Inducing labour at 39 weeks may be better for mother and baby

TAMPA, Florida — A new study suggests that many first-time mothers might want to consider an alternative to the traditional “watch and wait” approach of allowing a pregnancy to run up to 41 weeks.

For those who are healthy, inducing labour at 39 weeks lowers the risk of serious complications and caesarean delivery, according to a team of researchers led by Dr Charles J. Lockwood, dean of the Morsani College of Medicine at the University of South Florida (USF).

The USF team compared results they recorded from healthy pregnant women induced at 39 weeks to those who were induced at 41 weeks or beyond.

“After 41 weeks, continued pregnancy is associated with higher chances of stillbirth and increased risks to the mother,” Lockwood said. “There are three trends that are very concerning to us in obstetrics in the United States right now. The first is this progressive and disturbing increase in maternal mortality that is gone up over the past several years. The second is a trend that is been rising since 2007, which is an increase in stillbirth rates. And the third is the high C-section rate among US pregnancies over the past decade.”

The US is one of the few nations where maternal death rates are rising. In 2013, for example, it reported 28 maternal deaths for every 100,000 births, which was three times Canada’s rate, according to the research group Institute of Health Metrics and Evaluation. And the centres for disease control and prevention reports that the US sees about 24,000 stillbirths every year.

In 2016, Lockwood was asked to debate another physician, Dr Errol Norwitz, the chairman of obstetrics and gynaecology at Tufts University School of Medicine, on this topic at the annual American College of Obstetricians and Gynaecologists meeting in Washington, DC. The opportunity sparked his interest in learning more and led him to study ways to reduce pregnancy risks.

“Even with the effort to reduce C-section rates, they are more commonly happening because babies can’t fit [through vaginal birth] anymore,” Lockwood said. “Babies are getting bigger and bigger because of the obesity problem in this country.”

Obstetricians commonly recommend artificially stimulating labour and delivery around or after 41 weeks, according to guidelines set by the American College of Obstetricians and Gynaecologists. But the field has wrestled for years over the best timing for deliveries when the foetus is between 39 and 41 weeks old. The ongoing discussion has led to several studies similar to the USF research.

In the USF study, births induced at 39 weeks had reduced rates of caesarean deliveries, fewer maternal complications such as preeclampsia, which is related to high blood pressure, and fewer stillbirths and newborn deaths. The study also found that inducing labour earlier decreased the risk of birth injuries such as respiratory distress and shoulder dystocia, which occurs when an infant’s shoulder lodges behind the mother’s pubic bone.

“It makes sense that there is a lower morbidity rate,” Lockwood explained. “In those last one, two or three weeks of pregnancy, the baby is getting bigger and is less likely to fit. Then the mother is at more risk to develop complications.”

While the vast majority of patients do well after C-sections, they are costly to society, Lockwood said.

“We already spend too much on health care, and this further drives excess health care costs,” he said. “The procedure is a little more dangerous to the mother, too, with higher risks of clot in the lung and other complications. Multiple C-sections, which are more likely after a mother has had the first one, also increase the risk of massive haemorrhage, leading to that higher maternal death rate.”

Lockwood says more research is needed to understand the hospital system logistics and costs associated with elective induction at 39 weeks. Inducing early should not affect a mother’s health coverage because insurers often defer to physicians when it comes to decisions in the delivery room.

“Women have to make their own decision, it has to be their call,” he said. “They should have all the information they need to make an informed decision.”