Remission, continuation and incidence of eating disorders during early pregnancy: a validation study in a population-based birth cohort

Background. We internally validated previously published rates of remission, continuation and incidence of broadly defined eating disorders during pregnancy in the Norwegian Mother and Child Cohort (MoBa) at the Norwegian Institute of Public Health. Method. A total of 77 267 pregnant women enrolled at 17 weeks gestation between 2001 and 2009 were split into a training sample (n=41 243) from the version 2 dataset and a validation sample (n=36 024) from the version 5 dataset who were not in the original study. Internal validation of original rate models involved fitting a calibration model to compare model parameters between the two samples and bootstrap estimates of bias in the entire version 5 dataset. Results. Remission, continuation and incidence estimates remained stable. Pre-pregnancy prevalence estimates in the validation sample were: anorexia nervosa (AN; 0.1 %), bulimia nervosa (BN; 1.0 %), binge eating disorder (BED; 3.3%) and eating disorder not otherwise specified-purging disorder (EDNOS-P; 0.1 %). In early pregnancy, estimates were: BN (0.2 %), BED (4.8%) and EDNOS-P (<0.01 %). Incident BN and EDNOS-P during pregnancy were rare. The highest rates were for full or partial remission for BN and EDNOS-P and continuation for BED. Conclusions. We validated previously estimated rates of remission, continuation and incidence of eating disorders during pregnancy. Eating disorders, especially BED, during pregnancy were relatively common, occurring in nearly one in every 20 women. Pregnancy was a window of remission from BN but a window of vulnerability for BED. Training to detect eating disorders by obstetricians/gynecologists and interventions to enhance pregnancy and neonatal outcomes warrant attention.