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Pregnancy and Allergies


Updated December 04, 2012

Written or reviewed by a board-certified physician. See About.com's Medical Review Board.

Pregnancy is a special time for most women, although it can also be very uncomfortable. Most women experience some form of morning sickness, leg swelling, lower back pain, or simply a general feeling of being uncomfortable as labor nears. For women with allergies and asthma, however, pregnancy can include an entirely new set of problems. Asthma, allergic rhinitis and anaphylaxis can worsen or even start during pregnancy. Allergic reactions unique to pregnancy can also occur, such as various itchy skin rashes and rhinitis of pregnancy.

Allergies During Pregnancy

Nasal allergy symptoms during pregnancy can be caused by allergic rhinitis, sinusitis or non-allergic rhinitis. If a woman has had allergic rhinitis prior to pregnancy, this could worsen, stay the same, or even improve. This change in symptoms may be dependent upon many factors, including the presence of seasonal allergens, and an increase in pregnancy hormones.

Non-allergic rhinitis in pregnancy may also be due to an increase in pregnancy hormones, leading to nasal congestion, runny nose and post nasal drip. This is called rhinitis of pregnancy. The symptoms may mimic allergies, but since they are non-allergic in nature, they don't respond to treatment with antihistamines.

The pregnant woman with rhinitis is often concerned about the safety of medications during pregnancy, and may therefore avoid taking medications altogether. If avoidance of allergic triggers is not possible or successful, medications may be needed to control symptoms.

Learn more about treating allergy symptoms during pregnancy.

Asthma and Pregnancy

Asthma tends to follow a “rule of thirds” during pregnancy. This means that one-third of pregnant asthmatics get better, one-third get worse, and one-third remain the same as prior to pregnancy. Women who follow one pattern with one pregnancy tend to have similar patterns with future pregnancies, though it's more common for women with severe asthma to get worse during pregnancy, while those with mild asthma tend to improve.

The majority of asthma exacerbations occur during 24 to 36 weeks of gestation; only rarely does the asthma worsen significantly during labor and delivery. Usually asthma returns to its pre-pregnancy state within 3 months of delivery. It's very important for pregnant asthmatics to be followed closely by their personal physician during their entire pregnancy.

Learn more about the treatment of asthma during pregnancy.

Itching and Rashes During Pregnancy

Itching, with or without a rash, is a common symptom for many people. Itching can be the result of a skin disease, such as an allergic skin rash, or an internal medical issue such as liver or thyroid disease. A few unique diseases related to being pregnant can cause itching, although other conditions causing itching may have nothing to do with the pregnancy itself. Either way, having an itchy rash during pregnancy can add anxiety to an otherwise stressful time for many women.

Learn more about itching and rashes that uniquely occur during pregnancy.

Anaphylaxis During Pregnancy

Anaphylaxis is a severe allergic reaction, caused by the release of allergic chemicals, such as histamine, from allergic cells such as mast cells. Symptoms of anaphylaxis can include urticaria and angioedema, symptoms of asthma, vaginal and vulvar itching, uterine cramps, nausea/vomiting/diarrhea, and low blood pressure. Anaphylaxis can also occur during pregnancy, particularly during labor and delivery. This can represent a special danger to the fetus, because low blood pressure related to anaphylaxis in the mother can affect blood flow to vital organs in the fetus. Anaphylaxis during pregnancy is most often caused by medications or latex exposure encountered during labor and delivery.

Learn more about the causes and treatment of anaphylaxis during pregnancy.

DISCLAIMER: The information contained in this site is for educational purposes only, and should not be used as a substitute for personal care by a licensed physician. Please see your physician for diagnosis and treatment of any concerning symptoms or medical condition.

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