Intrauterine infection (chorioamnionitis): diagnosis, treatment and complications

Posted: 21/02/2023

This is the ninth article in the birth injury series, which follows a review of HIE. In this article the focus is on intrauterine infection, also known as ‘chorioamnionitis’: what it is, its causes, symptoms, treatment, and the risks it poses to mother and baby.

What is chorioamnionitis?

Intrauterine infection is when the membranes around the fetus, placenta and/or the amniotic fluid become infected, posing serious risks to mother and baby if left untreated. The infection occurs as a result of bacteria entering the tissues and membranes around the fetus. Most commonly these bacteria will come from the vagina and cervix, or through the mother’s blood via the placenta. On occasion infection can occur as a result of procedures such as amniocentesis or fetoscopy. The most common types of bacteria causing chorioamnionitis are E.coli and group B strep.

Chorioamnionitis is rare in full-term deliveries (more than 37 weeks’ gestation), affecting only around 1-4%. It is much more common in the case of premature births (less than 37 weeks’ gestation) where it affects 40-70% of births.

Risk factors for developing chorioamnionitis during pregnancy include urinary tract infection, STIs (trichomoniasis, chlamydia, gonorrhoea, syphilis or HIV), group B strep, and bacterial vaginosis.

In cases where waters have broken early – known as ‘pre-term prelabour rupture of membranes’ (P-PROM) - the risk of infection increases. A mother is described as having P-PROM if she has ruptured membranes before 37 weeks of pregnancy but is not in established labour.

What are the signs and symptoms of chorioamnionitis?

Symptoms include:

• High temperature
• Abdominal pain
• Tender/painful uterus
• Tachycardia (abnormally fast heart rate) in both mother and baby
• Vaginal discharge with unpleasant smell and/or unusual colour

It is critical that these symptoms are picked up to allow further investigations and a diagnosis to be made.

How can it be treated?

If chorioamnionitis is suspected, a blood test or vaginal swab test will be taken. Following a diagnosis, IV antibiotics will likely be administered to treat the infection and reduce the risk of complications for mother and baby.

The NICE guidelines, Preterm labour and birth (2015), recommend that all mothers with P-PROM should be given prophylactic oral antibiotics (erythromycin) for 10 days or until established labour. The purpose of this is to reduce the risk of infection developing.

What can happen if chorioamnionitis is left untreated?

Complications associated with chorioamnionitis can be significant and include:

• Premature birth
• Postpartum infection to mother
• Heavy bleeding after birth (known as ‘post-partum haemorrhage’)
• Neonatal sepsis (infection to baby)
• Chronic lung disease (to baby)
• Brain injury leading to cerebral palsy and other neurodevelopmental disabilities

A failure to diagnose and treat suspected choroamnionitis in a timely way can therefore lead to devastating consequences – for both mother and baby.

If you have been affected by any of these issues and want some professional advice, our specialist birth injury team is here to offer an informal discussion to let you know what your options are. Please call 0800 328 9545, email clinnegspecialist@penningtonslaw.com or complete our online assessment form.

Previous articles in this series:

• Shoulder dystocia: what is it, how is it caused, and what are the long-term effects?
• Erb's palsy: what it is and how to bring a claim
• Facial paralysis: why it occurs in newborn children, and how it should be treated
• Genetic disorders: Down's, Edwards' and Patau's syndrome
• Understanding hypoxic-ischemic encephalopathy (HIE)

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