This should include spirometry and a careful record of peak flows. Sleeping pills should generally be avoided even in patients with mild asthma other than for short-term use and only under careful physician supervision. Oxygen Use in Asthma When treating bronchial asthma, oxygen should be confined mainly to the emergency room and hospital setting, because only in severe attacks do oxygen levels drop significantly. Besides, oxygen will not relieve bronchial constriction or in any way shorten an asthma attack. There are some exceptions to this rule. Patients who have had severe, rapidly developing attacks in the past with low oxygen levels noted on admission to the hospital and who are difficult to control may keep an emergency oxygen cylinder at home. Patients with bronchial asthma and associated conditions such as congestive heart failure or other heart diseases who might not tolerate any drop in oxygen level may also keep a home emergency oxygen supply. Avoid routine use of oxygen in the home to treat uncomplicated bronchial asthma. Premenstrual Asthma Many women have noted premenstrual worsening of their asthma. Studies have demonstrated heightened sensitivity to various asthma triggers before menstruation. A further report revealed that premenopausal women are most likely to suffer an asthma attack in the premenstrual phase of the menstrual cycle when estrogen levels are lowest. Hormonal treatment by injecting progesterone has been given to patients who suffer severe premenstrual exacerbations of their asthma. Additional measures that are helpful involve a step-by-step increase in medication, possibly including a premenstrual increase in inhaled corticosteroid or a brief course of oral corticosteroid. Just as in pregnancy, asthma varies from patient to patient prior to menstruation. Recording peak flows should help identify this form of asthma. Menopause and Asthma After menopause, the relationship between asthma and estrogen is less clear. One study has suggested that hormone replacement therapy may actually increase the risk of developing asthma by 50 percent. Further studies are needed to clarify this finding.