Gab Kovacs1 and Paula Briggs2
(1)
Department of Obstetrics and Gynaecology, Monash University, Clayton, Victoria, Australia
(2)
Sexual and Reproductive Health, Southport and Ormskirk Hospital, Southport, UK
Varicella (Chicken Pox)
Definition
Incidence
Aetilogy and Pathogenesis
Clinical Assessment
Treatment
Complications
Prognosis
Genital Herpes
Definition
Incidence
Aetilogy and Pathogenesis
Clinical Assessment
Treatment
Complications
Prognosis
Cytomegalo Virus (CMV)
Definition
Incidence
Aetilogy and Pathogenesis
Clinical Assessment
Treatment
Complications
Prognosis
Toxoplasmosis
Definition
Incidence
Aetilogy and Pathogenesis
Clinical Assessment
Treatment
Complications
Prognosis
Listeria
Definition
Incidence
Aetilogy and Pathogenesis
Clinical Asessment
Treatment
Complications
Prognosis
Group B Strep
Definition
Incidence
Aetilogy and Pathogenesis
Clinical Asessment
Treatment
Complications
Prognosis
Varicella (Chicken Pox)
Definition
Varicella Zoster Virus (VZV) is a DNA virus of the herpes family. Infection results in a vesicular eruption of the skin.
Incidence
It is estimated to occur in 3 in 1,000 pregnancies
Aetilogy and Pathogenesis
The virus is transmitted by vesicular fluid from the blisters or respiratory fluid. The incubation period is 1–3 weeks. The person is infectious for 48 h before the rash appears and until after the lesions crust over. The virus remains dormant in the dorsal root ganglia of the sensory nerves, and can be reactivated along the nerve root distribution as shingles.
Infection can be prevented by immunisation before pregnancy using a live attenuated vaccine.
Clinical Assessment
History
The primary infection is a typical viral illness associated with flu- like symptoms. A characteristic itchy maculo-papular rash develops.
Examination
The rash is maculo-papular initially, followed quickly by a vesicular eruption.
Investigations
· Blood sample for varicella zoster (IgG)
· Culture from the vesicular fluid
· PCR testing from maculopapular rash or scabs
Treatment
Medical
· Prevention – Women pre-pregnancy should be asked about a history of chicken pox (this is 97 % reliable as an index of immunity). If this is negative, their immunity should be checked for varicella antibodies. If they are VZV negative, immunisation should be undertaken. As the immunisation is with an attenuated strain of live VZV, pregnancy should be avoided for 3 months following immunisation.
· Contact during pregnancy – If the contact is definitely confirmed, and the woman has no history of previous infection, her immunity should be checked as a matter of urgency. If it is confirmed that she is not immune, Varicella Zoster Immunoglobulin (VZIG) should be administered. This is effective up to 10 days after contact.
· Developing chicken pox during pregnancy –
Women who develop chicken pox during pregnancy should commence antiviral therapy within 24 h of the rash appearing (Aciclovir 800 mg, five times a day for 7 days). VZIG is of no benefit once the chicken pox rash has established.
Complications
Pneumonitis, neurological symptoms, haemorrhagic rash.
Prognosis
The infection may be transmitted to the foetus resulting in Foetal Varicella Syndrome. This is uncommon, but can cause eye defects, limb deformity and neurological abnormalities.
Genital Herpes
Definition
Herpes is caused by Herpes Simplex Virus type 1 – (HSV-1) or type 2 (HSV-2). When present during late pregnancy, it can be transmitted to the foetus resulting in neonatal herpes.
Incidence
In the UK, one in 60,000 live births results in neonatal herpes infection.
Aetilogy and Pathogenesis
Transmission to the foetus is almost always by direct contact through infected secretions. The highest risk to the foetus is if the woman acquires the infection for the first time during late pregnancy.
Clinical Assessment
History
Presentation is usually with painful vulval lesions, initially vesicles followed by ulceration.
Examination
· vesicles
· ulcers (which may become secondarily infected)
Investigations
PCR for HSV-1 and HSV-2
Viral Culture is possible
Blood immunological testing for HSV-1 and HSV 2 IgG and IgM
Treatment
Medical
Antiviral therapy – aciclovir should be administered to a woman who contracts primary herpes in the late third trimester (after appropriate confirmation). For women who experience primary HSV in early pregnancy, there is no evidence for benefit of antiviral therapy at the time of delivery.
Surgical
Major – Caesarean section should be recommended to all women who have a confirmed primary HSV infection in the last 6 weeks of pregnancy. This reduces the risk of transmission to the baby, but does not offer complete protection against neonatal disease.
Women with secondary infection in late pregnancy, should be offered the option of caesarian section.
Complications
If transmitted to the foetus, neonatal herpes has a high morbidity and mortality. There are three types of neonatal infection: skin and eye, central nervous system (CNS) infection, or disseminated multi-organ disease.
Prognosis
The multi-organ disease has the worst prognosis with mortality of up to 30 %. CNS infections have a 70 % morbidity.
Cytomegalo Virus (CMV)
Definition
CMV is one of the herpes viruses. Once someone is infected they carry the virus for life, but it is usually harmless. However when it is acquired in utero, it can cause hearing loss or developmental delay.
Incidence
About one third of women of childbearing age have not been infected with CMV. Of these, between 1 and 4 % have their first infection during pregnancy. One in three women who have their first CMV infection in pregnancy pass it onto their fetuses. Consequently, 1 in 150 children is born with congenital CMV and 20 % will have problems.
Aetilogy and Pathogenesis
CMV is spread through body fluids such as blood, urine, saliva or breast milk. It is also sexually transmitted. Neonatal CMV infection is acquired through the placenta, with the virus passing into the foetus’ circulation.
Infection after birth rarely causes problems
Clinical Assessment
History
Most infections are asymptomatic. Sometimes symptoms of a viral illness: fever sore throat, fatigue lymphadenopathy may be detected.
Examination
Children known to be infected with CMV at birth should have regular checks of hearing and eyesight.
Investigations
· Virus can be detected in blood, saliva or urine confirming the presence of infection
· The presence of CMV antibodies will confirm that the person has been infected, but not when it occurred. Presence of CMV IgM is not solely indicative of primary infection.
· The diagnosis of neonatal infection is on the basis of isolating the virus.
Treatment
Medical
There is no licensed treatment for CMV. The antiviral drug acyclovir may have some beneficial effect for children with CNS symptomatic infection, but can have serious side effects.
Complications
These only occur in minority of women who acquire a primary infection whilst pregnant. Even then 80 % of infected fetuses show no ill effects.
Prognosis
For the majority of fetuses who are infected with CMV the outcome is good.
Toxoplasmosis
Definition
Toxoplasmosis is spread by the parasite toxoplasma gondii. It usually only causes mild symptoms, but if contracted in pregnancy can be harmful to the foetus.
Incidence
Of non-immune women about 5 per 1,000 get infected during pregnancy
The incidence of congenital toxoplasmosis in the UK is 3/100,000
Aetilogy and Pathogenesis
Infected cats pass the parasites in their faeces. The woman may then be infected by contaminated soil, fruit or vegetables, or from raw meat that is contaminated by the excrement
The foetus is at risk if the mother acquires the infection during pregnancy. With chronic infection (>6 months) the mother’s immunity protects the child.
Clinical Assessment
History
Most people infected are asymptomatic. Some may experience mild flu-like symptoms.
Examination
There are no sigs
Investigations
Antibodies to Toxoplasma can be measured in the blood
Treatment
Medical
Pyrimethamine and sulfadiazine plus folinic acid can be used, although the parasite is not complete eliminated as it is intracellular.
Complications
· Toxoplasmosis increases the risk of early pregnancy loss
· Children with congenital toxoplasmosis may have cephalomegaly, or a small head
· Often there are no symptoms at birth, but develop symptoms of vision loss, intellectual disability and fits.
Prognosis
The infection by the parasites is chronic and can be reactivated, especially if the person becomes immune-compromised
Listeria
Definition
Infection caused by Listeria monocytogenes
Incidence
Whilst Listerosis is rare in the population (0.26 cases/100,000 individuals in the USA) pregnant women are ten times more likely to get listeria.
Aetilogy and Pathogenesis
Women get infected by eating contaminated food e.g. Uncooked meat, cheeses, processed meat and smoked seafood.
Clinical Asessment
History
May experience flu like symptoms
Examination
No specific signs
Investigations
Isolation of listeria from blood, spinal fluid or amniotic fluid- the culture takes 48 h to grow
Gram stain and culture from genital tract
Serological tests are of little value
Treatment
Medical
Ampicillin for 14 days for mother
If neonate infected ampicillin and gentamycin at birth
Complications
May cause early pregnancy loss, stillbirth, premature delivery, or life threatening infection in the newborn, meningitis and septicaemia in immune-comprimised adults.
Prognosis
Whilst the infection can be treated by antibiotics, prevention is best
Group B Strep
Definition
Group B streptococcus (Streptococcus agalactiae) (GBS) is a common pathogen in the female genital tract. It is the commonest cause of neonatal sepsis.
Incidence
Approximately 15–20 % of women are asymptomatic carries of GBS.
In the UK it is estimated that GBS infection affects 1 in 2,000 neonates.
Aetilogy and Pathogenesis
The infection is acquired by the neonate during birth.
Risk factors include; prematurity (<37 weeks of gestation), prolonged rupture of membranes (>18 h), maternal fever (>38 ° C), previous GBS affected baby, or current GBS infection in vagina or urine.
Clinical Asessment
History
GBS carriers are asymptomatic
Examination
There are no signs
Investigations
· Risk based or universal screening by vaginal and and/rectal swabs at 37 weeks
· Women with GBS in their urine should be treated with antibiotics
Treatment
Medical
Penicillin >4 h before delivery; If allergic- clindamycin or erythromycin.
Surgical
Major – If Elective Caesarean Section performed- chemoprophylaxis is not needed
Complications
One in 200 women with asymptomatic GBS will have a neonate who develops sepsis.
Prognosis
With appropriate chemoprophylaxis GBS infections of the neonate can be avoided