Syphilis in Pregnancy

Pathophysiology and Maternal-Fetal Transmission

Syphilis is a systemic infection caused by the spirochete bacterium Treponema pallidum. When a pregnant woman contracts this organism, the bacteria rapidly invade the bloodstream, causing a bacteremia that can cross the placenta at almost any stage of gestation.

Unlike many other infections that require a specific trimester to cross over, Treponema pallidum can infect the fetus as early as the ninth week of pregnancy. However, the severity of fetal damage often increases when transmission occurs in the second and third trimesters. The placenta itself becomes inflamed, proliferative endarteritis develops in the fetal vessels, and blood flow to the baby is compromised. This pathological process explains why untreated maternal syphilis frequently results in spontaneous abortion, stillbirth, non-immune hydrops fetalis, or severe congenital deformities at birth.

Clinical Stages of Syphilis in Pregnant Women

The clinical progression of syphilis is divided into distinct stages, each presenting unique diagnostic challenges during antenatal care.

• Primary stage: Characterized by a single, painless ulcer called a chancre at the site of inoculation, usually on the cervix, vagina, or vulva. Because these chancres are often hidden inside the reproductive tract and resolve on their own, pregnant women frequently miss them.
• Secondary stage: Features a generalized, non-pruritic rash that commonly appears on the palms of the hands and soles of the feet, accompanied by generalized lymphadenopathy and moist, wart-like lesions called condyloma lata.
• Latent stage: Asymptomatic phase where the infection is dormant but detectable only through positive serological tests. It is further split into early latent (acquired within the past year) and late latent periods.
• Tertiary stage: Rare in modern antenatal care due to screening, but involves severe cardiovascular and neurological damage.

Antenatal Screening and Diagnostic Testing

Routine screening for syphilis is a cornerstone of focused antenatal care in Nigeria. Every pregnant woman must be tested at her first booking visit, and high-risk women should be re-tested in the third trimester and at delivery.

Diagnostic tests are broadly divided into two categories:

1. Non-treponemal tests: These include the VDRL (Veneral Disease Research Laboratory) and RPR (Rapid Plasma Reagin) tests. They measure antibodies that are not specific to the bacterium but indicate active inflammation and disease activity. They are excellent for screening and monitoring treatment response because their titers rise and fall with disease activity.
2. Treponemal tests: These include the TPPA (Treponema pallidum particle agglutination) and various rapid diagnostic tests. They detect antibodies directed specifically against the organism's antigens. Once positive, these tests usually remain reactive for life, even after successful treatment.

Penicillin Treatment Regimens and Management

The undisputed gold-standard treatment for syphilis in pregnancy is Benzathine Penicillin G. No other antibiotic reliably crosses the placenta in therapeutic concentrations to treat the unborn fetus.

The dosage and duration depend entirely on the clinical stage diagnosed:

• Early syphilis (primary, secondary, and early latent): Administered as a single intramuscular injection of 2.4 million units of Benzathine Penicillin G.
• Late latent syphilis or syphilis of unknown duration: Requires three weekly doses of 2.4 million units of Benzathine Penicillin G intramuscularly.

Midwives must prepare clients for the Jarisch-Herxheimer reaction, an acute febrile reaction accompanied by myalgia and worsening of transient symptoms that can occur within 24 hours of the first injection due to the rapid destruction of spirochetes. While distressing, this reaction does not mean the patient is allergic to penicillin, though true penicillin allergies must be carefully investigated and managed through desensitization protocols when necessary.

Preventing and Managing Congenital Syphilis

Congenital syphilis is a devastating, entirely preventable condition that occurs when the infection is passed from mother to baby. Prevention relies on timely maternal screening and adequate treatment completed at least 30 days before delivery.

When treatment is delayed, inadequate, or administered late in the third trimester, the newborn may be born with congenital syphilis. Clinical signs in the neonate can include hepatosplenomegaly, snuffles (a persistent, infectious nasal discharge), generalized skin rash, periostitis, and characteristic bone changes.

Management requires a thorough neonatal evaluation, including physical examination, comparison of infant and maternal non-treponemal antibody titers, and sometimes cerebrospinal fluid analysis. Newborns confirmed to have congenital infection receive targeted courses of aqueous crystalline penicillin G or procaine penicillin G.

Nursing Care and Public Health Considerations in Nigeria

Managing syphilis in pregnancy extends beyond clinical treatment; it requires robust public health interventions. Midwives play a central role in overcoming stigma, ensuring partner notification, and promoting couple counseling.

Because reinfection is a major barrier to eradicating congenital syphilis, the sexual partner of the infected pregnant woman must be traced, tested, and treated simultaneously. Untreated partners guarantee reinfection during the same pregnancy.

Midwives should advocate for point-of-care rapid testing in community antenatal clinics where laboratory delays often lead to lost-to-follow-up patients. Integrating syphilis screening into routine Prevention of Mother-to-Child Transmission (PMTCT) programs for HIV maximizes resource use and protects maternal and child health across Nigeria.