Accuracy of maternal recall of gestational weight gain 4 to 12 years after delivery

There is growing interest in the relationship between gestational weight gain (GWG) and long-term maternal and child outcomes, yet little is known about the accuracy of long-term maternal recall of GWG. Our objective was to assess the accuracy of maternal recall of GWG at 4-12 years postpartum (mean, 8 years) compared with medical-record documented GWG, and compare recalled GWG to documented GWG with respect to their associations with adverse pregnancy outcomes including small for gestational age (SGA) birth, preterm birth, cesarean delivery, and postpartum weight retention (PPWR) (n = 503). Adequacy of recalled and documented GWG was assessed according to the 2009 Institute of Medicine (IOM) guidelines. We observed moderate agreement between documented and maternal self-reported GWG as continuous variables (r = 0.63, P < 0.01). When recalled GWG was used to categorize women, 45, 53, and 20% of women with inadequate, adequate, and excessive documented GWG were misclassified, respectively. When comparing models fitted with documented or recalled GWG, there were no meaningful differences in associations between inadequate GWG and SGA birth (odds ratio 2.2 (95% confidence interval: 1.3, 3.7) vs. 2.1 (1.2, 3.8), respectively) or excessive GWG and PPWR (2.5 (1.6, 3.9) vs. 2.5 (1.5, 4.0), respectively). However, the use of recalled GWG attenuated associations between inadequate GWG and PPWR (documented: 0.5 (0.3, 0.9) vs. recalled GWG: 1.3 (0.7, 2.3)) and excessive GWG and preterm birth (documented: 2.5 (1.4, 4.5) vs. recalled GWG: 1.5 (0.9, 2.7)). Our data suggest a varying degree of bias when using recalled GWG to study selected adverse outcomes.