Objective: To investigate whether isolated oligohydramnios at term is associated with increased rates of perinatal morbidity and mortality and whether induction of labor in term pregnancies with isolated oligohydramnios is superior to conservative management in reducing perinatal morbidity and mortality. Study Design: We searched databases from inception to May 2015. We included studies that evaluated isolated oligohydramnios at term and perinatal outcome. Each outcome was analyzed separately, performing a comparative analysis between the study and control groups. Results: Twelve studies were included with 35,999 women: 2,414 (6.7%) with isolated oligohydramnios and 33,585 (93.29%) with normal amniotic fluid index. Patients with isolated oligohydramnios had significantly higher rates of labor induction [odds ratio (OR) 7.56, confidence interval (CI) 4.58-12.48] and Cesarean sections (OR 2.07, CI 1.77-2.41). There were higher rates of an Apgar score <7 at 1 and 5 min (OR 1.53, CI 1.03-2.26, and OR 2.01, CI 1.3-3.09, respectively) and admission to the neonatal intensive care unit (OR 1.47, CI 1.17-1.84). There were no significant differences in cord pH <7.1 and meconium-stained amniotic fluid. In the single randomized trial comparing induction of labor with expectant management, no differences were found in any significant maternal or neonatal outcomes. Conclusion: Isolated oligohydramnios at term is associated with significantly higher rates of labor induction, Cesarean sections, and short-term neonatal morbidity.

Background: Whether placental location confers specific neonatal risks is controversial. In particular, whether placenta previa is associated with intra-uterine growth restriction (IUGR)/small for gestational age (SGA) remains a matter of debate.Methods: We searched Medline, EMBASE, Google Scholar, Scopus, ISI Web of Science and Cochrane database search, as well as PubMed (www.pubmed.gov) until the end of December 2018 to conduct a systematic review and meta-analysis to determine the risk of IUGR/SGA in cases of placenta previa. We defined IUGR/SGA as birth weight below the 10^thpercentile, regardless of the terminology used in individual studies. Risk of bias was assessed using the Cochrane Handbook for Systematic Reviews of Interventions. We used odds ratios (OR) and a fixed effects (FE) model to calculate weighted estimates in a forest plot. Statistical homogeneity was checked with the I²statistic using Review Manager 5.3.5 (The Cochrane Collaboration, 2014).Results: We obtained 357 records, of which 13 met the inclusion criteria. All study designs were retrospective in nature, and included 11 cohort and two case-control studies. A total of 1,593,226 singleton pregnancies were included, of which 10,575 had a placenta previa. The incidence of growth abnormalities was 8.7/100 births in cases of placenta previa vs. 5.8/100 births among controls. Relative to cases with alternative placental location, pregnancies with placenta previa were associated with a mild increase in the risk of IUGR/SGA, with a pooled OR [95% confidence interval (CI)] of 1.19 (1.10–1.27). Statistical heterogeneity was high with an I² = 94%.Conclusion: Neonates from pregnancies with placenta previa have a mild increase in the risk of IUGR/SGA.