New paternity tests work early in pregnancy
- Article by: ANDREW POLLACK
- New York Times
- June 19, 2012 - 9:59 PM
It is an uncomfortable question that, in today's world, is often asked by expectant mothers who had more than one male partner at the time they became pregnant. Who is the father?
With more than half of births to women under 30 now out of wedlock, it is a question that may arise more often.
Now blood tests are becoming available that can determine paternity as early as the eighth or ninth week of pregnancy, without an invasive procedure that could cause a miscarriage.
Besides relieving anxiety, the test results might allow women to terminate a pregnancy if the preferred man is not the father -- or to continue it if he is.
Men who clearly know they are the father might be more willing to support the woman financially and emotionally during the pregnancy, which some studies suggest might lead to healthier babies.
And if the tests gain legal acceptance, some lawyers say, women and state governments might one day pursue child support payments without having to wait until the birth. Under current law, "until and unless the pregnancy produces a child, any costs associated with it are regarded as the woman's personal problem," said Shari Motro, a law professor at the University of Richmond.
The testing itself, however, can be awkward because at least one of the possible fathers must contribute a blood sample.
A case in point
Courtney Herndon, after breaking up with her boyfriend, had a brief relationship with a man she regarded more as a friend. She found herself pregnant at age 19, without knowing which man was the father. The friend also wanted to know, so he agreed to the testing. He turned out to be the father, and the two agreed on child support even before the baby was born.
"I got the test done and was able to go on with my life," said Herndon, who lives in Fort Polk, La.
Estimates of the extent of paternal uncertainty vary.
Studies have found a discrepancy rate -- when the presumed father is not the biological father -- of anywhere from 0.8 percent to 30 percent, with the median being 3.7 percent, according to one review of such studies. Another study found that about 9 percent of birth certificates in Florida, even excluding births to teenage mothers, did not list the full names of the father, although it was not clear how much of this was related to uncertainty. Infant mortality was higher in those cases than if the father's name was on the birth certificate.
It has already been possible to determine paternity during pregnancy using amniocentesis or chorionic villus sampling, the same medical procedures used to test a fetus for Down syndrome. But those procedures are invasive and carry a small risk of inducing a miscarriage, so they are rarely used for paternity.
By contrast, the new tests require only blood samples from the pregnant woman and the potential father. And doctors generally do not have to be involved.
The tests analyze fragments of DNA from the fetus present in the mother's blood. The same approach is now also being used to noninvasively determine the gender of the fetus or whether it has Down syndrome. And last week, researchers demonstrated that they could even determine a fetus' entire genome this way.
On the market
Ravgen, a small company in Columbia, Md., has been offering its test on a limited basis and charges $950 to $1,650, said Dr. Ravinder Dhallan, the chief executive.
Another test was developed by a company in Silicon Valley called Natera and is marketed by DNA Diagnostics Center, a leading provider of conventional paternity tests. Thousands of the prenatal tests have been ordered since going on sale in August, executives say. The price is $1,775, compared with around $500 for a conventional postbirth paternity test.
Neither test has received a certification for accuracy that is necessary for use in child custody cases, although Natera has applied.
The certifying organization, the AABB, is seriously considering whether it should certify prenatal tests, said Eduardo Nunes, senior director for policy, standards and global development at the organization, formerly known as the American Association of Blood Banks.
© 2013 Star Tribune