Screening placentas may save more babies, local study shows

SINGAPORE - Substances in abnormal placentas, which can put women at high risk of miscarriages, have been identified as possible biomarkers in screening tests - paving the way for doctors to identify such women before their pregnancies run into trouble.

This finding came from a local study in which placentas - the nutrient-supply organ which connects mother to child - were collected from four groups of women just after they gave birth at National University Hospital (NUH).

One group was made up of six women with pre-eclampsia (pregnancy-induced hypertension), while another comprised nine pregnant women who previously had two or more miscarriages before the fifth month of pregnancy.

The miscarriages in these women were caused either by an overactive immune system which prevented the foetus - considered a foreign body because it contains cells from the father - from attaching to the womb or by "sticky blood" syndrome in which clots clog up the blood vessels running through the placenta, cutting off blood flow to the baby.

In the study, published in the journal Placenta in February last year, but was not released to the media until now, these two groups of patients were matched with healthy pregnant women of similar maternal and gestational age as controls.

The 15 women who were in danger of miscarriage received treatment and all 30 gave birth normally.

Dr Sheila Vasoo, a visiting consultant at NUH, said the 15 mothers needed treatment because the placenta cannot develop properly if the mother-to-be has high blood pressure or blood-clotting disorders.

These give rise to placentas which are highly inflammatory and constantly shed microparticles into the bloodstream. The research team also found that the particles shed could alter the woman's immune reaction to the foetus, which would then pose a danger to the foetus.

Dr Vasoo led the 10-member research team from NUH and the National University of Singapore in the three-year study.

They found that these microparticles had more clotting proteins - hence giving rise to "sticky" blood - as well as lower levels of a type of protein needed for cells to repair themselves.

Insufficient cell repair can cause the placenta to malfunction, leading to an increased chance of adverse pregnancies, she said.

Women in the risky groups, compared with those from the healthy groups, also had a different fat content in their microparticles.

The fat molecules were linked to pathways which caused inflammation and clotting, threatening the health of the placenta.

But while people with heart disease can take cholesterol-lowering drugs to alter the abnomal fat content in the microparticles, the same drugs cannot be given to women with high-risk pregnancies, as doctors do not know how they would impact the foetus' brain development.

With these biomarkers, it is hoped that doctors can take a proactive approach in detecting high-risk pregnancies and watching the women more closely, with the eventual aim of saving more babies, she added.

Professor Arijit Biswas, one of the study's authors and head of the division of maternal fetal medicine at NUH, said these findings will provide researchers "more insight into developing methods to predict poor foetal outcome and, perhaps in time to come, identify new methods to mitigate the effects of these lipids (fats) on the microparticle surface".

joanchew@sph.com.sg


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