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/m²), 30 were overweight (25-29.99 kg/m²), and 33 women were obese (≥30.0 kg/m²). 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 mm²/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.