The expectant mother may have another tool to help predict her unborn child's health. Scientists at the United Kingdom-based company MAP Diagnostics are working on a series of pregnancy tests, performed in a lab, that will analyze proteins in a mother’s urine to predict chances of Down syndrome, preeclampsia and other conditions that could affect her or her child. They're calling it the MAP Test, and they say it will make prenatal information much easier to come by.
“Up until now, tests have been quite poor. What we’re trying to do is create more information so people can make better decisions,” Stephen Butler, MAP’s founder and chief scientific officer, says.
Pregnancy tests check for the presence of human chorionic gonadotropin (hCG), a hormone that’s present in urine when an egg implants in the uterus. The MAP test goes one step further and looks at what's in the hCG. By analyzing that hCG, each test can find patterns of proteins, which indicate chromosomal abnormalities as well as twins, preeclampsia, chances of miscarriage and more.
The MAP test has been in the works for more than a decade. The members of the MAP team had been analyzing hCG samples for fertility studies at Yale and the University of New Mexico when they started to notice patterns.
“What we realized very quickly was that we could see structural differences in hCG that could identify complications or difficulties,” Butler says. “We looked at urine from different pregnancy issues. We had a collection of Down syndrome samples, and we could see pattern differences in the Down syndrome from the normal ones.”
The researchers are studying samples that they've already gathered for research. But, in practice, here's how the MAP test would work: a woman eight weeks into her pregnancy would give a urine sample at a lab, or send one in to her doctor to be tested. Using what is called a Matrix-Assisted Laser Desorption Ionization (MALDI) Time-of-Flight Mass Spectrometer, technicians spin out the separate proteins from the urine and then analyze these proteins for patterns. By running the sample through the spectrometer, they can test for aneuploid pregnancies—abnormal numbers of chromosomes, which lead to genetic conditions like Down syndrome—as well as gestational cancer, preeclampsia, gestational diabetes, ectopic pregnancy and more. They have to test for each condition individually, to look for the specific patterns, but the process is the same for each test. It takes just 15 minutes for a technician to run a test.
Currently, the most common way to diagnose Down syndrome and other chromosomal disorders in an unborn child is with an amniocentesis, a relatively invasive procedure that involves drawing amniotic fluid using a needle inserted into the mother's uterus. There are less invasive screening tests, which rely on blood draws and ultrasounds, but they only estimate a mother's risk of having a child with Down syndrome. The MAP team wanted to develop a urine test, instead of blood or amniotic fluid, that was more accurate, less invasive and cheaper.
There is some concern about the accuracy of the method, especially because it's still the early stages of testing, the sample sizes have been small, and it's dealing with highly sensitive decisions. “You wouldn’t want a lot of women being unnecessarily stressed or falsely reassured,” Zev Williams, an obstetrician and gynecologist at Yeshiva University's Albert Einstein College of Medicine, told The Telegraph.
The MAP group has tested about 1,000 samples. Some of the simpler tests, like for preeclampsia, could be available in six months. The Down Syndrome test will take longer to perfect. According to a paper published in March in Clinical Proteomics, they were able to distinguish Down syndrome in urine samples with 70 percent sensitivity, meaning they identified 70 percent of the cases, and 100 percent specificity, meaning there were no false positives. Butler says the group doesn’t have quite enough data to feel comfortable releasing the test yet, in part because of the heightened ethical and moral issues surrounding prenatal tests, abortion and Down Syndrome. But they have more samples coming in regularly.
The scientists presented their findings about both the twin test and the likelihood of miscarriages at the European Society of Human Reproduction and Embryology conference in Lisbon in June. The group will be presenting more results at the American Society for Reproductive Medicine conference in Baltimore this October.