A LEADING cause of maternal death, pre-eclampsia, usually affects only first-time mothers. But Kristy Herd has endured the traumatic condition, where the mother's immune system rejects the foetus, in all three of her pregnancies.
Mrs Herd's first child, Breanna, died at 14 months from brain cancer, and her five-week-old daughter, Hayley, is in the neonatal unit of Nepean Hospital. Mrs Herd, 38, also had pre-eclampsia while pregnant with her son Declan, who is now a healthy eight-year-old.
The only remedy for the disease is to deliver the baby, usually prematurely.
''This is a really traumatic condition,'' Mrs Herd, from Werrington, said. ''With Hayley, I woke up with some pain in my belly at 29 weeks, went in to hospital, and about 40 minutes later I was getting an emergency C-section. My partner wasn't there with me, my placenta ruptured, I lost a lot of blood and ended up in intensive care - I think I'm only just starting to get over it all.''
But there is now hope for detecting the condition before the symptoms of high blood pressure and swelling appear, following a study by University of Sydney researchers.
The study, published in this month's Journal of Reproductive Immunology, found the thymus - an organ of the immune system which sits behind the breastbone - was ''significantly'' smaller in foetuses where the mothers went on to develop pre-eclampsia.
The senior author of the study, Ralph Nanan, said doctors have no clinical marker to predict the condition before onset, though first pregnancies and obesity were risk factors. ''We think pre-eclampsia is an immune disease, as the mother's immune system rejects the foetus for unknown reasons,'' said Professor Nanan, from Sydney Medical School Nepean.
''So it is quite exciting to find that the thymus, the central immune organ of the foetus, is much smaller in pre-eclampsia children than children from healthy pregnancies.
''But we don't know yet what causes the thymus to be smaller in some children.''
Pre-eclampsia affects up to 10,000 Australian women each year, can be fatal to mother and child, and can lead to cerebral palsy, vision and learning problems in the child and seizures or coma in the mother.
The study looked at 53 pre-eclamptic and 120 healthy pregnancies and measured foetal thymus size between 17 and 21 weeks gestation.
Professor Nanan hopes further studies will allow doctors to pre-empt the disease. ''This would be particularly important for women in regional areas who may not be close to hospitals that can deal with complicated births,'' Professor Nanan said. ''Doctors could put a high-risk management plan in place from an earlier stage of pregnancy.''
The researchers are now conducting a prospective study of 1200 pregnant women to strengthen the findings and hope to develop a test for pre-eclampsia. They will also look at the relationship between the developing thymus and immune diseases and allergies.