Which of the following is considered a presumptive sign of pregnancy?

Amenorrhea is widely recognized as a presumptive sign of pregnancy due to its nature as a symptom that can indicate that conception has occurred. It refers to the absence of menstruation, which is one of the earliest and most common signs that a woman may be pregnant. While it is a strong indicator, amenorrhea is not definitive because it can also result from other factors such as stress, hormonal imbalances, or health issues unrelated to pregnancy.

In contrast, the detection of a fetal heartbeat, findings from a pelvic examination, and a positive urine test are considered more definitive indicators of pregnancy. A fetal heartbeat is an objective finding typically confirmed through ultrasound or Doppler technology, which provides clear evidence of an ongoing pregnancy. Pelvic examination findings often include changes such as softening of the cervix, but these are also more definitive in the context of pregnancy. Lastly, a positive urine test detects the presence of human chorionic gonadotropin (hCG), a hormone produced during pregnancy, and is commonly used for confirmation rather than initial suspicion.

Thus, amenorrhea stands out as a presumptive sign, making it significant for early pregnancy suspicion.