In a bid to gain professional success, women could be risking the pleasures of being a mother. A recent study has revealed that work stress can upset the fertility of women and reduce their chances of having children.

Researchers at the University of Utah carried out an international comparison of women in 37 different populations and cultures.

On comparing the waist-to-hip ratio of the women, researchers found that those who had successful careers were more likely to have flatter figures. Career women are more likely to look like Keira Knightley than Marilyn Monroe.

Previous studies have linked curvaceous figures (where the hips are 30 percent or larger in circumference than the waist) with improved fertility in women.

According to the latest study, career-women are likely to have androgynous figures, which indicate higher levels of androgens, rather than oestrogen, which is imperative for conceiving successfully.

Professor Elizabeth Cashdan, an anthropologist at the University of Utah, says that the hormonal profile linked to a slim-waisted, non-curvy shape has been proved to favor women in "resource competition, particularly under stressful and difficult circumstances."

Women, who are striving for professional success and bear the inevitable work stress, suffer a hormonal shift. Their oestrogen levels get affected and there is a subsequent rise of androgens, the hormones linked to competitiveness and strength.

The research, published in a recent issue of the journal Current Anthropology, says that women with demanding careers usually have more boyish figures, which are negatively correlated to fertility.

A 2004 study had suggested that women with hourglass figures had 30 percent higher levels of the reproductive hormone, estradiol, as compared to women with flatter figures. The curvaceous ones were also three times more likely to get pregnant.

Cashdan says a small waist and large hips are beneficial for women.

Besides being naturally attractive, women who have a waist-to-hip ratio of 0.7 (which means the waist is 70 percent the size of the hips), are less prone to chronic diseases.

Women striving for professional success can shield their fertility from getting affected by practicing stress reducing methods like exercise, proper diet and a good social life.