Does Excess First- or Second-Trimester Weight Gain Predict Excess Total Gestational Weight Gain? A Multicentre Prospective Cohort Study

Early excess gestational weight gain (GWG) has been examined as a predictor of total excess GWG in a few international studies; however, Canadian data are lacking. We sought to determine whether early (first- and second-trimester) excess GWG predicted total excess GWG. We conducted an a priori planned secondary analysis of a multicentre prospective study of English-speaking Ontario women with a singleton pregnancy between 80 and 206 weeks gestation. Our primary outcome was prediction of total excess GWG. We calculated the sensitivity, specificity, predictive values, and likelihood ratios, by body mass index (BMI), for excess first- and second-trimester GWG. Of the 970 women who met the inclusion criteria, 387 and 754, had first- and second-trimester weights recorded in their antenatal record, respectively. For normal, overweight, and obese women, the sensitivity of excess first-trimester GWG for total excess gain was 66%, 68%, and 65%, respectively; and the specificity was 48%, 43%, and 36%, respectively. The sensitivity of excess second-trimester GWG for total excess gain for normal weight, overweight, and obese women was higher, at 92%, 96%, and 95%, respectively; while the specificity was low at 31%, 16%, and 29%, respectively. In the first known Canadian study of early excess weight gain as the predictor of total GWG, we found that excess first-trimester GWG did not predict total excess GWG, but that the sensitivity of excess second-trimester GWG for excess total GWG was high across BMI categories. Nous avons étudié le gain pondéral gestationnel (GPG) excessif précoce comme facteur prédictif du GPG excessif total dans quelques études internationales; toutefois, il y a très peu de données canadiennes. Nous avons cherché à déterminer si le GPG excessif précoce (premier et deuxième trimestres) était prédictif d'un GPG excessif total. Nous avons mené une analyse secondaire planifiée a priori d'une étude multicentrique auprès d'Ontariennes anglophones ayant une grossesse monofœtale dont l’âge gestationnel se situait entre 80 et 206 semaines d'aménorrhée. Notre critère de jugement principal était la prédiction du GPG excessif total. Nous avons calculé la sensibilité, la spécificité, les valeurs prédictives et les rapports de vraisemblance, par indice de masse corporelle (IMC), pour le GPG excessif aux premier et deuxième trimestres. Nous avons consigné au dossier prénatal le poids de 387 femmes au premier trimestre et celui de 754 femmes au deuxième trimestr