Association of different types of abortions with neonatal outcomes in subsequent pregnancy

Abortion is an important issue that concerns all women. It holds great significance to investigate the correlation between various types of abortion histories and the neonatal outcomes of subsequent pregnancies. This retrospective cohort study included pregnant women who gave birth to singleton live-born in Shanghai First Maternity and Infant Hospital from 2016 to 2020 (n = 75 773). Women with a history of abortion, including spontaneous abortion (SAB) and induced abortion (IA), were included in the exposed group, and the remaining were included in the unexposed group. The main outcomes were birthweight and preterm birth in the subsequent pregnancy. Logistic regression models were used to estimate odds ratios (ORs) and 95% confidence intervals (95% CIs) for the association of maternal abortion history with birthweight and risk of preterm birth in subsequent pregnancy. Women who have experienced SAB history had an increased risk of delivering very low birth weight (VLBW) and preterm birth children, with (OR = 1.63, 95% CI = 1.15-2.32; OR = 1.38, 95% CI = 1.07-1.79). However, women with a history of IA were at greater risk of macrosomia (OR = 1.16; 95% CI = 1.06-1.27). We also observed that the likelihood of delivering a VLBW baby was heightened by the number of SAB occurrences (OR = 0.87, 95% CI = 0.54-1.38; OR = 1.84, 95% CI = 1.01-3.36, OR = 5.71, 95% CI = 3.21-10.15). Our study indicates that pregnant women with a history of SAB are at an increased risk of delivering VLBW infants and experiencing preterm labour. The risk is positively associated with the number of SABs. Conversely, women with a history of IA are more likely to deliver macrosomic infants.