Allergies during pregnancy linked with autism, ADHD

 

Despite a wealth of research, how and why autism and other neurodevelopmental disorders appear is still unknown. The search is on for any factors that might contribute to these psychological conditions. A recent study focuses on maternal allergies.

Theories linking allergies and psychological disorders receive further backing with a new study in rats.

Already, lines have been drawn between allergies and attention deficit hyperactivity disorder (ADHD) and autism.
Similarly, links are known to exist between inflammation and the risk of schizophrenia, ADHD, and autism.
However, although these connections have been glimpsed, the cellular mechanisms that underpin them are not understood; how do inflammatory and immune responses influence cognition and behavior?
Research, recently presented at Neuroscience 2016 - the annual meeting of the Society for Neuroscience in San Diego, CA - adds another piece to this unwieldy puzzle. The study was led by Kathryn Lenz, an assistant professor of psychology at Ohio State University.
Autism is three or four times more common in males than females; Lenz and colleagues set out to investigate this gender difference in rats.
To this end, the team first sensitized female rats to an egg white protein, ovalbumin, prior to them becoming pregnant. Fifteen days into the pregnancy, the rats were presented with the allergen to trigger an immune response.

"We're really interested in figuring out unknown factors in psychological disorders and in differences between male and female brain development as it relates to autism, ADHD, and other disorders."

Kathryn Lenz

Immune-mediated changes in rat pups

Once they had been sensitized, the team designed experiments to gauge whether the mother's immune response made measurable changes in the pups. Firstly, the levels and types of immune cells in the rat's developing brains were measured.
Secondly, behavioral differences in the rat pups were measured once they were born, such as their ability to learn, anxiety-like behavior, and their overall levels of activity.
Finally, Lenz and her team examined the density of dendritic spines in the pup's brains - points of synaptic connection between nerve cells in the rat's frontal cortex. Dendritic spines are important in cellular-level communication within the brain; a number of cognitive disorders show abnormalities in the numbers of dendritic spines and their maturity level.
The team found that the rats whose mothers had been exposed to an allergen had an increase in certain immune cells in the brain - called mast cells. They also showed a reduction in another type of immune cell - microglia. These differences were the same in both sexes.
Another marked change was seen in their behavior. Allergic mothers' offspring were hyperactive and demonstrated less anxiety-like behavior. Lenz says: "Young rats engage in social play and males are more rough and tumble and usually play much more than females." However, the males in the allergy group were found to roughhouse with their peers significantly less.
As Lenz explains: "The males born to the allergen-exposed mothers looked more like females. They were more socially reserved. They were really hyperactive but socially disengaged. That looks a bit like ADHD."

Mental flexibility altered by immune challenge

Differences were also seen when looking at the mental flexibility of the rats; those born to allergic mothers struggled more when challenged.
The team tested the rats by hiding Cheerios in terra-cotta pots. To find the treat, they had to follow rules and, each time, the researchers would tweak the rules, testing the pup's mental flexibility. Sometimes the pots would be covered in sandpaper, other times in velvet. The rats needed to be adaptable to uncover the prize.
All of the rats in the allergen group, regardless of gender, struggled to adjust to the differing trials. However, the males in the allergen group were found to struggle more than the females.
Further differences were unearthed when data from the dendritic spines was analyzed. The male rats born from allergen-exposed mothers had a reduction in number, whereas the females from the allergen group had an increase in number.

"This is evidence that prenatal exposure to allergens alters brain development and function and that could be an under-appreciated factor in the development of neurodevelopmental disorders."

Kathryn Lenz

Further studies will, of course, be necessary to flesh out these findings. However, they are an interesting addition to current knowledge. The connection between immune system and cognitive deficits seems solid; the next challenge will be converting this knowledge into treatments and preventions.
Learn how autism risk increases with prenatal exposure to banned chemicals.

Written by Tim Newman

 

If you can’t step outside without sneezing, chances are seasonal allergies are to blame. Pregnancy can cause enough symptoms as it is. But adding an itchy nose to an itchy belly can make for a long trimester.
Seasonal allergies cause symptoms, including:

• coughing
• sneezing
• itching
• runny nose

The condition can affect your breathing. So can pregnancy. Fortunately, there are many safe treatments you can use to relieve seasonal allergy symptoms.
You need to be careful of the medications you take and other treatments during pregnancy. Here’s what you need to know about treating seasonal allergies.

Part 2 of 6

What causes seasonal allergies?

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Your body’s immune system ideally fights against “bad guys” like flu viruses, colds, and other infection-causing organisms that seek to make you sick. But sometimes, your immune system reacts to things that really aren’t all that harmful to you. This is the case with seasonal allergies.
Seasonal allergies occur when your body reacts to allergens that tend to show up in a certain season. Seasonal allergies are usually your body’s reaction to pollen. Pollen is a powdery substance that forms the male sperms cells that fertilize plants so they can reproduce.
Common culprits of seasonal allergies include:

• cocklebur
• grasses
• molds
• pigweed
• ragweed
• trees
• tumbleweed

Depending on where you live, spring allergies can pop up around February and end in early summer. Fall allergies can take place in late summer and continue until late fall.
Pregnancy can make seasonal allergies worse. Also, a condition called “rhinitis of pregnancy” can cause similar symptoms to seasonal allergies. This usually occurs in the last trimester. But the cause of rhinitis of pregnancy is extra hormones, not allergens.

Part 3 of 6

At-home treatments for seasonal allergies

Moms-to-be with seasonal allergies can use several at-home treatments to relieve their symptoms. Some examples include:

• Creating a saline nasal spray by combining 8 ounces of warm water with 1/4 salt to the water. You can add this to a spray or squeeze bottle to irrigate and soothe irritated nasal passages. Neti pots are another option.
• Watching news reports and checking pollen counts daily. During episodes of large pollen counts, pregnant women can avoid too much time outdoors to keep exposure down.
• Avoiding going outdoors between 5 a.m. and 10 a.m., the times when pollen counts are usually the highest.
• Taking showers and changing clothing after being outside. This can help remove pollen that builds up on hair and clothing.
• Wearing a protective filter mask when doing outdoor activities like mowing the lawn or gardening.
• Wearing over-the-counter nasal strips at night. These position the nasal passages so they’re more open. This reduces a person’s symptoms.

If you can avoid whatever’s causing your seasonal allergies, you can often keep your symptoms at bay.

Part 4 of 6

Medications for seasonal allergies during pregnancy

Most pregnant women can safely take over-the-counter allergy medications. Examples of medications that have research to support that they’re safe for pregnant women to take (as of currently available data) include:

• cetirizine (Zyrtec)
• chlorpheniramine (ChlorTrimeton)
• diphenhydramine (Benadryl)
• loratadine (Claritin)

There are always risks when taking any medication during pregnancy. Women should talk with their doctors before taking allergy medicines to make sure they aren’t potentially harmful.
While doctors consider many oral over-the-counter medications safe for seasonal allergies, using both oral and nasal spray decongestants isn’t as studied or well-known.
Use of nasal sprays may be safer than oral decongestants. That’s because nasal sprays aren’t as likely to be absorbed into the bloodstream. An example is oxymetazoline, an ingredient in brands like Afrin and Neo-Synephrine.
Women should exercise caution when using nasal sprays for more than three days. This is because using decongestants for longer can make allergy symptoms worse by causing nasal swelling.
Some women also get allergy shots. These are compounds of allergens that are injected as a means to desensitize a person to an allergen. If a woman becomes pregnant while she is in the course of her allergy shots, she can usually keep getting them.
Pregnancy isn’t a good time to start getting allergy shots. It’s possible they can cause strong allergic reactions. Without knowing a woman’s reaction, it’s best to delay starting allergy shots until after giving birth.

Part 5 of 6

Allergy medications to avoid during pregnancy

Doctors haven’t widely studied some medicines regarding their safety in pregnancy. This is because it isn’t ethical to perform testing on pregnant women. As a result, most information about medications is due to reports and knowledge about general medication safety.
According to the American College of Allergy, Asthma, & Immunology (ACAAI), several medications aren’t considered safe. During the first trimester, it’s especially important to consider the potential risks and benefits because the baby is developing the most then.
Unsafe treatments during pregnancy include:

• Pseudoephedrine (Sudafed): While some studies found that pseudoephedrine is safe in pregnancy, there have been reports of an increase in abdominal wall defects in the babies of mothers who used the medication during pregnancy, according to the ACAAI.
• Phenylephrine and phenylpropanolamine: These decongestants are considered “less desirable” than taking pseudoephedrine, according to the ACAAI.

Part 6 of 6

Next steps

If your seasonal allergy symptoms have made sleep evasive or are interfering with your daily activities, treatments are available that are likely safe for you and baby.
Always talk to your doctor about any concerns you have regarding medications. You can also read medication labels carefully to ensure your medicines don’t have a warning for pregnant women (manufacturers are legally required to list their pregnancy safety information).
If you have questions on specific allergy medicines, visit the website MotherToBaby.org. This site is operated by the Organization of Teratology Information Specialists, whose members study medication safety for pregnant and breast-feeding moms.
Pregnancy and seasonal allergies are self-limiting conditions. Your due date will come and blooming season will end. It’s important you stay as comfortable as possible while you navigate both.

You asked, we answered

• What remedies are helpful for allergies during pregnancy?
• The safest methods are taking simple steps such as trying to avoid known allergens and saline nose drops. When this doesn’t work, over-the-counter antihistamines such as Claritin, Zyrtec, and Tavist are acceptable. Sudafed can be used after the first trimester with caution if other methods fail. Almost all of these medications are category C which means there aren’t sufficient studies available to assure safety, yet there are no significant known problems with these drugs. If the problem is severe or is not responding to home remedies, seek the advice of a doctor. 
  - Michael Weber, MD