ALGORITHM FOR LISTENING TO FETAL HEARTBEAT
Listening to the fetal heartbeat
Explain to the pregnant woman that fetal heart activity is considered the
most accurate and objective indicator of fetal health in the ante - and intranatal
periods.
Before starting the procedure, it should be noted that auscultation of the fetal
heartbeat is performed mainly to determine the fetal heart tones, which are
considered reliable signs of pregnancy. By listening to heart tones, the condition of
the fetus is determined, which is of fundamental importance during pregnancy and
childbirth.
Competencies:
Professional competence - mastering the practical skill “method of the fetal
heartbeat auscultation”
Communicative competence - easily explain to the “patient” the necessity of
the diagnostic procedure
Method of fetal heart tones auscultation
Fetal heart tones are usually listened to with an obstetric stethoscope,
starting from the second half of pregnancy (fig. 1), in the form of rhythmic, clear
beats, and determine its frequency, which is 110-170 beats per minute. An
obstetric stethoscope differs from the usual one by a wider funnel, which it is
applied to the naked abdomen of a pregnant woman. External examination of the
pregnant woman and auscultation of the fetal heartbeat should be carried out in
non-sterile rubber gloves. To facilitate the calculation of the fetal heart rate, two
heartbeats are taken as one, followed by doubling the results obtained. When
listening to the fetal heartbeat, your hands should not touch the pregnant woman’s
stomach or the stethoscope. Pulsation of the mother's aorta, or uterine noises that
occur in large blood vessels that run in the side walls of the uterus and coincide
with the pulse of a pregnant woman, is sometimes confused with the heartbeat of
the fetus. Sound signs that are created by the fetus, in addition to heart tones,
include noises of the vessels of the umbilical cord, deaf non-rhythmic movements
of the fetus that do not coincide with the pulse of a pregnant woman, as well as
non-rhythmic noises of the intestines of a woman. To differentiate, it is necessary
to listen to the fetal heartbeat and simultaneously count the mother's pulse on the
radial artery using a stopwatch.
Fig. 1. An obstetric stethoscope
Before starting auscultation of the fetal heartbeat, palpation of the pregnant
woman's abdomen should be performed. Make sure that there is no pain syndrome.
Then, facing the mother, determine:
the shape of a pregnant woman’s stomach;
the height of the uterine fundus standing (according to the gestation period)
(fig. 2)and the Leopold’s maneuvers;
estimated the volume of amniotic fluid (normal, poly-, oligohydramnion);
fetal articulation – the I and the II Leopold’s maneuvers;
fetal position – the II Leopold’s maneuver;
position and type of fetal position – the II Leopold’s maneuver;
fetal presentation – the III Leopold’s maneuver.
Fig. 2. Height of the uterine fundus standing depending on the term of
pregnancy
Please note that the degree of the fetal head insertion in the case of cephalic
presentation is determined after 37 weeks of pregnancy by – the IV Leopold’s
maneuver.
In a case of cephalic presentation, the best place for the heartbeat
auscultation is below the navel. In a case of pelvic presentation – above the navel
(fig. 3).
M.S. Malinovskyi proposed the following rules for the fetal heartbeat
auscultation:
in a case of the occipital presentation – near the head below the navel on the
side where the back faces, in the posterior view – from the abdomen along
the anterior axillary line;
in a case of the facial presentation – below the navel on the side where the
chest is located (in the first position – on the right, in the second – on the
left);
in a case of the transverse position – near the navel, closer to the head;
in a case of the pelvic presentation – above the navel, near the head, on the
side where the back of the fetus faces.
You can note that the lack of information content of listening to the fetal
heartbeat using an obstetric stethoscope or in the case of certain clinical situations
(overweight of a pregnant woman with metabolic syndrome with significant
development of subcutaneous addiposital tissure in the anterior abdominal wall,
when the placenta is located along the anterior wall of the uterus, etc.) implies the
use of more accurate methods of objective assessment of fetal heart activity.
The study of fetal heartbeat in dynamics is carried out using
cardiotocographic monitoring (CTG) and ultrasound scanning (USI). You can note
that currently the determination of the fetal biophysical profile (FBP) from the 30th
week of pregnancy is used to assess the intrauterine state of the fetus. The sum of
points of individual biophysical parameters (reactivity of fetal heart activity to a
non-stress test (NST) during cardiography, fetal respiratory movements, fetal tone
and motor activity, amniotic fluid volume and placental maturity using ultrasound)
is estimated.
Periodic auscultation of the fetal heart in the phase of rapid opening of the
cervix (the first period of Labor) is performed every 15 minutes., and in the second
period of labor – at least every 5 minutes. or after every attempt.
Fig. 3. Places where the fetal heartbeat is listened to.
1. Anterior view, first position, cephalic presentation;
2. Posterior view, first position, cephalic presentation;
3. Anterior view, second position, cephalic presentation;
4. Posterior view, second position, cephalic presentation;
5. Anterior view, first position, cephalic presentation;
6. Posterior view, first position, pelvic presentation;
7. Anterior view, second position, pelvic presentation;
8. Posterior view, second position, pelvic presentation.
WHEN EXAMINATION IS FINISHED
Voice the received data: frequency of the fetal heartrate and either it is pathological
or normal.
