Reply to: Re: Risk of pre‐eclampsia after gastric bypass: a matched cohort study.

The clear dose-dependent weight loss effect that we found in our study2 strongly supports the importance of gastric-bypass-induced weight loss on pre-eclampsia risk. I Sir, i We find it unlikely that the effect of calcium and vitamin D supplementation would be large enough to be equal to/compete with the metabolic and weight loss effects of gastric bypass in severely obese women and thereby, as van Gelder et al.1 put it, make it 'challenging to distinguish between the effect of gastric bypass itself and the effect of vitamin D and calcium supplementation'. Although calcium and vitamin D supplementation could have contributed to the substantial risk reduction of pre-eclampsia in the gastric bypass group, we do not agree with van Gelder et al. SP 1 sp that stating 'gastric bypass in itself is effective in the prevention of pre-eclampsia may still be considered premature'. [Extracted from the article]