Does Excess First- or Second-Trimester Weight Gain Predict Excess Total Gestational Weight Gain? A Multicentre...

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.