Clinical overview
Infection in pregnancy is core FCOG(SA) business because, in South Africa, sexually transmitted infections and their downstream complications sit at the intersection of two of the country's largest maternal and perinatal burdens: a generalised HIV epidemic and a high background prevalence of treatable STIs. The triennial Saving Mothers reports (NCCEMD) consistently place non-pregnancy-related infections — overwhelmingly HIV/AIDS and its complications — among the leading causes of maternal death, while syphilis and untreated STIs drive stillbirth, preterm birth, low birthweight and neonatal sepsis. Many of these losses are avoidable with a cheap, well-rehearsed package: screen early, treat the woman and her partner, retest, and protect the baby at delivery.
The objective focuses you on three threads that recur in every antenatal clinic: syphilis (a screenable, curable cause of devastating but preventable congenital disease), Group B Streptococcus (GBS) (a commensal that becomes the most important cause of early-onset neonatal sepsis), and the broader basket of STIs — chlamydia, gonorrhoea, trichomoniasis, bacterial vaginosis, herpes and the syndromic presentations of vaginal discharge and genital ulcer disease. Throughout, HIV is the silent co-traveller: it amplifies STI transmission and complications, and STIs amplify HIV transmission. The SA approach is syndromic management at primary care, layered on universal antenatal screening for syphilis, HIV and (increasingly) other infections, all anchored in the National Integrated Maternal and Perinatal Care Guideline (NDoH, 2024). Read this chapter alongside hiv-in-pregnancy, antenatal-booking and preterm-birth-and-pprom.
Core knowledge
Syphilis
Syphilis is caused by the spirochaete Treponema pallidum. It is transmitted sexually and transplacentally at any gestation and in any stage of maternal disease, with vertical transmission risk highest in early (primary, secondary, early latent) infection where spirochaetaemia is greatest. Untreated maternal syphilis classically causes a spectrum: miscarriage, stillbirth, hydrops, preterm birth, intrauterine growth restriction, neonatal death, and the stigmata of congenital syphilis (rhinitis/"snuffles", hepatosplenomegaly, rash, periostitis, and late features such as Hutchinson teeth and interstitial keratitis). Stillbirth and perinatal death are the dominant SA burden.
Staging matters because it determines treatment duration:
- Primary — painless chancre at inoculation site.
- Secondary — disseminated: maculopapular rash (including palms/soles), condylomata lata, mucous patches, lymphadenopathy.
- Early latent — asymptomatic, infection acquired within the preceding ~12 months.
- Late latent / latent of unknown duration — asymptomatic, beyond ~12 months or unknown.
- Tertiary — gummatous, cardiovascular, neurosyphilis (uncommon in pregnant women).
Serology underpins diagnosis. Treponemal tests (TPHA/TPPA, treponemal EIA, and rapid point-of-care treponemal tests) confirm exposure but stay positive for life. Non-treponemal tests (RPR, VDRL) are quantitative, correlate with disease activity, and are used to monitor treatment response — a fourfold (two-dilution) drop in titre signals adequate response. SA antenatal services increasingly use on-site rapid syphilis tests (often dual HIV/syphilis devices) so that a positive result is actioned the same day rather than lost to follow-up.
Group B Streptococcus
Streptococcus agalactiae (Lancefield group B) colonises the gastrointestinal and genital tract of a substantial minority of women asymptomatically. It is the leading cause of early-onset neonatal sepsis (EONS) — sepsis, pneumonia or meningitis in the first week of life (most within 24–48 hours), acquired by vertical transmission during labour and delivery. Late-onset disease (after the first week) is less clearly prevented by intrapartum measures.
The protective strategy is intrapartum antibiotic prophylaxis (IAP) to the mother, which suppresses transmission during passage through the colonised tract; antenatal treatment of colonisation does not prevent EONS because recolonisation occurs. Two strategies exist internationally: universal antenatal culture-based screening (a recto-vaginal swab at around 35–37 weeks, as favoured in some high-income settings) versus a risk-factor-based approach. RCOG Green-top Guideline 36 sets out the UK position and the recognised risk factors. South African public-sector practice, constrained by laboratory capacity, has historically leaned on a risk-factor approach rather than universal culture; you must follow the current local protocol and the NDoH Maternity Guideline (NDoH, 2024). Key recognised risk factors include: previous infant with invasive GBS disease, GBS bacteriuria in the current pregnancy, intrapartum pyrexia, prematurity (<37 weeks), and prolonged rupture of membranes.
Other STIs
- Chlamydia trachomatis and Neisseria gonorrhoeae — frequently asymptomatic in women; cause cervicitis, and in pregnancy are associated with preterm birth, PPROM and postpartum endometritis. Vertical transmission at delivery causes neonatal conjunctivitis (ophthalmia neonatorum) and, for chlamydia, neonatal pneumonia.
- Trichomonas vaginalis — frothy discharge, "strawberry cervix"; associated with preterm birth and low birthweight.
- Bacterial vaginosis — overgrowth of anaerobes with loss of lactobacilli; associated with preterm birth and PPROM, though treatment of asymptomatic BV has not reliably reduced preterm birth.
- Genital herpes (HSV) — the major risk is neonatal herpes, highest when a woman acquires a primary genital HSV infection in the third trimester (no protective transplacental antibody, high viral shedding at delivery). See current BASHH HSV-in-pregnancy guidance.
- Genital warts (HPV) — rarely a delivery problem; do not in themselves mandate caesarean.
These cluster into the two SA syndromic categories you will manage daily: vaginal discharge syndrome (VDS) and genital ulcer disease (GUD).
Assessment
History and examination
Take a focused sexual and obstetric history: symptoms (discharge, dysuria, ulcers, itch, lower abdominal pain), partner symptoms and number of partners, prior STIs, HIV status and ART, allergies (especially penicillin), and gestation. Examine for genital ulcers, lymphadenopathy, the rash of secondary syphilis (palms/soles), discharge character, and signs of pelvic infection. Always assess the pregnancy itself — fetal heart, fundal height, signs of preterm labour or ruptured membranes.
Investigations
- Syphilis serology at booking is universal and mandatory in SA antenatal care. The 5th-edition guideline supports early booking screening and a repeat test later in pregnancy (re-screening in the third trimester / around 32 weeks and at delivery in high-prevalence settings) so that infections acquired after booking are caught. Use a treponemal test (often rapid) to detect, and RPR/VDRL titre to stage activity and monitor response.
- HIV testing — offered to all at booking, repeated at scheduled antenatal visits per the Prevention of Vertical Transmission (PVT) programme; an essential co-test because STIs and HIV travel together.
- Syndromic STI assessment — SA primary care uses syndromic management (treat the syndrome, not a specific lab-confirmed organism) per the SAHCS 2022 STI Guidelines and the NDoH STI guidelines/EML. Where available, NAAT (nucleic acid amplification testing) for chlamydia and gonorrhoea improves precision but is not universally accessible.
- GBS — bacteriuria found on routine antenatal MSU is significant; recto-vaginal culture at 35–37 weeks where universal screening is offered.
Levels of care
Uncomplicated screen-positive syphilis and syndromic STIs are managed at primary care / midwife obstetric units. Refer to district/regional level for penicillin allergy requiring desensitisation, suspected congenital syphilis, treatment failure, neurosyphilis, primary HSV near term, severe sepsis, or any preterm labour/PPROM driven by infection (see high-risk-pregnancy-risks).
Management
Syphilis — treat early, treat the partner, retest
Benzathine penicillin G (benzathine benzylpenicillin) is the only adequate treatment for maternal and fetal syphilis and the only agent reliably preventing congenital infection.
- Early syphilis (primary, secondary, early latent): benzathine penicillin G 2.4 million units IM, given as a single dose (standard teaching). Some authorities and SA practice favour additional weekly doses in pregnancy to maximise fetal cure — follow the dosing in the current NDoH STI guideline/EML and the SAHCS 2022 STI Guidelines.
- Late latent / unknown duration: benzathine penicillin G 2.4 million units IM weekly for three doses (standard teaching).
- Begin treatment the same day as a positive rapid test; do not wait for confirmatory titres.
Penicillin allergy: there is no proven non-penicillin alternative that treats the fetus. The correct course is penicillin desensitisation and treatment with penicillin (refer for inpatient desensitisation) rather than substituting a macrolide. Confirm the allergy is genuine.
Watch for a Jarisch–Herxheimer reaction within hours of the first penicillin dose — fever, rigors, myalgia and, in pregnancy, uterine contractions and transient fetal heart-rate changes. Warn the woman, treat symptomatically with antipyretics, and in later pregnancy treat where there is fetal monitoring capacity; do not let fear of this reaction delay treatment.
Partner notification and treatment is essential — an untreated partner re-infects the woman and the fetus. Retest with RPR/VDRL to confirm a fourfold titre fall. Examine and treat the neonate per paediatric/congenital syphilis protocol; a baby of an inadequately treated mother (or treated <30 days before delivery) is managed as potentially infected.
Figure J17.1 — Same-day syphilis screening, penicillin treatment, partner management and fetal-protection checklist.
Group B Streptococcus — the intrapartum drill
The intervention that prevents early-onset neonatal sepsis is intrapartum antibiotic prophylaxis (IAP) — given in labour or after rupture of membranes, not antenatally.
Offer IAP when any apply (risk-factor approach, per local protocol / RCOG GTG 36):
- previous baby with invasive GBS disease
- GBS bacteriuria in this pregnancy
- known GBS colonisation this pregnancy (where screening is done)
- preterm labour (<37 weeks)
- intrapartum pyrexia (≥38°C)
- prolonged rupture of membranes
Regimen (standard teaching, confirm against local EML): intravenous benzylpenicillin as soon as labour is established, repeated through labour until delivery; IV clindamycin for penicillin-allergic women (check local sensitivities). Aim to give the first dose ideally ≥4 hours before delivery for maximum neonatal benefit, but give it even if delivery is imminent. Pair this with vigilant newborn observation for signs of sepsis and a low threshold for neonatal review — see neonatal-resuscitation and puerperal-complications.
Figure J17.2 — Risk-factor triggers and timing for intrapartum GBS prophylaxis to prevent early-onset neonatal sepsis.
STIs — syndromic management
SA primary care treats syndromically, covering the likely organisms for the presenting syndrome (per SAHCS 2022 STI Guidelines and NDoH STI guidelines/EML), because lab confirmation is often unavailable and delay is harmful:
- Vaginal discharge syndrome (VDS): cover gonorrhoea, chlamydia and trichomonas/BV per the current algorithm. In pregnancy, avoid drugs contraindicated by gestation and use pregnancy-appropriate agents per the STG/EML.
- Genital ulcer disease (GUD): cover syphilis and HSV (and other regional causes) per the algorithm; always send/perform syphilis serology in any GUD presentation.
- Lower abdominal pain syndrome (PID): uncommon in an intrauterine pregnancy but consider; treat and investigate for an alternative cause.
- Chlamydia/gonorrhoea confirmed: treat with the pregnancy-appropriate regimen in the current guideline and test of cure as recommended.
- Genital herpes: first-episode genital HSV is treated with aciclovir; suppressive aciclovir from ~36 weeks reduces recurrences and shedding at term. Primary genital HSV acquired in the third trimester is an indication to discuss caesarean delivery because of high neonatal-herpes risk; recurrent HSV with no active lesions at delivery does not mandate caesarean. Follow current BASHH HSV-in-pregnancy guidance.
For every STI: treat the partner(s), screen for co-infection (HIV and syphilis at minimum), counsel on condoms, and document. Integrate with the Prevention of Vertical Transmission (PVT) cascade — first-line ART in SA is TLD (tenofovir + lamivudine + dolutegravir) per the NDoH National Consolidated Guidelines (2026). Note the 2026 syphilis-in-pregnancy schedule: rapid treponemal tests first-line, repeated through pregnancy, and all syphilis-related stillbirths are notifiable.
Emergency drill — chorioamnionitis / intrauterine infection (maternal sepsis): maternal fever, tachycardia, uterine tenderness, offensive liquor, fetal tachycardia. This is an obstetric emergency. Recognise → resuscitate (the sepsis six: high-flow O₂, IV broad-spectrum antibiotics, IV fluids, blood cultures + lactate, monitor urine output) → deliver. The definitive treatment of intrauterine infection is delivery of the baby and placenta, alongside antibiotics — do not temporise. Escalate to senior/regional care. See RCOG GTG 64 (maternal sepsis) and shock-management.
Figure J17.3 — Syndromic STI management loop in pregnancy, with HSV near-term decisions and chorioamnionitis sepsis escalation.
Red flags / pitfalls
- Treating syphilis with anything other than penicillin in pregnancy. Macrolides/erythromycin do not reliably cross to treat the fetus. Penicillin allergy → desensitise, do not substitute.
- Not retesting. A single negative booking test misses infection acquired later — re-screen in the third trimester and at delivery in high-prevalence settings. Equally, failing to repeat RPR misses treatment failure or reinfection.
- Forgetting the partner. Untreated partners reinfect the woman and fetus; STI control is a couple/contact issue, not an individual one.
- Treating GBS colonisation antenatally and thinking the baby is protected. Only intrapartum prophylaxis prevents early-onset sepsis; recolonisation negates antenatal courses.
- Withholding penicillin for fear of Jarisch–Herxheimer. Warn, monitor, treat — but treat.
- Missing the link with HIV. Every STI presentation is an HIV-testing opportunity; untreated STIs raise HIV transmission both ways.
- Mislabelling a third-trimester primary HSV as "just a recurrence" and proceeding to vaginal delivery — primary infection near term is the high-risk scenario for neonatal herpes.
- Lost to follow-up. The commonest SA failure is not diagnostic but systems — same-day rapid testing, on-site treatment and partner tracing exist precisely to prevent the screen-positive woman from slipping through.
- Treating asymptomatic bacterial vaginosis expecting to prevent preterm birth — the evidence does not support this; treat symptomatic disease.
Evidence anchors
- National Integrated Maternal and Perinatal Care Guideline for South Africa (NDoH, 2024), NDoH — the SA obstetric source of truth for antenatal syphilis and HIV screening, re-screening, and intrapartum care.
- SAHCS 2022 STI Guidelines (Southern African HIV Clinicians Society) and the NDoH STI guidelines / Standard Treatment Guidelines + EML — syndromic management of vaginal discharge and genital ulcer disease, and pregnancy-appropriate regimens.
- National Consolidated Guidelines for the Prevention and Management of HIV… in Pregnant & Breastfeeding Women (NDoH, published January 2026) — supersedes the 2023 ART + 2019 PMTCT guidelines; first-line TLD; Prevention of Vertical Transmission (PVT) + STI–HIV integration; rapid-treponemal syphilis screening schedule.
- Saving Mothers / NCCEMD (latest triennium) — non-pregnancy-related infection (HIV) among leading maternal-death causes; infection-driven stillbirth and perinatal loss.
- RCOG Green-top Guideline No. 36 — Group B Streptococcal disease, early-onset prevention — risk-factor recognition and intrapartum antibiotic prophylaxis principles.
- RCOG Green-top Guideline No. 64 — Maternal sepsis — recognition and the sepsis-management drill.
- BASHH HSV-in-pregnancy guidance (current) — first-episode vs recurrent HSV, third-trimester primary infection and mode of delivery, suppressive aciclovir from ~36 weeks. (Note: RCOG GTG 30 on genital herpes is archived; substitute BASHH.)
- WHO STI Treatment Guidelines and WHO Guidelines for STI screening in HIV-positive populations (2022) — international alignment.
Note on hedged facts: benzathine penicillin and benzylpenicillin/clindamycin regimens, the 35–37-week GBS swab window, the ≥4-hour IAP target, the fourfold RPR drop, and HSV suppression from ~36 weeks are stated as standard teaching — verify exact doses, intervals and re-screening gestations against the current NDoH STI guideline/EML and the 5th-edition Maternity Guideline before clinical use.