The research was presented a the Royal College of Obstetrics and Gynaecology in Montreal, Canada by Winnie Lo - a clinical nurse specialist from St Mary's Hospital, UK.
The links between obesity and problems conceiving and complications during pregnancy are already well known. However, this study looks specifically at recurrent miscarriage - often a mystery.
The research team followed 696 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.
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.
However, researchers warn that crash diets during pregnancy are potentially harmful. Weight should be lost before pregnancy.
