Tharangrut Hanprasertpong1, Vorapong Phupong. 1. Department of Obstetrics and Gynecology, Faculty of Medicine, Chulalongkorn University, Rama IV Road, Pathumwan, Bangkok 10330, Thailand.
Abstract
OBJECTIVE: To establish reference ranges for first trimester embryonic/fetal heart rate in normal pregnant women. MATERIALS AND METHODS: This was a cross-sectional study. We performed ultrasonogram in 319 normal pregnant women, gestation age between 6(+0) and 14(+6) weeks and measured embryonic/fetal heart rates using M-mode. The embryonic/fetal heart rates were analyzed according to gestational ages (GA). RESULTS: Data of 319 pregnancies were analyzed and the outcome revealed the mean of fetal heart rate according to gestational age. The mean embryonic heart rates during the 6th-7th week of gestation are lower when compared with the other gestational ages. At the 8th week of gestation, the embryonic heart rate is maximum. Then the embryonic/fetal heart rate gradually decreased to 161 beats/min at the 14th week of gestation. The regression equation for embryonic/fetal heart rate (beat/min) [y] according to GA (day) [x] was y = -53.124 + 6.1333x + (-0.0407)x ( 2 )(r (2) = 0.525; P < 0.001). CONCLUSION: Embryonic/fetal heart rates during the 6(+0) and 14(+6) week of gestation are related to GA. Our reference ranges may be useful for further studies such as for prediction of adverse pregnancy outcome in threatened abortion.
OBJECTIVE: To establish reference ranges for first trimester embryonic/fetal heart rate in normal pregnant women. MATERIALS AND METHODS: This was a cross-sectional study. We performed ultrasonogram in 319 normal pregnant women, gestation age between 6(+0) and 14(+6) weeks and measured embryonic/fetal heart rates using M-mode. The embryonic/fetal heart rates were analyzed according to gestational ages (GA). RESULTS: Data of 319 pregnancies were analyzed and the outcome revealed the mean of fetal heart rate according to gestational age. The mean embryonic heart rates during the 6th-7th week of gestation are lower when compared with the other gestational ages. At the 8th week of gestation, the embryonic heart rate is maximum. Then the embryonic/fetal heart rate gradually decreased to 161 beats/min at the 14th week of gestation. The regression equation for embryonic/fetal heart rate (beat/min) [y] according to GA (day) [x] was y = -53.124 + 6.1333x + (-0.0407)x ( 2 )(r (2) = 0.525; P < 0.001). CONCLUSION: Embryonic/fetal heart rates during the 6(+0) and 14(+6) week of gestation are related to GA. Our reference ranges may be useful for further studies such as for prediction of adverse pregnancy outcome in threatened abortion.