Mamas on Bedrest: Untreated Asthma in Mamas Leads to Low Birth Weight (Girl) Babies

July 15th, 2011

I had an asthma attack when I was pregnant with my son in 2005. It was the weirdest thing because I had not had an asthma attack in years and didn’t even have a rescue inhaler available. I called my OB’s service (of course this happened over the weekend) and a rescue inhaler and steroid inhaler were prescribed and I was referred to a pulmonologist for evaluation.

To my surprise, the pulmonologist advised that I continue taking the steroid inhaler for the duration of my pregnancy and into the early post partum. I asked my pulmonologist if the steroid inhaler was safe for me and my son and he told me that it is very important that I breath easily and exchange adequate oxygen so the I can provide adequate oxygen to my son.

Just one day ago, I learned that there is another reason why it is important for asthmatic mamas to be placed on maintenance steriod inhalers.  Research studies show that asthmatic mamas who are not placed on maintenance steroid inhalers are at risk for delivering low birth weight infants and female babies are most often affected.

Dr. Norman Swan a physician and research  journalist at The Hunter Medical Research Institute Newcastle, New South Wales addressed this very topic in an  interview with Dr. Vicky Clifton, Researcher at the Mothers and Babies Research Centre, The Hunter Medical Research Institute Newcastle, New South Wales. In the interview, Dr. Clifton explained the link between maternal asthma and low birth weight infants.

“What we’re observing is that low birth weight is associated with female babies and it’s associated with asthmatic mothers that don’t use their inhaled steroids to control their asthma…Mothers who are not treated adequately usually have smaller female babies.”

At the time of the interview in 2005, Dr. Clifton and other researchers were not sure why female infants were more often affected and what other growth and development impairments occurred. The one thing that was sure is that children who are born to mothers with asthma grew on a different (slower) growth curve than childen born to non-asthmatic mothers. Furthermore, children born to asthmatic mothers who took maintenance steroid inhalers while pregnant were less likely to be born low birth weight and were less likely to grow on a slower growth curve than their asthmatic, non-treated counterparts. Follow up studiess on the children are being conducted to determine if any other effects of asthma occurred.

The explanation for the asthma link to low birth weight infants is as follows:

“You see these glucocorticoids are stress hormones. The cortisol from the mum gets into the baby’s blood stream and seems to affect the female foetus by making the baby reduce her own steroid production. Male foetuses on the other hand, seem to resist their mum’s steroids better…what seems to be happening is that an enzyme barrier in the placenta which stops maternal steroids getting into the baby remains up in males but drops in females of asthmatic mothers under this stress. Anyway, the result in females is that their organs don’t grow as well.”

The take home message from this interview is that any asthmatic pregnant mama should be taking maintenance steroid inhalers and her asthma should be monitored and managed closely. Here are Dr. Clifton’s final comments in the interview:

” Preventative treatment, the use of inhaled steroids by asthmatic women plays a very important role in protecting against the effects that we’ve observed on the foetus. It’s quite important for asthmatic women to have an asthma action plan specifically tailor-made for their pregnancy. We find that asthma does change as pregnancy progresses and that it’s important that women have an idea of how to treat it. There’s a great deal of fear about using inhaled steroids for what effect it may have on the developing baby but in fact our data is starting to say it’s important that they use it because the inflammatory effects of the disease have a greater effect on the baby than the actual treatment.”

Mamas on Bedrest: If you have asthma, Get evaluted and obtain and take maintenance steroid inhalers.

The full interview by Dr. Norman Swan of Dr. Vicky Clifton, “Asthma and the link with low birth weight babies” can be heard on ABC Radio’s The Health Report.

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