Untergewicht in der Schwangerschaft

The objective of this retrospective study was to examine the effect of a low maternal pre-pregnancy BMI (<18.5) on pregnancy- and birth risks and neonatal outcome. Further this study aimed to assess the influence of gestational weight gain in the group of pregnant women with BMI <18.5, on these risks and neonatal outcome. The sample included 223,469 women giving birth to a child in the years 2001 – 2008 in Hessen, Germany and were registered in the “hessische Perinatalerhebung”. Included are all women with singleton pregnancies and a pre- pregnancy BMI under 25. The sample sizes were 13,413 in the group of women with a pre-pragnancy BMI under 18.5 and 210,056 in the group of women with a prepragnancy BMI between 18.5 and 25. Groups were compared using X2–Tests, significance levels were set by 5% and associations were examined using logistic regression. In this study women who are underweight are significant younger and smoke more often. A Pre-pregnancy BMI under 18.5 is significant associated with a lower risk for Gestational Hypertension (OR 0.434) and Gestational Diabetes (OR 0.611). Even a high gestational weight gain did not raise the risk significantly in this group. Significant higher risks could be shown for anaemia (OR 1.381), premature delivery (OR 1.381), placental insufficiency (OR 1.413), cervical incompetence (1,631) and preterm labour (OR 1,736). Gaining less than 12kg weight in pregnancy raised these risks even more. On the contrary, gaining over 17 kg in pregnancy did reduce these risks. Looking on the neonatal outcome children, born by women with a pre-pregnancy BMI under 18.5, are more often born with a weight less than 2500gr. And they had an intrauterine growth restriction. Also it was associated with treatment in paediatric clinic. A reduced risk could be shown for macrosomia. Following risks did not show a significant association with the pre pregnancy BMI: APGAR, pH, Base Excess and resuscitation of the newborn. All these associations were significant after logistic regression, controlling for the confounders; Age, smoking and weight gain. In Summary women with a pre-pregnancy BMI under 18.5 kg have a higher risk for small and premature babies. This risk is even higher when these women gain less than 12 kg weight during pregnancy. On contrary this risk can be reduced by gaining more than 17 kg in pregnancy. Gaining over 17 kg did not raise any other pregnancy or birth risks in this group, nor was associated with a negative neonatal outcome. In conclusion, underweight women should be encouraged to gain more weight than currently recommended. Following this advice negative outcome of small and premature babies, such as metabolic syndrome and cardiovascular problems in future life, could be reduced.