Expectant mothers in Australia are increasingly having their babies' births scheduled weeks before their due date, according to a new study.
But that hasn't lowered the risk of stillbirth, as some had hoped. In fact, researchers found that babies born even just a few weeks before their due date were slightly more likely to suffer from complications such as respiratory distress and feeding issues.
"Without a medical indication that is strong and clear right now, a planned delivery is not supported due to the fact that consequences after birth are likely to be relevant and severe," said Dr. Karna Murthy, a pediatrics professor at Chicago's Northwestern University, who was not involved in the study.
A baby's due date is 40 weeks after the first day of the mother's last period. For scheduled births, moms can be induced by medications and deliver vaginally or have their babies via Cesarean section.
In some cases, there are good reasons to stop a pregnancy short and deliver the baby early, such as if the mother has severe preeclampsia, which is high blood pressure and protein in the urine.
The condition is risky for the health of the mom, and delivering the baby early is considered a safer option than letting the pregnancy go on.
In other cases, such as if the mom has diabetes or there are low fluid levels around the baby, it's not clear whether scheduling a birth early is less risky than letting the mother go into labor on her own, said Murthy.
"There is a widely held perception of a change in obstetric decision making that has lowered the threshold at which and for which planned birth occurs," the researchers write in their report in the American Journal of Obstetrics and Gynecology.
The result is that preterm births have become more popular around the world, with increases seen in both C-sections and inductions. In the U.S., for example, about one of every three babies is now born through a C-section.
To see whether planned births have also increased in Australia, and if there are health benefits to planning births, Jonathan Morris at the Royal North Shore Hospital in Sydney and colleagues collected information on all births in New South Wales, Australia, from 2001 and 2009. The study included only single births.
Births that were planned between 33 and 39 weeks of pregnancy rose during the study period, from 19 percent of all births in 2001 to 26 percent in 2009.
Both inductions and C-sections became more popular; inductions rose from nine percent of all births in 2001 to 11 percent in 2009, while early, planned C-sections rose from 10 to 15 percent.
At the same time, severe health problems among newborns increased slightly, from three percent of all births in 2001 to 3.2 percent in 2009.
Among the babies whose births were scheduled between 33 and 39 weeks, 4.5 percent had a major health complication and 43 out of every 10,000 died.
In comparison, 3.3 percent of babies whose moms went into labor naturally and delivered between 33 and 39 weeks had a severe health problem and 40 out of every 10,000 died.
No change in stillbirths
The rate of stillbirths held steady during the study period, occurring about twice out of every 1,000 babies born after 32 weeks.
The study could not pinpoint what caused the health differences among the babies - it could be linked to the preterm birth itself or to health conditions that made mothers schedule the birth. Nor could it tease out why more and more women are having their births scheduled early.
Murthy speculated that patient preferences could be at work or that physicians feel they might be less likely to face a malpractice claim if they induce a pregnancy that carries some potential risks.
"Most have suggested that the rise is to try to reduce the risk of stillbirth...This is not proven true in this study or others," he said.
The researchers found that some of the conditions associated with having a birth scheduled early shifted over the years.
For example, high blood pressure among mothers and fetal distress, two medical reasons for planning an early birth, became less common among the mothers.
Diabetes among the moms and having their water break early became more common, however, among the moms who had a planned birth. But it's not clear that hastening the birth will offset the risks from those conditions.
Morris and his colleagues say improved medical care for babies may have changed how doctors view the risks of early delivery. But the net risk-benefit balance for planned births needs more study, they write, as do the reasons driving the uptick in planned births.