An Extra Push to Greet the New World

Inducing labor at 40 weeks may offer better outcomes than waiting

(RxWiki News) By the time most women's due dates roll around, they may be more than ready to greet their newborns, but it's unclear if inducing women at week 40 is as safe as continuing to wait.

In fact, it could be very slightly safer.

A recent study provides evidence that inducing women close to their due date - set at the 40th week of pregnancy - leads to better survival rates for their babies and less likelihood of needing a cesarean section than if they are not induced.

"Inducing women at week 40 is safe."

Lead author Sarah Stock, a clinical lecturer and subspecialty trainee in maternal fetal medicine at the University of Edinburgh's Tommy's Centre for Reproductive Health, and colleagues looked at the survival rates of over one million babies born between the 37th and 41st week of pregnancy.

The authors gathered their data from Scottish obstetric units from 1981 to 2007, which included 938,364 births that were not induced and 176,136 births that were electively induced.

They focused only on situations where the mothers chose to be induced, so births where induction was deemed medically necessary, such as with pre-eclampsia or problems with the baby, were not included.

They found that stillbirths and newborn deaths occurred in 0.08 percent of births where labor was induced, compared to 0.18 percent of births where the pregnancy continued until natural labor occurred.

It's important to note, however, that both rates are extremely low. It would take approximately 1,040 women to choose induction over waiting for natural labor to prevent a single stillbirth or newborn death.

Further, the rates of admission to the NICU were higher among the babies who were born to mothers who elected to be induced.

The researchers said their findings do not necessarily mean that women should choose to be induced at 40 weeks, but that it is helpful for doctors and patients to know that doing so is safe and perhaps even better than waiting.

"Doctors worry that inducing healthy pregnant women before 41 weeks increases the risk of caesarean section," Dr. Stock said. "Our study suggests that there is no increased risk of caesarean with induction at any time from 39 weeks onwards."

She added that more studies would be necessary and that mothers should still realize the greater risk that their babies will need care in the NICU.

"Whilst further studies are needed, our study suggests that the risks for women and their babies of induction at around 40 weeks are less than we thought, and the benefits may be greater," she said. "So clinicians should perhaps not be as concerned about agreeing to a request from a pregnant woman to be induced at around 40 weeks of pregnancy."

The study appeared online May 10 in BMJ. The research was funded by the Chief Scientist Office of the Scottish Health and Care Directorate. The authors declared no conflicts of interest.

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Review Date: 
May 15, 2012