A pregnant woman and her partner should be tested for the presence of Herpes Simplex Virus 1 and Herpes Simplex 2 IgG antibodies (HSV 1 and HSV 2 IgG Ab). This is a blood test. This test should be done at first prenatal visit. If you have been exposed to herpes virus or have had an outbreak, the virus is still in your body. In response to this virus, your immune system will produce antibodies which are found in your blood. These antibodies last for life.
Antibodies are good - they usually prevent the virus from attacking your baby. The lack of antibodies means you can catch herpes. It takes your body approximately 8-12 weeks to develop antibodies (known as seroconversion) that could prevent herpes transmission to your fetus or newborn. Therefore, first infection during the last trimester of pregnancy (28-40 weeks) poses the greatest risk for your baby to become infected with neonatal herpes.