Miscarriage and malformations

© 2012 Springer-Verlag Berlin Heidelberg. All rights are reserved. Prevalence of overweight and obesity in women of childbearing age is increasing in parallel with that of the general population with a negative impact on pregnancy. Increased rates of miscarriage and congenital malformations are among the untoward effects of high pregestational body mass index on pregnancy outcome. The rate of spontaneous abortion has been addressed in spontaneous pregnancies in women with recurrent miscarriages and especially in women receiving any form of fertility treatment. Miscarriages are approximately 50% higher in obese women. Suggested mechanisms include poor egg quality, but especially endometrial dysfunction and abnormal environment. The rate of major congenital malformations (any of them, neural tube defects (NTD), cardiac) depicts an increment with increasing maternal body mass index. The risk is more apparent for NTD and less so for cardiac defects or any major congenital malformation. The risk is evident in obese women whereas overweight women have a smaller risk that is appreciated in meta-analysis (for NTD OR is around 1.2 in overweight and 1.8 in obese women). Suggested mechanisms include increased nutrient availability leading to increased oxidative stress, increased insulin and cytokine concentrations, and decreased folate availability.