Between 10-30% of women normally have GBS in their vagina and bowel. Approximately 20% of women will test positive to Group B streptococcus [GBS] during pregnancy. GBS is a transient bacterium, that means it is there sometimes and other times is not.
***Key Points***
If Group B strep is present during pregnancy, labour or birth, it does not affect you but if your baby is exposed to it during birth, for example if your waters break some time before birth, there is a chance your baby can become unwell.
You will be offered a test to see if the bacteria are present in your vagina at around 36 weeks of pregnancy. If positive, you will be offered antibiotics during labour. There is a small chance that your baby can develop an infection if exposed to GBS
***Key Points***
***Testing for GBS Streptococcus***
The GBS swab is a test that you can do yourself – you insert a swab (a bit like a cotton bud) into your vagina (only about one centimetre) and around your anus, then you put the swab into a tube that comes with the swab. Usually your midwife or doctor will give you the kit to do the test yourself and you complete it in the bathroom during one of your antenatal appointments.
***Testing for GBS Streptococcus***
***I have tested positive – what does this mean?***
If the test results are positive, it means that when your waters break in labour or before labour, you will be offered antibiotics (usually penicillin) to help protect the baby from becoming unwell. A very small number of babies exposed during labour may develop a serious infection such as meningitis, pneumonia or blood poisoning. This is thought to affect about 1 to 2 babies in every 1000 live births. When the infection occurs during labour it is called ‘early-onset GBS disease’ and may happen up until about 6 days after the birth. When it happens later, up until 3-6 months after the birth, it is called ‘late-onset GBS disease’.
Some hospitals offer the test to everyone who is pregnant, others will offer it only to people who are considered high risk, this is called routine testing and risk-based testing respectively. Antibiotic treatment for women who screened positive to GBS has been shown to be effective in reducing the chance of the newborn developing early onset GBS disease in 86-89% of cases. There is no high level evidence to support screening to prevent GBS disease but some other studies have shown some benefits of screening in the reduction of GBS transmission.
***I have tested positive – what does this mean?***
***Is my baby at risk?***
You might be considered high risk if you have had GBS in a previous pregnancy, or a previous baby with a GBS infection, or you are at a higher risk of having a pre-term birth. Your baby might also be at higher risk of being infected with GBS if your waters are broken for a long time [18 hours] before the birth, if you give birth or your waters break before you are 37 weeks pregnant or you have a high temperature during labour.
***Is my baby at risk?***
***After birth***
After the birth, if you were positive to GBS your baby will be monitored for the first couple of days to make sure they are not becoming unwell
Although rare, some babies become very unwell from exposure to GBS in the weeks after the birth. If you notice your baby seems unwell, is lethargic or sleepy, the legs and arms look floppy, appears to be having difficulty breathing or not feeding well you should seek help urgently. Call triple zero [000] or go to your local emergency department.
***After birth***
References
Pregnancy Birth Baby – Group B strep test
