Purpose: to evaluate the evolution in the embryo heart rate in the first trimester of pregnancy. Patients and Methods: in a prospective study 206 pregnant women were evaluated in the first trimester of pregnancy, by transvaginal color Doppler sonography, using Aloka, SSD-2000 apparatus, with a 5-MHz transvaginal transducer. All examinations were performed by the same examiner, with the determination of embryo heart rate. The patients were classified into groups according to the gestational age, in half-week intervals from the 5th week of pregnancy on. Pregnancy outcome was evaluated by ultrasonography at the end of second and third trimesters. Mean and standard deviation were determined for each evaluated gestational age. Results: it was possible to determine normal values for embryo heart rate. Mean embryo heart rate showed changes with gestational age, ranging from 110 ± 14 bpm at the 6.0th week to 150 ± 12 bpm at the 14.0th week. Conclusions: transvaginal pulsed color Doppler equipment enabled cardiovascular evaluation in early pregnancy, being a noninvasive method and innocuous to the embryo. These values would be useful in new studies on dopplervelocimetry in this period of pregnancy.
Ultrasonography; Dopplervelocimetry; Fetal heart rate; Normal pregnancy
