New research published in the Lancet showed an extraordinary link between the father of an unborn child and a potentially dangerous condition, called pre- eclampsia, in the pregnant woman.
The longer the father has a sexual relationship with the mother before she conceives their child, the less likely she is to develop the condition, it shows.
Pre-eclampsia, which strikes mostly in the second half of pregnancy, leads to high blood pressure, swollen ankles and protein in the urine. If left untreated it can be fatal and is one of the main causes of maternal death in many western countries.
The joint US/French study investigated 957 women in the Caribbean who had babies at the University Hospital of Pointe-a- Pitre, Guadeloupe.
It found that the risk of developing the condition is significantly increased when conception occurs within the first year of a sexual relationship.
If a woman becomes pregnant within only four months she is nearly 12 times more likely to develop pre-eclampsia than if she lives with her man for more than a year before conception. And if she changes partners and has another child she increases the risk by five times.
Professor David Clark, from McMaster University, Ontario, Canada, said illness could be avoided if the woman lives with her partner for longer before becoming pregnant by him.
Exposure to semen from a woman's partner before conception apparently plays a vital part in prevention.
Doctors now think that some components of semen contain proteins that mimic those present in parts of the tissues linked to the growing foetus. If an immune response is directed against these proteins it may prevent proper development of the placenta.Reuse content