Effectiveness of multimodal nutrition interventions during pregnancy to achieve 2009 Institute of Medicine gestational weight gain guidelines: a systematic review and meta-analysis.

BACKGROUND In 2009, the Institute of Medicine (IOM) published a revision to its 1990 recommendations on gestational weight gain (GWG). The objective of this review is to update a previous systematic review and meta-analysis to evaluate the effectiveness of nutrition interventions in achieving recommended GWG. METHODS We conducted updated literature searches in MEDLINE® (2012 through 2019), Web of Science (2012 to 6 February 2017), Embase (2016 through 2019), and Cochrane Central Register of Controlled Trials (2012 through 2019). Literature published before January 2012 was identified from a published systematic review. We included controlled trials conducted in the U.S. or Canada among generally healthy pregnant women that compared nutrition interventions with or without exercise to controls (e.g., usual care) and reported total GWG or rate of GWG based on the 2009 IOM GWG guidelines. Two independent investigators conducted screening, data extraction, and risk-of-bias (ROB) assessment. Random-effects meta-analyses were conducted when data were sufficient. RESULTS Eighteen unique studies were included, of which 11 were conducted in women with overweight or obesity. Nutrition interventions, compared to controls, had a similar effect on total GWG (mean difference = -1.24 kg; 95% CI [-2.65, 0.18]; I2=67.6%) but significantly decreased second and third trimester rate of GWG (-0.07 kg/week; 95% CI [-0.12, -0.03]; I2=54.7%). Nutrition interventions also reduced the risk of exceeding IOM's rate of GWG targets (pooled RR = 0.71; 95% CI [0.55, 0.92]; I2=86.3%). Meta-analyses showed no significant differences in achieving IOM's total GWG or any secondary outcome (e.g., preterm birth or small/large for gestational age) between groups. Most studies were assessed as having some or high ROB in at least two domains. CONCLUSION Multimodal nutrition interventions designed to meet the 2009 IOM's GWG targets may decrease the rate of GWG over the second and third trimesters but may not decrease total GWG.Key messagesExcessive gestational weight gain is associated with higher risk of many adverse maternal and fetal outcomes and represents a public health concern in the United States and Canada.Nutrition interventions designed to meet the 2009 IOM GWG guidelines may decrease the rates of GWG over the second and third trimesters but may not be effective at reducing total GWG.