30th June 2023

Infection

The change from cell-mediated to humoral-mediated immunity makes pregnancy a time of relative immunocompromise. Several infections are known to cause fetal and congenital complications. Alongside the more traditional TORCH organisms discussed below, zika virus, malaria, influenza, hepatitis B, HIV, gonorrhoea and chlamydia can also cause maternal and neonatal compromise. E. Coli and Group A streptococcus are the most common infections leading to severe maternal sepsis.

TORCH

Toxoplasmosis, Other (syphilis, chickenpox, parvovirus 19) Rubella, Cytomegalovirus and Herpes Simplex make up the TORCH pathogens known to cause congenital infections, developmental delay and fetal compromise.

Syphilis is screened for at booking, and a positive result should be followed up by sexual health and obstetrics with urgent treatment given. Effective treatment is highly effective in preventing congenital syphilis.

Toxoplasmosis, chickenpox, parvovirus-19, rubella and CMV are not tested on booking bloods, but if infection or exposure is suspected, IgM and IgG levels are checked. The presence of IgM indicates acute infection; IgG indicates previous exposure. Blood saved at booking is therefore checked to see if this exposure and subsequent immunity occurred prior to pregnancy.

Women are asked about herpes simplex infection at booking; primary infection at or around delivery is an indication for Caesarean section. Prophylactic acyclovir is given from 36/40 to reduce the risk of a flare of recurrent herpes.