A potentially life-threatening pregnancy complication is linked with a gene mutation but women can lower their risk by controlling weight when they are expecting, Australian researchers say.
Pre-eclampsia involves high blood pressure and fluid retention and can cause damage to the kidneys and liver. About 7% of pregnancies are affected by pre-eclampsia.
The researchers say they have found a genetic variant involving the AGT2R gene, which may predispose women to pre-eclampsia.
However, the genetic variant is only associated with pre-eclampsia when the pregnant mother is overweight or obese.
Overweight or obese women who developed pre-eclampsia were twice as likely to have the gene variation, as were their male partners. Their babies were three times more likely to carry the variant, the study found.
"This is a condition that can run in families," said Professor Claire Roberts from the University of Adelaide's Robinson Institute.
"With both the mother and the father passing on their variant genes to their children, this places the child at greater risk of parenting a pre-eclamptic pregnancy.
Professor Roberts says the genetic variant is linked with restricted blood flow to the placenta.
"Impaired blood flow in the uterine artery is characterised by a 'notching effect' that appears on a Doppler ultrasound at 20 weeks gestation. Uterine artery notching has previously been associated with .pre-eclampsia, and this restricted blood flow is due to impaired placental development," Professor Roberts said.
The researchers say the genetic variant has only a subtle effect in women of normal weight, but in overweight and obese women it appears to independently contribute to the risk of pre-eclampsia.
"Understanding this association could help to predict which women are likely to develop pre-eclampsia," Professor Roberts said.
"However, it also helps to reinforce the message that a normal weight prior to pregnancy will lower the risk of serious complications - being overweight or obese increases the risk of complications,” she added.
The study has been published online in the journal Placenta.