CMV serology (IgG and IgM) and viral loads

• Both IgG and IgM negative: unlikely to be CMV infection
• IgG negative at booking, then IgG positive later in pregnancy: new infection
• IgG positive, IgM negative: past maternal infection
• IgG positive, IgM positive: check CMV IgG avidity
  • if low avidity likely to be maternal CMV infection within last 3-4 months

Antenatal ultrasound

Features include:

• IUGR
• Intracranial ventriculomegaly/calcification, microcephaly, periventricular leukomalacia
• Hyperechoic ('bright') bowel 
• Ascites, hydrops fetalis
• Pleural or pericardial effusions
• Oligo- or polyhydramnios 
• Hepatomegaly
• Abdominal calcification 
• Pseudomeconium ileus
• Thickened placenta

Indications for testing

• Evidence of maternal primary CMV infection in pregnancy
• Antenatal ultrasound suggestive of congenital CMV (cCMV) 
• Petechiae/purpura
• Hepatosplenomegaly
• Prolonged or conjugated hyperbilirubinaemia with transaminitis
• Unexplained thrombocytopenia
• Microcephaly
• Intracranial calcification or ventriculomegaly
• Chorioretinitis
• Seizures with no other explanation
• Severe pneumonia
• Cataract
• Failed hearing screen

Investigation results

• CMV PCR urine or mouth swab 
  • soak mouth swab in saliva for 1 min; send in viral transport medium to regional laboratory
  • if negative and high-risk CMV also send urine 

Other congenital infection screen depending on features (not exclusive)

• Toxoplasma (hydrocephalus, microcephaly, convulsions, generalised infection)
• Syphilis (rash, rhinitis, hepatosplenomegaly, jaundice, thrombocytopenia)
• Rubella (cataract, deafness, microcephaly)
• Zika (maternal/paternal travel, microcephaly) 

Further investigations

• Full blood count, liver enzymes, bilirubin, renal function
• Blood CMV viral load
  • if unknown whether infection is congenital request initial bloodspot card to be tested for CMV PCR
• Ophthalmic assessment
• Audiology: brainstem-evoked response – urgent (to offer treatment by aged 4 weeks)
• Head ultrasound
• if ultrasound head abnormal or seizures, MRI head 

• Postnatal acquired CMV – no treatment

Mild cCMV

• Asymptomatic – no CNS involvement, including sensorineural hearing loss
  • isolated IUGR
  • hepatomegaly with normal liver enzymes
  • isolated raised ALT/AST
  • mild thrombocytopenia 
• No treatment

Moderate cCMV

• Discuss with infectious diseases specialist if:
  • >2 weeks mild features
  • >2 mild features

Severe cCMV

• Significant organ involvement:
  • significant liver enzyme abnormalities
  • marked hepatomegaly
• Any CNS disease
  • isolated sensorineural hearing loss
  • retinitis
  • microcephaly
  • cranial ultrasound or MRI brain abnormalities
• Treat: valganciclovir 16 mg/kg oral 12-hrly for 6 months
  • if not tolerating oral feeds, ganciclovir 6 mg/kg IV [prepared by pharmacy (cytotoxic)] over 1 hr, 12-hrly for 6 weeks
• Discuss side effects vs benefits with parents:
  • advantages: potential reduced risk of deafness and developmental delay
  • disadvantages: during treatment reversible blood dyscrasia; long-term unknown risk to fertility and malignancy
• Start treatment as soon as possible
  • if diagnosis delayed can be started aged ≤1 month 

• Do not discourage infected women from breastfeeding their own uninfected, term babies (CMV can be transmitted via breastfeeding, but benefits of feeding outweigh risks posed by breastfeeding as a source of transmission)
• Avoid breastfeeding of premature baby if mother is positive and baby asymptomatic

• Enter on CMV surveillance register (discuss with paediatric infectious disease specialist)
• Ganciclovir IV: FBC, LFT, U&E at least twice weekly 
• Valganciclovir oral: FBC, LFT, U&E weekly for first 4 weeks, then monthly until completion
• Audiology: 3 monthly for first year, then 6 monthly for 3 yr, then annually until aged 6 yr for both asymptomatic and symptomatic congenitally infected babies 
• Paediatric infectious diseases specialist: as soon as possible in first month, then annually until aged 2 yr
• Ophthalmology: at least annually until aged 5 yr if symptomatic/signs at birth
• Neurodevelopmental assessment: aged 1 yr 
  • if delayed development discuss MRI brain with radiology