Objectives: Extended-released nifedipine is used for maintenance tocolysis in pregnancies with high risk of preterm labour, but there are several concerns regarding the use of this calcium-channel blocker in normotensive pregnant women, because of its cardiovascular effects. On fetus, the safety of nifedipine administered as tocolytic agent in normotensive patients should be monitored through repeated Doppler evaluations of fetal hemodynamics. Methods: We enrolled 46 normotensive pregnant women with singleton pregnancies and high risk of preterm labour due to myometrial hipercontractility. The gestational age was between 24-32 weeks. The tocolytic therapy consisted by extended-release nifedipine (60 mg daily; 14 days ±6). Maternal hemodynamic status was monitorised by measuring the blood pressure and the maternal heart rate. Fetal hemodynamics was monitored through repeated Doppler evaluation of uteroplacental and fetal circulation, by measuring the PI and RI of the uterine, umbilical and middle cerebral arteries. Results: Although extended-release nifedipine affected the maternal hemodynamics (it decreased the diastolic blood pressure and increased the maternal heart rate in 32 patients -69,56%), the fetal hemodynamics showed no statistical significant changes (p < 0,05). Conclusions: The maternal hemodynamic changes during the maintenance tocolysis with nifedipine had no influence on the fetal circulation and did not affect the fetal well-being status. So, we consider nifedipine therapy during the second and the third trimester of pregnancy as being safe for both, mother and fetus, inclusive in normotensive patients.

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