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63: Macrosomia has roots in early placental development

      Objective

      Macrosomia (MACRO: ≥4000g) is associated with adverse neonatal outcomes and has been associated with modifiable risk factors such as weight gain and glycemic control. An early predictor of MACRO may identify patients for whom effective interventions can reduce their risk of macrosomia. We sought to determine if early placental size may be associated with the development of macrosomia.

      Study Design

      3D ultrasound volume sets were obtained at 11-14 weeks (N=578) and at 20-22 weeks (N=373) in a prospective cohort of singleton pregnancies. VOCAL (4DVIEW, GE) was used to calculate placental volume (PV). PV was normalized to gestational age to yield placental quotient (PQ). In addition, mean placental diameter (MPD) was the mean of 4 traced measurements of the maternal surface of the placenta taken every 45° degrees around the placental circumference. Potential confounders were included in multivariable regression models for the prediction of MACRO.

      Results

      7.6% (44/587) of our cohort had a MACRO infant. MACRO was associated with a higher median maternal age (33 vs 32y; P=0.09) and BMI (26.4. vs 24.6; P=0.01), a lower rate of nulliparity (4.6% vs 19.9%, P=0.01) and a higher rate of diabetes (6.8% vs 2.1%, P=0.08). Race was not significantly associated with MACRO (P=0.37). Both 1st and 2nd trimester placental measures were significantly associated with the development of MACRO (Table). These associations remained significant after adjusting for potential confounders. ROC analysis showed no significant difference in the predictive ability of the various adjusted models (P>0.05). Thus, 1st trimester placental measurements were similarly predictive of MACRO as 2nd trimester measures.

      Conclusion

      Early placental size is associated with the development of macrosomia even after adjusting for potential confounders. A non-invasive, point-of-care test that can identify those at greatest risk of MACRO may be useful in allowing for targeted counseling and interventions regarding diet, weight gain and diabetes screening that may impact pregnancy outcomes.
      Tabled 1
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      *Descriptive data expressed as median (interquartile range); **1st trimester models adjusted for nulliparity, BMI, and DM; 2nd trimester models adjusted for nulliparity and DM.