Screening for the human immunodeficiency virus (HIV) is a routine element of comprehensive prenatal care due to the concern over mother-to-child transmission. HIV attacks the body’s immune system and, if left untreated, can be passed from a pregnant person to their baby during gestation, labor, delivery, or through breastfeeding. Identifying the virus early in pregnancy is the most effective measure available to protect both the mother and the newborn, allowing for immediate medical intervention. The primary goal of universal screening is to virtually eliminate the possibility of the baby acquiring the infection through highly effective treatments.
Standard Practice for Prenatal Screening
Yes, HIV testing is a standard part of prenatal care for all pregnant individuals in the United States and many other countries. Major health organizations, including the Centers for Disease Control and Prevention (CDC) and the American College of Obstetricians and Gynecologists (ACOG), advise this universal screening. Relying on a risk assessment alone would fail to identify all individuals living with HIV.
The screening process uses an “opt-out” approach. The pregnant person is notified that an HIV test will be performed as a routine part of the prenatal blood panel unless they specifically decline the test. This method increases testing rates and is considered the standard of care to ensure the highest number of cases are identified. The testing must always be voluntary, respecting the individual’s right to refuse the screening.
The Timing and Types of HIV Testing
The initial HIV test is performed as early as possible in pregnancy, often during the first prenatal visit. This early timing allows for the maximum window for treatment initiation, which reduces the risk of transmission. The most common screening method used is a fourth-generation antigen/antibody test.
This test simultaneously looks for HIV antibodies, which the body produces in response to the virus, and the p24 antigen, a viral protein that appears earlier than antibodies. A repeat screening is recommended during the third trimester, preferably before 36 weeks, for individuals at high risk for new infection or those living in areas with high rates of HIV. Repeat testing is necessary because a new infection acquired late in pregnancy can carry a high viral load, significantly increasing the transmission risk.
If a pregnant person arrives for labor and delivery without documented HIV status, a rapid HIV test is offered immediately. These rapid tests deliver results quickly, sometimes in 30 minutes or less, using a finger prick or oral fluid sample. This expedited testing allows for timely administration of prophylactic antiretroviral medication to the mother and baby if the result is reactive.
Preventing Mother-to-Child Transmission
The justification for universal prenatal screening is the success of Prevention of Mother-to-Child Transmission (PMTCT) protocols. Without medical intervention, the risk of transmission from an HIV-positive mother to her child ranges from 15% to 45%. With proper diagnosis and adherence to treatment, this risk drops to less than 1%.
This reduction is achieved through antiretroviral therapy (ART) for the pregnant person. ART involves a combination of three or more drugs taken daily to suppress the amount of HIV in the blood, known as the viral load. Achieving an undetectable or very low viral load is the primary goal because it prevents the virus from passing through the placenta or during delivery.
Starting ART immediately upon diagnosis is important for the health of both the mother and the fetus. The longer the mother is on effective therapy, the higher the chance of having a suppressed viral load at delivery. This continuous treatment during pregnancy and labor has made the virtual elimination of vertical transmission an achievable public health goal.
Immediate Steps Following a Positive Result
Upon receiving a positive HIV diagnosis, medical management begins immediately with intensified antiretroviral therapy for the mother. The health care team selects an ART regimen that is effective at suppressing the virus and safe for use during pregnancy. The mother’s viral load is closely monitored throughout the pregnancy to ensure the medication achieves viral suppression.
The plan for delivery is determined by the mother’s viral load near term. If the viral load is suppressed to a very low level, a vaginal delivery is considered safe. A planned Cesarean section at 38 weeks may be recommended if the viral load is high (above 1,000 copies/mL) or unknown. This surgical delivery method further reduces the risk of the baby contacting the virus in the birth canal.
Immediately after birth, the newborn is given prophylactic antiretroviral medication, often for four to six weeks. This neonatal ART acts as an additional layer of protection against potential exposure. In the United States, formula feeding is recommended for all infants born to HIV-positive mothers, as the virus can be transmitted through breast milk.