The heart of the fetus begins to decline already in the fifth week of pregnancy, and by the 9th week it is a fully formed organ, with two ventricles and two atria. By the nature of the heartbeat, the viability of the child is judged in the early stages of development, and in the second half of pregnancy the heart rate (HR) reflects the condition of the fetus.
Fetal heart rate is the norm
In the first trimester, the frequency of cardiac strokes in the fetus is constantly changing. This is due to the fact that during the first weeks of pregnancy the vital organ is only being formed, and the part of the nervous system that is responsible for its work has not yet developed. Thus, at 6-8 weeks, the heart beat rate of the fetus is 110-130 beats per minute, at 9-10 weeks the norm of heart rate in children is 170-190 beats per minute. From the 11th week of pregnancy to the very birth, a normal heartbeat of the fetus is 140-160 beats per minute.
Deviations in the work of the heart
Unfortunately, malfunctions in the work of a small heart can occur already in the early stages of pregnancy: if the heartbeat is not recorded at an embryo length of 8 mm, this may be a sign of a stagnant pregnancy. A woman is recommended to undergo a second ultrasound examination in a week, after which she is diagnosed.
Deviations from normal heart rate (an increase in the heart rate to 200 beats per minute or a decrease to 85-100 beats per minute) in most cases indicate a child's unhappiness. Rapid palpitation of the fetus (tachycardia) can be observed in the following cases:
- fetal hypoxia of mild degree (if the pregnant woman is long in a stuffy room);
- physical activity of the baby or mother;
- increase in the tone of the uterus;
- emotional overexcitation of the future mother.
The muffled and weak heartbeat of the fetus (bradycardia) speaks of:
- severe intrauterine hypoxia;
- presence of fetoplacental insufficiency;
- water scarcity or polyhydramnios;
- pelvic presentation of the fetus.
The arrhythmic heartbeat of the fetus indicates the presence of congenital heart defects or intrauterine hypoxia of the baby.
How is the fetal heart rate determined?
There are several ways to determine and evaluate cardiac activity of the fetus: auscultation (listening to the heartbeat of the fetus with the help of a midwifery stethoscope), ultrasound, cardiotocography (CTG), and echocardiography (ECG).
In the early stages of pregnancy, the question "What heartbeat at the fetus?" Will help ultrasound: using a transvaginal sensor, cardiac contractions can be detected as early as 5-6 weeks. Usual (transabdominal) ultrasound registers heart function from about 6-7 weeks. Determine the fetal heartbeat in different weeks of pregnancy on ultrasound and on three screening studies. In everyday practice obstetrician-gynecologists use a stethoscope, listening with his help the work of the heart through the abdominal wall. Auscultation of cardiac tones is possible from the 20th week of pregnancy, and sometimes - since the 18th week.
At approximately 32 weeks, the fetal heart rate was examined with CTG. This method allows you to record the work of the fetal heart, contraction of the uterus and the motor activity of the child. Regular CTG is mandatory if the future mother suffers from severe form of gestosis, chronic or infectious diseases, as well as if placental abnormalities are observed, fetal hypotrophy, low water or polyhydramnios. During childbirth, CTG is performed in the case of premature or delayed pregnancy, with weakness of labor or rhodostimulation.
Fetal ECG is conducted at 18-28 weeks and only on the following indications:
- the age of the mother is over 38;
- the available births of children with congenital heart disease;
- congenital heart defects in a future mother;
- fetal hypotrophy;
- detection of abnormalities in the work of the heart, other pathologies and genetic abnormalities in ultrasound of the fetus;
- diabetes mellitus in women;
- infectious diseases during pregnancy.
In this study, only the heart of the fetus is examined, its work is evaluated, as well as the blood flow in different departments (using the Doppler regime).