Diabetic and hypertensive disorders following early pregnancy loss: a systematic review and meta-analysis

Background: Spontaneous and induced abortions are common outcomes of pregnancy. There is inconsistent evidence of an association between early pregnancy loss and subsequent diabetic and hypertensive disorders in women. This systematic review and meta-analysis evaluated evidence on the risk of the subsequent development of pregnancy and non-pregnancy related diabetic and hypertensive disorders in women who experienced an early pregnancy loss. Methods: Systematic searches were conducted in seven electronic databases (CINAHL Plus, Ovid/EMBASE, Ovid/MEDLINE, ProQuest, PubMed, Scopus, and Web of Science) from inception to 22nd December 2023. Studies were included if they reported an exposure of spontaneous abortion (SAB), induced abortion (IA) or recurrent pregnancy loss (RPL) with an outcome of gestational diabetes mellitus, pre-eclampsia, gestational hypertension, and non-pregnancy related diabetic and hypertensive disorders. Risk of bias was assessed using Risk of Bias Instrument for Non-Randomized Studies of Exposures (ROBINS-E). Random effects meta-analysis was used to pool odds of developing diabetic and hypertensive disorders following an early pregnancy loss. This study is registered with PROSPERO (CRD42022327689). Findings: Of 20,176 records, 60 unique articles were identified for full-text review and 52 met the inclusion criteria, representing a total population of 4,132,895 women from 22 countries. Thirty-five studies were suitable for meta-analysis, resulting in a pooled odds ratio (OR) of 1.44 (95% confidence interval (CI) 1.23-1.68) for gestational diabetes mellitus following a prior SAB and a pooled OR of 1.06 (95% CI 0.90-1.26) for pre-eclampsia following a prior SAB. RPL increased the odds of developing pre-eclampsia (OR 1.37 95% CI 1.05-1.79). There was no association between IA and diabetic and hypertensive disorders. Interpretation: A prior SAB was associated with increased odds of gestational diabetes mellitus, but not pre-eclampsia. However, women who experienced RPL had an increased risk of subsequent pre-eclampsia. Future research is required to establish evidence for an association between early pregnancy loss with non-pregnancy related diabetic and hypertensive disorders. Funding: National Health and Medical Research Council.