Herpes simplex, pregnancy and childbirth
Having herpes simplex does not affect fertility or the ability to conceive. Talk to your doctor about taking antiviral tablets if you need to prevent outbreaks when you want to conceive. This is safe.
Early pregnancy – first and second trimester
A primary infection at this time will not affect the baby or cause a miscarriage. It used to be thought that there might be an increased risk of miscarriage if the mother caught genital herpes in the first three months. Now we know there is no evidence for this at all. A primary infection will not cause miscarriage.
Having outbreaks during pregnancy is normal. These will not harm the baby. Some women have more outbreaks during pregnancy. You may choose to take aciclovir 400 mg three times daily from 36th week of pregnancy to ensure you don’t have an outbreak at term.
If you have caught herpes simplex before becoming pregnant you can give birth normally. This is stated in the 2014 Guidelines for herpes simplex and childbirth from the Royal College of Obstetrics and Gynaecology together with the British Association for Sexual Health and HIV. If you wish, you can take aciclovir 400 mg three times daily from 36 weeks on, to ensure you don’t have an outbreak during the birth.
Towards the end of pregnancy, babies in the womb receive antibodies to all the infections that their mothers have previously caught. These antibodies protect the baby from catching these viruses during childbirth and afterwards, longer when the mother breast feeds. After that, this protection fades away.
During pregnancy, herpes simplex only causes concern:
- If the mother has a first infection during the last few months of pregnancy because there may not be time for the baby to acquire antibodies from the mother before the birth. Taking aciclovir 400 mg three times daily will probably be prescribed by your obstetrician and may prevent the need for a C-section.
- If baby is being born before 32 weeks (very premature). These babies do not have full antibody protection so they could be infected during the birth if the mother has sores.
In these cases, there is a danger that the baby could contract herpes simplex so a Caesarean-section is usually performed. Women who do not have genital herpes should be careful not to catch it in the last two months of pregnancy – as explained above. This means that if their partners are already infected (facially or genitally) they should avoid contact that might transmit the virus to the mother.
A referenced “Pregnancy and Childbirth” leaflet is available to members.
If a baby under 1 month old develops herpes simplex, we call it neonatal herpes. This is very rare, and usually this is because the mother does not have herpes simplex herself, so the baby has no antibodies. Read more.
Can I pass genital herpes on to a baby or toddler?
A person with genital sores who is looking after a baby or toddler will not infect the child. Read more.
Small babies can be susceptible to viruses. Don’t kiss other people’s babies when you have a cold sores on the face.