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How Much You Weigh Before Pregnancy May Affect Your Child’s Risk for Allergies

Pregnant woman holding belly

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Key Takeaways

  • A new study found that the pregnant mom's weight before becoming pregnant is linked to the development of allergic diseases in their children.
  • Obesity produces inflammation in the mother’s body, which can reach the fetus, and become a factor in developing allergies.
  • The goal of looking at pre-pregnancy weight is to help achieve a healthy pregnancy for both mother and baby.

A parent’s actions impact their child during pregnancy—from what they eat or drink to the amount of exercise they get to the prenatal vitamins they take. While what the parent does during pregnancy is important, a new study shows that what they do before becoming pregnant can be just as impactful.

The study, published in Paediatric and Perinatal Epidemiology notes that a mother’s weight before pregnancy can affect her child’s risk for allergies. The findings help pregnant individuals realize the tremendous part their health plays in the outcome of their child’s health.

“Understanding the link between pre-pregnancy weight and risks of developing allergic diseases may inspire pregnant people to make healthful choices to set their children up for a healthy life,” states Sebastian Srugo, MSc, an epidemiologist in Canada and lead author of the study.

The study casts light on the link between a parent’s weight before getting pregnant and their child's potential for life-long allergies. In addition to the study findings, we provide information on symptoms of allergic diseases in kids and steps people can take to have a healthy pregnancy for both the parent and baby.

All About the Study

Researchers from the University of Ottawa wanted to find out whether there was a link between the mothers’ weight or weight gain during pregnancy, and their kids’ development of allergies. To learn more, they gathered health records from the healthcare system in Ontario, Canada. Researchers pulled records from 2012 to 2014 for almost 250,000 live births.

The records provided details on the mother’s prenatal weight prior to pregnancy. This allowed researchers to determine her body mass index (BMI) using height and weight information. Records also helped researchers determine each mother's gestational weight gain (GWG), or how much weight they added during the pregnancy.

Sebastian Srugo

The main findings were that ... children born to mothers who were obese had 8% higher risk of developing asthma.

— Sebastian Srugo

The children were then followed from birth up to age 7 years old to see if they developed asthma, dermatitis, anaphylaxis, or rhinitis. The findings lined up with researchers’ expectations.

"The main findings were that children born to mothers who were underweight had a 6% higher risk of developing eczema in early childhood. We also found that children born to mothers who were obese had an 8% higher risk of developing asthma,” notes Srugo.

The results may help individuals who are planning to become pregnant take steps to prepare themselves physically, making choices to aid in a healthy pregnancy.

“This is significant because it may indicate that the weight gain during pregnancy itself may not be a pro-inflammatory process leading to allergy development in offspring, but that the baseline weight of pregnant women before they gain weight plays a larger role,” notes Armeen Poor, MD, a pulmonologist at Metropolitan Hospital in New York City.

Researchers say the study is the largest of its kind. The large sample size allowed for diversity in the study participants, but the study still had limitations. Because researchers took a retroactive look at the health records, there was no way to gather behavioral information on the mothers. Study authors say unhealthy diet habits, a lack of exercise, and poor sleep patterns could have had a negative impact on a child developing allergic diseases, but they didn't have this information to take into account.

Armeen Poor, MD

This is significant because it may indicate that...the baseline weight of pregnant women, before they gain weight, plays a larger role [in developing allergies].

— Armeen Poor, MD

Still, the results lined up with previous studies. A study in China found that the children who had the highest risk of asthma were born to women who were overweight prior to pregnancy and had extreme gestational weight gain. A European study found that overweight or extremely overweight pre-pregnancy weight was linked to an increased risk of allergic reactions in children, specifically wheezing.

Allergic Diseases in Children

The American College of Allergy, Asthma, & Immunology notes that allergies are the sixth leading cause of chronic illness in the United States. More than 24 million people nationwide deal with asthma; six million of those are children.

The symptoms of some of the most common allergic diseases can range from mild and requiring a watchful eye, to severe and potentially requiring hospitalization. It’s important to know what symptoms to look for so you can know how to help your child.

Asthma

Asthma can have a number of triggers, including tobacco smoke, pets, mold, and even cleaning products. “The symptoms of asthma entail episodic shortness of breath, [wheezing] and chest tightness, often precipitated by an allergen or strong odor,” notes Dr. Poor. Difficulty breathing can impact day-to-day physical activity.

Dermatitis

National Eczema Association notes that atopic dermatitis (AD) is the most common form of eczema, and that about 13% of children nationwide deal with AD. It is influenced by genetics, though external factors can also play a part. Itchy skin, redness or a rash, and open sores can all be symptoms of the condition.

Rhinitis

Allergic rhinitis is also called hay fever. It can be seasonal, flared up by pollen and outdoor allergens, or perennial, caused by dust mites, cockroaches, or mold. Sneezing, itchy eyes, and runny nose are all symptoms of rhinitis. If decreasing exposure to the elements that cause a reaction isn’t enough, some children may need medication or allergy shots to mitigate symptoms.

You should consult your healthcare provider for any questionable symptoms or reactions you observe in your child, and outline an effective course of treatment.

Link Between Pre-Pregnancy Weight and Allergic Disease

Factors of obesity cause the condition to impact not only the parent’s health but also their child’s.

“Previous research has shown that obesity is an inflammatory condition and that, during pregnancy, this inflammation can reach the developing fetus. Therefore, we and others have theorized that obesity may alter the normal development of the fetal immune system and potentially lead to higher risk of developing allergic disease in childhood,” Srugo explains.

In fact, a study out of Korea concluded that obesity produced a state of chronic low-grade inflammation in the body.

The link between pre-pregnancy obesity and children’s allergies is important because it shows how pivotal proper healthcare and nutrition is for a person who plans to become pregnant, even before conception.

Weight Gain During Pregnancy

It’s important to gain weight in a healthy way during pregnancy. Not gaining enough weight has been linked to delivering a baby that has developmental delays.

Healthy weight gain depends upon your weight prior to getting pregnant. It also depends on if you are pregnant with one baby, twins, or triplets. Your doctor can help you determine a healthy weight gain for your pregnancy.

Weight Loss During Pregnancy

Experts don’t recommend trying to lose weight during pregnancy. It can rob the growing baby of needed nutrients and contribute to an increased risk of illness. There are rare cases when a person is extremely overweight, and their weight may endanger the pregnancy, that weight loss may be recommended.

Again, working in conjunction with your healthcare provider is critical to achieve a healthy pregnancy weight for you.

Preparing for a Healthy Pregnancy

When looking at weight as it relates to the pregnancy, the goal is to have a healthy, happy parent and baby. Making sure you are at a healthy weight for you before becoming pregnant can make a big difference in the outcome of your pregnancy, and your baby’s future.

“The most important takeaway for pregnant people is: the healthier you can be during pregnancy, the healthier your child will be,” Srugo notes. “To prepare for healthy pregnancies, besides a healthy weight, pregnant people should try to eat healthier, sleep well, and exercise often; all those factors together will lead to healthier pregnancies and healthier children,” he concludes.

What This Means For You

The study notes that your weight before pregnancy impacts your child’s health. Working to achieve a healthy weight through proper diet and exercise before becoming pregnant can diminish the risk of your child dealing with allergic diseases. The effort beforehand can lead to a healthier outcome for both parent and child in the end.

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9 Sources
Verywell Family uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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