Management of Obesity and Pregnancy: What is the evidence

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Management of Obesity and Pregnancy What is the
evidence?

• A/Prof Leonie Callaway
• Obstetric Physician
• Royal Brisbane and Womens Hospital

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An evolving epidemic What do we do?
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Overview

• Preconception Care
• Interventions during pregnancy
• Current guidelines
• Monitoring/Screening
• Limiting weight gain
• Models of care
• Diet
• Exercise
• Metformin
• Aspirin
• Interconception Care

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Preconception Care

• Obesity is a modifiable risk factor which should
  be addressed in preconception care (Johnson et
  al. MMWR Recomm Rep 2006)
• BUT obesity AND unplanned pregnancy associated
  with poorer SES
• Poor compliance with simple preconception
  measures such as folic acid supplementation
• Some evidence of benefit from preconception care
  in women with pregestational diabetes (Wilhoite
  et al. Diabetes Care 2003)

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Preconception Care Weight loss prior to
pregnancy

• Evidence that weight loss improves pregnancy
  outcomes
• Population cohort study weight loss pre
  pregnancy reduces the risk of gestational
  diabetes (Glazer et al. Epidemiology 2004)
• Case control laparoscopic adjustable gastric band
  studies complication rates are similar to the
  non obese population (Dixon et al. Obstet
  Gynecol 2005)
• Randomized trial of the Health Hunters obesity
  prevention program targeted at risk women aged
  18-28 - one year supported diet and exercise
  improved weight and fitness (Eiben and Lissner.
  Int J Obesity 2006)
• Potential for well designed studies of
  preconception care programs aimed at addressing
  obesity

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Preconception Care Women in IVF clinics

• Prospective observational study Infertile obese
  women who lose weight have improved spontaneous
  ovulation, spontaneous pregnancy rates, response
  to fertility therapy, reduced miscarriage rates
  (Clark et al. Hum Reprod 1998)
• Potential for well designed studies
• Weight loss or bariatric surgery for obese women
  contemplating IVF
• Careful assessment for co-morbidity in obese
  women considering IVF (ie type 2 diabetes,
  vascular disease)

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Preconception Care Folic acid in obese women

• Are neural tube defects in obese women related to
  inadequate circulating levels of folic acid?
• Do obese women need higher doses of folic acid?
• No answers as yet epidemiological evidence that
  neural tube defects persist in obese women
  despite food fortification (Ray et al. BJOG
  2004)
• Needs further investigation

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Interventions in Pregnancy Current Guidelines

• American College of OG (2005)
• Height and weight measured in all women
• Weight gain guidelines (IOM)
• Dietary advice
• Consider screen for GDM at presentation
• Consider cardiac evaluation if BMIgt35
• Anaesthetic consultation
• Careful thromboembolism prophylaxis
• If not pregnant preconception counselling,
  provision of information regarding risk, weight
  loss prior to pregnancy

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Interventions in Pregnancy Current Guidelines

• RCOG Consensus View (2007)
• BMI should be measured in all pregnant women, and
  weight measured at every clinic visit
  interpregnancy weight change should also be
  recorded
• Diet, exercise and psychopathology should be
  attended to
• Women with a BMI of over 35 should not have
  infertility investigation or treatment until
  their BMI is less than 35, and ART should be
  reserved for women with a BMI under 30.
• Aspirin 75 mg/day from 12 weeks if BMIgt35
• Consider high dose folic acid (5mg per day)
• Consider antenatal thromboprophylaxis if
  additional risk factors
• Detailed anomaly scan
• GTT at 28 weeks

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Interventions during pregnancy
Monitoring/Screening

• Weighing pregnant women
• Early OGTT
• Early screening for vascular disease
• Anomaly screening
• High risk model of care with regular screening
  for preeclampsia early urinary protein
  estimation and baseline blood pressure
  measurement

All based on expert opinion, underpinned by good
data about increased risk in obese pregnant women
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Interventions during pregnancy Limiting weight
gain

• IOM guidelines 7-11.5 kg for overweight women
• 6 kg for obese women (Abrams et al. Am J
  Clin Nutr 2000)
• Cohort study (n245 526) Obese women who gained
  less than 8 kg had a reduced risk of PET, CS and
  LGA and an increased risk of SGA (Cedergren. Int
  J Gynaecol Obstet 2006)
• RCT 10 x 1 hour dietary counselling women in
  intervention arm had less weight gain (6.6 kg vs
  13.3 kg p0.002) and improved metabolic function
  (insulin, leptin, glucose) (Wolff et al. Int J
  Obesity 2008)
• RCT Stepped care, behavioural intervention,
  nutritional advice, encouragement to exercise
  FAILED to limit weight gain (Polley et al. Int
  J Obes Relat Metab Disord 2002)
• Current large RCT underway to examine important
  obstetric outcomes (Dodds, Crowther et al)

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Interventions during pregnancy Models of Care

• Guidelines support
• Multidisciplinary care (obstetricians,
  physicians, ultrasonographers, maternal-fetal
  medicine specialists, dieticians, physios,
  anaesthetists)
• Physical requirements (beds, theatre beds etc)
• High risk pregnancy care
• Need for health services research and detailed
  economic analysis of models of care
• Potential to examine the impact of models of care
  on pregnancy and neonatal outcomes

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Interventions during pregnancy Diet

• Most information about diet is extrapolated from
  women with GDM
• Recent Cochrane Review (2008) no clear evidence
  regarding benefits of low GI diets or low fibre
  diets in preventing gestational diabetes
• No RCTS in pregnancy of low fat vs higher protein
  diets

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Interventions during pregnancy Exercise

• One RCT in obese pregnant women
• Improved fitness (Santos et al. Obstet Gynecol
  2005)
• Cochrane review of exercise in pregnant women
  studies too small and methodologically flawed to
  make any conclusions
• Need for exercise interventions with adequate
  power to examine impacts on maternal and neonatal
  outcomes

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Interventions during pregnancy Metformin

• Only evidence regarding metformin relates to
  women with PCOS and women with GDM
• Potentially worth further investigation

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Interventions in pregnancy Aspirin

• Suggested in some guidelines
• Extrapolated from studies about preeclampsia
  prevention (Cochrane review)

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Interventions in Pregnancy Postpartum care

• Guidelines and expert opinions suggest
• Timely uterotonics
• Thromboprophylaxis
• Surveillance for infections
• Expert lactation support

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Interconception Care

• Modest amounts of weight loss between pregnancies
  can reduce the risk of GDM in subsequent
  pregnancies (Glazer et al. Epidemiology 2004)
• Guidelines suggest
• Nutrition counselling
• Exercise programs
• Weight management support
• Follow up of complications of pregnancy (eg
  hypertension, gestational diabetes)
• Important time in shaping family habits
• Potential for high quality interconception care
  trials

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Conclusions

• Some high quality evidence to guide our practice
• Most of our current practice is based on
  guidelines and opinion most of which seems
  sensible
• We need to contribute to expanding the evidence
  base to care for these women
• Pregnancy and establishment of a new family is a
  unique time period

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