Low perinatal risk with term pregnancies conceived with infertility treatment

Key takeaways:

• In pregnancies conceived with infertility treatment, the lowest perinatal risk was at 39 weeks.
• Delivery risk at 37 and 38 weeks was higher vs. delivery risk in the subsequent gestational week.

Delivery at 39 weeks gestation among pregnancies conceived with infertility treatment was associated with the lowest perinatal risk when comparing delivery risk at a given vs. subsequent gestational week, researchers reported.

“Neither the Society for Maternal-Fetal Medicine nor the American College of Obstetricians and Gynecologists provides a recommendation for the timing of delivery in pregnancies conceived with infertility treatment; instead, these organizations recommend shared and individualized decision-making given the absence of data,” Ira Hamilton, MD, a fellow and resident in the department of obstetrics and gynecology at the University of Cincinnati College of Medicine, and colleagues wrote. “Ideal time of delivery optimizes outcomes by balancing the risks of stillbirth of a continuing pregnancy against poor perinatal outcomes, such as low Apgar scores, NICU admission, respiratory distress, seizures and infant death, associated with early-term delivery.”

Hamilton and colleagues used U.S. birth and death data from 2014 to 2018 to conduct a cohort study, published in JAMA Network Open, of 178,448 singleton term pregnancies that were conceived with infertility treatment and delivered at term (37 to 42 weeks gestation).

The primary outcome was optimal timing of delivery, which was ascertained by comparing the delivery risk at a given gestational week with that of the subsequent gestational week.

Overall, in the cohort, mean maternal age was 34.2 years and mean gestational age was 39.2 weeks. The stillbirth rate was 0.14% and the infant death rate was 0.07%. The stillbirth rate per 10,000 ongoing pregnancies increased with each week of gestation, with the lowest rate at 37 weeks (3.1 per 10,000 ongoing pregnancies) and the highest at 42 weeks (21 per 10,000 ongoing pregnancies). The rate of infant death per 10,000 live births was lowest at 39 weeks among pregnancies conceived with infertility treatment (6.2 per 10,000 live births) and with assisted reproductive technology (5.2 per 10,000 live births).

Delivery risk at 37 weeks (1,005 vs. 628 per 10,000 live births) and 38 weeks (625 vs. 483 per 10,000 live births) was higher compared with delivery risk in the subsequent gestational week.

Researchers observed an increased delivery risk in the subsequent gestational week compared with delivery risk at 39 weeks (599 vs. 479 per 10,000 live births). In addition, delivery risk in the subsequent gestational week was not significant at 40 weeks (639 vs. 594 per 10,000 live births) and 41 weeks (701 vs. 633 per 10,000 live births) compared with delivery risk at 39 weeks.

“The findings suggest an increased risk of adverse perinatal outcomes with both early-term and late-term delivery among patients who conceived with infertility treatment,” the researchers wrote.