Association of previous stillbirth with subsequent perinatal outcomes: a systematic review and meta-analysis of cohort studies

Objective We conducted a systematic review and meta-analysis to examine the relationship between stillbirths and various perinatal outcomes in subsequent pregnancies. Data sources PubMed, the Cochrane Library, Embase, Web of Science, and CNKI databases were searchedup to July 2023. Study eligibility criteria Cohort studies reported the association between stillbirths and perinatal outcomes in subsequent pregnancies. Study appraisal and synthesis methods We conducted this systematic review and meta-analysis in accordance with the PRISMA guidelines. Statistical analysis was performed using R and STATA software. We used random effects models to pool each outcome of interest. We performed a meta-regression analysis to explore the potential heterogeneity. The certainty (quality) of evidence assessment was performed the GRADE approach. Results Nineteen cohort studies were included which involving 4,855,153 participants. From these studies we identified 28,322 individuals with previous stillbirths who met the eligibility criteria. After adjusting for confounders, evidence of low to moderate certainty indicates that compared to women with previous live births in subsequent pregnancies, women with previous stillbirths had higher risks of recurrent stillbirth (OR: 2.68, 95% CI: 2.01 to 3.56), preterm birth (OR: 3.15, 95% CI: 2.07 to 4.80), neonatal death (OR: 4.24, 95% CI: 2.65 to 6.79), SGA/IUGR (OR: 1.3, 95% CI: 1.0 to 1.8), low birth weight (OR: 3.32, 95% CI: 1.46 to 7.52), placental abruption (OR: 3.01, 95% CI: 1.01 to 8.98), instrumental delivery (OR: 2.29, 95% CI: 1.68 to 3.11), labour induction (OR: 4.09, 95% CI: 1.88 to 8.88), caesarean section (OR: 2.38, 95% CI: 1.20 to 4.73), elective caesarean section (OR: 2.42, 95% CI: 1.82 to 3.23), and emergency caesarean section (OR: 2.35, 95% CI: 1.81 to 3.06), but had lower rate of spontaneous labour (OR: 0.22, 95% CI: 0.13 to 0.36). However, there was no association between previous stillbirths and pre-eclampsia (OR: 1.72, 95% CI: 0.63 to 4.70) in subsequent pregnancies. Conclusions Our systematic review and meta-analyses provide a more comprehensive understanding of adverse pregnancy outcomes associated with previous stillbirths. These findings could be used to inform counselling for couples who are considering having a baby after a previous stillbirth.