"Obesity has become a major health problem across the world. In the UK, obesity affects one‐fifth of the female population ( Anonymous, 2001 ). Maternal obesity has been reported as a risk factor for adulthood obesity in offspring ( Parsons et al ., 2001 ). Obesity may also lead to a poor pregnancy out-come, such as sudden and unexplained intrauterine death ( Froen et al ., 2001 ), and in women with polycystic ovary syndrome (PCOS) receiving infertility treatment is associated with an increased risk of miscarriage ( Hamilton‐Fairley et al ., 1992 ; Wang et al ., 2000 ). However, in the general population there is less evidence for a link between obesity and spontaneous miscarriage ( Risch et al ., 1990 )."