Cold Sores, Herpes (HSV) + Breastfeeding
If you have ever had a cold sore, you are not alone. Herpes simplex virus (HSV) is incredibly common, and many parents are understandably anxious when HSV and breastfeeding appear in the same sentence. The good news is that, in most situations, breastfeeding is safe, and clear precautions can significantly reduce any risk to your baby.
This guide explains what HSV is, how it is transmitted, and how to breastfeed safely if you have cold sores or herpes.
What Is Herpes Simplex Virus (HSV)?
HSV is a viral infection with two main types:
• HSV-1 – commonly causes cold sores around the mouth
• HSV-2 – usually causes genital herpes
Many adults carry HSV without symptoms, and outbreaks can be triggered by stress, illness, or fatigue.
According to the World Health Organization, HSV-1 affects a large proportion of the global population, often acquired in childhood.
How Is HSV Transmitted?
HSV spreads through direct skin-to-skin contact with active sores or blisters.
It is important to understand that:
• HSV does not pass through breast milk
• Transmission risk comes from contact with an active lesion
• Newborns are more vulnerable to severe infection if exposed directly
Breastfeeding With HSV: What the Evidence Says
Major health bodies including the CDC, WHO and NSW Health Mothersafe agree:
Breastfeeding is safe if there are no active lesions on the breast
Breastfeeding can continue if lesions elsewhere are fully covered
Careful hygiene significantly reduces risk
What If There Is a Cold Sore on the Breast?
If a herpetic lesion appears on the breast or nipple:
• Do not breastfeed from the affected side
• Do not use expressed milk from that breast (discard it)
• Continue feeding from the unaffected breast if possible
• Resume feeding once the lesion has completely healed
This approach protects your baby while helping maintain breastfeeding overall.
Cold Sores on the Mouth or Face
If you have a cold sore on your lip or face:
• Cover the lesion where possible
• Avoid kissing your baby until healed
• Wash hands before feeds, cuddles, or handling pump equipment
These simple steps are highly effective in preventing transmission.
Antiviral Medication and Breastfeeding
Antiviral medications such as aciclovir and valaciclovir are commonly prescribed for HSV.
Current evidence shows they are generally compatible with breastfeeding, with minimal transfer into breast milk. Treating outbreaks promptly may also shorten healing time and reduce discomfort.
Always discuss medication use with your healthcare provider.
Seek Some Medical Support…
Contact a healthcare professional urgently if:
• Your baby develops fever, rash, poor feeding or lethargy
• You are unsure whether a lesion is herpes
• You need help protecting milk supply during a pause in feeding from one breast
Early support matters.
Some Reassurance…
HSV is common. Breastfeeding with HSV is usually safe. With the right guidance, parents can continue feeding confidently while protecting their baby.
If you are unsure, reach out to a midwife, GP or IBCLC for personalised advice.
References
• Centers for Disease Control and Prevention (CDC). Herpes Simplex Virus and Breastfeedinghttps://www.cdc.gov/breastfeeding-special-circumstances/hcp/illnesses-conditions/herpes.html
• World Health Organization (WHO). Herpes Simplex Virus Fact Sheethttps://www.who.int/en/news-room/fact-sheets/detail/herpes-simplex-virus
• NSW Health Mothersafe. Cold Sores in Pregnancy and Breastfeedinghttps://www.seslhd.health.nsw.gov.au/sites/default/files/groups/Royal_Hospital_for_Women/Mothersafe/documents/coldsorespb20.pdf
• Breastfeeding Support. Herpes and Breastfeedinghttps://breastfeeding.support/herpes-and-breastfeeding/