Article Text

Maternal Medicine Posters
Clinical and metabolic profiles of very severely obese pregnant women and their associations with birth weight
  1. S Forbes1,3,
  2. RM Reynolds1,3,
  3. G Harold2,3,
  4. F Howie2,
  5. FC Denison2,3,
  6. JE Norman2,3
  1. 1Endocrinology Unit, BHF Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, United Kingdom
  2. 2MRC Centre for Reproductive Health, University of Edinburgh, Edinburgh, United Kingdom
  3. 3Tommy's Centre for Maternal and Fetal Health, University of Edinburgh, Edinburgh, United Kingdom


Introduction During gestation diminished maternal insulin sensitivity (IS) increases the availability of fuels allowing fetal growth. Class III obesity (OB; BMI≥40kg/m2) is associated with reduced IS but it is not known how nutrient availability differs and how this impacts on birth-weight versus normal pregnancies (CON).

Methods 213 OB (median(interquartile range) 43.2(41.1-46.3)kg/m2) and 87 CON (BMI 22.6(21.2-23.5)kg/m2) pregnant Caucasians had maternal anthropometrics, fasting glucose, NEFA and insulin concentrations recorded at 16, 28 and 36 weeks(wk). Premature births (4 OB, 1 CON) were excluded.

Results Weight gain (WG) was greater in CON vs. OB (10.4(7.6-13.0)kg vs. 5.2(2.4-8.3)kg; p<0.0001; 16-36wk). Glucose, NEFA and insulin were higher in OB vs. CON throughout pregnancy (p<0.0001). IS was lower in OB vs. CON (p<0.0001), decreasing with gestation (all p<0.02). Glucose peaked at 28wk: OB (16wk 4.5(4.2-4.7)mmol/l; 28wk 4.6(4.3-4.9)mmol/l; 36wk 4.5(4.1-4.8)mmol/l; p=0.05) and CON (16wk 4.2(4.1-4.4)mmol/l; 28wk 4.2(4.0-4.5)mmol/l; 36wk 4.1(3.9-4.3)mmol/l; p=0.0003). NEFA troughed at 28wk: OB (16wk 0.49(0.41-0.60)mmol/l; 28wk 0.44(0.37-0.55)mmol/l; 36wk 0.50(0.39-0.61)mmol/l; p=0.005) and CON (16wk 0.31(0.25-0.40)mmol/l; 28wk 0.29(0.22-0.36)mmol/l; 36wk 0.33(0.27-0.46)mmol/l; p=0.03). Birth weights after adjusting for gestational age, gender, parity, smoking and social-class were greater in OB 3610(3280-3980)g vs. CON 3600(3260-3860)g (p=0.03). In multivariate regression, 36wk glucose in OB (p=0.03) versus 28wk NEFA, BMI and WG in CON were associated with birth-weight (all p<0.05).

Conclusion OB women were more insulin resistant vs. CON during pregnancy, with greater glucose, NEFA and insulin concentrations and greater adjusted birth-weights. Glucose was associated with birth weight in the OB and NEFA in the CON which may indicate altered fetal preference for metabolites during these pregnancies.

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