NATIONAL HARBOR, MARYLAND — Women who experience an adverse pregnancy outcome during their first pregnancy are significantly more likely to experience either the same or any adverse pregnancy outcome in a subsequent pregnancy than are those with no adverse pregnancy outcome during a first pregnancy, based on data from more than 4000 individuals.
Adverse pregnancy outcomes (APOs) occur in approximately 20%-30% of pregnancies and contribute to significant perinatal morbidity, William A. Grobman, MD, of The Ohio State University, Columbus, said in a presentation at the Pregnancy Meeting sponsored by the Society for Maternal-Fetal Medicine (abstract 17).
Risk factors for APOs include nulliparity and prior APOs, as well as age, body mass index, and blood pressure, he said. However, less is known about factors identified early in a first pregnancy that might predict an APO in a second pregnancy, he explained.
Dr. Grobman and colleagues used data from the nuMoM2b Heart Health Study, a cohort of more than 10,000 nulliparous women at eight sites in the United States.
The current study included a subset of individuals with two pregnancies of at least 20 weeks’ gestation who were followed for up to 7 years after delivery via telephone and in-person visits and for whom APO information was available.
An APO was defined as any of a range of outcomes including hypertensive disorders of pregnancy, preterm birth at less than 37 weeks’ gestation, small-for-gestational age at birth (less than 5th percentile for weight), gestational diabetes, or fetal death.
The goal of the study was to determine patterns of APOs across two pregnancies, and to identify factors in the first pregnancy that might be associated with these patterns, Dr. Grobman said.
The study population included 4253 women from the nuMOM2b; of these, 1332 (31%) experienced an APO during their first pregnancies.
Women with an APO during the first pregnancy were significantly more likely to have a second APO than were those with no initial APO (40% vs. 15%), said Dr. Grobman. Overall, the APO that occurred most frequently in the first pregnancy was the one most likely to occur in the second.
However, “the increased risk for an APO during a second pregnancy was greater for any APO in women with a history of any APO compared to women with no prior APO,” he said.
In this study, the most common APOs were gestational diabetes and hypertensive disorders of pregnancy.
“In general, no risk markers were associated with a particular pattern of APO development,” Dr. Grobman said.
However, some markers from the first trimester of the first pregnancy were significantly associated with an APO in the second pregnancy, including body mass index, age older than 35 years, blood pressure, and cardiometabolic serum analytes. Also, the magnitude of APO recurrence risk was highest among non-Hispanic Black individuals compared with other ethnicities.
The findings were limited by a lack of data on placental pathology, Dr. Grobman noted during the discussion. However, the findings underscored the need to better understand the risk factors for APOs and develop prevention strategies, he said. The results also emphasize the need to account for transitions of care for patients who experience an APO, he added.