DOES EXCESS FIRST TRIMESTER WEIGHT GAIN PREDICT EXCESS TOTAL GESTATIONAL WEIGHT GAIN?

Abstract

Objectives Previous European data found that excess first trimester (T1) gestational weight gain (GWG) predicted total excess GWG. Our objective was to determine whether excess T1 GWG predicts total excess GWG, stratified by prepregnancy BMI for normal weight, overweight and obese Canadian women. Methods English-speaking women with a singleton pregnancy between 8+0 and 21+6 weeks were recruited from 12 obstetrical, family medicine and midwifery centres across Ontario. Excess weight gain (>2.0 kg) in the first trimester (up to 13+6 weeks) was used to predict excess total GWG. GWG was classified as “excess” or “within” the Institute of Medicine/Health Canada guideline. Descriptive statistics summarized data. Prediction was calculated using positive predictive value (PPV) and positive likelihood ratio (+LR). Sensitivity, specificity, negative predictive value (NPV) and negative LR (-LR) were also calculated. SAS 9.4 was used. Results Among the 353 women, 38.5% had T1 GWG above guidelines, while 61.5% gained within or below guidelines. Baseline characteristics between women with excess T1 were similar to those gaining within or below the guidelines. For normal, overweight, obese and all women, the predictive values of excess T1 GWG for excess total GWG were: PPV (57%, 80%, 68%, 65%) and +LR with 95% confidence intervals [(1.51 (1.06-2.15), 0.97 (0.51-1.84), 0.98 (0.49-1.95), 1.25 (0.94-1.65)]. Conclusions In this first Canadian study, excess T1 GWG was common, but unlike previous European publications, did not strongly predict total excess GWG. Excess GWG is an important determinant of maternal-fetal health, and its prediction warrants further research, to enable earlier interventions.