The study involved 2,507 first-time pregnant women. The researchers quizzed the women about the length of time they had been in relationship with their baby's biological father. Women who were in long-term relationships with their partners had lesser chances of suffering from a condition called pre-eclampsia, which is the occurrence high blood pressure during pregnancy.

Furthermore women in steady relationships were also less likely to deliver smaller babies as compared to women who had gotten pregnant after a whirlwind courtship.

Dr Larry Chamley, the lead author of the study, who is a Associate Professor of Obstetrics and Gynaecology at Auckland, said that these findings lend credence to theories that women were helped by prolonged exposure to "paternal antigens", which are found in the sperm. "This paper seems to tip the weight of evidence back in favour of suggesting that prolonged semen exposure is protective," he added.

The details of the study are published in the Journal of Reproductive Immunology.

The researchers also report that women in short-term relationships tended to have undersized babies. While the report is based on a relatively small sample, it does provide yet another reason for women to be in a steady relationship. Not only does it result in mental peace, but it is also likely to give women a chance to conceive healthy kids.