Secular trends in pregnancy weight gain in German women and their influences on foetal outcome: a hospital-based study

Background: Increasing rates of overweight have been reported. In Germany, women of childbearing age are especially affected. Those women are at increased risks of several peri-and postnatal complications. The purpose of this study was to carry out Germany's first study in terms of secular trends of overweight and weight gain during pregnancy related to foetal clinical outcomes (birth weight, Apgar score and umbilical blood pH). Methods: A database maintained by a large regional university hospital in Cologne, Germany was used to evaluate clinical routine data from 1996 to 2012. 11771 women (23.5 +/- 5.4 years; 18-48 years), who gave birth to a live singleton child (> 2000 gram) were included. Recommended weight gain during pregnancy was based on IOM guidelines: Total weight gain range for underweight (initial BMI < 18.5 kg/m(2)) is 12.5-18 kg/28-40 lbs respectively, for normal-weight (initial BMI 18.5-24.9 kg/m(2)) is 11.5-16 kg/25-35 lbs respectively, for overweight (initial BMI 25.0-29.9 kg/m(2)) is 7-11.5 kg/15-25 lbs respectively and for obese (initial BMI >= 30.0 kg/m(2)) is 5-9 kg/11-20 lbs respectively. A one-way variance analysis was employed to test for differences in particular factors in various groups. Multiple linear regression analysis was used to model impact factors. Results: Over the second analysed period (2005-2012), the number of women with high weight gain increased from 33.8% to 42.9% (p < 0.001). 54.5% overweight and 57.7% obese women were affected (p < 0.001). Women with high weight gain were 54.5% significantly more likely to give birth to an infant >= 4000 grams than women with normal (31.7%) or low weight gain (13.8%, p < 0.001). Women with normal weight gain had significantly better foetal outcomes in terms of the Apgar score at 5 min and umbilical cord blood pH. Conclusion: These data confirm an increase in maternal weight gain before and during pregnancy. An excessive weight gain is accompanied by macrosomia, lower Apgar scores and pH-value. Women should therefore be advised about the risks of obesity before and during pregnancy as well as excessive maternal weight gain during pregnancy.