Obesity linked to repeated miscarriages

Sep 23 2008

Research carried out by specialists in Britain has found that women who have experienced a number of miscarriages are more likely to continue to miscarry if they are obese - they say obesity significantly increases the risk of further miscarriages.

A study carried out at St Mary's Hospital, Imperial College, London, set out to investigate the effect of body mass index (BMI) on unexplained recurrent (three or more) miscarriages.

The study involved 696 women who attended a specialist clinic between 1996 and 2007 - all had undergone comprehensive investigations along with their partners and those for whom no identifiable cause could be established for miscarrying, were classed as "unexplained" recurrent miscarriage.

At their first consultation each woman had her BMI measured and was placed into one of four categories: underweight; normal; overweight; and obese.

Of the women, more than half were of normal weight, 30% were overweight, and 15% were obese, meaning they had a body mass index (BMI) of 30 or above.

The older the woman, the higher chance she had of having another miscarriage, but, when the figures were adjusted to account for this, obesity emerged as another possible factor.

The researchers found that while there was no difference in the miscarriage rates for overweight, normal and underweight women, the risk of further miscarriage increased sharply for obese women.

Winnie Lo, a clinical nurse specialist at St Mary's says this is the first study to look directly at the link between BMI and recurrent miscarriage and it shows that obese women who experience recurrent miscarriage are at greater risk of subsequent pregnancy loss.

Nurse Lo says all women with recurrent miscarriage should be weighed at their first consultation and those who are found to be obese should be counselled regarding the benefits of weight loss in increasing their chances of a successful pregnancy and programmes should be put in place to help with the weight loss process.

Experts in obesity warn that trying to lose weight when already pregnant is potentially dangerous and they recommend trying to lose weight before trying to become pregnant.

The research was presented by Nurse Lo at the Royal College of Obstetricians and Gynaecologists (RCOG) 7th International Scientific Meeting in Montreal.