Maternal obesity
Risks of obesity in pregnancy by BMI class, preconception care (5 mg folic acid, drug-specific washout for GLP-1 receptor agonists and tirzepatide, bariatric surgery timing), weight gain targets and the LIMIT trial, early diabetes testing, aspirin, VTE scoring, anaesthetic and birth planning, and postpartum follow-up.
Tier 1Condition
Written with AI assistance and fact-checked against the sources below. For exam study, not clinical decisions. How notes are made
At a glance
- Obesity is a BMI of 30 kg/m2 or more at the first antenatal visit. About 45% of Australian women are overweight or obese when they become pregnant (RANZCOG 2022).
- Almost every complication becomes more common, and risk rises with BMI class. Stillbirth risk is raised even in class I.
- Preconception: aim for weight loss, take 5 mg folic acid and 150 µg iodine, stop weight-loss drugs, and screen for diabetes, hypertension and sleep apnoea.
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Sources
- Mounjaro (tirzepatide) Australian Product Information, sections 4.5 and 4.6 (oral contraceptives; stop at least 1 month before a planned pregnancy)AU/NZmedsinfo.com.au (sponsor Product Information), October 2026
- Ozempic (semaglutide) Australian Product Information, section 4.6 (stop at least 2 months before a planned pregnancy)AU/NZmedsinfo.com.au (sponsor Product Information), November 2026
- Management of obesity in pregnancy (C-Obs 49)AU/NZRoyal Australian and New Zealand College of Obstetricians and Gynaecologists, March 2022 (review due March 2027; no newer version found November 2026)
- Australian Pregnancy Care Guidelines (weight, BMI and gestational weight gain)AU/NZLiving Evidence for Australian Pregnancy and Postnatal Care, funded by the Australian Government Department of Health, Living guideline, 2024 onwards
- VTE risk assessment table (adapted from RCOG Green-top guideline 37a)AU/NZSociety of Obstetric Medicine of Australia and New Zealand, Current SOMANZ resource (uploaded 2024)
- Obesity in pregnancy: ACOG Practice Bulletin No. 230American College of Obstetricians and Gynecologists, Obstet Gynecol 2021;137:e128-44, 2021
- Use of glucagon-like peptide-1 receptor agonists in pregnancy and lactation (practice advisory)American College of Obstetricians and Gynecologists, October 2026
- Wegovy (semaglutide) and Mounjaro (tirzepatide) summaries of product characteristics, section 4.5 and 4.6European Medicines Agency, Current EPAR product information, accessed November 2026
- Mounjaro (tirzepatide) prescribing informationUS Food and Drug Administration, 2022 label, section 7.2 and 8.3
- Antenatal lifestyle advice for women who are overweight or obese: LIMIT randomised trialDodd JM et al., BMJ 2014;348:g1285, 2014
- Last updated
- 14 November 2026
What changed
- 14 November 2026 Personal emails, About story and Australian-style copy