STIs in pregnancy triple risk of preterm birth

Sexually transmitted infections during pregnancy are linked to higher risks of preterm birth, stillbirth and babies born smaller than expected, a large Australian study has found.

Researchers analysed almost 60,000 births in the Northern Territory between 2005 and 2020, identifying strong associations between maternal infections and adverse birth outcomes.

Congenital syphilis was found to triple the risk of preterm birth and more than double the risk of growth restriction — when a baby is smaller than expected for its gestational age.

Other common infections — including chlamydia, gonorrhoea and trichomoniasis — were also significantly linked to babies being small for gestational age. Gonorrhoea was associated with almost double the risk of stillbirth.

Researchers from Curtin University’s School of Population Health and enAble Institute examined the impact of maternal STIs in a region with some of Australia’s highest infection rates.

“This research shows STIs during pregnancy may lead to potentially devastating outcomes,” said Dr Jennifer Dunne, lead author.

“Current STI screenings happen early in pregnancy, but we need additional checks later in pregnancy, especially in high-risk areas.

“Many of these infections are common, preventable and treatable — we just need to be able to catch them in time to treat them as early as possible.”

The findings highlight ongoing inequalities in healthcare access, particularly in remote and regional areas where barriers to timely testing and treatment persist.

“Barriers to timely testing and treatment still exist in isolated communities,” said co-author Dr Jacqui Hendriks.

“Our research suggests a need to strengthen culturally appropriate, accessible services to improve outcomes for parents and babies.

“This includes follow-up care in remote settings, plus targeted education to raise awareness of STIs in pregnancy and the importance of early antenatal care.”

Although current Australian guidelines recommend STI screening early in pregnancy, the researchers say further testing later on could help detect infections in time to avoid complications.