FETAL ALCOHOL SYNDROME
FETAL HEART MONITORING
fetal alcohol syndrome
A rare condi-
tion consisting of a combination of
congenital
defects that result from the
continuous consumption of excessive
amounts of
alcohol
by the mother
throughout
pregnancy
. The
affected
baby has diminished growth, delayed
mental development, a small head, a
small brain, and small eyes. He or she
may have a cleft palate, a small jaw,
heart defects, and joint abnormalities.
As a newborn, the baby sucks poorly,
sleeps badly, and is irritable as a result
of alcohol withdrawal. Almost one-fifth
of affected babies die during the first
few weeks of life; and many who survive
are, to some degree, mentally and
physically handicapped.
fetal circulation
Blood circulation in
the fetus is different from the normal
circulation after birth (see
circulatory
system
). The fetus neither breathes nor
eats. Therefore, oxygen and nutrients
are obtained and waste products such
as carbon dioxide are removed via the
placenta
. Fetal blood reaches the pla-
centa through blood vessels in the
umbilical cord
. The maternal and fetal
circulations are separated by a thin
membrane in the placenta, which allows
the exchange of nutrients and waste
products. The other fundamental differ-
ence in circulation is that most blood
bypasses the lungs in the fetus through
2
special channels in the fetal heart.
Blood passes from the right atrium of
the heart to the left atrium through the
foramen ovale. Another channel, known
as the ductus arteriosus, allows blood
to pass from the pulmonary artery to
the aorta. Both channels normally close
after birth. In rare cases, they fail to
close, causing a congenital heart disor-
der (see
heart disease, congenital).
fetal distress
The physical stress experi-
enced by a fetus during labour as a
result of its not receiving enough oxygen.
During a contraction, the uterus tight-
ens and reduces the oxygen supply from
the placenta to the fetus. If, in addition,
there are problems, such as pressure on
the umbilical cord or the mother's los-
ing blood, there may be an inadequate
amount of oxygen reaching the fetus.
Fetal distress may cause the baby's
heart-rate to slow or to fail to show nor-
mal variability, which can be recorded
on a cardiotocograph (see
fetal heart
monitoring
).
Acidosis
(high acidity in
the body), which can be detected in a
sample of blood taken from the scalp,
indicates that the oxygen supply to the
fetus is inadequate. Signs of
meconium
in the amniotic fluid can also be an
indication of fetal distress.
Fetal distress sometimes occurs as a
temporary episode, but, if acidosis is
severe, the distressed fetus may need
to be delivered promptly by
caesarean
section, forceps delivery,
or
vacuum
extraction.
(See also
childbirth.)
fetal heart monitoring
The use of an
instrument to record and/or listen to
an
unborn
baby's heartbeat during
pregnancy and labour. Monitoring is
carried out at intervals throughout preg-
nancy if tests indicate that the placenta
is not functioning normally or if the
baby's growth is slow. During labour,
monitoring can detect
fetal distress,
in
which oxygen deprivation causes abnor-
mality in the fetal heart-rate.
The simplest form of fetal heart moni-
toring involves the use of a special fetal
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