A new cheap test could predict a woman’s risk of having a premature birth or preeclampsia in the first half of pregnancy, scientists said.
The accurate test carried out between 15 and 20 weeks would allow doctors to start treatments early to prevent early births or complications later in pregnancy.
In doing so, researchers say it could curb the leading cause of death in children under five in America (premature birth), and the leading direct cause of maternal death (preeclampsia).
Currently there is a test for premature births but it is expensive and only screens for spontaneous preterm birth, not for signs that could lead to indicated preterm births or for preeclampsia.
The accurate test carried out between 15 and 20 weeks would allow doctors to start treatments early to prevent early births or complications later in pregnancy
Preeclampsia is a potentially fatal pregnancy complication marked by a mother’s high blood pressure that affects some women usually during the second half of pregnancy from around 20 weeks.
It affects up to eight percent of pregnancies in the US, and two percent in the UK.
About one in 10 US babies are born premature, compared to eight in 100 British babies – meaning they are delivered before their 37th week of gestation.
They are at increased risk of death, respiratory problems, cerebral palsy and other neurological problems, as well as the risk of longer term developmental problems.
Preterm birth is often associated with inflammation and has many potential causes, including an acute infection in the mother, exposure to environmental toxins, or chronic conditions like hypertension and diabetes.
The new test developed by University of California San Francisco scientists screens for 25 biomarkers of inflammation and immune system activation, as well as for levels of proteins that are important for placenta development.
If you or someone you know is pregnant, or has just had a baby, be sure to watch for these signs of preeclampsia:
- water retention
- swelling in the legs
- abnormal amount of protein in urine
- elevated blood pressure
Combined with information on other risk factors, such as the mother’s age and income, the test can predict whether a woman is at risk for preterm birth with more than 80 percent accuracy.
In the highest risk pregnancies of premature births before 32 weeks or in women with preeclampsia, a potentially fatal pregnancy complication marked by high blood pressure in the mother, the test predicted nearly 90 percent of cases.
The comprehensive test captures both spontaneous preterm births, which occurs when the amniotic sac breaks or contractions begin spontaneously, and ‘indicated’ preterm birth, in which a doctor induces labor or performs a cesarean section because the health of the mother or baby is in jeopardy.
Associate professor of epidemiology and biostatistics Dr Laura Jelliffe-Pawlowski said: ‘There are multifactorial causes of preterm birth, and that’s why we felt like we needed to build a model that took into account multiple biological pathways
‘The model works especially well for early preterm births and pre-eclampsia, which suggests that we’re effectively capturing severe types of preterm birth.’
The screen was developed from blood samples taken from 400 women as part of routine prenatal care during the second trimester, comparing women who went on to give birth before 32 weeks, between 32 and 36 weeks, and after 38 weeks (full-term).
Researchers first tested the samples for more than 60 different immune and growth factors, ultimately narrowing the test down to 25 factors that together could help predict risk for preterm birth.
When other data, including whether or not the mother was over 34 years old or if she qualified as low income, improved the accuracy of the test by an additional six per cent.
The test could help prevent some cases of preterm birth.
Based on a woman’s probability of preterm birth derived by the test, she could discuss with her doctor how best to follow-up and try to lower her risk.
Some cases of preterm birth, including those caused by preeclampsia, can be prevented or delayed by taking aspirin, but treatment is most helpful if started before 16 weeks.
Doctors could also evaluate high-risk women for underlying infections that may have gone undetected but could be treated.
For others, close monitoring by their doctor could help flag early signs of labor like cervical shortening that can be staved off with progesterone treatment.
Dr Jelliffe-Pawlowski added: ‘We hope that this test could lead to more education and counselling of women about their level of risk so that they know about preterm birth and know what preeclampsia or early signs of labor look like.
‘If we can get women to the hospital as soon as possible, even if they’ve gone into labour, we can use medications to stave off contractions.
‘This might give her some additional days before she delivers, which can be really important for the baby.’
Dr Jelliffe-Pawlowski said the new screen would likely be a fraction of the cost, making it more accessible to women who need it the most.
She said: ‘One of the reasons we’re most excited about this test is that we see some potential for it addressing preterm birth in those most at risk, including low-income women, women of colour, and women living in low-income countries.
‘We want to make sure that we’re developing something that has the potential to help all women, including those most in need.’
The study was published in the Journal of Perinatology.