Tommy's PregnancyHub

Causes of premature birth

It’s not always possible to explain the causes of preterm birth and why it happens. There are risk factors for being born early, such as infection, placental problems or genetic problems, but in many cases the cause is unknown.

Most preterm babies arrive early without warning. However, some pregnancies are known to be at risk of ending in preterm birth.

We still have a lot to learn about premature birth so it's not always possible to explain the causes and why it happens. There are maternal and baby risk factors for being born early, such as infection, placental problems or genetic problems for example, but in many cases the cause is unknown. 

This is partly why prevention of premature birth is still in need of extensive research - without knowing the causes, a treatment is difficult. Tommy's invests more than £400,000 annually into prematurity research.

Although the cause of premature birth cannot often be determined all the conditions below are risk factors for premature birth. This means that if you have one of these premature birth is more likely to happen.

Cone biopsy and LLETZ
Intrahepatic cholestasis of pregnancy (ICP)
Pre-eclampsia and premature birth
Intrauterine infection (chorioamnionitis)
Fetal growth restriction (FGR)
Type 1 or type 2 diabetes in pregnancy
Lifestyle factors and premature birth
Antiphospholipid syndrome (APS)
Uterine abnormality
Cervical incompetence
Waters breaking early (PPROM)
Placental abruption
Low-lying placenta (placenta praevia)
Gestational diabetes

 

Review dates

Last reviewed: 1 April, 2017
Next review: 1 April, 2020