Effects lasting into adolescence of exposure to betamimetics in utero

The range of the predictable within-day change in blood pressure, assessed as the circadian blood pressure amplitude, is greater in newborns who have been exposed in utero to betamimetics than in those not exposed. A larger circadian blood pressure amplitude is also found in infants and children with a positive versus those with a negative family history of high blood pressure. In adulthood, an excessive circadian blood pressure amplitude is associated with a 6-fold increase in risk of ischaemic stroke. To determine whether the large circadian blood pressure amplitude associated with intrauterine exposure to betamimetics in newborns persists later in life, the progeny of mothers who had had similar obstetric situations but had been treated either with spasmolytics (not including betamimetics) or with betamimetics to prevent premature labour was assessed. The blood pressure of 43 adolescents aged between 11 and 14 years was measured at 15-minute intervals for 2 days with an ambulatory monitor; an echocardiogram was also taken. A multiple regression analysis accounting for gender- and age-related changes revealed a dose-dependent effect of betamimetic exposure on the circadian blood pressure amplitude of the offspring. Exposed children also tended to have a larger left ventricular mass index. Thus, in utero exposure to betamimetic drugs may have cardiovascular effects lasting into adolescence.