When you’re expecting, your doctors seem to test for everything. Any little thing they find is cured or treated. But when you reach your third trimester, they sometimes want to test you again, even when your results were negative in the first trimester. What’s going on?
Sexually transmitted infection (STI) tests
STIs can pose a serious risk to baby, including brain damage, blindness, deafness, and pneumonia [1]. The infections most commonly screened are:
HIV;
Hepatitis B;
Hepatitis C;
Syphilis.
False negatives aren’t unusual in testing. For example, HIV has an incubation period of up to a year, and hepatitis B, up to nine weeks, leading your test to come back negative during that incubation period [2]. Antibodies might not be detected during the first test. And of course, you can become newly infected during pregnancy, too.
For these reasons, it’s best practice to re-test in the third trimester. Knowledge about an STI will allow you to take the necessary precautions to protect yourself and baby.
TORCH stands for toxoplasmosis, other (a disease such as syphilis, varicella, HIV, mumps, or parvovirus), rubella, cytomegalovirus, and herpes simplex. This group of diseases can be dangerous for baby’s development, as he can contract them in utero [3].
There is no need to test for TORCH unless you have a reason to investigate, such as a herpes outbreak during pregnancy. False positives are relatively common. Treatment will vary by infection and individual, as your doctor will make sure the treatment is not potentially more harmful to baby than the infection itself.
