Jennie, I found this info that might ease your mind.
Week 8 & 9 Gestational Age (Fetal Age 6-7 weeks)
By this point in the pregnancy, everything that is present in an adult human is present in the developing embryo. The embryo has reached the end of the embryonic stage and now enters the fetal stage. A strong fetal heartbeat should be detectable by ultrasound, with a heart beat of 140-170 bpm by the 9th week.
*The normal rate is generally considered to be between 120 and 160 beats per minute.
The rates are typically higher (140-160) in early pregnancy, and lower (120-140) toward the end of pregnancy.
Past term, some normal fetal heart rates fall to 110 BPM.
There is no correlation between heart rate and the gender of the fetus.