Short interbirth interval and adverse pregnancy outcomes: a Bayesian network approach

Area of Science:

• Reproductive Health
• Perinatal Epidemiology
• Obstetrics

Background:

• Interbirth interval (IBI) is the time between consecutive births and is associated with perinatal outcomes.
• Understanding the impact of short IBI on adverse perinatal events is crucial for maternal and child health.
• Previous studies suggest a link between short IBI and negative pregnancy outcomes.

Purpose of the Study:

• To investigate adverse perinatal events, including preterm birth (PTB), low birth weight (LBW), and birth defects, following short interpregnancy intervals (IBI).
• To analyze these outcomes in a large South American population, considering various confounding factors.
• To elucidate the complex relationships between IBI, maternal characteristics, and perinatal outcomes using advanced statistical methods.

Main Methods:

• An observational, retrospective, hospital-based study was conducted, including live- and stillbirths (malformed and nonmalformed).
• Logistic regression and Bayesian networks were employed to analyze the risk of short IBI and adverse outcomes, adjusting for confounders like maternal age and previous abortion.
• Key outcomes assessed included PTB, LBW, and specific birth defects such as gastroschisis.

Main Results:

• The rate of short IBI was 2%-3%. Young maternal age (≤19 years) was a significant risk factor for short IBI, while older mothers (≥30 years) had a lower risk, mediated by previous abortion.
• Short IBI was a significant risk factor for LBW after adjusting for confounders, but not for PTB.
• An unadjusted association between short IBI and gastroschisis was observed, but this disappeared after adjusting for confounders; young maternal age and previous abortion were directly linked to gastroschisis.

Conclusions:

• Short interpregnancy intervals are directly associated with adverse perinatal outcomes, primarily low birth weight, especially in younger mothers.
• The relationship between short IBI and preterm birth or gastroschisis is indirect, mediated by factors such as young maternal age and a history of abortion.
• Maternal age and prior abortion history are critical factors influencing both short IBI and specific birth defects, highlighting the need for targeted interventions.