How to Identify a Boy or a Girl in Pregnancy

By Erica Loop
An ultrasound provides a picture of your baby during pregnancy.

If you want to know before your baby’s gender before it's born, you’ll need to consult a medical professional who can run definitive diagnostic tests. Your obstetrician or nurse midwife may suggest an ultrasound, a villus sampling or an amniocentesis to determine whether you’ll need to decorate in blue or in pink.

Sound Wave Ultrasound Technology

Ultrasound is a non-invasive technique that can help to identify your baby's gender. A sonographer will use sound waves to capture a picture of your growing baby. This can help you identify the sex only after you are 18 to 20 weeks pregnant, notes the American Pregnancy Association. The traditional method of ultrasound provides a two-dimensional or flat picture. Some doctors’ offices may offer 3-D sonography. This creates a more life-like, three-dimensional image. The size or position of your baby may affect the sonographer’s ability to clearly see your baby’s genital area, according to University of Pittsburgh Medical Center.

Chorionic Villus Sampling

Chorionic villus sampling is an invasive procedure in which the doctor either places a catheter through your cervix or inserts a needle through your abdomen and into the uterus to take a tissue sample from the placenta, Johns Hopkins Medicine explains. This procedure is typically done between the 10th and 12th weeks of pregnancy. Although chorionic villus sampling can help to identify the sex of your baby, it is typically used to test for chromosomal abnormalities. This procedure may cause your water to break and may result in cramping, miscarriage, infection or preterm labor. Your doctor may recommend a less risky option for identifying the gender of your baby.

Noninvasive Blood DNA Testing

Some lab tests may reveal your baby's gender. Cell-free fetal DNA tests are non-invasive measures that can detect the Y chromosome in the mother’s blood, and only males have the Y chromosome. Studies on this type of blood plasma test show that it is highly reliable, according to "Journal of the American Medical Association." The tests work best after 20 weeks of gestation. Even though your doctor will need to take a blood sample from you, cell-free fetal DNA testing is not invasive in the same way as chorionic villus sampling or amniocentesis. This reduces the risks to you and your baby.

Amniocentesis Procedures

Amniocentesis is an invasive test that can identify genetic abnormalities as well as your baby’s gender. A needle is used to remove some of the amniotic fluid that surrounds your baby. It is usually done after 16 weeks of pregnancy, according to the Emory University School of Medicine Department of Gynecology and Obstetrics. This procedure runs the risk of miscarriage, infection, bleeding and leaking amniotic fluid. A comparision of the miscarriage rate among women having amniocentesis at 24-weeks gestation or less and those opting against it found no notable difference, according to an article titled "Pregnancy Loss Rates After Midtrimester Amniocentesis" in the journal "Obstetrics and Gynecology." There is, however, a very small risk that the needle could injure your baby.

About the Author

Based in Pittsburgh, Erica Loop has been writing education, child development and parenting articles since 2009. Her articles have appeared in "Pittsburgh Parent Magazine" and the website PBS Parents. She has a Master of Science in applied developmental psychology from the University of Pittsburgh's School of Education.