Finding a cold sore while you are pregnant can feel worrying, especially when you already have so much to think about during pregnancy. The reassuring news is that, according to NHS guidance, aciclovir cream can usually be used during pregnancy, but it is always best to check with a pharmacist or doctor before starting treatment.
Cold sores are caused by the herpes simplex virus, a common virus that many adults already carry. Once someone has the virus, it remains in the body, which means having a cold sore during pregnancy does not automatically mean there is a risk to your baby.
However, a first ever cold sore outbreak during pregnancy, or an outbreak that happens close to your due date, should be discussed with a healthcare professional promptly. Getting the right advice at the right time can help ensure you receive appropriate care.
This guide explains how cold sores are managed during pregnancy, including the use of aciclovir cream, when other treatments such as aciclovir tablets may be considered, common causes and triggers including sunlight, ways to reduce the chance of outbreaks, and when to speak to a midwife, pharmacist or GP for further advice.
What Causes Cold Sores (Herpes Simplex Virus), and Are They Different During Pregnancy?
Cold sores are caused by the herpes simplex virus, usually type 1 (HSV 1). Once you have been infected, often during childhood, the virus stays inactive in the body and can reactivate from time to time, causing the familiar tingling, blistering and scabbing around the lips or mouth.
Pregnancy does not change how the virus behaves, but factors such as hormonal changes, stress, tiredness and a lowered immune response may contribute to outbreaks in some people.
It is also important to understand the difference between oral cold sores and genital herpes, as they are linked but have different considerations during pregnancy. Oral cold sores are usually caused by HSV 1 around the mouth, while genital herpes is more commonly caused by HSV 2, although HSV 1 can also cause genital infections.
The main pregnancy related concern with herpes is neonatal herpes, which can occur if a baby is exposed to the virus during delivery. This risk is mainly linked to a first episode of genital herpes infection, particularly if it happens later in pregnancy. A recurring cold sore on the lip is generally considered a lower risk situation, but it is still important to follow good hygiene practices and seek medical advice if you have concerns.
If you experience your first ever herpes infection during pregnancy, speak to your midwife, GP or healthcare professional promptly, as the advice and treatment approach may depend on the type of infection and stage of pregnancy.
Can You Use Cold Sore Cream When Pregnant?
Yes, aciclovir cold sore cream can usually be used during pregnancy. NHS guidance states that aciclovir can be used in pregnancy, but it is still recommended to check with a pharmacist or doctor before starting treatment.
Aciclovir cream is applied directly to the affected area on the lips and is only absorbed in small amounts into the body. This is one of the reasons it is commonly considered as a treatment option for cold sores during pregnancy.
For the best chance of helping symptoms, apply aciclovir cream as soon as you notice the early signs of a cold sore, such as tingling, itching or burning around the lips. Some people notice these warning signs before a blister appears.
Cold sores can spread from the early tingling stage until the sore has fully healed, so avoid kissing, sharing utensils or having direct contact with the affected area during this time.
If your cold sore has not started improving after 9 days of using aciclovir cream, NHS guidance recommends speaking to a doctor. Many cold sores clear naturally within around 10 days, but persistent or worsening symptoms should be checked by a healthcare professional.
Is Aciclovir Safe in Pregnancy? What the Evidence Says
Aciclovir is not specifically licensed for use during pregnancy, but it has been widely used in pregnant women for many years. NHS guidance states that aciclovir can usually be used during pregnancy when it is considered appropriate, and available evidence has not shown an increased risk of birth defects.
This applies to aciclovir cream and, when recommended by a healthcare professional, oral aciclovir tablets.
If you are considering oral aciclovir during pregnancy, whether for a more severe outbreak, a first episode of infection, or recurring symptoms, speak to your doctor or prescriber first. They can consider your individual circumstances and decide whether antiviral treatment is appropriate.
Cold sores often clear within 7 to 14 days, although healing time can vary from person to person.
For more information about medicine safety during pregnancy, the NHS recommends using resources such as the Best Use of Medicines in Pregnancy (BUMPS) website, which provides specialist information about medicines used during pregnancy.
If a cold sore is uncomfortable or painful, paracetamol is generally considered suitable for pain relief during pregnancy. However, always follow advice from your healthcare professional, especially if you have any concerns or other medical conditions.
The most suitable treatment, including whether cream or tablets are appropriate, depends on your individual situation. Aciclovir should be used according to advice from a pharmacist, doctor or prescriber.
Aciclovir in Pregnancy by Trimester
There is no separate NHS guidance suggesting that aciclovir cream should be used differently depending on the trimester. Because it is applied directly to the affected area and only small amounts are absorbed into the body, it is generally considered suitable throughout pregnancy when advised by a healthcare professional.
The approach may be different when oral antiviral tablets are being considered, especially in the later stages of pregnancy or for conditions such as genital herpes. In some situations, a prescriber may recommend antiviral treatment during the final weeks of pregnancy to help manage recurring genital herpes and support delivery planning.
This is decided on an individual basis with your healthcare team and is not something to manage without medical advice.
What About Abreva or Docosanol While Pregnant?
Abreva contains the active ingredient docosanol and is a commonly used cold sore treatment in the United States. It is available over the counter there, which is why some people in the UK may search for it when looking for cold sore treatments.
However, docosanol is not the standard over the counter cold sore treatment recommended in UK pharmacies. Aciclovir cream is more commonly used in the UK, and there is more UK specific guidance and pregnancy safety information available for aciclovir.
If you are pregnant and considering using docosanol or any cold sore treatment that is not routinely recommended in the UK, speak to a pharmacist or doctor first. They can help you understand whether it is suitable for your situation and discuss available treatment options.
Cold Sores During Pregnancy and Neonatal Herpes: When to Seek Medical Advice
Most cold sores during pregnancy can be managed at home with treatments such as aciclovir cream and simple self care measures, including staying hydrated and avoiding triggers. However, there are some situations where it is important to seek medical advice promptly:
A first ever cold sore outbreak during pregnancy. If you have never had a cold sore before and develop one during pregnancy, contact your midwife or GP for advice. A first infection can sometimes cause more noticeable symptoms, such as feeling unwell or flu like symptoms, and may need further assessment.
A cold sore close to your due date. If you develop a cold sore in the final weeks of pregnancy, let your midwife or healthcare team know so they can advise you as part of your delivery planning.
Signs of a more serious or spreading infection. Seek medical advice if you have symptoms such as a fever, widespread blistering beyond the usual lip area, sores in other areas of the body, or any signs that the infection may involve your eyes.
A weakened immune system. If you have a condition or are taking treatment that affects your immune system, speak to your doctor or pharmacist before treating a cold sore yourself.
After your baby is born, avoid kissing your newborn or allowing an active cold sore to come into contact with your baby. The herpes simplex virus can be more serious in newborn babies, so good hand hygiene and avoiding direct contact with the sore are important until it has fully healed.
Does Sun Exposure Cause Cold Sores?
Sunlight does not cause cold sores or the herpes simplex virus itself. Cold sores only develop if you already carry the HSV 1 virus.
However, sunlight can be a trigger for some people who already have the virus. Other common triggers include illness, tiredness, stress and hormonal changes. This means sun exposure may contribute to an outbreak, but it does not create a cold sore infection from scratch.
If you notice that your cold sores appear after spending time in the sun, taking steps to protect your lips from UV exposure may help reduce the chance of future outbreaks.
Can Titanium Dioxide Trigger Cold Sores?
No. Titanium dioxide does not cause cold sores.
Titanium dioxide is a mineral ingredient commonly used in some sunscreens and lip balms because it helps protect the skin by reflecting UV rays. In fact, using a lip balm with sun protection ingredients such as titanium dioxide or zinc oxide may help reduce sun related triggers for people who are prone to cold sores.
If sunlight is one of your triggers, using an SPF lip balm can be a simple way to help protect your lips when outdoors.
Can You Go on a Sunbed With a Cold Sore, or If You Are Prone to Them?
If you are prone to cold sores, it is best to avoid triggers that you know can cause outbreaks. NHS guidance includes sunbeds as a possible trigger for some people.
Sunbeds expose the skin to concentrated UV rays, including the lips, so they are not considered a safer alternative to sunlight for people who experience sun related cold sore outbreaks. They do not treat or prevent cold sores and may trigger an outbreak in some people.
How to Reduce Sun Triggered Cold Sore Outbreaks
If sunlight is a known trigger for your cold sores, protecting your lips from UV exposure may help reduce outbreaks.
NHS guidance recommends using a lip balm with SPF 15 or higher when spending time in the sun and reapplying it as needed, especially during longer periods outdoors.
Alongside sun protection, it can help to keep aciclovir cream available if recommended for you, so it can be used at the earliest signs of a cold sore, such as tingling or itching. Prevention steps can reduce the chance of outbreaks but cannot guarantee that cold sores will not return.
Things to Know: Quick Summary
| Question | Answer |
|---|---|
| Is aciclovir safe in pregnancy? | Usually yes, but check with a pharmacist or doctor first; not formally licensed for pregnancy but widely used with a good safety record |
| Can I use cold sore cream when pregnant? | Yes, topical aciclovir cream has minimal systemic absorption and is typically a first-line option |
| Does sun exposure cause cold sores? | It triggers outbreaks in people who already carry the virus; it doesn't cause the underlying HSV-1 infection |
| Can I go on a sunbed with a cold sore? | NHS guidance advises avoiding sunbeds if they're a known trigger for you |
| Does titanium dioxide trigger cold sores? | No, it's a protective sunscreen ingredient, not a trigger |
| What SPF should I use on my lips? | SPF 15 or above, per NHS guidance |
| When should I contact a midwife or GP? | First-ever outbreak, any outbreak close to your due date, or signs of a spreading infection |
| Can I use Abreva (docosanol) while pregnant? | It's a US-market product without the same UK clinical guidance or pregnancy data as aciclovir; check with a pharmacist |
Comparing Cold Sore Treatment Options
| Treatment | Form | Typical use | Notes |
|---|---|---|---|
| Aciclovir 5% cream | Topical | Applied at first sign of tingling | Minimal systemic absorption; generally considered suitable during pregnancy, but check with a pharmacist or doctor first |
| Aciclovir tablets | Oral | Prescriber-directed, for more severe or frequent outbreaks | Not specifically licensed for use during pregnancy, but may be prescribed when clinically appropriate following individual assessment |
| Valaciclovir | Oral | Prescriber-directed alternative to aciclovir tablets | Related antiviral with different dosing frequency; prescriber-led |
| Valtrex | Oral | Branded valaciclovir | Same active ingredient category as generic valaciclovir |
| Docosanol (Abreva) | Topical | US-market product | Limited UK clinical guidance and pregnancy-specific data compared with aciclovir |
This comparison is for general information only and does not recommend one treatment as more effective than another. Treatment suitability depends on an individual clinical assessment.
Cold Sore Treatment Pricing in the UK
Pricing varies by product, pack size and whether cream or tablets are needed. As a general guide, topical creams tend to sit at the lower end of the price range, with oral antivirals priced higher to reflect prescription-only status and systemic treatment.
| Treatment | Typical starting price |
|---|---|
| Aciclovir 5% cream | From around £9 |
| Aciclovir tablets | From around £13 |
| Valaciclovir | From around £19 |
| Valtrex | From around £35 |
Prices change regularly and should be confirmed at checkout. If you're pregnant, always confirm treatment suitability with a pharmacist or prescriber before ordering, regardless of price.
Getting Cold Sore Treatment Online
If you prefer not to wait for a GP appointment, a UK regulated online pharmacy may offer access to cold sore treatment through an online consultation and clinical review by a qualified prescriber where appropriate.
Complete a short online health assessment, including details about your symptoms, medical history, whether you are pregnant or breastfeeding, and any current medicines you take. This is especially important if this is your first cold sore outbreak during pregnancy.
A UK licensed prescriber will review your information before deciding whether treatment is suitable for you. Online treatment should support, not replace, your usual maternity or GP care, especially if there are pregnancy related concerns or symptoms that need further assessment.
Choose your treatment, whether that is a suitable cream or another antiviral option, with clear pricing shown before you complete your order.
Receive discreet, tracked delivery where available, with no indication of the contents on the outside packaging.
When choosing an online provider, check that they are GPhC registered, provide a genuine clinical assessment, display pricing clearly, and offer access to pharmacist support if you have questions. If you have symptoms of genital herpes, a first infection, or pregnancy related concerns, you may be advised to speak with your GP, midwife or a specialist clinic for further assessment.
