(P10-006-24) Associations Between Glucose Concentrations in Pregnancy and Placental Weight and Lesions

Objectives: Gestational diabetes mellitus (GDM) affects 8.3% of live births in the US and is associated with a heavier placenta and more vascular malperfusion lesions, likely due to higher blood glucose. We aimed to examine relationships between glucose concentrations, screening tests, and placental outcomes, hypothesizing that maternal glucose is related to placental outcomes even in pregnancies without GDM.

Methods: We conducted secondary analysis of medical record data, from singleton pregnancies with placentas sent to pathology at Northwestern Memorial Hospital from 2011-2022 (n=12,546). Data included maternal demographic data, glucose challenge test concentrations (GCT), diagnosis of GDM, and pathology reports with placental weight and vascular malperfusion lesions: accelerated villous maturation, delayed villous maturation, increased syncytial knots, and increased perivillous fibrin deposition. We categorized glucose groups: pass/pass (GCT <140 mg/dL and no GDM diagnosis), fail/pass (GCT ≥140 mg/dL and no GDM diagnosis), and fail/fail (GCT ≥140 mg/dL and GDM diagnosis). We examined the relationship between GCT and glucose groups with placental weight using linear regression, and the relationship between GCT and glucose groups with malperfusion lesions using log binomial regression. All models were adjusted for maternal age, race, parity, gestational age at birth, and infant sex.

Results: Of placentas sent to pathology, 4.9% were from pregnancies diagnosed with GDM. Overall mean (SD) placental weight was 431.1 (112.4) g and prevalence of any malperfusion lesion was 53%. For every 10 mg/dL increase in GCT, adjusted mean placental weight was 3.2 g (95% confidence interval: 2.6, 3.8) higher. Both fail/pass (adjusted mean difference: 13.2 [8.4, 17.9] g) and fail/fail (adjusted mean difference: 22.6 [13.9, 31.4] g) groups had higher placental weight compared to pass/pass. GCT and glucose groups were not associated with placental lesions (p>0.05).

Conclusions: Continuous glucose concentrations and a failed screening test (with or without GDM) were associated with placental weight, but not placental lesions.

Funding Sources: Medical chart extraction was conducted within existing NIBIB R01 granted to The Pennsylvania State University and Northwestern University (1R01EB030130-01A1).