Antibiotics are recommended in preterm labour to stop group B streptococcal transmissionBMJ 2017; 358 doi: https://doi.org/10.1136/bmj.j4271 (Published 13 September 2017) Cite this as: BMJ 2017;358:j4271
Women who go into preterm labour before 37 weeks of pregnancy should be offered antibiotics to prevent transmission of group B streptococcal (GBS) disease to their offspring, new guidelines from the Royal College of Obstetricians and Gynaecologists have recommended.1
“This guidance provides clear advice to doctors and midwives on which women should be offered antibiotics to avoid passing GBS infection on to their babies,” said Peter Brocklehurst, professor of women’s health at the University of Birmingham and coauthor of the guideline. “In particular, we hope to reduce the number of early onset group B strep infections and neonatal deaths in babies born before 37 weeks.”
Group B streptococcus is the most common cause of severe early onset infection in newborn infants. Latest available figures from 2015 show that it affects 0.57 in every 1000 births in the UK and Ireland, and the incidence is increasing.
The bacterium occurs in the bowel and lower vaginal tract flora in around 25% of women and can be transmitted to offspring during labour. The vast majority of these babies experience no ill effects, but a small proportion develop potentially serious infection. With prompt treatment, 17 in 20 babies who have early onset GBS infection diagnosed recover fully, but two are left with some level of disability and one in 20 dies.
How best to prevent early onset GBS disease is controversial. US guidelines recommend that all pregnant women should be offered screening for group B streptococcus and that antibiotics should be offered to those found to be colonised with the bacterium. But the UK National Screening Committee has recommended against routine screening because of a lack of evidence of benefit and the potential for harm from increased antibiotic use.
The new UK guideline is based on a review of all published articles on group B streptococcus and pregnancy since 2011. It found that the risk of women transmitting GBS disease was highest in those with preterm labour, as 22% of babies with the infection diagnosed in 2015 were born prematurely.
The guideline committee found that the risk of early onset GBS disease was four times higher in preterm babies, as around one in 500 develops the infection, compared with one in 2000 babies born at term. And the mortality rate was around 10 times higher, at 20-30% in babies born before 37 weeks, compared with 2-3% in full term babies.
On the basis of this evidence the guideline recommends offering intravenous antibiotics to all women who go into preterm labour, to prevent transmission of GBS infection. It also recommends offering intrapartum antibiotic prophylaxis to all women who have a previous baby with early or late onset GBS disease.
Janice Rymer, vice president of education for the Royal College of Obstetricians and Gynaecologists, said that the new recommendations should help to reduce the large variation in current UK practice.
She said, “This revised guideline will provide standardised treatment of pregnant women with GBS and reduce the risk of their babies developing the infection. The guideline also aims to raise awareness of GBS by recommending that all pregnant women are provided with an appropriate information leaflet, which the [Royal College] is now updating.”