Perinatal infections II: CMV, parvovirus B19, varicella, rubella and Zika

Also known as Congenital cytomegalovirus · CMV in pregnancy · Parvovirus B19 · Slapped cheek disease · Congenital varicella syndrome · Congenital rubella syndrome · Congenital Zika syndrome · TORCH infections

Exam-exhaustive FRANZCOG reference on the five vertical-transmission viral infections a candidate must hold — CMV (trimester-by-trimester transmission, primary vs recurrent, the valaciclovir treatment and secondary-prevention evidence, hygiene prevention), parvovirus B19 (erythroid progenitor tropism, MCA-PSV surveillance, intrauterine transfusion), varicella (VZIG and aciclovir post-exposure, congenital varicella syndrome risk by gestation), rubella (the CRS triad and pre-pregnancy MMR), and Zika (travel, mosquito and sexual-transmission prevention). RANZCOG C-Obs 64 anchored, globally tagged to MRCOG and ABOG.

high18 referencesUpdated 26 July 202615 min readVerification in progress

Practise this topic

8 MCQs

One-line fellowship answer

Five vertical-transmission viruses belong in one mental folder: CMV (the commonest congenital infection — primary transmits in about a third, recurrent in under two per cent; high-dose valaciclovir 8 g per day is the treatment and secondary-prevention evidence; hygiene prevents most primary infections), parvovirus B19 (erythroid progenitor tropism causes anaemia and hydrops; surveillance is middle cerebral artery peak systolic velocity over 1.5 multiples of the median, with intrauterine transfusion), varicella (congenital syndrome risk concentrated before 20 weeks; post-exposure VZIG or aciclovir within the window), rubella (the cataracts–cardiac–deafness triad; pre-pregnancy MMR is the whole prevention story) and Zika (travel, mosquito and sexual-transmission prevention). RANZCOG C-Obs 64 is the ANZ anchor.^[1]^[9]^[11]^[17]

A childcare worker at 9 weeks books in for her first antenatal visit, a teacher at 20 weeks is sent up with a hydropic fetus after a slapped-cheek outbreak, and a returning traveller asks whether her recent rash was Zika. Three women, one question for you: which infection, what is the fetal risk, and what do you do today. This topic is the answer, organised way station asks it.^[5]^[9]

Overview and definition

These five viruses share one thing — they cross the placenta and damage the developing fetus — and differ on almost everything else: transmissibility, the gestational window of risk, the preventability, and the treatment. The candidate who holds the five in one frame, but treats each on its own numbers, passes this station.^[5]^[9]

CMV

Commonest congenital infection (~0.64% birth prevalence)
Primary transmits ~32%, recurrent ~1.4%
Teratogenic to the developing brain; sensorineural hearing loss is the key long-term sequela
No vaccine; hygiene is primary prevention
High-dose valaciclovir 8 g/day for treatment and secondary prevention

Parvovirus B19

~30% vertical transmission on maternal infection
Tropism for erythroid progenitors via the P antigen
Causes fetal anaemia, high-output failure, hydrops
MCA-PSV surveillance; intrauterine transfusion for severe anaemia
Survival with IUT is high (~85% in severe hydrops)

Varicella

Congenital syndrome risk concentrated before 20 weeks
Highest risk 13 to 20 weeks (~2%); under 13 weeks ~0.4%
Maternal zoster carries essentially no fetal risk
Post-exposure VZIG or aciclovir within the window
Postpartum vaccine for the non-immune

Rubella / Zika

Rubella: CRS triad of cataracts, cardiac, deafness; pre-pregnancy MMR prevents it
Rubella: risk concentrated in first trimester; vaccines since 1969
Zika: congenital Zika syndrome — microcephaly with intracranial calcifications
Zika: travel, mosquito and sexual-transmission prevention
Zika: adverse outcomes regardless of trimester

^[1] ^[8] ^[11] ^[17] ^[14]

References18Show

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