O98.113 Syphilis complicating pregnancy, third trimester

Name of the Condition

• Syphilis complicating pregnancy, third trimester (ICD Code: O98.113)

Summary

This condition refers to syphilis infection in a pregnant individual during the third trimester, where the disease may affect both maternal and fetal health. Syphilis is a sexually transmitted infection caused by the bacterium Treponema pallidum and requires specialized management during this stage of pregnancy to prevent transmission to the fetus and mitigate maternal complications.

Causes

Syphilis complicating pregnancy is caused by infection with Treponema pallidum, which can be transmitted through sexual contact or from mother to fetus during pregnancy. The infection may be newly acquired or reactivated in individuals with latent syphilis, and physiological changes during pregnancy can influence disease progression.

Risk Factors

• Unprotected sexual contact with an infected partner
• Lack of prenatal syphilis screening
• History of syphilis or other sexually transmitted infections
• Substance use (e.g., injection drugs)
• Limited access to prenatal care

Symptoms

• Painless sores (chancres) at the infection site (primary stage)
• Rash on the palms, soles, or trunk (secondary stage)
• Fever, fatigue, or swollen lymph nodes
• Asymptomatic presentation in some cases
• Late-stage symptoms (e.g., neurological or cardiovascular issues) if untreated

Diagnosis

Diagnosis involves screening for syphilis using serological tests, including nontreponemal tests (e.g., RPR, VDRL) and confirmatory treponemal tests (e.g., FTA-ABS, TPPA). Testing is typically performed during prenatal visits, with additional evaluation if exposure is suspected. The timing of infection and stage of pregnancy may influence testing protocols.

Treatment Options

Treatment involves parenteral penicillin, the preferred antibiotic for syphilis during pregnancy. The dosage and duration depend on the stage of infection and gestational age. Close monitoring of maternal and fetal status is essential, with follow-up serological testing to ensure treatment efficacy.

Prognosis and Follow-Up

With appropriate treatment, maternal and fetal outcomes generally improve, reducing the risk of congenital syphilis. Follow-up includes repeat serological testing at recommended intervals to confirm response to therapy and monitor for reinfection. Fetal ultrasound may be used to assess for complications, particularly in the third trimester.

Complications

• Congenital syphilis in the fetus, potentially leading to stillbirth, prematurity, or neonatal death
• Maternal transmission of infection to the fetus
• Progression of syphilis to later stages if untreated
• Increased risk of other sexually transmitted infections

Lifestyle & Prevention

• Consistent use of barrier methods (e.g., condoms) to reduce sexual transmission
• Routine prenatal screening for syphilis as part of standard care
• Avoidance of high-risk sexual behaviors
• Prompt treatment of syphilis in sexual partners to prevent reinfection

When to Seek Professional Help

Seek medical attention if symptoms of syphilis (e.g., sores, rash, fever) develop or if exposure to an infected partner is suspected. Pregnant individuals should undergo regular prenatal care to ensure early detection and management of syphilis.

Tips for Medical Coders

Document the trimester of pregnancy (third trimester) and confirm the presence of syphilis complicating the pregnancy. Ensure the code O98.113 is used when the condition is specifically identified during the third trimester. Include details of maternal screening, treatment, and fetal monitoring to support accurate coding and clinical context.