Gestational Diabetes Mellitus Enhances In-Utero Fetal Overgrowth in Female Offspring from Obese Black Women

Obesity (body mass index (BMI) ≥30.0 kg/m 2 ) is a significant health concern among women of childbearing age and is a known risk factor for gestational diabetes mellitus (GDM). Mississippi reports a high prevalence of obesity (40.8%), with Black individuals disproportionately affected. Research indicates that GDM and increasing maternal BMI separately correlate with maternal and neonatal morbidity and large for gestational age (LGA) offspring. LGA infants face long-term cardiometabolic risks. Our lab found that maternal obesity in Black and White women increases offspring birthweight compared to offspring from Black and White women with normal BMIs. Interestingly, we found that compared to offspring from obese White women, offspring from obese Black women have enhanced excess birthweight as maternal obesity status increases. Furthermore, we found that obese Black women are at greater risk of developing GDM. Yet, the combined effects of maternal obesity and GDM on offspring from Black women are not well defined. Thus, this study tested the hypothesis that combined prenatal maternal obesity and GDM exacerbate excess fetal growth in offspring from Black women. We assessed fetal growth by ultrasound and birth records from adult obese Black women with (n=50) and without (n=50) GDM at the University of Mississippi Medical Center. These women were singleton pregnancies with no other underlying chronic health conditions. There were no differences in maternal BMI, pregnancy weight change, or gestational age between groups (Table 1). Our data indicated that at ≤32 weeks gestation, estimated fetal weight and abdominal circumference did not differ. However, at ≥32 weeks gestation, estimated fetal weight was higher in fetuses of obese mothers with GDM compared to fetuses of obese mothers without GDM (2703 ± 459.3g vs. 2465 ± 533.1g; p<0.05). Estimated abdominal circumference, a marker of cardiometabolic disease risk, was also larger in these fetuses (317.6 ± 21.49cm vs. 302.8 ± 26.03cm; p<0.05). This difference was maintained until birth, and offspring from obese mothers with GDM had elevated birthweight versus offspring from women without GDM (3462 ± 517.4g vs. 3178 ± 381.5g; p<0.05). Female and male offspring from women with obesity and GDM were larger than females from women with obesity alone (GDM Female: 3447 ± 512.2g, GDM Male: 3472 ± 529.9g vs. Obese Female: 3122 ± 364.1g; p<0.05). This study indicates that combined obesity and GDM enhance excess fetal growth from late gestation to birth, promoting cardiometabolic risk in offspring. Additionally, the study suggests that maternal metabolic health in Black women impacts female offspring growth in utero more than males. In conclusion, our findings highlight that the perinatal in-utero environment programs offspring cardiometabolic health. However, more studies are necessary to determine the physiological mechanisms and racial differences underlying enhanced in-utero fetal overgrowth to guide prenatal care. Department of OBGYN and The Mississippi Center of Clinical and Translational Research This abstract was presented at the American Physiology Summit 2025 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.