Newly expectant parents can now learn whether they will be welcoming a boy or a girl into their growing family faster than ever. Recent analysis has found that a simple blood test can determine the sex of a fetus with surprising accuracy at only about seven weeks of pregnancy. Details of the research were recently published in the Journal of the American Medical Association.
Benefits of gender prediction testing
The blood test works by scanning the blood of the mother-to-be for fetal DNA, looking for fragments of the male (Y) chromosome to determine if the fetus is a boy. If the chromosome is not present, the fetus is a girl.
The test informs new parents of the gender of the baby considerably earlier than procedures such as ultrasound, whis is typically scheduled during the second trimester of pregnancy to determine gender.
Another benefit of the test is that it carries less risk of miscarriage than more invasive tests like chorionic villus sampling and amniocentesis, which are also normally scheduled during the second trimester of pregnancy. In addition, the new test can help identify at-risk babies at an early stage of pregnancy, which is highly important among families with a history of gender associated diseases.
Some experts are concerned that a few hopeful parents will use the test as a resource for selecting the sex of their child. But according to study researcher Diana Bianchi, executive director for the Mother Infant Research Institute at Tufts Medical Center, it is not likely that the tests will change sex-selective abortion in the U.S. She pointed out, “It’s a theoretical issue now, but people are already doing it using ultrasound.”
Test Accuracy
Currently, blood tests that detect gender are not widely available in the U.S., although they have been been offered for purchase over the Internet for several years. Due to claims of result accuracy at early stages of pregnancy, genetic researchers were prompted to conduct an investigation into just how reliable the tests may be.
Blood test result in determining the baby's gender has a very high accuracy
Led by Stephanie Devaney of the National Institutes of Health in Bethesda, Maryland, the research team analyzed a total of 57 previous studies involving 3,524 pregnancies of males, and 3,017 pregnancies females. Findings of the analysis revealed that the tests have a sensitivity of 95.4 percent.
The test was found to be more accurate for boys, as overall results were 98.8 accurate in predicting the birth of a boy, and 94.8 accurate for the birth of a girl. However, test accuracy improved with the length of gestation to near perfect at 20 weeks.
According to the National Institutes of Health, the screening can also benefit fetuses at risk for congenital adrenal hyperplasia. The condition causes girls to have ambiguous genitalia, which can be prevented in the womb with an injection of steroids into the mother-to-be. Bianchi noted that boys with the condition do not require the treatment. However, she pointed out that early determination of the sex of the fetus can decrease the number of women treated with steroids they don’t actually need.
The estimated cost for the test in the U.S. is more more than $400. Santa Clara, California-based Consumer Genetics Incorporated sells an early gender determination blood test online called “Pink or Blue” for $25 plus $265 or more for laboratory testing. According to Terry Carmichael, the company’s executive vice president, the test is 95 percent accurate and uses a lab technique developed by company scientists from the same type of testing evaluated in the new analysis. A similar test is sold by San Diego-based Sequenom Incorporated.
