Let’s talk about ultrasound first. Ultrasound can help determine the gender of your baby in some cases as early as 15 weeks, but is easiest to see after 18 weeks. Things that can affect the ability to see gender on ultrasound include size of the uterus, position of the baby, and body habitus. Mostly, it depends on the position of the baby. How often can it be wrong? A lot of this is based on the experience of the technologist performing the ultrasound. The accuracy of an ultrasound is probably around 90%.
In the last couple of years, the technology to perform accurate genetic testing has exploded and more and more women are getting cell free fetal DNA tests that can accurately predict the gender of the baby. Cell free fetal DNA was invented to detect genetic disorders such as trisomy 13, 18 and 21. But it can also determine gender. How does this test work? Some fetal cells enter the maternal circulation and this access to genetic material of the fetus has allowed us to screen for genetic disorders and look for the presence of a Y chromosome with a simple blood test. If a Y chromosome is present, then you are having a boy. Now, the accuracy of this test really depends on when the test is performed. We generally recommend that the test be performed after ten weeks. Studies have shown that the sensitivity (true positive rate) and specificity (true negative rate) of the cffdna test in accurately determining gender was 95 and 99% in the first trimester and 98 and 99% respectively in the second trimester. While slightly more accurate in the second trimester, it is still very accurate in determining the gender of your baby.
My friend just got “SneakPeek”. How accurate is it? Unfortunately, some insurances will not cover cffdna testing if you are low risk (under the age of 35 and no other risk factors). Because of this, we have found that patients are using SneakPeek to bypass their insurance. SneakPeek utilizes CFFDNA technology and can be performed as early as 9 weeks. The accuracy of Sneak Peak is very similar to CFFDNA testing performed in our office since it utilizes the same technology. However, the manner in which the sample is submitted, it does not test for genetic abnormalities such as down’s syndrome. This test costs around $80. We do not recommend it if your insurance will cover a portion of the cost for CFFDNA test simply because it does not perform screening for genetic disorders. However, if your insurance does not cover the test and you just want to know the gender, the likelihood of it being accurate is very good.