A retrospective longitudinal observational study of 17,397 women from 149 countries with diverse socioeconomic backgrounds evaluated predictors of gestational weight gain outside National Academy of Medicine recommendations. Routine health data collected from the Monash Health Network in Australia between 2017 and 2021 were analyzed. Overall, 31.5% of women gained less than recommended, 35.7% gained the recommended amount, and 32.8% gained more than recommended.

Using multinomial logistic regression, researchers found that women who were overweight at the start of pregnancy had a 4.05 times higher adjusted relative risk (aRRR) of excessive gestational weight gain (GWG) compared with women of healthy weight (95% CI, 3.37-4.80), and women with obesity had a 6.64 times higher aRRR (95% CI, 5.27-8.37). Women of Polynesian origin had a 3.12 times higher risk of excessive GWG compared with Caucasian women (95% CI, 1.49-6.57). Underweight women had higher risks of inadequate weight gain (aRRR, 1.90; 95% CI, 1.28-2.82), and Indigenous and African-born women were also more likely to have inadequate weight gain compared with Caucasians. Multiparous women had lower risks of excessive GWG compared with nulliparous women.

Using weight data collected between 10 and 25 weeks of gestation, researchers developed a prediction tool to identify women at risk of inadequate or excessive GWG by term.¹ The tool achieved an area under the curve (AUC) of 0.81 for the 15-25 weeks model, 0.80 for the 15-20 weeks model, and 0.69 for the 10-15 weeks model.¹ Internal validation showed 88% correct classification for the 15-25 weeks cohort, 80.3% for the 15-20 weeks cohort, and 61.4% for the 10-15 weeks cohort. Concordance between classifications at 10-15 weeks and 15-20 weeks was 75%.

The mean maternal age was 30.1 years, and the mean prepregnancy BMI was 25.8 kg/m². Among the cohort, 49.4% of Polynesian women were classified as obese, compared with 28.4% of Caucasian women and 4.1% of Southeast Asian women. Birthweight outcomes differed significantly by GWG category, with mean birthweights of 3272 g, 3408 g, and 3544 g for insufficient, recommended, and excessive GWG groups, respectively.

Socioeconomic status was not significantly associated with GWG outcomes. Weight data were obtained from both clinical measures and self-reported information. The study authors stated that "these findings generated from a diverse population accurately identify those at risk of suboptimal GWG and subsequent adverse pregnancy outcomes during pregnancy," and suggested that the prediction tool could assist healthcare providers in targeting interventions to optimize maternal and child health outcomes. No competing interests were reported.

Source: BMJ Open