Brief sexual relationships 'increase health risks for mother and baby'

Published on Friday 13 November 2009 21:23

WOMEN are more likely to have complicated pregnancies and underweight babies if they have been sleeping with the father for less than six months, new research claims.

The controversial findings of the medical study suggest the risks are halved for mothers who have had longer sexual relationships with the biological father of their child.

Mothers who suffered from the potentially dangerous pregnancy condition pre-eclampsia were twice as likely as other women to have been in a relationship of six months or less with the father.

They also run a similarly greater risk of giving birth to underweight infants, said the study of 2,500 mothers by researchers from the University of Auckland in New Zealand. The researchers, from the obstetrics, gynaecology and biochemistry departments, said they knew their findings would be seen as controversial.

Pre-eclampsia is a form of hypertension brought on by pregnancy and can lead to complications with childbirth. It is often seen as a problem with first-time mothers.

But the study, published in the Journal of Reproductive Immunology, suggests new partners rather than becoming a new mother may be a major factor.

The obstetrics team behind the study believe long-term relationships help women's immune systems to build up a tolerance to proteins called antigens in a man's sperm.

It takes time to do this and, for those getting pregnant, a relationship of less than six months with the biological father was less likely to succeed in creating the immunity.

Without this protection from what are called "paternal antigens", a woman's immune system cannot cope and can react violently during pregnancy, with even organ failure a possibility.

This also means women who have been with their partners for more than six months, but who have used condoms during that time, would not enjoy the same protection as they might through exposure to sperm.

The report said: "Women who developed pre-eclampsia had a shorter duration of sexual relationship (than the others].

"Compared with (the others] women with pre-eclampsia were twice as likely to have a relationship of less than six months.

"Although the issue of whether prolonged semen exposure does protect against developing pre-eclampsia is not yet resolved, this paper seems to tip the weight of evidence back in favour of suggesting that prolonged semen exposure is protective."

Much research is being carried out to find the causes of treatment of pre-eclampsia.

Mild pre-eclampsia affects around one in 14 women, and usually occurs after the 20th week of pregnancy.

The condition does not always need treatment, and in many cases regular check-ups are all that is required.

While drugs can be used to reduce blood pressure, this does not prevent it.

The only cure is to deliver the baby, but this can cause problems if it means the child is born very prematurely.

About one in 100 women with pre-eclampsia develop the serious complication eclampsia.