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The review reports evidence from meta-analyses on smoking cessation, alcohol reduction, diet and physical activity at reducing the risk of adverse health outcomes. The outcomes vary, yet diet and physical activity appear to be the variables with the most significant impact on maternal and infant health.

Fetal and infant health is related to maternal behaviours during pregnancy. Some adverse pregnancy outcomes such as maternal and perinatal mortality, low birthweight, and preterm birth share common risk factors associated with an unhealthy lifestyle. International guidelines for pregnancy behaviour recommendations exist but need some clarification in some cases like alcohol consumption.

Furthermore, there is a lack of data on recognising similarities or differences between interventions for specific behaviours, which motivated a systematic review of 602 English language meta-analyses published since 2011. The review was set to examine the effectiveness of interventions on improving health-related outcomes for women and infants and explore shared behavioural techniques of those interventions. Pregnant women were the target population for the reviewed papers’ inclusion criteria. As for the intervention, the included papers needed to relate to maternal smoking, alcohol, diet or physical activity behaviours.

At the end of the selection, 332 meta-analyses of maternal health outcomes related to maternal weight, gestational diabetes (GDM), hypertensive disorders, mode of delivery and “others” were analysed. The other 270 meta-analyses presented the infant health outcomes and included fetal growth, gestational age at delivery, mortality and admission to the neonatal intensive care unit (NICU). Moreover, most of the evidence identified with this review was related to diet and physical activity intervention. Unfortunately, there were only two systematic reviews on evidence for smoking interventions and health outcomes, and no reviews on health outcomes from alcohol interventions.

Regarding the outcome itself, physical-activity-only interventions had the most effective impact on maternal health outcomes, reducing GDM. Within the infants’ outcomes, fetal growth and gestational age at delivery were highly impacted. By comparing the behaviours and population subgroups, evidence suggests particular effectiveness of smoking cessation for increasing birthweight. In contrast, diet-only interventions appear most effective at reducing weekly gestational weight gain (GWG). Concerning preterm deliveries, meta-analyses of the effectiveness of diet and physical activity interventions showed a significantly reduced risk of preterm delivery. Other interventions like counselling, feedback, or incentives had no significant effect. Interventions on women with a Body Mass Index (BMI) in the overweight or obese categories had the most considerable GWG and GDM reductions.

Previous reports have shown promising effects of smoking and alcohol interventions at changing maternal health outcomes. This systematic review reports the opposite trend and sets physical activity and diet to be the docking point for improvement. Explanations for the conflicting findings in the meta-analyses might be related to unmeasured factors. It is also worth mentioning that the review’s data gap from lower-middle-income and low-income countries compromises the validity and effectiveness of the interventions strategies globally.

One of the aims of a systematic review of systematic reviews is to describe the current evidence’s extent and gaps to inform future research. There is a clear necessity to conduct further analyses on the benefits of a healthy lifestyle for maternal and infant health outcomes.

Paper available at: MDPI, Journal Nutrients

Full list of authors: Louise Hayes, Catherine McParlin, Liane B Azevedo, Dan Jones, James Newham, Joan Olajide, Louise McCleman and Nicola Heslehurst

DIO: 10.3390/nu13031036