Asthma in Swedish children conceived by in vitro fertilisation.
OBJECTIVES: To investigate a proposed association between in vitro fertilisation (IVF) and child asthma. DESIGN: The risk for asthma after IVF was estimated as ORs using Mantel-Haenszel analysis. SETTING: The Swedish Medical Birth Register. PATIENTS: Of the 2 628 728 children born in 1982-2007 and surviving the perinatal period, 31 918 were conceived by IVF. Presence of asthma was define