Mosquito Bites Pregnancy Zika West Nile Risk: What to Know

• ACOG (American College of Obstetricians and Gynecologists): “Pregnant women should take steps to avoid mosquito bites, particularly in areas with active Zika or West Nile virus transmission.” They emphasize that while the risk of complications from a single bite is low, prevention is key.
• CDC (Centers for Disease Control and Prevention): “Zika virus infection during pregnancy can cause microcephaly and other severe brain defects. Pregnant women should not travel to areas with risk of Zika.” For West Nile, they note that while most infections are mild, severe cases can lead to neurological issues in both mom and baby.
• NHS (UK National Health Service): “There’s no evidence that West Nile virus causes problems in pregnancy, but it’s still sensible to avoid mosquito bites.” They recommend using insect repellent containing DEET (up to 50%) and wearing long sleeves.

So, what’s the actual risk? Let’s break it down:

• Zika virus: The biggest concern. If you’re infected during pregnancy, there’s a 5-10% chance your baby could develop Zika-related birth defects, including microcephaly, vision problems, and joint issues. The risk is highest in the first trimester but remains throughout pregnancy.
• West Nile virus: About 1 in 150 people infected develop severe illness, which can include encephalitis (brain inflammation) or meningitis. While rare, severe cases during pregnancy have been linked to miscarriage and developmental delays.
• Dengue and chikungunya: These viruses can cause high fever, joint pain, and rash. While they’re not typically linked to birth defects, severe cases can lead to complications like preterm labor or low birth weight.

Bottom line: You don’t need to panic if you get a mosquito bite, but you should take steps to avoid them—especially in high-risk areas. If you’ve been bitten and develop symptoms like fever, rash, or joint pain, call your provider right away.

Mosquito bite safety by trimester

First trimester: The highest-risk window

The first trimester is when your baby’s organs are forming, making it the most vulnerable time for infections like Zika. If you’re traveling to or living in an area with active Zika transmission, the CDC recommends postponing your trip if possible. If you can’t avoid it, take extra precautions:

• Use EPA-approved insect repellents (more on these below).
• Wear long sleeves, pants, and socks—even in hot weather.
• Stay in air-conditioned or screened-in areas.
• Avoid standing water (mosquitoes breed in it).

If you’ve already been bitten and are worried, don’t stress. The risk of transmission from a single bite is low. Monitor for symptoms (fever, rash, joint pain) and call your provider if they appear.

Second trimester: Still cautious, but slightly lower risk

By the second trimester, your baby’s organs are more developed, but infections can still cause complications. The risk of Zika-related birth defects decreases slightly, but it’s not zero. West Nile virus can still affect your baby’s nervous system, so prevention remains important.

Continue using repellent and protective clothing. If you’re in a high-risk area, consider mosquito netting for your bed or stroller. If you develop symptoms after a bite, your provider may recommend testing for Zika or West Nile.

Third trimester: Don’t let your guard down

While the risk of Zika-related birth defects is lower in the third trimester, the virus can still affect your baby’s brain and nervous system. West Nile virus can also cause complications like preterm labor or low birth weight. Plus, severe infections can make you very sick, which isn’t good for you or your baby.

Keep up your prevention efforts until delivery. If you’re traveling, check the CDC’s Zika travel maps for updates on active transmission areas. If you’re bitten and develop symptoms, call your provider—even if you’re close to your due date.

Breastfeeding: Focus on protecting yourself

Good news: Zika and West Nile virus are not transmitted through breast milk. If you’re bitten while breastfeeding, your main concern is protecting yourself from infection. Use the same prevention methods (repellent, clothing, netting) to avoid bites.

If you do get sick, the CDC says it’s safe to continue breastfeeding. In fact, your breast milk may even pass on antibodies to your baby, offering some protection against future infections.

How many mosquito bites increase Zika risk in pregnancy?

This is one of the most common questions—and the answer isn’t straightforward. There’s no magic number of bites that guarantees infection. The risk depends on:

• Whether the mosquitoes in your area carry Zika (or another virus).
• How long you’re exposed to mosquitoes.
• Whether you’re using repellent or other protections.

Here’s what we know:

• One bite from an infected mosquito can transmit Zika. It only takes a single bite from a mosquito carrying the virus to infect you. That said, not all mosquitoes carry Zika, so the odds of a random bite transmitting the virus are low—unless you’re in an area with active transmission.
• More bites = higher risk. The more you’re bitten by infected mosquitoes, the higher your chances of infection. This is why prevention is so important in high-risk areas.
• No “safe” number of bites. The CDC doesn’t give a specific number of bites to avoid because the risk varies so much. Instead, they focus on prevention: use repellent, wear protective clothing, and avoid high-risk areas when possible.

If you’ve been bitten multiple times and are worried, don’t panic. The risk of transmission is still relatively low, especially if you’re not in a Zika-active area. But do monitor for symptoms (fever, rash, joint pain) and call your provider if they appear.

What mosquito repellent is safe for pregnant women in the third trimester?

By the third trimester, you’re probably tired of pregnancy precautions—but mosquito protection is still important. The good news? Most EPA-approved insect repellents are safe to use in the third trimester (and throughout pregnancy). Here’s what to look for:

How to use repellent safely during pregnancy:

• Apply after sunscreen. Put on sunscreen first, let it dry, then apply repellent.
• Avoid spraying on cuts or irritated skin. Stick to intact skin and clothing.
• Don’t spray directly on your face. Spray onto your hands first, then apply to your face (avoiding eyes and mouth).
• Wash it off when you come inside. Use soap and water to remove repellent at the end of the day.
• Reapply as needed. Follow the product’s instructions—most last 4-8 hours.

If you’re unsure which repellent to choose, the EPA’s repellent search tool can help you find one that fits your needs.

Can I use DEET or picaridin for mosquito protection while pregnant?

Yes, DEET and picaridin are both considered safe for pregnant women. Here’s what you need to know about each:

DEET

• Safety: DEET has been used for decades and is one of the most studied insect repellents. The CDC, ACOG, and NHS all consider it safe during pregnancy when used as directed.
• Effectiveness: DEET is highly effective against mosquitoes, ticks, and other biting insects. A 20-30% concentration provides 4-8 hours of protection.
• How to use: Apply to exposed skin and clothing (not under clothing). Avoid spraying directly on your face—use your hands to apply it instead. Wash it off when you come inside.
• Brands to try:
  • OFF! Deep Woods Insect Repellent (25% DEET)
  • Repel 100 Insect Repellent (98% DEET, for high-risk areas)

Picaridin

• Safety: Picaridin is a synthetic compound that’s just as effective as DEET but odorless and less greasy. It’s considered safe during pregnancy by the CDC and ACOG.
• Effectiveness: A 20% concentration provides 6-8 hours of protection. It’s also effective against ticks and flies.
• How to use: Apply to skin and clothing, just like DEET. It’s a good option if you have sensitive skin or dislike the smell of DEET.
• Brands to try:
  • Sawyer Picaridin Insect Repellent (20%)
  • Natrapel Picaridin Insect Repellent (20%)

What about natural repellents? We’ll cover those in the next section, but the bottom line is: DEET and picaridin are the most effective and well-studied options for pregnancy. If you’re in a high-risk area, they’re your best bet for protection.

What are the risks of West Nile virus from mosquito bites during pregnancy?

West Nile virus is another mosquito-borne illness that can affect pregnant women. While most people infected with West Nile don’t develop symptoms, about 1 in 5 will experience fever, headache, body aches, and fatigue. In rare cases (about 1 in 150), the virus can cause severe neurological diseases like encephalitis or meningitis.

Here’s what you need to know about West Nile virus during pregnancy:

• Risk to your baby: The research on West Nile virus in pregnancy is limited, but some studies suggest it may increase the risk of miscarriage, preterm birth, or developmental issues. A 2019 study in Emerging Infectious Diseases found that pregnant women with West Nile virus were more likely to have babies with low birth weight or neurological abnormalities. However, the overall risk is still considered low.
• Symptoms to watch for: If you develop fever, headache, muscle weakness, or confusion after a mosquito bite, call your provider. Severe cases can lead to seizures, paralysis, or coma.
• Testing and treatment: There’s no specific treatment for West Nile virus. If your provider suspects you’re infected, they may recommend blood tests or imaging (like an MRI) to check for complications. Most people recover on their own with rest and fluids.
• Prevention is key: Since there’s no vaccine or cure, the best way to protect yourself is to avoid mosquito bites. Use EPA-approved repellents, wear long sleeves, and eliminate standing water around your home.

If you’ve been bitten and are worried about West Nile, don’t panic. The odds of severe illness are low, but it’s always a good idea to monitor for symptoms and call your provider if you’re concerned.

Are natural mosquito repellents safe for pregnant women?

If you’re hesitant to use chemical repellents like DEET or picaridin, you’re not alone. Many pregnant women prefer “natural” options—but are they actually safe and effective? Here’s what you need to know:

Oil of lemon eucalyptus (OLE)

• Safety: The CDC considers OLE safe for pregnant women when used as directed. It’s derived from the leaves of the lemon eucalyptus tree and contains PMD (para-menthane-3,8-diol), the active ingredient that repels mosquitoes.
• Effectiveness: OLE is one of the few natural repellents that’s as effective as low concentrations of DEET. It provides about 4-6 hours of protection.
• How to use: Apply to skin and clothing, just like DEET. Avoid using “pure” lemon eucalyptus oil—it’s not the same as OLE and isn’t EPA-approved.
• Brands to try:
  • Repel Lemon Eucalyptus Insect Repellent
  • Cutter Lemon Eucalyptus Insect Repellent

Citronella

• Safety: Citronella is generally recognized as safe (GRAS) by the FDA, but its effectiveness is limited. The CDC doesn’t recommend it as a primary repellent because it only provides short-term protection (30-60 minutes).
• Effectiveness: Citronella candles or sprays can help repel mosquitoes in small, enclosed areas, but they’re not reliable for outdoor use.
• How to use: Use citronella candles in combination with other methods (like wearing long sleeves or using a fan to blow mosquitoes away). Avoid applying citronella oil directly to your skin—it can cause irritation.

Other natural repellents (lavender, peppermint, etc.)

• Safety: Essential oils like lavender, peppermint, and tea tree oil are not EPA-approved for mosquito repellency. While they may offer some short-term protection, they’re not as effective as DEET, picaridin, or OLE.
• Effectiveness: Most essential oils provide less than 1 hour of protection. They’re not a reliable standalone option, especially in high-risk areas.
• Risks: Some essential oils can cause skin irritation or allergic reactions. Avoid applying them directly to your skin, and never ingest them.

Bottom line: If you’re in a low-risk area, natural repellents like OLE or citronella may offer some protection. But if you’re in a high-risk area (or traveling to one), the CDC and ACOG recommend using EPA-approved repellents like DEET or picaridin for the best protection.

How to prevent mosquito bites during pregnancy without chemicals?

If you’d rather avoid chemical repellents altogether, there are still plenty of ways to protect yourself from mosquito bites. Here are some non-chemical strategies to try:

Wear protective clothing

• Long sleeves and pants: Covering up is one of the simplest ways to avoid bites. Opt for lightweight, breathable fabrics to stay cool in hot weather.
• Permethrin-treated clothing: Permethrin is an insecticide that kills mosquitoes on contact. You can buy pre-treated clothing (like Insect Shield) or treat your own clothes at home. The CDC considers permethrin safe for pregnant women when used as directed.
• Socks and closed-toe shoes: Mosquitoes love ankles and feet, so keep them covered.

Use mosquito netting

• Bed nets: If you’re sleeping in an area without screens or air conditioning, a mosquito net can provide a physical barrier between you and the bugs. Look for nets treated with permethrin for extra protection.
• Stroller and baby carrier nets: If you’re out and about with your little one, a net can protect both of you from bites.

Eliminate standing water

• Mosquitoes breed in standing water, so eliminating it around your home can reduce the number of bugs. Check for water in:
  • Flowerpot saucers
  • Gutters
  • Birdbaths
  • Old tires
  • Kiddie pools
• Change the water in pet bowls and vases weekly.

Use fans outdoors

• Mosquitoes are weak fliers, so a strong breeze from a fan can keep them away. Set up a fan on your patio or deck to create a mosquito-free zone.

Avoid peak mosquito hours

• Mosquitoes are most active at dawn and dusk. If possible, stay indoors during these times or take extra precautions (like wearing long sleeves) if you’re outside.

Try a Thermacell device

• Thermacell devices use heat to release a repellent into the air, creating a 15-foot protection zone. They’re EPA-approved and considered safe for pregnant women. They’re a great option for camping, picnics, or backyard lounging.

Remember: While these methods can help reduce your risk, they’re not foolproof. If you’re in a high-risk area, the CDC still recommends using EPA-approved repellents for the best protection.

What should I do if I get a mosquito bite while pregnant?

First, take a deep breath. Most mosquito bites are harmless, even during pregnancy. But if you’ve been bitten, here’s what to do:

1. Clean the bite

• Wash the area with soap and water to reduce the risk of infection.
• Avoid scratching—it can break the skin and introduce bacteria.

2. Apply a cold compress

• Use a cold pack or a damp cloth to reduce swelling and itching.
• Apply for 10-15 minutes at a time.

3. Use an anti-itch cream

• Over-the-counter hydrocortisone cream (1%) is generally safe during pregnancy. Apply a thin layer to the bite to relieve itching.
• Avoid creams with added antihistamines or pain relievers unless your provider says it’s okay.
• Calamine lotion is another safe option for itch relief.

4. Take an oral antihistamine (if needed)

• If the itching is severe, you can take an oral antihistamine like diphenhydramine (Benadryl) or loratadine (Claritin). Both are considered safe during pregnancy, but check with your provider first.

5. Monitor for symptoms

• Most mosquito bites will heal on their own within a few days. But if you develop any of the following symptoms, call your provider:
  • Fever
  • Rash
  • Joint pain
  • Headache
  • Muscle weakness
  • Confusion
• These could be signs of a mosquito-borne illness like Zika or West Nile virus.

6. When to seek medical care

• If the bite becomes increasingly red, swollen, or painful, it could be infected. Call your provider if you notice:
  • Increasing redness or warmth around the bite
  • Pus or drainage
  • Red streaks extending from the bite
  • Fever or chills

If you’ve been bitten in a high-risk area (or traveled to one recently), your provider may recommend testing for Zika or West Nile virus. This usually involves a blood test, and in some cases, an ultrasound to check on your baby’s development.

Side effects and risks of mosquito bites during pregnancy

While most mosquito bites are harmless, there are some risks to be aware of—especially if you’re bitten by a mosquito carrying a virus like Zika or West Nile. Here’s what to watch for:

Local reactions (common, not dangerous)

• Itching, redness, and swelling at the bite site are normal. These symptoms usually go away within a few days.
• Scratching can lead to infection, so try to avoid it.

Allergic reactions (rare, but possible)

• Some people have an allergic reaction to mosquito saliva, which can cause:
  • Large areas of swelling (more than 2 inches across)
  • Hives or rash
  • Swollen lymph nodes
• If you experience these symptoms, call your provider. They may recommend an antihistamine or steroid cream.

Mosquito-borne illnesses (serious, but rare)

• Zika virus:
  • Risk to baby: Microcephaly, brain abnormalities, vision/hearing problems, joint issues.
  • Symptoms in mom: Fever, rash, joint pain, red eyes (conjunctivitis). About 80% of people infected don’t have symptoms.
  • When to worry: If you develop symptoms within 2 weeks of a bite (or travel to a Zika-risk area), call your provider.
• West Nile virus:
  • Risk to baby: Miscarriage, preterm birth, low birth weight, neurological issues.
  • Symptoms in mom: Fever, headache, body aches, fatigue. Severe cases can cause confusion, seizures, or paralysis.
  • When to worry: If you develop neurological symptoms (like confusion or muscle weakness), seek medical care immediately.
• Dengue fever:
  • Risk to baby: Preterm birth, low birth weight, miscarriage.
  • Symptoms in mom: High fever, severe headache, joint/muscle pain, rash. Severe cases can cause bleeding or shock.
  • When to worry: If you develop a high fever (over 101°F) after a bite, call your provider.
• Chikungunya:
  • Risk to baby: Rarely, the virus can be passed to the baby during delivery, causing neurological issues.
  • Symptoms in mom: Fever, severe joint pain, rash, headache.
  • When to worry: If you develop severe joint pain or fever after a bite, call your provider.

Remember: The risk of these complications is low, especially if you’re not in a high-risk area. But if you develop symptoms after a bite, don’t hesitate to call your provider. Early detection and monitoring can make a big difference.

Safer alternatives for mosquito protection during pregnancy

If you’re looking for effective ways to avoid mosquito bites without relying solely on chemical repellents, here are some safer alternatives to consider. Each option has its pros and cons, so you can mix and match based on your needs and comfort level.

• OFF! Deep Woods Insect Repellent (25% DEET)

  Why it’s safe: DEET is the gold standard for mosquito protection and is recommended by the CDC, ACOG, and NHS for pregnant women. This formula provides up to 8 hours of protection and is effective against Zika- and West Nile-carrying mosquitoes.

• Repel 100% Picaridin Insect Repellent

  Why it’s safe: Picaridin is odorless, less greasy than DEET, and just as effective. It’s a great option if you’re sensitive to DEET or prefer a more “natural” feel. The CDC considers it safe during pregnancy.

• Natrapel Insect Repellent (Oil of Lemon Eucalyptus)

  Why it’s safe: Oil of lemon eucalyptus (OLE) is the only plant-based repellent recommended by the CDC. It provides about 6 hours of protection and is a good choice if you prefer to avoid synthetic chemicals. Just make sure you’re using a product with OLE (not “pure” lemon eucalyptus oil).

• Mosquito Netting for Bed

  Why it’s safe: Mosquito netting is a chemical-free way to protect yourself while sleeping. Look for nets treated with permethrin for extra protection. This is especially useful if you’re traveling or sleeping in an area without screens or air conditioning.

• Insect Shield Clothing

  Why it’s safe: Insect Shield clothing is pre-treated with permethrin, an insecticide that kills mosquitoes on contact. The CDC considers permethrin safe for pregnant women when used as directed. These clothes are a great option for outdoor activities like hiking or gardening.

• Thermacell Mosquito Repellent Device

  Why it’s safe: Thermacell devices use heat to release a repellent into the air, creating a 15-foot protection zone. They’re EPA-approved and considered safe for pregnant women. They’re perfect for camping, picnics, or backyard lounging.

• Long Sleeves and Pants

  Why it’s safe: Covering up is one of the simplest ways to avoid bites. Opt for lightweight, breathable fabrics to stay cool. You can also treat your clothes with permethrin for added protection.

• Fans for Outdoor Use

  Why it’s safe: Mosquitoes are weak fliers, so a strong breeze from a fan can keep them away. Set up a fan on your patio or deck to create a mosquito-free zone. This is a great chemical-free option for outdoor gatherings.

Related mosquito and bite risks: Safety at a glance

Mosquito bites aren’t the only insect-related concern during pregnancy. Here’s a quick look at other bites and infections, along with their risks and safety verdicts.

Item	Verdict	Notes
Tick bites	⚠️ Caution advised	Ticks can carry Lyme disease, which may increase the risk of Editor's pick for this topic Sponsored pick Nature Made — Nature Made Prenatal Multi + DHA (Softgels, 150-count) USP-verified prenatal with DHA — pharmacist's #1 choice. $50View → Sponsored pick Nordic Naturals — Nordic Naturals Prenatal DHA (Strawberry Softgels) Premium fish-oil DHA in strawberry softgels — gentle on the stomach. $55View → About the Author When Shubhra Mishra was expecting her first child in 2016, she was overwhelmed by conflicting food advice — one site said yes, another said never. By the time her second baby arrived in 2019, she realized millions of mothers face the same confusion. That sparked a five-year journey through clinical nutrition papers, cultural diets, and expert conversations — all leading to BumpBites: a calm, compassionate space where science meets everyday motherhood. Her long-term vision is to build a global community ensuring safe, supported, and free deliveriesfor every mother — because no woman should face pregnancy alone or uninformed. 🌿 🌍 Stand with mothers, shape safer guidance Join a small circle of experts who review BumpBites articles so expecting parents everywhere can decide with confidence. Apply via web formoremail contact@bumpbites.health ⚠️ Always consult your doctor for medical advice. This content is informational only. Long-form pregnancy guides Hand-curated deep-dive guides — go beyond the article above. Complete Pregnancy Nutrition Master GuideTrimester-by-trimester pregnancy nutrition — the orchestrating hub. Foods to Avoid in PregnancyThe full pregnancy food-avoidance list with the science behind each. First Trimester Survival GuideEating through nausea, fatigue + aversions in T1. More Pregnancy guides Mother Age 45 Pregnancy Risks: What to Expect for Safety and Timing MTX contraindications: Hepatic, renal & hematologic screening Mucinex and Pregnancy: Is It Safe to Use During Pregnancy? Mucus Plug Discharge Pregnancy Signs and What to Expect NIPT false positives: Understanding confined placental mosaicism NIPT Results Explained: What Positive or Negative Means Next No Cry Sleep Solution: Gentle Ways to Help Your Baby Sleep Non-Invasive Prenatal Testing: How Prior Risk Affects PPV Accuracy can you have menstruation and be pregnant What to Expect During a Non-Stress Test in Pregnancy See all Pregnancy guides → ⬆️ Back to Top