Is It a Boy or Girl? First Trimester Blood Test May Tell

Blood test to determine gender

Soon after a woman learns she is pregnant, one of the first questions on her mind is, “Is it a boy or girl?” New research from South Korea describes findings that could result in a simple blood test that can answer the question during the first trimester.

Get an answer within a few weeks of conception

South Korean researchers discovered that various ratios of DYS14 and GAPDH, two enzymes that can be extracted from a pregnant woman’s blood, can reveal whether her child will be a boy or a girl. According to the study, which is published in the FASEB Journal, this test would be the first one of its kind.

The discovery was made when Hyun Mee Ryu, MD, PhD, a researcher at Cheil General Hospital and Women’s Healthcare Center at the KwanDong University School of Medicine in Seoul, Korea, and colleagues analyzed blood samples from 203 pregnant women during their first trimester.

According to Ryu, use of this technique “can reduce the need for invasive procedures in pregnant women carrying an X-linked chromosomal abnormality and clarify inconclusive readings by ultrasound.”

Other tests during pregnancy

Two of the invasive tests Ryu referred to include amniocentesis and chorionic villus sampling. Amniocentesis involves removing a small amount of amniotic fluid from the sac that surrounds the fetus in the uterus. It can be done at around week 16 of gestation.

An amniocentesis is usually done to help identify gene or chromosome abnormalities, such as Down syndrome, to detect neural tube defects such as spina bifida, and to diagnose an infection. An amniocentesis generally is not performed just to determine a baby’s gender.


Chorionic villus sampling involves removing a small piece of placenta tissue from the uterus and can be done at 10 to 12 weeks after a woman’s last menstrual period. The test is used to study the DNA, chromosomes, and signs of disease and genetic disorders, therefore it can also identify the gender of the baby.

Possible complications of an amniocentesis include miscarriage, leaking of amniotic fluid, vaginal bleeding, and infection or injury to the fetus. For chorionic villus sampling, possible complications may include infection, rupture of the membranes, bleeding, and miscarriage.

Currently, the typical way to find out if a baby will be a boy or a girl is for the mother-to-be to undergo an ultrasound during the second trimester at 18 to 20 weeks’ gestation. Although an ultrasound can be done safely much earlier in the pregnancy, the gender of the baby cannot be determined before 18 weeks.

In 2010, there was a report in The Telegraph that a blood test had been developed that could detect an unborn child’s DNA and identify the sex of the baby during the first trimester. The test, which was developed by Dr. Esther Guetta of the Sheba Medical Centre in Israel, was a research tool and available at only a few private clinics.

At the moment, expectant mothers and fathers will have to use another test to get the answer to the question, “Is it a boy or girl?” as more work is necessary before this new first trimester blood test will be available.

Ji Hyae Lim, So Yeon Park, Shin Young Kim, Do Jin Kim, Ji Eun Choi, Min Hyoung Kim, Jun Seek Choi, Moon Young Kim, Jae Hyug Yang, and Hyun Mee Ryu. Effective detection of fetal sex using circulating fetal DNA in first-trimester maternal plasma. FASEB J. January 2012 26:250 doi:10.1096/fj.11-191429
The Telegraph, Nov. 2, 2010

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