Syphilis Screening in Pregnancy
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Direct answer
Screening every pregnant woman for syphilis with a non-treponemal test — VDRL or RPR — at the first antenatal visit is among the cheapest interventions in obstetrics, and India's programme context favours point-of-care dual HIV-syphilis tests at high-prevalence sites; congenital syphilis is entirely preventable when treatment precedes birth. A reactive screen is confirmed with a treponemal test (TPHA or FTA-ABS), because false positives — pregnancy itself, malaria, leprosy, autoimmune disease, recent vaccination — pepper non-treponemal assays in Indian populations. Treatment is benzathine penicillin G 2.4 million units intramuscularly as a single dose for early syphilis (primary, secondary or early latent of under two years) and the same dose weekly for three consecutive weeks for late latent or unknown duration; penicillin-allergic women in pregnancy are desensitised and treated with penicillin rather than given alternatives. Neonatal signatures include snuffles, desquamating rash and hepatosplenomegaly, and later Hutchinson's triad.
What you must remember
- Screening test: VDRL or RPR (non-treponemal, cheap, quantitative — titres track treatment response) on every pregnant woman at booking; retest in the third trimester and at delivery in high-risk women.
- Confirmation: TPHA or FTA-ABS (treponemal, specific) after any reactive screen — the sequence "screen non-treponemal, confirm treponemal" is the exam's fixed order; dual point-of-care tests detect both antibody classes at once.
- Treatment doses: benzathine penicillin G 2.4 million units IM single dose for primary, secondary and early latent syphilis; 2.4 million units IM weekly x 3 for late latent, tertiary or unknown duration — at least 30 days before delivery for the fetus to benefit.
- Jarisch-Herxheimer reaction: fever, rigors and uterine contractions within hours of treatment in the second half of pregnancy can precipitate fetal distress and even labour — counsel, monitor, and treat supportively; it is not an allergy.
- Penicillin allergy in pregnancy: desensitise and give penicillin — azithromycin and doxycycline are not the pregnancy answer because of resistance and tooth effects respectively.
- Follow-up: quantitative VDRL titres at 1, 3, 6 and 12 months; a fourfold titre drop (two dilutions) by 6-12 months confirms response; a fourfold rise means reinfection or treatment failure.
- Congenital syphilis — early: snuffles (blood-stained nasal discharge, the most characteristic), maculopapular desquamating rash involving palms and soles, hepatosplenomegaly, jaundice, anaemia, pseudoparalysis of Parrot from painful osteochondritis.
- Congenital syphilis — late: Hutchinson's triad — interstitial keratitis, Hutchinson's teeth (notched, barrel-shaped upper incisors), eighth-nerve deafness; plus saddle nose, sabre shins and rhagades.
- Neonatal management: benzyl penicillin 50,000 units/kg/day IV (commonly quoted) for 10-14 days for proven or highly probable disease; examine and treat, do not simply observe, an infant of an inadequately treated mother.
From screening test to treatment dose
Follow the pathway at a district hospital. A 22-year-old primigravida at 12 weeks returns a VDRL reactive at 1:8. Step one repeats the sample and sends TPHA — positive. Step two stages the disease: a painless genital ulcer four months ago means early latent (under two years) syphilis; no lumbar puncture is needed for early disease. Step three treats with benzathine penicillin 2.4 million units IM as a single dose after counselling on the Jarisch-Herxheimer reaction — and because she is beyond 20 weeks in the alternative timeline, the team observes fetal heart monitoring after the injection. Step four notifies the partner, treats him, and retests her VDRL titre at 1, 3, 6 and 12 months expecting a fourfold fall.
Now the neonatal branch. The same woman, lost to follow-up, delivers at 36 weeks having had her dose at 32 weeks — inside the 30-day window, so the fetus is likely protected; the baby is examined, serology followed, but treatment withheld if fully well and maternal cure documented. Had she delivered untreated, the newborn with snuffles and a peeling palm rash receives benzyl penicillin for 10-14 days, with long-bone radiographs and liver function tests. The whole topic compresses to one sentence: find it with a cheap test, kill it with one to three injections, and time the cure at least a month before birth.
How NBE phrases it
Question shapes: pick the confirmatory test after a reactive VDRL (TPHA); pick the dose for late latent (three weekly 2.4 MU injections — the single-dose option is the distractor); recognise Jarisch-Herxheimer in a treated woman with fever and contractions (supportive care, not penicillin allergy); and pair Hutchinson's triad or snuffles with congenital syphilis in the paediatric crossover stem. The false-positive list — pregnancy, malaria, leprosy, SLE — is a favourite standalone multiple-choice.
Frequently asked questions
Which test screens for syphilis in pregnancy and which confirms it?
VDRL or RPR screens (quantitative, inexpensive); TPHA or FTA-ABS confirms — non-treponemal first, treponemal second.
What is the treatment of syphilis in pregnancy?
Benzathine penicillin G 2.4 million units IM as one dose for early syphilis, or the same dose weekly for three weeks for late latent or unknown duration, completed at least 30 days before delivery.
How is a pregnant woman with penicillin allergy managed for syphilis?
By desensitisation and penicillin administration — alternatives are inadequate in pregnancy, so allergy is managed around, not instead of, penicillin.
What is the Jarisch-Herxheimer reaction?
An acute febrile response with myalgia and uterine contractions within hours of treatment, from released treponemal antigens — monitored supportively, especially after 20 weeks, because fetal heart changes can follow.
What are the early and late signs of congenital syphilis?
Early: snuffles, desquamating rash of palms and soles, hepatosplenomegaly and pseudoparalysis of Parrot; late: Hutchinson's triad of interstitial keratitis, notched incisors and deafness.