In general, a woman’s fetal heartbeat can be detected around 42 days of pregnancy, but because each woman’s menstrual cycle is different, the time to detect the fetal heartbeat may be delayed for some women, so most women can basically detect the fetal heartbeat at 50 days of pregnancy. For women with a delayed menstrual cycle, ovulation is often delayed, so the time of conception will be delayed, and the appearance of the fetal heartbeat will be delayed. Therefore, when the ultrasound is performed on the 42nd day of pregnancy, no fetal heartbeat can be seen, and even no obvious gestational sac can be seen, especially in women with polycystic ovary syndrome. For women with a menstrual cycle of 28 to 30 days, an ultrasound can be performed at about 50 days of pregnancy to confirm the diagnosis, and under normal circumstances, the fetal heart can be seen. If the fetal heart is not visible at this time, then you can consider to check again after a week, if there is still no fetal heart, then you should consider the possibility of an empty sac.