A Pap smear can scoop up fetal cells for genome testing | Science News



Support credible science journalism.

Subscribe to Science News today.


A Pap smear can scoop up fetal cells for genome testing

The technique may be helpful for treating some disorders before birth

7:00am, November 22, 2016
9 week ultrasound

EARLY DAYS  This ultrasound is of a 9-week-old fetus. A new test using fetal cells obtained from a Pap smear can scan a fetus’s genome as early as five weeks.

Sponsor Message

Scanning a fetus’s genome just a few weeks after conception may soon be an option for expecting parents. Mom just needs to get a Pap smear first.

By scraping a woman’s cervix as early as five weeks into a pregnancy, researchers can collect enough fetal cells to test for abnormalities linked to more than 6,000 genetic disorders, researchers report November 2 in Science Translational Medicine. It’s not clear exactly how fetal cells make their way down to the cervix, says study coauthor Sascha Drewlo of Wayne State University School of Medicine in Detroit. But the cells may invade mom’s mucus-secreting glands, and then get washed into the cervical canal.

Current prenatal tests include amniocentesis and chorionic villus sampling, but they work later in pregnancy: at least 12 weeks for amnio and at least nine weeks for CVS. Amnio requires a long needle threaded through a pregnant woman’s belly and uterus; CVS often does, too. Instead, Drewlo’s team gathered fetal trophoblast cells, which give rise to the placenta, and were able to examine the genomes of 20 fetuses.

The new technique, which can work with as few as 125 fetal cells, could one day help physicians care for their tiniest patients. For some genetic conditions, such as congenital adrenal hyperplasia, early detection means mom can take some medicine to “actually treat the fetus in utero,” Drewlo says.


C.V. Jain et al. Fetal genome profiling at 5 weeks of gestation after noninvasive isolation of trophoblast cells from the endocervical canal. Science Translational Medicine. Published online November 2, 2016. doi: 10.1126/scitranslmed.aah4661. 

Further Reading

T.H. Saey. A more accurate prenatal test to predict Down syndrome. Science News. Vol. 187, May 2, 2015, p. 18.

N. Seppa. Updated Pap smear detects ovarian, uterine cancers. Science News. Vol. 183, February 9, 2013, p. 12.

Get Science News headlines by e-mail.

More from Science News

From the Nature Index Paid Content