Pregnancy Interventions to Improve Birth Outcomes: What Are the Effects on Maternal Outcomes? A Scoping Review.

Interventions in pregnancy are commonly evaluated for their effects on birth outcomes because maternal infection and poor nutrition are the primary contributors to adverse pregnancy outcomes, especially in low- and middle-income countries (LMICs). However, the extent to which such interventions directly impact maternal health and nutrition has not been succinctly characterized. We conducted a scoping review of systematic reviews and meta-analyses of 27 pregnancy interventions to summarize the evidence of impact on maternal outcomes. Overall, these were reported incompletely, and we failed to find any evidence for eight interventions. Influenza vaccination, insecticide-treated bed nets, intermittent preventive treatment for malaria, anthelmintic therapy, and treatment of bacterial vaginosis, asymptomatic bacteriuria, and periodontal disease during pregnancy provided direct benefit to women, with reductions in infection risk. Nutritional interventions such as micronutrient supplementation and balanced energy and protein improved outcomes of maternal anemia and gestational weight gain, particularly in deficient populations. Calcium and low dose aspirin significantly reduced the risk of pre-eclampsia. These findings highlight antenatal interventions benefitting maternal health and provide insights into pathways for impacting birth and infant outcomes.