During pregnancy in a human female, in which of the following periods can the embryo's heartbeat be detected with the help of ultrasound?

Step-by-step solution

In human embryonic development, the heart begins to form and starts beating around the 4^ th week (approximately 21 to 22 days) after conception. However, the heartbeat is initially too faint to be detected. It becomes clinically detectable for the first time using a transvaginal ultrasound around the 6^ th week of pregnancy. Answer: 6^ th Week