Relation between pregestational obesity and characteristics of the placenta.

Objective:To evaluate the morphology of the placenta in patients with pregestational overweight (OW), pregestational obesity (PGOB), or normal weight. Methods:A cross-sectional study including women (n = 114) >= 20 years of age with a singleton pregnancy was carried out. The groups were integrated according to pregestational body mass index (BMI): 51 patients had a normal BMI (18.5-24.99 kg/m(2)), 30 were overweight (25-29.99 kg/m(2)), and 33 women were obese (>= 30.0 kg/m(2)). A morphometric study of the placenta was performed and the placental maturity index (PMI) was calculated according to the formula: PMI = number of vasculo-syncytial membranes (VSM) in 1 mm(2)/VSM thickness. In the histopathological study, the presence of infarcts, calcifications, hemorrhage, thrombosis, fibrosis, cysts, and edema was determined. Results:The weight and length of newborns at birth were greater in the group with PGOB (p < .01). We observed a lower number of VSM (29 +/- 9 versus 39 +/- 13 and 34 +/- 11) and a greater thickness (1.05 +/- 0.24 versus 0.95 +/- 0.08 and 0.89 +/- 0.09) and, therefore, a lower PMI (29.75 +/- 12.63 versus 40.88 +/- 15.25 and 39.28 +/- 14.4) in the group of women with PGOB compared with the group of women with OW or normal weight (p < .01). The histopathological analyses showed a greater frequency of edema and cysts in the PGOB group. Conclusion:PGOB is associated with a higher placental weight and newborn weight, a lower PMI, and the presence of histopathological alterations. The preceding points highlight the importance of promoting an appropriate pregestational weight in women of reproductive age.