Microarray findings in pregnancies with oligohydramnios – a retrospective cohort study and literature review

Objective: To explore the risk for abnormal chromosomal microarray analysis (CMA) findings in pregnancies with oligohydramnios. Methods: Data from all CMA analyses performed due to oligohydramnios between 2013 and 2017 were retrospectively obtained from the Israeli Ministry of Health database. The rate of clinically significant (pathogenic and likely pathogenic) findings was compared to a local cohort of pregnancies with normal ultrasound, yielding a 1.4% rate of abnormal CMA results. In addition, a search was conducted through the PubMed database addressing the issue. Results: Fifty CMA analyses were performed due to oligohydramnios. The 2% risk for clinically significant CMA finding in pregnancies with oligohydramnios did not differ from the control population of 5541 pregnancies with normal ultrasound – relative risk (RR) 1.4 [95% confidence interval (CI) 0.2–10.2]. Literature search yielded 394 titles, of which four relevant articles were selected, all using fetal karyotyping. Conclusion: There is yet insufficient evidence to support invasive prenatal testing in pregnancies with isolated oligohydramnios.