Women who deliver before their third trimester need more counseling about steps they can take to reduce the risk of a future preterm birth, according to new research at Magee–Womens Hospital of UPMC.

The findings were presented at the American Congress of Obstetricians and Gynecologists annual meeting.

Periviable births, which occur in less than one percent of pregnancies, are those that occur during 20 to 26 weeks of gestation, right before and around the time when it is possible for a fetus to survive outside the womb. Babies born during this period account for more than 40 percent of all infant deaths and those who survive are at risk for severe neurodevelopmental complications.

Women who have had one periviable birth have a higher risk of a future early delivery, said Katherine Himes, MD, assistant professor of obstetrics, gynecology and reproductive sciences at Magee, who led the study. Findings suggest two key factors are particularly important to minimize this risk – waiting at least 18 months before a subsequent pregnancy and daily injections of progesterone beginning between 16 to 20 weeks of gestation of the next pregnancy.

At Magee, where 10,000 babies are born each year, 361 women had periviable births during the study period of 2008 to 2014. Of those, 63 (17 percent) had another pregnancy and delivered at Magee. Nearly one third of this group delivered before 34 weeks, and 13 percent had another periviable birth.

Almost half of the women were pregnant again in less than 12 months, and two thirds had an interval between pregnancies less than the recommended 18 months. Nearly one fifth did not receive progesterone in their next pregnancy.

While the counseling to avoid getting pregnant for at least 18 months and to take progesterone during subsequent pregnancies typically takes place during the postpartum visit that is recommended six weeks following delivery, only 56 percent of women who had a periviable birth returned for this visit. Those who did not return were substantially less likely to receive progesterone injections than the women who did attend their postpartum visit (57 percent vs. 94 percent).

“Clearly, there is significant room for improvement in our communication with women about how to minimize the risks of a subsequent preterm birth,” said Himes. “Since these mothers spent a significant amount of time in the neonatal intensive care unit with their babies, it could be beneficial to reach out to the mothers while they are in the NICU, rather than relying on the postpartum visit.”