Antenatal Screening Programmes

Question 1

What infections are routinely screened for at booking?

Answer 1

HIV
Hepatitis B (HBsAg)
Syphilis
(Rubella immunity screening removed from routine in April 2016 — MMR offered postnatal if non-immune)
(Hepatitis C NOT routinely screened — only if risk factors)

Question 2

What is the management if a woman is HIV positive in pregnancy?

Answer 2

Antiretroviral therapy (ART) — continue if already on; start if new diagnosis. Aim for undetectable viral load
Viral load checked at 36 weeks determines mode of delivery:
<50 copies/mL → vaginal delivery supported
50 copies/mL → planned CS at 38-39 weeks

Very high viral load → CS + IV zidovudine during procedure
Avoid: breastfeeding (UK guidance), invasive procedures (FBS, FSE), artificial ROM if possible (if detectable VL), membrane sweeping
Baby: Antiretroviral prophylaxis (zidovudine/nevirapine depending on risk) for minimum 2-4 weeks
Baby testing: HIV DNA PCR at birth, 6 weeks, 12 weeks, HIV antibody at 18-24 months
Notify: Antenatal results should be shared with paediatric team with consent

Question 3

What is the management of Hepatitis B in pregnancy?

Answer 3

Refer to hepatologist/infectious diseases
Check: HBeAg, anti-HBe, viral load, LFTs
If high viral load (≥200,000 IU/mL or HBeAg positive) → tenofovir in third trimester
Baby at birth (within 24 hours):
ALL babies of HBsAg+ mothers: Hep B vaccine
High-risk babies (high VL/HBeAg+): Hep B vaccine + HBIG
Further vaccine doses at 1 and 12 months
Test baby for HBsAg at 12 months
Breastfeeding: SAFE (not contraindicated)

Question 4

What is the management of syphilis in pregnancy?

Answer 4

IM benzathine penicillin G (or procaine penicillin for 10-14 days if primary/secondary)
If penicillin-allergic → desensitise and give penicillin (or consider erythromycin but less effective for fetal treatment)
Partner notification and treatment
Monitor with serial RPR/VDRL titres
Congenital syphilis risks: miscarriage, stillbirth, hydrops fetalis, hepatosplenomegaly, rash, saddle nose, Hutchinson’s teeth
Refer to GUM

Question 5

What is the management if a pregnant woman is exposed to varicella (chickenpox)?

Answer 5

1. Check VZV IgG antibody status
2. If immune (positive IgG) → reassure
3. If non-immune (negative IgG) → VZIG (varicella zoster immunoglobulin) within 10 days of exposure
4. If non-immune and develops chickenpox:
   <20 weeks: Risk of fetal varicella syndrome (limb hypoplasia, skin scarring, eye/CNS abnormalities) — ~1-2% risk if 13-20 weeks
   >20 weeks: Lower fetal risk but maternal risk of varicella pneumonia remains
   Around delivery (5 days before to 2 days after): Risk of neonatal varicella (severe) — give baby VZIG and may need IV aciclovir
5. Treat mother with oral aciclovir if presents within 24 hours of rash and >20 weeks (or any gestation if severe)
6. Avoid contact with other pregnant women
7. VZV vaccine is LIVE → CONTRAINDICATED in pregnancy

Question 6

What is the management if a pregnant woman is exposed to rubella?

Answer 6

Check rubella IgG and IgM

If IgG positive → immune → reassure
If non-immune and exposed:
Confirm contact (was it rubella?)
Check IgM and IgG (acute and convalescent)
If confirmed rubella infection:
<16 weeks: High risk of congenital rubella syndrome (deafness, cataracts, cardiac defects, microcephaly) — discuss with fetal medicine; termination may be discussed
16-20 weeks: Risk of deafness only
>20 weeks: Minimal risk

MMR vaccine is LIVE → CONTRAINDICATED in pregnancy

Offer MMR postpartum to non-immune women (safe while breastfeeding)

Advise avoid pregnancy for 1 month after MMR

Question 7

What is the management of parvovirus B19 (slapped cheek) exposure in pregnancy?

Answer 7

Check parvovirus IgG and IgM
If IgG positive → previous immunity → reassure
If IgG negative/IgM positive → acute infection
Risks:
Fetal anaemia → hydrops fetalis → fetal death
Risk highest at 9-20 weeks (but risk present throughout)
Transplacental infection of fetal erythroid precursors
Management:
Serial USS (weekly for 8-12 weeks after exposure) looking for hydrops (ascites, oedema, pericardial/pleural effusion)
Serial MCA Doppler (middle cerebral artery peak systolic velocity — elevated in fetal anaemia)
If hydrops → intrauterine blood transfusion (fetal medicine centre)
No vaccine, no antiviral treatment
Overall fetal loss rate ~9% if infected <20 weeks

Question 8

What is the management of toxoplasmosis in pregnancy?

Answer 8

NOT routinely screened for in UK

Advise prevention: wash hands after handling raw meat, wash fruit/veg, avoid cat faeces/litter trays, wear gloves gardening

If acute infection suspected → check IgG/IgM, IgG avidity

If confirmed acute infection:
Spiramycin (first trimester) — reduces transmission
Pyrimethamine + sulfadiazine + folinic acid (after first trimester) — treats fetal infection

Congenital toxoplasmosis: hydrocephalus, intracranial calcifications, chorioretinitis, seizures

Risk of fetal transmission increases with gestation (but severity of disease decreases)

Question 9

What is the management of Group B Streptococcus (GBS) in pregnancy?

Answer 9

NOT routinely screened for in UK (no universal antenatal screening)
Detected incidentally on vaginal/urine culture
Intrapartum antibiotic prophylaxis (IAP) indicated if:
GBS detected in current pregnancy (urine or vaginal swab)
Previous baby with GBS disease
Chorioamnionitis / intrapartum fever ≥38°C
Preterm labour (<37 weeks) — some guidelines
IV benzylpenicillin (first-line) — loading dose 3g then 1.5g 4-hourly until delivery
Alternative if penicillin-allergic: IV clindamycin (if sensitive) or vancomycin
Give as soon as labour starts / membranes rupture
Baby observed for 12-24 hours post-delivery for signs of sepsis