Nearly four percent of U.S. babies born before full-term without medical reason

Labor induction or cesarean delivery without medical reason before a baby is considered full-term at 39 weeks, or an "early elective delivery," is associated with health problems for mothers and babies.

The study, led by University of Minnesota School of Public Health Assistant Professor Katy Kozhimannil, Ph.D., M.P.A., in collaboration with Children's Hospital of Philadelphia researchers Michelle Macheras, M.A., and Scott A. Lorch, M.D., M.S.C.E., appears in this month's edition of the journal Medical Care.

Researchers reviewed data linking birth certificates with hospital records for all births in California, Missouri and Pennsylvania between 1995 and 2009. The three states represent approximately 20 percent of all U.S. births and encompass a wide range of sociodemographic characteristics and geographic locations.

"Our study showed that early elective deliveries made up more than 3 percent of U.S. births each year over the past 20 years. This may seem to be a small number, but with 4 million births a year in the U.S., each percentage point represents 40,000 babies," said Kozhimannil. "In addition, we showed that there are important sociodemographic differences in the chances a pregnant woman has an early electivecesarean or an early elective induction of labor."

The chance of early elective induction was higher among women:

• 35 years of age or older, white with higher education levels
• Who were privately insured
• Who gave birth at rural or nonteaching hospitals

Early elective cesareans were more likely for women:

• Less than 20 years old or over 35 years old
• Who were black
• Who had higher education levels
• Who gave birth at smaller-volume hospitals

"There are misunderstandings about when a baby is ready to be born," said Kozhimannil. "Since our findings show there are differences in who is having an early elective delivery, the importance of a full-term birth needs to be communicated to all women, not just those who may traditionally be considered high risk for elective procedure or high risk for poor outcomes."

Kozhimannil explained that contrary to the commonly-held belief that babies born after 37 weeks are considered "term," the American College of Obstetricians and Gynecologists and the Society for Maternal-Fetal Medicine say a pregnancy is full term only after 39 weeks.

The study found that infants born by early elective cesareans were 60 percent more likely to stay longer in the hospital and more than twice as likely to have respiratory distress compared to infants born on or after 39 weeks. Infants born via early elective induction were also more likely to stay in the hospital longer than expected.

"While prior work has shown that early elective delivery policies can be highly effective within particular healthcare systems, there is a need to address this issue at the population level," said Kozhimannil. "It is our hope that this study will add fuel to the ongoing efforts to educate pregnant women and influence clinical and policy environments to facilitate healthy, full-term deliveries whenever possible."