Infections in pregnancy

STI

All pregnant women should be screened for STIs, since they are some of the key causes of problems:

• Herpes simplex - neonatal herpes is rare, but has a 50% mortality. Transmission occurs through vaginal delivery, thus if there is any sign of HS, the mum gets a c-section.
• Syphilis - caused by Treponema pallidum, this can lead to congenital disease, or stillbirth. Treatment prevents foetal damage, but doesn't reverse it.
• HIV - Vertical transmission to the foetus happens in 15%, but retroviral treatment can dramatically reduce this.
• Hepatitis B - Can cause neonatal hepatitis, but can be prevented with administration of immunoglobulin.
• Chlamydia - As well as causing PID and infertility, is linked to prematurity and neonatal conjunctivitis.
• Gonorrhoea - Same as chlamydia, but less common.

Non STI

• β-haemolytic streptococcus - about 20% of pregnant women have this in their genital tract. 75% of their babies get the disease, and 1 in 100 get neonatal sepsis; the commonest cause of severe sepsis in babies. With screening, antibiotics can be given in birth, preventing most deaths.
• Herpes zoster - chickenpox in pregnancy can be fatal to the mother. Transfer to the foetus is rare, but infection before childbirth can cause neonatal infection, and this has a high mortality. It's bad!
• Rubella - maternal infection in early pregnancy causes foetal abnormalities, such as deafness, cardiac disease and mental retardation. After 16 weeks, the risk is very low. Vaccine is contraindicated in pregnancy.
• Parvovirus - known as 'slapped cheek'. Usually caught from children. Causes anaemia and death in 10% of affected foetuses, usually before 20 weeks. Some problems can be treated with in utero transfusion.
• CMV - usually subclinical. Infection at any point causes neonatal infection in 40%. Problems in the child are rare, but can be prevented with neonatal treatment of the infection.
• Bacterial vaginosis - Can cause preterm labour, which antibiotics can prevent.
• Listeriosis - rare, but its the reason pregnant mums should avoid soft cheeses, since it can cause foetal death.
• Toxoplasmosis - pretty rare, and there are a few nasty sequallae, but they are very rare.