Hormone fluctuations make women more asthma-prone than men, say reports that find relationship between asthma and menstrual cycle.

The reports say women in the ages of 20-50 years are three times more prone to asthma and are likely to be hospitalised compared to men despite comparable spirometry, according to health portal HealthCentral.

The reports were presented at the annual meeting of the American College of Allergy, Asthma and Immunology, in Anaheim, California, Friday.

Studies have demonstrated a relationship between asthma and the menstrual cycle, with 46 percent of women's hospital admissions perimenstrual, and up to 40 percent of women having premenstrual asthma symptoms, it said.

As many as eight percent of pregnant women have asthma. Pregnant women with asthma or those who are planning a pregnancy face unique concerns about controlling their asthma symptoms and the safety of medications, the report said.

"When we look at the reproductive phases of a woman's lifecycle, we find in children under age 12, asthma is more common in boys than in girls, an expert said.

Around puberty the ratio changes, with asthma becoming more common in girls than in boys, the expert added.

Women with asthma experience more symptoms during their premenstrual and menstrual weeks with peak symptoms two to three days before menses. Many are not aware of this pattern, and keeping a diary of their symptoms is very helpful.

Another expert noted that oral contraceptives have been shown to have a beneficial impact on asthma.

"Non-asthmatic women on oral contraceptives have a higher total lung capacity. Airways are more stable in women with asthma who take oral contraceptives, and several small studies have shown their asthma does improve."