Avoiding allergens during pregnancy - is it worth it? - Strefa Alergii
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Avoiding allergens during pregnancy – is it worth it?

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Future mothers often wonder whether it is worth excluding allergenic products such as nuts, grains, chicken eggs, or cow's milk from their diet. Will doing so protect their child from developing allergy symptoms in the early years of life? What kind of allergy tests should be done if worrisome symptoms arise?

The importance of a diet during pregnancy

Pregnancy is undoubtedly a very unique period in a woman’s life, full of changes and challenges that her body must meet. From now on, not only does the body take care of its proper functioning, but it also provides all the necessary substances for the developing baby.

A woman’s diet plays a crucial role during this time and influences the stages of the unborn child’s development. We know very well that all kinds of stimulants, fast food, and highly processed foods should be definitely avoided. We limit sweets and salty snacks. We don’t eat raw or undercooked meat or eggs. We avoid sushi, as well as unpasteurized products or milk.

Knowing the list of products not recommended for consumption during pregnancy, future mothers often wonder:

What about allergenic products, such as nuts, grains, chicken eggs, or cow’s milk (even pasteurized one)?

Is it worth reducing the amount of these foods in the diet during pregnancy? Will it protect my child from developing allergy symptoms in the early years of their life?

Increased occurrence of allergies in children

These questions are not surprising at all, especially considering the observed increase in the number of people struggling with allergic diseases. In the case of children, the percentage is around 30% [1]. Furthermore, there have been no scientific reports so far indicating a possible decrease in this trend. It is worth knowing that the risk of developing allergies is influenced by genetic and environmental factors:

  • For individuals with allergic diseases in the family, the risk of developing allergies is higher compared to those without such diseases. If at least one parent has an allergy, the risk ranges from 20% to 40%, while if both parents are allergic, it increases to 60% [2].
  • Breastfeeding reduces the risk of developing allergic diseases [2].
  • Air pollution and exposure to cigarette smoke may contribute to the development of allergies [3].
  • According to the hygiene hypothesis, frequent contact with potential allergens (cats, dogs, rural living) prevents allergies [1].

So, can limiting a child’s exposure to specific allergens during fetal life reduce the risk of developing allergies?

Avoiding Allergens During Pregnancy

The human immune system develops during the fetal period. However, the E antibodies (IgE) responsible for the development of allergies appear as early as the 11th week of fetal life [1]. Knowing these facts, we can suggest that exposure to allergens during the prenatal period may play a role in the development of allergies in children.

Nevertheless, scientific research has not been able to prove that avoiding allergenic foods during pregnancy can reduce the risk of allergies in children [4] [5] [6].

Furthermore, the elimination of foods considered to be the most common allergens, which also provide valuable nutrients, can have an unfortunate impact on the mother or the fetus, leading to:

  • Lower average birth weight.
  • Increased risk of preterm birth.
  • Slower fetal weight gain.
  • Nutritional deficiencies.

In one study [4], it was observed that women who were on a diet that did not include cow’s milk and chicken eggs gained significantly less weight during pregnancy compared to women who did not eliminate these foods. This happened even though supplementation was implemented for them. This was in order to provide the nutrients found in the previously mentioned products. Neither the amount nor the frequency of consumption of allergenic foods during pregnancy was associated with an increased risk of developing allergies in children. In contrast, their restriction may have led to the appearance of nutritional deficiencies.

Diagnosing Allergies During Pregnancy

Avoiding exposure to allergens may also have another side. When the expectant mother is an allergy sufferer and experiences troublesome symptoms, limiting contact with potential allergen sources aims to minimize the occurrence of reactions and improve the future mother’s health. It is estimated that one in five pregnant women suffers from allergic diseases. This is particularly manifested by nasal rhinitis or asthma.

Allergic symptoms that occurred before pregnancy may subside. Sometimes, however, they can become more severe during this special period in a woman’s life. Whatever happens, it is worth monitoring your body. It is also important to take appropriate action as soon as possible.

Women who have been under the care of an allergist should not discontinue treatment on their own. Symptoms associated with allergies, especially severe ones like shortness of breath, can have an unfavourable impact on the developing child and even lead to oxygen deprivation. Therefore, an immediate visit to a specialist will clear up any doubts that may arise. It will also be an opportunity to modify the amount and type of medicines that are safe for the baby.

Expectant mothers who observe worrying allergy symptoms should also visit their doctor to identify the source of the problem. The diagnosis of an allergy during pregnancy should be based on a thorough medical history. The specialist may then recommend blood allergy tests. It is advisable to choose multi-parameter quantitative tests, which guarantee the reliability of the results obtained and speed up the diagnostic process. If the source of allergy is difficult to pinpoint, molecular allergy diagnostic tests can help. Up to 300 allergens can be determined in a single test and the cause of unpleasant symptoms can be detected.

Skin tests are not recommended at this particular time, as they are performed in vivo, so in consequence the allergen introduced under the skin can trigger an unwanted reaction.

Natalia Palus

translation: Julia Majsiak

[1] Samoliński B., et al., Wyniki badań programu Epidemiologia Chorób Alergicznych w Polsce, http://ecap.pl/oprojekcie.html [dostęp z dnia 15.02.2021], 2005
[2] https://www.mp.pl/pacjent/pediatria/zywienie/52607,jak-zapobiegac-alergii-na-pokarmy [dostęp z dnia: 10.02.2021]
[3] Swincow G., Czerwionka-Szaflarska M., Zawadzka-Gralec A., Z czego wynika powszechne występowanie alergii wśród dzieci?, Nowa Pediatria 3/2006, s. 74-79.
[4] Fälth-Magnusson K, Kjellman NI. Development of atopic disease in babies whose mothers were receiving exclusion diet during pregnancy–a randomized study. J Allergy Clin Immunol. 1987 Dec;80(6):868-75. doi: 10.1016/s0091-6749(87)80279-8. PMID: 3693764.
[5] Bunyavanich S, Rifas-Shiman SL, Platts-Mills TA, et al. Peanut, milk, and wheat intake during pregnancy is associated with reduced allergy and asthma in children. J Allergy Clin Immunol. 2014;133(5):1373-1382. doi:10.1016/j.jaci.2013.11.040
[6] Venter C, Pereira B, Voigt K, Grundy J, Clayton CB, Higgins B,Arshad SH, Dean T. Factors associated with maternal dietary intake ,feeding and weaning practices, and the development of food hyper-sensitivity in the infant.Pediatr Allergy Immunol 2009: 20: 320–327