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Performing an Antenatal Examination
Carrying out the examination
Don’t forget that a pregnant woman is still an entire person and
consider the need for an interpreter if English is not the patient’s first
language. Using clear and simple terms understandable to the patient, explain
the need to perform a general physical examination, to measure her blood pressure,
perform a urinalysis and to examine her abdomen to assess fetal growth.
General inspection (demeanour, pallor, scars, tattoos or rashes)
Observations (BP, RR, HR)
- Thyroid examination
- CVS examination, specifically the blood pressure
- Respiratory system examination
- Abdominal obstetrical examination: Uncover the patient’s abdomen
from the xiphisternum to the pubic hairline, ensuring adequate exposure while
allowing for patient modesty. Abdominal wall relaxation is maximised by the
patient resting her arms alongside her abdomen, rather than behind her head.
The patient’s legs may also be slightly flexed at the hips to aid relaxation.
It is wise to advise the mother to indicate if she should feel weak or nauseous
as a consequence of lying supine, as the pregnancy may compress the inferior
vena cava and compromise venous return.
The abdomen is initially thoroughly inspected. In particular, the presence
of an abdominal mass arising from the pelvis consistent with pregnancy,
scars, pigmemtation or other skin lesions are noted. Fetal movements may
be observed.
The uterine fundal height is palpated with either the fingers of both hands
or the ulnar border of the left hand. The uterine fundal height is related
to the abdominal landmarks of the symphysis pubis, umbilicus and the xiphisternum.
An alternate assessement of fetal growth is provided by measurement of the
symphysis fundal height. A tape measure is placed at the level of the uterine
fundus and with the centimetre markings of the tape obscured, the tape is
placed in the midline over the abdomen to reach the superior aspect of the
pubic bone. The symphysis –fundal height is recorded in centimetres and related
to the known gestational age. Generally, the uterine fundal height in centimetres
corresponds to the gestation in weeks, the range being plus or minus three
weeks. A clinical evaluation of a pregnancy being “small for dates” or “large
for dates” is based on this measurement. Fetal growth is clinically assessed
by appreciation of serial measurements of symphysis fundal height. The finding
of “small for dates” or “large for dates” should prompt the question of accuracy
of dates, fetal size, liquor volume and number of fetuses.
The fetal lie is determined by gently but firmly compressing the abdomen,
with both hands in the abdominal lumbar regions. A longitudinal, oblique
or transverse lie will thus be detected. The fetal presentation is identified
by gently placing both hands on the mother’s lower abdomen in the direction
of the pubis. A hard cranium, soft buttocks or no presenting part may be
felt. Should the presentation not be cephalic, the fetal head is identified
by sequential ballotment over the mother’s abdomen. A sensation of a bobbing
tennis ball under water describes the sensation on locating the fetal head.
Engagement of the fetal head is determined by evaluating the extent of the
head palpable per abdomen, described in terms of fifths of the fetal head.
It may simply be described as being free, fixed or engaged (2/5 palpable).
The fetal heart is best heard over the fetal back, particularly when listening
with a pinard stethoscope. The fetal back is generally felt as a firm even
mass on one side of the maternal abdomen. The hand held doppler instrument
detects the fetal heart by identifying the optimal sound direction by rotation
of the transducer on the maternal abdomen. The fetal heart is counted for
15 seconds and multipled by four. A normal fetal heart rate is 110 –160 beats
per minute.
At the completion of the examination the mother is aided to rise from the
supine position. An evaluation of fetal growth, lie, presentation, engagement
and fetal heart rate is recorded. The mother is reassured as appropriate.
Summarize history and examination findings and proposal of a management
plan - eg Y is 26 year old woman, gravida three, para two who presents to
the antenatal clinic for her scheduled check up at 36 weeks gestation. Her
expected date of delivery is 20.10.01 based on her last menstrual period and
supported by an early ultrasound at 12 weeks gestation. Her pregnancy is progressing
normally. Clinical examination shows a healthy mother. The uterine fundal
height of 38cm is appropriate for her gestational age of 36 weeks, the fetal
lie is longitudinal, the presentation cephalic and the head is engaged. The
fetal heart rate was recorded as 140 per minute. Y plans to continue shared
care with her GP with weekly visit henceforth until term.
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