New clues for complications in pregnancy
Izelle Theunissen, MRC News
Scientists at the MRC's Perinatal Mortality Research Unit have found that the
father may contribute to the mother of a baby developing pre-eclampsia.
Every minute a woman dies in pregnancy or childbirth - and 99 out of every 100
of these women live in developing countries. Among deaths from causes which are
directly attributable to complications of pregnancy (other than abortion), about
25% are associated with pre-eclampsia (pregnancy-induced high blood pressure).
According to Prof. David Hall of the MRC's Perinatal Mortality Research Unit,
pre-eclampsia can lead to failure of the kidneys and liver as well as
convulsions. "But whereas pre-eclampsia affects first pregnancies of
patients in developed countries, our research has shown that here, as in other
developing countries, it's a disease affecting subsequent pregnancies," he
says.
In research findings published recently in the International Journal of
Gynecology and Obstetrics, Prof. Hall and colleague Dr Gideon Verwoerd offer an
interesting explanation for this phenomenon.
They studied a group of 120 women who had had more than one pregnancy and a
group of 100 women who were pregnant for the first time. "We've found the
length of unprotected sexual exposure to the father of the baby to be very
important. If the woman had been having unprotected intercourse with the father
of the baby for longer than 6 months before conception of the child, she is less
likely to develop pre-eclampsia," says Dr Verwoerd.
According to Prof. Hall, this may be explained by the achievement of
immunological tolerance towards the new partner after at least 6 months of
unprotected sex. "Sperm cells, like almost all human tissue, can elicit an
immune response. But if the woman is exposed to the sperm cells for long enough,
she 'develops tolerance' to the cells and is therefore at lower risk of
developing pre-eclampsia," he explains.
The study team also investigated the influence of primipaternity (having a new
father in the index pregnancy) on the incidence of pre-eclampsia. After taking
risk factors such as smoking, age and previous hypertension in pregnancy into
account, they found that primipaternity had no significant influence on the risk
of pre-eclampsia. Their uncorrected data indicated, however, that both
primipaternity and length of sexual cohabitation raised the risk of the woman
developing pre-eclampsia.
The scientists are quick to point out that immunological tolerance and
primipaternity are but two of the many factors that can influence whether or not
a pregnant woman develops pre-eclampsia. "It's a combination of many
factors. If she had pre-eclampsia with a previous pregnancy, or if her mother
developed pre-eclampsia during her pregnancies, it increases a woman's risk. If
she suffers from underlying hypertension or kidney disease, it increases her
risk. This isn't the whole answer, but it's part of the picture, which is
becoming clearer," Prof. Hall says.
Article courtesy of the MRC news
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