Tam Metin PDF (3983 KB) - Marmara Medical Journal

Marmara Medical Journal 2006;19(2);46-51
Emel Altuncu, et al.
The incidence of low birth weight in 5000 liveborn infants and the etiology of fetal risk factors
DISCUSSION
In this study, incidence of LBW infants was
9.14% and this was similar to the literature 13 .
Previous studies have reported similar results, for
example, the LBW rates in two different studies in
Turkey were 8.7% and 10%, respectively 14,15 . In
many developed countries, LBW rates are around
5% 12 . The rate of LBW in our study was similar
to rates reported in developed countries. The
similarity to developed countries can be based
upon the contribution of only live born neonates.
The perinatal mortality (34.9‰) is very high in
our country and a great number of LBW and very
LBW infants are lost during parturition 4 . So this
leads to misinterpretation of the outcome.
Although multiple gestations represented only
2.09% of the live births, they account for a
disproportionately large share of adverse
pregnancy outcomes. With the development of
obstetrical approaches, the incidence of multiple
gestations began to increase. The risk of giving
birth to a LBW infant increased significantly in
multiple gestations in our study and 80% of
multiple gestations resulted in preterm birth.
Studies dealing with the aetiology of LBW have
shown us that, female sex is an important risk
factor and this is attributed to the predisposition of
the female sex to the other risk factors 6,16,17 . In
our study, the rate of male and female sex among
LBW infants was similar and this led us to
conclude that the sex of the infant did not affect
the weight of the baby.
Other important results were the significant
differences in the method of delivery and the
presentations of neonates between the LBW and
NBW groups. The rate of caesarean section was
much higher in the LBW births (32.3%) than in
the NBW births (21.6%). Delivery by way of
caesarean section was seen more frequently in
LBW infants and this indicated once more that
LBW infants were more prone to morbidity and
mortality.
The rate of cephalic presentation was 93.5% in the
LBW group, but 98.7% in the NBW group. When
compared with cephalic presentation, breech
births were associated with an increased rate of
LBW. Whereas, the overall incidence of breech
presentation in deliveries is only 3% to 4%, for
infants weighing less than 2500g at birth, the
incidence may be 30% or greater. As compared
with the NBW infants, birth trauma and umbilical
cord prolapsus are seen more commonly in LBW
and/or breech births. During labour, the umbilical
cord passes the cervix before the head, so the
umbilical cord is entrapped in between the cervix
and head. After the beginning of compression,
delay in labour increases hypoxia. With a LBW
infant, the size of the head is even greater in
relation to that of the buttocks and the chance of
entrapment is markedly increased. This condition
results in increased hypoxia and because it needs
traction, it can cause trauma to the spinal cord and
skeletal system. Goldenberg and Nelson found
that, during labour, the premature fetus in breech
presentation was 16 times more likely to die than
the premature fetus in vertex presentation 18 . For
these reasons, in LBW neonatesthe most rational
method of delivery is caesarean section 19 . In view
of this information it may be said that,
identification of high-risk pregnancies and choice
of appropriate method of delivery have been
successfully achieved in our hospital parallel to
the literature.
Intrauterine growth retardation (IUGR) is a
frequently reported outcome among infants with
congenital malformations. The presence of IUGR
may indicate an underlying structural abnormality
or aetiologically it may predispose to defects
rather than vice versa 20 . The rate of congenital
malformations was 6.2% in the LBW group, 3.3%
in the NBW group indicating a strong association
between LBW and malformations. Among the
LBW neonates with isolated or multiple
congenital malformations, 2.5% were SGA and
3.7% were premature. However, the incidence of
congenital malformations in all SGA babies, was
5.8%. In our preterm population, malformation
incidence was 6.5%, but 54% of the preterm
infants with congenital anomalies were preterm
SGA babies. If we take full term and preterm
SGA infants into consideration together, 72% of
LBW infants with congenital anomalies were
SGA. In a study reported in our hospital in 1999,
congenital malformations was the fourth leading
cause of death (11.4%) in perinatal mortality
cases 4 . The significant role of congenital
malformation in the aetiology of the LBW,
especially for IUGR, causing an increase from
3.3% to 8% in the risk of LBW indicates a need to
check for malformations by performing antenatal
ultrasonography more strictly in IUGR
fetuses.Furthermore, it emphasızes the need for a
higher number of more developed genetic
laboratories.
There was a limitation in this study. Because our
study was performed in a maternity ward, if there
were no symptoms or sings reflecting congenital
infections, we did not check for congenital
50