One current practice guideline recommends myringotomy with tympanostomy tube insertion (M&T) for young children in whom middle-ear effusion (MEE) has persisted for 3 months, and another recommends the procedure after MEE has persisted for 4 to 6 months provided that a bilateral hearing loss of > or=20 dB is present. Sequelae of M&T are not uncommon, but the extent to which these sequelae are attributable to M&T itself or to the middle-ear disease that prompted the procedure or to both has not been clear. Our objective in the present study was to examine the prevalence of various tympanic membrane (TM) abnormalities in otherwise healthy children at the age of 5 years and hearing levels at the age of 6 years in relation to persistent MEE and M&T in the children's first 3 years of life. In a prospective study of child development in relation to early-life otitis media, we randomly assigned 429 children who met specified criteria regarding the persistence of MEE in their first 3 years of life to undergo M&T either promptly (the "early-treatment" group) or after a defined extended period if MEE remained present (the "late-treatment" group). We also followed a representative sample of 241 children who ranged from having no MEE to having MEE whose cumulative duration fell just short of meeting randomization criteria for the clinical trial (the "nontrial" group). Most of the children in each group underwent both otomicroscopic examination at the age of 5 years and audiometric testing at the age of 6 years, at times when they were free of MEE. Among these children, M&T had been performed in 82.3% of those in the early-treatment group, 38.1% of those in the late-treatment group, and 3.0% of those in the nontrial group. At the age of 5 years, we found 1 or more types of TM abnormality in 1 or both ears in 70.7%, 42.5%, and 9.5% of the children in the early-treatment, late-treatment, and nontrial groups, respectively. Within the 3 groups, however, among children who received tubes, the proportions who had an abnormality of some type were similar, namely, 82.6%, 80.4%, and 83.3%, respectively. The corresponding proportions among children who had not received tubes were 15.4%, 19.3%, and 7.2%, respectively. Segmental atrophy and tympanosclerosis were the most common abnormalities found. At the age of 6 years, mean pure-tone average audiometric thresholds in the early-treatment, late-treatment, and nontrial groups, respectively, were 6.18 dB, 5.49 dB, and 4.63 dB in left ears and 6.17 dB, 6.02 dB, and 4.32 dB in right ears. The thresholds in the early- and late-treatment groups did not differ significantly, but the thresholds in the early- and late-treatment groups were each significantly higher than in the nontrial group. Within the early- and late-treatment groups, we found no significant relation between hearing levels and the presence or type of TM abnormalities. In otherwise healthy children who have persistent MEE during their first 3 years of life, ready resort to M&T results in far more TM abnormalities at age 5 than does selective management in which most children do not receive the procedure. With these differing approaches, however, hearing levels at age 6 do not differ. Regardless of whether children with persistent early-life MEE receive M&T, they have more TM abnormalities at age 5 and negligibly poorer hearing at age 6 than do children who had less or no otitis media. Longer term otologic and audiologic outcomes of persistent early-life MEE and of M&T remain to be determined. In view of 1) the present findings and the remaining uncertainties concerning sequelae, 2) the fact that M&T involves certain immediate risks--albeit minimal--and substantial cost, and 3) previously reported findings in the study's randomized clinical trial that show no developmental advantage at ages 3 and 4 years accruing from children's having received prompt M&T, a prolonged period of watchful waiting seems desirable in otherwise healthy children who are younger than 3 years and have persistent, asymptomatic MEE that is not complicated by sensorineural or severe conductive hearing loss, balance dysfunction, or severe TM retraction.