Recurrence Risk of Pregnancy Complications in Twin and Singleton Deliveries

This study aimed to estimate and compare the recurrence risk of preterm birth (PTB), gestational diabetes mellitus (GDM), gestational hypertension (GH), and preeclampsia and eclampsia (PE and E) in subsequent pregnancy groups (index-subsequent) of singleton-singleton (n = 49,868), twin-singleton (n = 448), and singleton-twin (n = 723) pregnancies.

Birthing individuals from the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD) Consecutive Pregnancy Study (2002-2010) with ≥ 2 singleton or twin deliveries were examined. Adjusted relative risks (aRR) and 95% confidence intervals (CI) for recurrent PTB, GDM, GH, and PE and E were estimated using Poisson regression models with robust variance estimators.

The aRR of PTB and GDM ranged from 1.4 to 5.1 and 5.2 to 22.7, respectively, with the greatest recurrence relative risk for both conditions in singleton-singleton subsequent pregnancies (PTB: aRR = 5.1 [95% CI: 4.8-5.5], GDM: aRR = 22.7 [95% CI: 20.8-24.8]). The aRR of GH and PE and E ranged from 2.8 to 7.6 and 3.2 to 9.2, respectively, with the greatest recurrence relative risk for both conditions in twin-singleton subsequent pregnancies (GH: aRR = 7.6 [95% CI: 2.8-20.5], PE and E: aRR = 9.2 [95% CI: 2.9-28.6]).

Recurrence relative risk was increased for PTB, GDM, GH, and PE and E in all subsequent pregnancy groups, which varied in magnitude based on the birth number of the index and subsequent pregnancy. This information provides insight into risk management for subsequent pregnancies including multiples.

· Recurrence risk for all conditions is persistent in all subsequent pregnancy groups.. · The magnitude of risk varies by the presence of multiples in the index or subsequent pregnancy.. · Singleton-singleton pregnancies are at the greatest risk of PTB.. · Singleton-singleton pregnancies are at the greatest risk of GDM.. · Twin-singleton pregnancies are at the greatest risk of hypertensive disorders..