What is the reason for not hearing the fetal heartbeat?

2 months ago

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One of the worries that may occupy the minds of pregnant women is the defect or disease in the fetus. One of these defects can be not hearing the heart of the fetus. Naturally, this case can be scary and terrifying for many mothers, but in many cases, this lack of heartbeat is not a sign of the fetal heart not forming. The following is discussed in relation to this issue.

Formation of fetal heart

All major systems and organs of the fetal body develop between the fourth and eighth weeks This period is called organogenesis period. During this period, more than ever, the fetus can undergo irreparable changes in the formation of body parts due to various factors. These factors can An incomplete gene or a variety of genetic syndromes. There may also be environmental factors such as the use of certain drugs or maternal diseases such as diabetes. Heart as an organ that is necessary for life. It is the first organ to form. It must act quickly to protect the developing fetus. Even before the four chambers of the heart are complete, it begins to beat. The structure of the fetal heart is initially in the form of a hollow and slightly curved tube, which is approximately 2.5 to 3 mm long until the 22nd day of fetal development. From twenty-eight days, the first contractions in the heart chambers begin. From the fifth to the seventh week of pregnancy, the formation of the fetal heart is confirmed using vaginal ultrasound (earlier) and from the abdomen.

Stages of fetal heart formation

Not hearing the fetal heartbeat can have several meanings, including:

- No heart formed at all - The heart examination was not done at the right time - abortion - The fetus is located outside the uterus - The heart is located at a point outside the normal place

Sometimes the heart that was beating before stops beating for various reasons. This point should be noted. Hearing the sound of the fetal heart does not mean that the heart is healthy. Sometimes, despite heart defects, the heart of the fetus has a regular beat, and to determine the type and severity of the heart abnormality, an echo of the heart of the fetus is needed. Related article What is fetal heart monitor and how is it done?

### No heart formed at all

But in the ultrasound, the observed mass is not a fetus and there is no heartbeat.

Because with increasing gestational age, the probability of seeing the fetal heart rate increases. The next step is a vaginal ultrasound, generally much more accurate in early pregnancy than an abdominal ultrasound. Before eight weeks of pregnancy, a transvaginal ultrasound gives the best results.

### Abortion

Not hearing the sound of the fetal heart or no heartbeat in the follow-up ultrasound if a follow-up ultrasound is performed after one week. and there is no change in it (still no heartbeat). Miscarriage is more likely. But there are many exceptions to the "heartbeat up to seven weeks" rule. You've probably heard of people who believe they've miscarried or are not pregnant. But then they continued with their normal pregnancy.

This is also one of the reasons for not hearing the fetal heartbeat. Related article What is fetal heart monitor and how is it done? This place can be anywhere in the abdomen, such as inside the abdomen, on the ovary, inside the tubes connected to the uterus, in all these cases, because the fetus is not in its normal place; Therefore, the heartbeat is not observed in the usual ultrasound.

There is a rare heart anomaly where the heart is not in its normal place. But it is located outside the body in places such as inside the abdomen, on the side of the neck or on the chest. In these cases, it is possible to not hear the sound of the fetal heart in a normal ultrasound.

The spectrum of these defects can range from very slight which does not cause any problems during pregnancy and after, to very severe and contrary to life. Minor problems are small holes in the wall between the chambers of the heart, slight narrowings in the valves and vessels connected to the heart. Severe problems can be such that half of the cavities and vessels connected to the heart are not formed. Many of these severe heart problems in their course before birth lead to miscarriage or death of the fetus in the womb. Sometimes the conduction pathways of the heartbeat are incompletely formed. It varies from harmless irregular heartbeats to complete heart block. Most of the heart defects can be detected by performing fetal heart echo. In many cases, by performing appropriate treatment measures at the right time, the best outcome for this pregnancy was achieved.

Is it possible to miscalculate the gestational age?

Accuracy in the date of the beginning of pregnancy, if a pregnant woman thinks she is at least seven weeks and has an ultrasound that does not detect the heartbeat of the fetus. Consider that the date calculation may be wrong. In early pregnancy, having an irregular ovulation pattern can cause errors in the calculation. > For further reading, I suggest you refer to the following articles. https://www.healthline.com/health/pregnancy/abnormal-fetal-heart-tracings How many weeks is it to hear the fetal heartbeat? **Dr. Saeed Bitarafan, specialist in pediatric cardiology and fetal echocardiography**