Preconception and periconception interventions to prevent adverse birth outcomes
This is a summary of the following paper: Partap U, Chowdhury R, Taneja S et al (2022) Preconception and periconception interventions to prevent low birth weight, small for gestational age and preterm birth: A systematic review and meta-analysis. BMJ Global Health, 7, e007537. https://pubmed.ncbi.nlm.nih.gov/35948345/
A growing body of evidence supports the potential benefits of interventions delivered prior to conception regarding the risk of adverse birth outcomes, including low birth weight (LBW), small for gestational age (SGA) deliveries and preterm birth (PTB). However, a better understanding is needed of the effects of such interventions to identify knowledge gaps and inform future prevention strategies.
This article presents findings from a systematic review and meta-analysis examining the impact of interventions delivered during the pre- and periconception (until pregnancy is detected) periods, or from preconception throughout pregnancy, on LBW, SGA and PTB. Of the 58 identified studies, most examined health and nutrition interventions, with little research being carried out on other relevant areas such as environmental health and social interventions. There were also few studies available for any single comparison, limiting the authors’ ability to draw conclusions on whether specific interventions – such as food supplementation during preconception and pregnancy versus during pregnancy only – reduce the risk of individual outcomes.
Findings suggested that only health interventions aiming to reduce early adverse pregnancy outcomes were associated with reduced risk of SGA and PTB among women with previous miscarriage. No clear impact on any primary outcome was shown for preconception and periconception nutrition interventions, including multiple micronutrient supplementation, folic acid supplementation with or without iron and food supplementation. Proposed reasons for the uncertainty of evidence included (1) insufficient evidence from a limited number of studies to meaningfully assess impact; (2) relatively short durations (three to six months) of supplementation prior to conception; (3) poor levels of adherence to interventions; and (4) inadequacy of the intervention provided. In low- and middle-income countries (LMICs), where most interventions were implemented, micronutrient or food supplementation delivered in the preconception period may be insufficient to improve pregnancy outcomes, particularly in contexts where the burden of undernutrition remains high among women of reproductive age.
The review highlights the beneficial effects of preconception nutritional supplementation (iron and folic acid or food supplementation) on maternal anaemia during the second and third trimesters, although this was not related to primary outcomes. Provision of preconception and periconception nutritional supplementation containing folic acid was also associated with a reduced risk of birth defects (primarily neural tube defects). Since antenatal care attendance often occurs late during pregnancy in LMICs, these findings suggest potential opportunities to improve maternal micronutrient and anaemic status by extending micronutrient supplementation interventions to the preconception period.
Overall, this review highlights the dearth of relevant high-quality evidence and the need for further well-designed studies on the effectiveness of preconception nutrition, health, environmental and social interventions in preventing adverse outcomes, including LBW, SGA and PTB. The authors suggest that future research should prioritise integrated, multicomponent interventions that address different determinants of preconception health, including women’s education, empowerment and equity to infrastructure, as well as water supply and sanitation. Attention should also be given to intervention timing and duration and other underlying characteristics that may affect overall impact, such as preconception nutritional status or geographic region.