Relation between pregestational obesity and characteristics of the placenta.

To evaluate the morphology of the placenta in patients with pregestational overweight (OW), pregestational obesity (PGOB), or normal weight. A cross-sectional study including women ( = 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), 30 were overweight (25-29.99 kg/m), and 33 women were obese (≥30.0 kg/m). 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/VSM thickness. In the histopathological study, the presence of infarcts, calcifications, hemorrhage, thrombosis, fibrosis, cysts, and edema was determined. The weight and length of newborns at birth were greater in the group with PGOB ( < .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 ( < .01). The histopathological analyses showed a greater frequency of edema and cysts in the PGOB group. 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.