After 35 days of pregnancy in the early stages, you can go to the hospital for an ultrasound. At this time, we often see terms like gestational sac, fetal bud, and fetal heart on the report. So, what exactly are the gestational sac, fetal bud, and fetal heart?
1. Gestational Sac: Between 30 to 40 days of pregnancy, an oval or eggplant-shaped sac-like structure can be seen on the ultrasound. This is actually the primitive embryonic tissue surrounded by the amniotic membrane and blood vessels, known as the gestational sac. Its location at the fundus, anterior wall, posterior wall, upper part, or middle part of the uterus is all normal. The gestational sac is the primitive placental tissue, a tiny embryo enveloped by the amniotic membrane and a network of blood vessels, representing the earliest form of pregnancy.
2. Fetal Bud: Between 40 to 50 days of pregnancy, the fetal bud forms. Through ultrasound, you can see the embryo growing within the gestational sac. This small fetal bud gradually differentiates and grows, eventually becoming a true fetus.
3. Fetal Heart: Between 50 to 60 days of pregnancy, the fetal heart’s pulsation can be observed via ultrasound, marking the first appearance of the fetal heart. The presence of a fetal heart indicates that the embryo is currently viable. The fetal heart is usually the last to appear, and listening to it can provide information about the fetus's health. Generally, around 7 weeks of pregnancy, the fetal heartbeat can be seen using ultrasound equipment; around 12 weeks, a Doppler fetal heart monitor can detect the heartbeat; and between 17 to 20 weeks, the fetal heart can be heard using a regular stethoscope on the abdomen. Before birth, the fetal heart sound is the only link between the baby and the outside world, serving as an important indicator of fetal health. A normal fetal heart rate ranges from 120 to 160 beats per minute, sounding regular, without gaps, with a consistent rhythm and moderate strength, akin to the "tick-tock" of a clock.
The gestational sac, fetal bud, and fetal heart appear in chronological order. First comes the gestational sac, followed by the fetal bud, and finally the fetal heart. These three major indicators, along with a series of other indicators like progesterone and HCG, being normal, indicate that the fetus is in very good health.
