Maternal Obesity Influences Placental Nutrient Transport, Inflammatory Status, and Morphology in Human Term Placenta

Maternal obesity has a significant impact on placental development. However, this impact on the placenta's structure and function (ie, nutrient transport and hormone and cytokine production) is a controversial subject.

We hypothesized that maternal obesity is associated with morphologic, secretory, and nutrient-related changes and elevated levels of inflammation in the placenta.

We collected samples of placental tissue from 2 well-defined groups of pregnant women from 2017 to 2019. We compared the 2 groups regarding placental cytokine and hormone secretion, immune cell content, morphology, and placental nutrient transporter expressions.

Placenta were collected after caesarean section performed by experienced clinicians at Centre Hospitalier Intercommunal (CHI) of Poissy-Saint-Germain-en-Laye.

The main inclusion criteria were an age between 27 and 37 years old, no complications of pregnancy, and a first-trimester body mass index of 18-25 kg/m2 for the nonobese (control) group and 30-40 kg/m2 for the obese group.

In contrast to our starting hypothesis, we observed that maternal obesity was associated with (1) lower placental IL-6 expression and macrophage/leukocyte infiltration, (2) lower placental expression of GLUT1 and SNAT1-2, (3) a lower placental vessel density, and (4) lower levels of placental leptin and human chorionic gonadotropin production.

These results suggest that the placenta is a plastic organ and could optimize fetal growth. A better understanding of placental adaptation is required because these changes may partly determine the fetal outcome in cases of maternal obesity.