Mosquito bites are a common annoyance, but for pregnant individuals, the concern extends beyond simple irritation to potential health risks for both mother and developing baby. Mosquitoes are often more drawn to expectant mothers than to non-pregnant individuals. Understanding why this attraction occurs and what dangers certain mosquito-borne diseases pose during gestation is important. Numerous highly effective and safe methods exist to prevent bites and manage symptoms, providing reassurance that proactive steps can significantly reduce risk.
Why Pregnancy Increases Mosquito Attraction
The appeal of pregnant people to mosquitoes is rooted in several physiological changes that occur during gestation. A major factor is an increase in the amount of carbon dioxide exhaled, which acts as a powerful attractant for mosquitoes from a distance. Individuals in the later stages of pregnancy may exhale up to 21% more carbon dioxide than those who are not pregnant, making them easier targets to locate.
Another draw for mosquitoes is the slight elevation in body temperature common during pregnancy. Researchers have observed that the abdomen of a pregnant person can be approximately 0.7 degrees Celsius warmer than that of a non-pregnant person. Mosquitoes use heat sensors to find sources of blood, and this warmer skin temperature helps the insects home in on their target.
Specific Disease Risks During Pregnancy
The primary danger of mosquito bites during pregnancy lies in the transmission of specific viruses and parasites that can negatively affect maternal health and fetal development. Zika virus represents a significant threat, particularly when infection occurs early in gestation. The virus can be transmitted vertically from mother to fetus, with estimated vertical transmission rates reaching up to 47% following first-trimester infection. Infection in the first trimester carries the highest risk of severe fetal complications, including microcephaly and other serious neurological and ocular defects, collectively known as congenital Zika syndrome.
Malaria, caused by a parasite transmitted by Anopheles mosquitoes, poses substantial risk to both the mother and the developing fetus, particularly the severe form caused by Plasmodium falciparum. Maternal infection can lead to placental malaria, associated with serious complications like severe maternal anemia. Fetal outcomes can include stillbirth, miscarriage, preterm delivery, and intrauterine growth restriction, which often results in low birth weight.
Dengue fever, a viral illness, can be transmitted from a pregnant person to their baby, especially when the infection occurs close to the time of delivery. Maternal dengue infection is associated with adverse outcomes such as low birth weight and premature birth. If the mother develops severe dengue, the risk of preterm birth and low birth weight can significantly increase. West Nile Virus (WNV) is also a concern, though the risk of vertical transmission and adverse effects on the baby is considered low.
Safe Prevention Methods for Expectant Mothers
Protecting against mosquito bites is a primary defense against these diseases. The Centers for Disease Control and Prevention (CDC) and the Environmental Protection Agency (EPA) recommend using EPA-registered insect repellents containing specific active ingredients:
- DEET
- Picaridin
- IR3535
- Oil of Lemon Eucalyptus (OLE), also known as para-menthane-diol (PMD)
When selecting a repellent, check the concentration of the active ingredient for safety and effectiveness. DEET is considered safe when used as directed, with the recommended concentration being 30% or less for pregnant individuals, as higher concentrations do not offer significantly greater protection. Picaridin is another effective option, with products containing up to 20% concentration recommended. Repellents should be applied only to exposed skin, not under clothing, and never used on damaged or irritated skin. If applying to the face, spray a small amount onto the hands first and then gently pat it onto the face.
In addition to topical repellents, non-chemical methods provide an important layer of defense. Wearing loose-fitting, long-sleeved shirts and long pants minimizes skin exposure, which is useful during peak mosquito hours (dawn and dusk). Treating clothing and gear with permethrin is a complementary strategy, but this product should never be applied directly to the skin. Environmental measures, such as ensuring all windows and doors have intact screens and eliminating any standing water where mosquitoes breed, further reduce the local population.
Managing Bite Symptoms Safely
Even with diligent prevention, a mosquito bite may occur, and managing the resulting itch and swelling requires safe treatment during pregnancy. For localized irritation, non-prescription topical treatments are the preferred first step, as they minimize systemic absorption. Applying a cool compress or a paste made of baking soda and water directly to the bite can help reduce swelling and discomfort.
Calamine lotion is a safe and soothing option for relieving itchiness. Low-strength hydrocortisone cream (1%) can also be used sparingly for a short duration, but consult a healthcare provider before use if the bite covers a large area. For stronger, widespread allergic reactions, certain oral antihistamines are considered safe during pregnancy. Loratadine (Claritin) and Cetirizine (Zyrtec) are preferred non-drowsy options, particularly after the first trimester. Acetaminophen is the preferred over-the-counter pain reliever for minor aches associated with a bite, but nonsteroidal anti-inflammatory drugs (NSAIDs) like ibuprofen should be avoided, especially after the 20th week of pregnancy.