faq9

Herpes in pregnancy

What risks are associated with genital herpes in pregnancy?

Herpes simplex virus (HSV) may be passed from a woman with genital herpes to her child at birth. This is a serious and potentially fatal condition for the newborn infant but fortunately it is very rare (approximately 1 in every 15,000 to 20,000 live births in Australia).
HSV is most easily passed from mother to child if the woman is infected with the virus for the first time at the time of delivery. The risk is much lower for infants born of mothers with a previous history of genital herpes.

What are the risks if the mother has genital herpes?

If you are pregnant and have a history of genital herpes, the risk of passing the infection on to your newborn baby is extremely small. This is because the amount of the virus being shed from your genitals is relatively small. Also, the antibodies your immune system has produced to control the virus can cross over into the circulation of the unborn foetus, giving some protection.
The risk of passing HSV to your child is greatest if there is an outbreak of herpes symptoms at the time of the delivery. Outbreaks earlier in the pregnancy are usually of little consequence.
If you are pregnant and have a history of genital herpes, you should inform you obstetrician (the doctor managing your pregnancy). He/she will examine you carefully for signs of herpes at or near the estimated confinement date. If there is evidence of an outbreak of herpes, he/she may choose to deliver the baby by Caesarean section to reduce the chance of transmission of HSV from your genitals to the baby.

What are the risks if the mother has never had herpes but her partner is affected?

The highest risk of passing herpes simplex virus to the newborn infant occurs when a woman contracts the virus for the first time at or near the time of delivery. This is because during a first attack of genital herpes, the virus is shed from the genitals and cervix in much higher levels than in later recurrences. Also, the immune system has not yet had time to manufacture antibodies against HSV to cross into the foetal circulation and protect against the virus.
If you are pregnant and you have never had an outbreak of genital herpes or cold sores, and your partner has a history of genital herpes or cold sores, there is a chance that you will be infected by HSV for the first time during the pregnancy. There is, however, also a chance that you already carry the virus but are unaware of this. (See Is it possible to have and/or transmit genital herpes without knowing it?). To clarify this situation, you may wish to have a blood test to determine whether you have ever been infected by HSV. If the test shows that you have never been in contact with the virus you may wish to take extra precautions to reduce the chance of being infected during your pregnancy.