Throughout childhood, asthma is generally more common in boys than in girls. This trend reverses during puberty when more girls develop asthma for the first time. By the age of 18 years, asthma is more common in girls. Although we don't know exactly why this happens, it may be that hormones play a part. Hormonal changes certainly affect asthma in adolescent girls.
Some girls find their asthma is worse around the time their periods start for the first time.
However, other factors such as the pressures of starting a new school and emotional stress need to be taken into account as well. Their symptoms usually settle down once their menstrual cycle becomes established. However, some women continue to find that their asthma gets worse before their period. If you have noticed that your asthma is harder to control at certain times of the month, you are not alone. Studies have shown that around one third of women think their symptoms are worse just before or during menstruation.