Poster Australasian Diabetes in Pregnancy Annual Scientific Meeting 2013

INCREASING MATERNAL BODY MASS INDEX AND GESTATIONAL DIABETES MELLITUS – INDEPENDENT AND COMBINED EFFECTS ON PREGNANCY OUTCOMES (#114)

Casey Nottage 1 , Wendy Scheil 2 , Bill Hague 3 , Graeme Tucker 4 , Peter Clifton 5
  1. BakerIDI Heart and Diabetes Institute, Adelaide, SA, Australia
  2. Pregnancy Outcome Unit, Epidemiology Branch, SA Health, Adelaide, SA, Australia
  3. Robinson Institute, University of Adelaide, Women's and Children's Hospital, Adelaide, SA, Australia
  4. Health Statistics, Epidemiology Branch, SA Health, Adelaide, SA, Australia
  5. BakerIDI Heart and Diabetes Institute, Adelaide, SA, Australia

Background Increased maternal Body Mass Index (BMI) is a well-established risk factor for developing gestational diabetes mellitus (GDM). Obesity and GDM are also independently associated with adverse pregnancy outcomes (APO). Epidemiological examination of the independent and combined associations of these conditions with pregnancy outcomes is warranted.
Objectives To determine the independent and combined associations of GDM and obesity with pregnancy outcomes.

Methods Data from 58,233 singleton pregnancies from 2009-2011 in the South Australian Pregnancy Outcome Unit’s population database were reviewed. BMI was recorded prior to 20 weeks gestation in 42,153 (72.4%). Those with a BMI <18.5 kg/m2 or with pre-existing diabetes (n = 1,573) were excluded. The remaining 40,580 pregnancies were analysed using logistic regression models with interactions for 4 BMI categories and GDM (with adjustment for age, parity, ethnicity, smoking status and hospital type (where appropriate)), resulting in eight groups which allowed examination of the associations of hyperglycaemia only, increased BMI categories only and the combined effects of hyperglycaemia and increased BMI category.

Results For several APOs, such as induction, caesarean section, pregnancy induced hypertension, post-partum haemorrhage, maternal length of stay, need for special care or intensive care nursery admission, large for gestational age, macrosomic infants and infant length of stay, there was an increased odds ratio (OR) with increasing BMI category for all women, regardless of GDM status. There was also an increased OR for these outcomes for pregnancies complicated by GDM compared with non-GDM pregnancies within each BMI category. The highest ORs were seen in pregnancies with the double effect of obesity or severe obesity and GDM. In pregnancies not complicated by GDM there was an increase in OR for these outcomes with increasing BMI category.


Conclusions In this large population study, maternal obesity and GDM are associated with APO, both independently and when combined. The combination of obesity and GDM has a stronger association with APO than either factor alone.