396 - Placental Pathology and Fetal Growth in Pregnancies Complicated By Obesity

Poster Number: 396
Publication Number: 396.134

Samantha Hietalati, University of California - San Diego, La Jolla, CA, United States; Donna Pham, UC San Diego Jacobs Medical Center, Fountain Valley, CA, United States; Harneet Arora, University of California, San Diego School of Medicine, Stevenson Ranch, CA, United States; Marina Mochizuki, University of California, San Diego, La Jolla, CA, United States; Gisselle Santiago, University of California, San Diego, La Jolla, CA, United States; Jordan E. Vaught, UCSD, San Diego, CA, United States; Erika Lin, University of California, San Diego School of Medicine, San Diego, CA, United States; Karen Mestan, University of California, San Diego School of Medicine, San Diego, IL, United States; Mana M. Parast, University of California San Diego, La Jolla, CA, United States; Marni Jacobs, University of California, San Diego, San Deigo, CA, United States

Background: Obesity has been described as an inflammatory condition with resulting systemic effects. In combination with pregnancy, obesity is associated with several comorbidities and pregnancy complications, but specific effects of obesity on the placenta and the potential downstream effects on fetal growth have not been well-studied. We sought to explore the relationship between obesity, placental pathology, and fetal growth.

Objective: To evaluate the placental pathologies associated with obesity in pregnancy and possible effects on fetal growth.

Design/Methods: A cohort of 1467 women with singleton pregnancies from 2011-2020 was identified from an ongoing obstetric registry, with available placental pathology data, as well as demographic, obstetric, and neonatal variables. Maternal weight categories were defined as: normal weight (BMI < 25) and obese (BMI ≥30) based on earliest weight recoded during gestation; the overweight category (BMI 25-29.9) was excluded for the purposes of this analysis. Associations between obesity, placental pathology, and fetal growth were assessed.

Results: Pregnancies from 573 normal weight and 536 obese women were included. Maternal obesity was associated with large-for-gestation (LGA) placental disc (12% vs. 6%), increased incidence of decidual vasculopathy (DV; 37% vs. 11%), accelerated villous maturation (AVM; 19% vs. 14%), intervillous thrombi (IVT; 15% vs. 7%), chronic villitis (CV; 19% vs. 13%), and normoblastemia (40% vs. 25%). Of these, AVM, DV, and normoblastemia were associated with small for gestational age (SGA) infants, irrespective of obesity. In the setting of obesity, however, AVM appeared to have a more significant effect on fetal growth, decreasing mean birthweight percentiles from 37.6 to 27.0 in normal weight mothers, but from 54.3 to 31.9 in obese mothers (p=0.01).Conclusion(s): Maternal obesity is associated not only with placental inflammation (CV), but also with evidence of maternal vascular disease (DV), abnormal placental development (AVM), abnormal maternal blood flow in the placenta (IVT), and intrauterine hypoxic stress (normoblastemia). Our analysis suggests that while obese patients are more likely to have LGA babies, in the presence of specific patterns of placental injury (namely AVM), there could be a more severe blunting of fetal growth. Future analyses will focus on the effects of placental pathology on neonatal outcomes, beyond birthweight.