Failure to see the heartbeat at this stage may indicate an abnormal pregnancy.The early fetal heart normally beats between 90 to 100 beats per minute.It records high-frequency sound waves that create an image (see Reference 4).Normally, ultrasounds before until week 4 of pregnancy shows nothing in the uterus and serve no purpose.This is because the transducer does not need to send sound waves through multiple layers of muscle and tissue to “pick up” the returning images.
This is because although every little embryo is unique, there are still defining characteristics of development which apply to all embryos at particular stages of early gestational development.
One is via the abdomen – transabdominally and the other is through the vagina – transvaginally.
Some sonographers believe that at seven weeks of gestation, transvaginal ultrasound provides the best and most accurate visualisation.
Transvaginal ultrasound can see embryonic development about a week before transabdominal ultrasound, the American Pregnancy Association (APA) states.
A transducer, a wand-shaped probe, is inserted into the vagina and pressed against the vaginal walls directly next to the uterus.