "kick tests," during which you count the baby's movements for a set period of time. For some women, 41 weeks marks the beginning of nonstress tests, in which a fetal monitor measures the baby's heart rate to see how he's faring during his extended stay in the womb.
"The monitoring is important because there's a risk of fetal distress as the amniotic fluid diminishes," a common occurrence in post-term pregnancies, Moyer explains. Cushioned by less fluid, the baby may wind up resting on the umbilical cord, which reduces his supply of nourishment and oxygen. This in turn leads to distress, causing him to pass stool into the amniotic fluid, which can result in airway blockage.
In addition to nonstress tests, many women also have regular ultrasounds to determine amniotic-fluid levels as well as the baby's size, and they may be asked to undergo stress tests. Mild contractions are induced by nipple stimulation or an injection of Pitocin, and the baby's heart rate is monitored to see how well he's likely to cope with the rigors of true labor.