EFFECTS LASTING INTO ADOLESCENCE OF EXPOSURE TO BETAMIMETICS IN-UTERO

The range of the predictable within-day change in blood pressure, asse ssed as the circadian blood pressure amplitude, is greater in newborns who have been exposed in utero to betamimetics than in those not expo sed. A larger circadian blood pressure amplitude is also found in infa nts and children with a positive versus those with a negative family h istory of high blood pressure. In adulthood, an excessive circadian bl ood pressure amplitude is associated with a 6-fold increase in risk of ischaemic stroke. To determine whether the large circadian blood pres sure amplitude associated with intrauterine exposure to betamimetics i n newborns persists later in life, the progeny of mothers who had had similar obstetric situations but had been treated either with spasmoly tics (not including betamimetics) or with betamimetics to prevent prem ature labour was assessed. The blood pressure of 43 adolescents aged b etween 11 and 14 years was measured at 15-minute intervals for 2 days with an ambulatory monitor; an echocardiogram was also taken. A multip le regression analysis accounting for gender- and age-related changes revealed a dose-dependent effect of betamimetic exposure on the circad ian blood pressure amplitude of the offspring. Exposed children also t ended to have a larger left ventricular mass index. Thus, in utero exp osure to betamimetic drugs may have cardiovascular effects lasting int o adolescence.