Group B Strep
This month is group B strep awareness month. Group B streptococcus, or GBS, is a common and normally harmless bacteria that comes and goes. This bacteria can however be very serious for newborns, who can pick up the bacterial infection as they pass through the vaginal canal. Babies that contract group B strep can develop meningitis, septicaemia and pneumonia. If you’re found to have group B strep, antibiotics are recommended at 4 hour intervals during labour which will pass through the placenta and provide protection to your baby.
So how common is group B strep in newborns? Well in a study of 148,000 newborns between 2000 and 2008, 94 tested positive for GBS an hour after birth. In the UK, approximately 1 in every 1000 babies born develops a GBS infection.
The problem with group B strep is that it’s transient, meaning the infection comes and goes. Testing for group B strep isn’t routine on the NHS, so a private test would need to be arranged if you were concerned about infection, and this needs to be done between 35 and 37 weeks of pregnancy. If you test positive, this doesn’t necessarily mean you would still have the infection at the time of birth, but your health care team will suggest antibiotics as a precaution. Similarly if you test negative, it doesn’t mean you will not have the infection at the time of labour. In studies, 91% of pregnant people tested for GBS were still negative during labor and 9% we’re positive, meaning they developed GBS between being tested and giving birth and did not receive antibiotic. On the reverse, of those pregnant people who tested positive, 84% were still positive at the time of giving birth and 16% of those who were positive were then negative during birth and received antibiotics unnecessarily (Young et al. 2011).
Testing positive for group B strep should not affect your birth place choices. Water birth is still an option if you require antibiotics, as stated by the Royal college of Obstetricians and Gynaecologists, however home birth may be harder to get agreement to as some NHS trusts may not permit IV antibiotics in a home birth setting because of the risk of an allergic reaction to the medications administered. If you test positive for GBS and are hoping for a home birth you will need to discuss this option with your midwifery team.
When deciding whether to test and treat for group B strep, it’s important to research and understand both the risks and benefits. The chances of a group B infection in baby is low, but the risk if they do is high. It is also important to consider the impact of antibiotics on newborns and the affect this can have on their microbiome. A course of antibiotics will not only destroy harmful bacteria, but also beneficial ones as well. Ultimately it’s a personal decision whether to test for group B strep, but it is important to be aware of the risk and your options.
If you’d like to read the research on group B strep, I recommend https://evidencebasedbirth.com/groupbstrep/ and https://www.sarawickham.com/topic-resources/group-b-strep-resources/