Intended for healthcare professionals

Practice ABC of obesity

Obesity and reproduction

BMJ 2006; 333 doi: (Published 30 November 2006) Cite this as: BMJ 2006;333:1159
  1. Jane E Ramsay, consultant obstetrician and gynaecologist1,
  2. Ian Greer, professor of obstetrics and gynaecology2,
  3. Naveed Sattar, professor of metabolic medicine2
  1. 1Ayrshire Maternity Unit, Kilmarnock
  2. 2University of Glasgow
  1. Correspondence to: Naveed Sattar nsattar{at}

The effect of adiposity is manifest in nearly every aspect of female reproductive life, whether as a metabolic or reproductive complication or as a technical problem affecting clinical issues such as ultrasonography or surgery. Indeed, obesity is present in 35% of maternal deaths in the United Kingdom.

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Potential effects of adiposity before and during pregnancy

Such concerns are particularly important given recent evidence of a doubling in the prevalence of obesity in young women attending for antenatal care in maternity hospitals in the UK (in some places, almost one in five are now obese). In the United States, where obesity rates are generally even higher, the American College of Obstetricians and Gynecologists has issued guidance on the impact of obesity on pregnancy.

Gynaecological concerns

Strong evidence shows that insulin resistance is an integral part of polycystic ovarian syndrome, especially in obese women. In most women with the syndrome, hyperinsulinaemia—driven or revealed by excess weight gain—promotes ovarian androgen secretion and abnormal follicular development, leading to dysfunctional ovarian and menstrual activity.

Endocrine and clinical effects of obesity and insulin resistance in. Adapted from Harborne et al. Lancet 2003;361:1894-901

Androgens are carried in the circulation bound to sex hormone binding globulin (SHBG). Conditions of high androgen and insulin concentrations are associated with lower levels of SHBG, resulting in high free androgen activity. Thus, clinical manifestations of polycystic ovarian syndrome are associated with androgen activity and include hirsutism, acne, and alopecia, as well as oligomenorrhoea and ovulation failure.

Medications that contain oestrogen (such as the combined contraceptive pill) or ovulation induction drugs (resulting in high levels of endogenous oestrogen) may be associated with an increased risk of venous thromboembolism in obese women. The combined effect of obesity and the combined contraceptive pill results in a 10-fold increased risk of venous thromboembolism in women with a body …

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