Vonck S, Lanssens D, Staelens AS, et al. - Researchers examined the maternal circulatory variations during pregnancy between obese and normal-weight women. A total of 232 evaluations were conducted in the obese group, whereas 919 evaluations were done in the non-obese group. With regard to non-obese women, in obese women during the first and second trimester, the overall cardiovascular function is constant with a high volume/low resistance circulation. In the third trimester, the cardiac output of obese women drops from 9.2 L/min to 8.5 L/min whereas this is not valid in the non-obese women. Concurrently, the constantly lower peripheral vascular resistance in obese vs non-obese women passes. Hence, between non-obese and obese women, the circulatory gestational adaptations were usually comparable. The results in the third trimester imply that pregnancy in obese women begins as a state of high volume/low resistance load, eventually shifting to volume overload with a reduction of cardiac output and disappearance of low vascular resistance. This evolving makes obese women exposed to gestational hypertensive diseases.