My kids were both born early: my daughter at 32 weeks, my son at 36. So there was reason for me to worry about developmental difficulties. Now, though, a new study says babies born after their due dates may have an increased risk for complications, too.
The study found that post-term delivery, even among low-risk pregnancies, is associated with increased short-term risks to newborns, including illnesses and infections, which land them twice as frequently in Neonatal Intensive Care Units (NICUs).
"There are women who refuse induction of labor, even more than two weeks past their due date," said Dr. Liran Hiersch of TAU's Sackler Faculty of Medicine and Rabin Medical Center in Israel. "Without the relevant data, it is difficult for doctors to convince them otherwise. Maybe now, with this research and further studies in hand, we can convince them that even though their pregnancies had experienced no complications—and they are being monitored, say, every three days—they're potentially risking infection, illness, and other unforeseen complications by refusing medical intervention."
Dr. Hiersch and his team examined the electronic records of all women who delivered babies at Rabin Medical Center over a five-year period. They compared the neonatal outcomes of three groups: those born at 39-40 weeks; those born at 41 weeks; and those born at 42 weeks and later, or "post-date pregnancies."
"Although previous studies demonstrated an increased risk of complications for newborns born in the post-term period, most of these studies included women with pregnancy-related complications, such as small fetuses, hypertension, and diabetes mellitus," said Dr. Hiersch. "The isolated effect of the prolonged pregnancy could not be determined. For this reason, we included in our analysis only women with low-risk pregnancies in order to more clearly determine the effect of gestational age at delivery on neonatal outcome."
They found that infants born past 42 weeks had about twice the risk of contracting infections, experiencing respiratory difficulties, and being admitted to NICUs than those born at 39-40 weeks.
"Our study implies that even in otherwise low-risk pregnancy, it is advisable not to postpone delivery beyond 42 weeks," Dr. Hiersch said. "Therefore, it is reasonable to offer induction of labor to women reaching that time of pregnancy and maybe a little earlier."