Prenatal care is designed to protect the health of both the pregnant individual and the developing fetus. Routine screening for sexually transmitted infections (STIs) is a standard component of this comprehensive care. This screening process is fundamentally a form of preventative medicine, working to identify and treat infections that often present with no symptoms. Early detection allows for timely intervention, which dramatically reduces the risk of serious complications for the pregnancy and the newborn. Testing is necessary due to the serious potential for mother-to-child transmission, ensuring a healthy outcome.
Routine Screening During the First Prenatal Visit
Initial STI testing is typically performed during the first prenatal visit. This timing ensures that any existing infection is identified and treated quickly, maximizing the window for therapeutic success before the infection can cause significant harm to the fetus. The core panel of tests recommended for all pregnant individuals includes screening for Human Immunodeficiency Virus (HIV), Syphilis, and Hepatitis B. These three infections are routinely tested because of their potential for severe fetal harm and the existence of effective treatments to prevent transmission.
Screening for Chlamydia and Gonorrhea is also standard protocol, particularly for those under 25 years old or those with specific risk factors. Testing methods are generally straightforward and non-invasive, involving a simple blood draw for HIV, Syphilis, and Hepatitis B. Chlamydia and Gonorrhea screening often utilizes a urine sample or a self-collected vaginal swab, which are both quick and easy to perform. This initial panel establishes a baseline health status and is considered a mandatory step in prenatal care, regardless of a person’s perceived risk.
The primary goal of this early and widespread screening is to catch infections that may have been acquired before or early in the pregnancy. Since many STIs are asymptomatic, the pregnant individual may be completely unaware they are infected, underscoring the importance of this routine testing. Identifying these infections early provides the medical team with the greatest opportunity to implement curative or suppressive therapies. The standard protocol ensures that the most common and consequential infections are addressed from the outset of care.
Specific STIs Requiring Repeat Screening
While the first prenatal visit covers the initial screening, certain circumstances require repeat testing later in the pregnancy to account for new exposures. Third-trimester rescreening, generally performed between 28 and 32 weeks of gestation, is recommended for individuals considered to be at an increased risk of infection. This repeat screening focuses specifically on HIV, Syphilis, and Hepatitis B, which can be newly acquired during the pregnancy. High-risk factors include having a new sex partner, having multiple partners during the pregnancy, or living in an area with a high prevalence of these infections.
The rescreening is particularly important for Syphilis, as a newly acquired infection in the third trimester carries a high risk of transmission to the fetus. Similarly, individuals under the age of 25 or those with continued high-risk behavior are often retested for Chlamydia and Gonorrhea in the third trimester. This later screening acts as a safety net, detecting infections acquired after the initial visit that could be transmitted to the newborn during delivery.
Testing for other infections, such as Herpes Simplex Virus (HSV) or Human Papillomavirus (HPV), is not typically part of the routine universal screening process. HSV testing is usually only performed if a person reports symptoms like active genital lesions or has a known exposure near the time of delivery. HPV screening follows the same schedule as for non-pregnant individuals, focusing on cervical cancer prevention. These infections are handled on a targeted, as-needed basis, differing from the routine panel.
Risks of Untreated Infections to Mother and Fetus
Early and repeat STI screening is necessary due to the consequences of untreated infections for both mother and child. Syphilis, if untreated, can cross the placenta and lead to congenital syphilis, resulting in miscarriage, stillbirth, or severe, lifelong health problems for the newborn, including bone damage, blindness, and deafness. Untreated HIV carries a significant risk of mother-to-child transmission during pregnancy, labor, or breastfeeding, potentially leading to the baby developing HIV infection.
Chlamydia and Gonorrhea pose risks such as preterm delivery, low birth weight, and premature rupture of membranes for the mother. If the newborn is exposed to these bacteria during delivery, they can develop serious eye infections (neonatal conjunctivitis) or pneumonia. Hepatitis B transmitted during birth can lead to the baby becoming a chronic carrier of the virus, resulting in long-term liver disease or liver cancer. These outcomes justify the screening protocols, as the infections can cause effects at various stages of fetal development and birth.
Managing a Positive Diagnosis
Effective management strategies are in place to minimize risk following a positive STI diagnosis during pregnancy. Bacterial infections like Syphilis, Chlamydia, and Gonorrhea are treated with antibiotics deemed safe for use during pregnancy. Syphilis is curable with penicillin, which is the only treatment proven to eliminate the infection from the fetus as well as the mother. The pregnant individual is closely monitored after treatment to ensure the infection has been eradicated.
Viral infections such as HIV are treated with a combination of safe antiretroviral medications. These medications reduce the viral load to an undetectable level, which lowers the risk of transmission to the baby to less than one percent. If active Herpes Simplex Virus lesions are present at the time of delivery, a cesarean section may be recommended to prevent the baby from contacting the virus. Treatment and monitoring protocols provide a clear path forward, mitigating the potential harm associated with these infections.