Subfertility and the use of assisted reproductive technologies (ARTs) may increase the risk of asthma in offspring according to a study published in Thorax. The risk for asthma also appears to increase with increasing number of early miscarriages.
Asthma is a common long-term inflammatory disease of the airways of the lungs. It is characterized by variable and recurring symptoms, reversible airflow obstruction, and bronchospasm. Symptoms include episodes of wheezing, coughing, chest tightness, and shortness of breath. These episodes may occur a few times a day or a few times per week. Depending on the person, they may become worse at night or with exercise.
Asthma is thought to be caused by a combination of genetic and environmental factors. Environmental factors include exposure to air pollution and allergens. Other potential triggers include medications such as aspirin and beta blockers. Diagnosis is usually based on the pattern of symptoms, response to therapy over time, and spirometry.
Asthma is classified according to the frequency of symptoms, forced expiratory volume in one second (FEV1), and peak expiratory flow rate. It may also be classified as atopic or non-atopic, where atopy refers to a predisposition toward developing a type 1 hypersensitivity reaction. There is no cure for asthma. Symptoms can be prevented by avoiding triggers, such as allergens and irritants, and by the use of inhaled corticosteroids.
Long-acting beta agonists (LABA) or anti-leukotriene agents may be used in addition to inhaled corticosteroids if asthma symptoms remain uncontrolled. In children with acute asthma exacerbations who report chest pain, physicians frequently obtain chest radiographs (CXRs), according to a study published in Pediatric Emergency Care.
Despite their common use, a substantial percentage of CXRs fail to produce positive findings, which researchers suggest support the rationale of limiting their use in children. The researchers aimed to determine whether ART procedures or factors associated with subfertility are the driving force behind the increased risk for asthma in children conceived with ART.
They linked information from the Medical Birth Registry of Norway (MBRN) and the Norwegian Mother and Child Cohort Study (MoBa) for all children born between January 1998 and March 2009. Of the 474,402 children in the MBRN, 20,189 (4.3%) had developed asthma. Of the 75,797 children in the MoBa, 3229 (4.3%) had developed asthma.
The investigators defined asthma as the use of asthma medication in the 12 months before the child turned 7. The investigators found that children conceived with ART were up to 42% more likely to have asthma than children conceived naturally. When compared with children whose parents had spontaneously conceived after 12 months or longer, children conceived with ART were 22% more likely to have asthma.