15 / 83
C
esarean
delivery
and
prematurity
R
ev
A
ssoc
M
ed
B
ras
2015; 61(6):489-494
493
analyzed, and the outcomes of those born vaginal-
ly were compared to the cases of C-section.
•
•
Outcome: maternal and neonatal morbidity and
mortality.
•
•
Result: using logistic regression, the authors found
that birth weight less than 1,100 g presented as the
sole predictor of neonatal adverse outcomes, which
were not related to mode of delivery. Regarding ma-
ternal morbidity, the authors found that C-sections,
compared with vaginal deliveries, led to more mor-
bidity (46
versus
10%, respectively).
8. Riskin A, et al. (
B
).
14
•
•
Design: non-concurrent observational longitudi-
nal study (1995 to 2000).
•
•
Population: births of singletons in cephalic presen-
tation with gestational age from 24 to 34 weeks
(n=2,955) and weight ≤1,500 g were analyzed.
•
•
Outcome: neonatal morbidity and mortality.
•
•
Result: in this study, the authors found a cesarean
section rate of approximately 51.7% indicated main-
ly due to maternal hypertensive disorders or prepar-
tum hemorrhage. The rate of mortality previous to
hospital discharge was lower after indication of C-
-section (13
versus
22%); however, using multivariate
analysis with adjustments for other risk factors re-
lated to mortality, the authors found that the mode
of delivery did not have an effect on the survival of
the newborns (OR=1 with 95CI: 0.74 to 1.33).
9. Wylie BJ, et al. (
B
).
15
•
•
Design: non-concurrent observational longitudi-
nal study (1994 to 2003).
•
•
Population: live births of singletons in cephalic pre-
sentation and with a very low birth weight (500 to
1,500 g) were analyzed.
•
•
Outcome: neonatal morbidity and mortality.
•
•
Result: from a sample of 1,216 cesarean births and
1,250 vaginal births, it was not possible to conclude
that C-sections offer an advantage in terms of lower
neonatal morbidity compared to vaginal deliveries.
D
iscussion
C-sections are known to be associated with an increased
risk of respiratory morbidity in the newborn, caused by
hormones and physiological changes associated with la-
bor and necessary for lung maturation
12
(
B
). C-section in
preterm pregnancies is also particularly problematic re-
garding surgical technique, given that the lower segment
may not be formed and, thus, a vertical incision in the
upper part of the uterus may be required. In this situa-
tion, further complications may occur, including increased
blood loss and increased risk of uterine rupture in sub-
sequent pregnancies
11,13
(
B
).
The concept of planned C-section in preterm deliv-
eries implies the possibility of accurately diagnosing and
performing a C-section early in the period of labor, or
right before it, and, therefore, as explained above, the risk
of preterm birth is increased.
The studies in this review should be viewed with cau-
tion on account of their distinct populations, which makes
it difficult to compare data. In a retrospective study, the
assessment of preterm fetuses, especially those with very
low birth weight (weighing less than 1,500 g) did not al-
low to identify evidence that C-section could provide pro-
tection with regard to the reduction of neonatal morbid-
ity and mortality
5
(
B
). In addition, subsequent analysis
conducted by the same author found that for newborns
considered intermediate and late preterm, that is, with
gestational age between 32-36 weeks, an indication of C-
-section, weighing logistic regression analysis, showed in-
crease in the risk of neonatal morbidity and mortality
6
(
B
). However, other retrospective studies failed to identi-
fy significant differences between the delivery routes in
the mortality analysis of preterm infants (gestational age
between 30 to 35 weeks and 24 to 34 weeks)
10,14
(
B
).
With respect to fetal birth trauma, no significant dif-
ferences between preterm births by C-section or vaginal
delivery were identified
8
(
B
). After assessing maternal out-
comes, the authors were able to identify higher morbid-
ity for women undergoing C-section compared to vagi-
nal delivery
11
(
B
).
F
inal
recommendations
In the absence of other obstetrical indications that make
it necessary to perform the delivery by upper route,
planned C-section for the birth of preterm fetuses in ce-
phalic presentation should not be indicated with the pur-
pose of fetal protection.
R
eferences
1.
Mathews TJ, MacDorman MF. Infant mortality statistics from the 2003
period linked birth/infant death data set. Natl Vital Stat Rep. 2006; 54(16):1-
29. PubMed PMID: 16711376.
2. Graham WJ, Hundley V, McCheyne AL, Hall MH, Gurney E, Milne J. An
investigation of women’s involvement in the decision to deliver by caesarean
section. Br J Obstet Gynaecol. 1999; 106(3):213-20. PubMed PMID: 10426639.
3.
Jadad AR, Moore RA, Carroll D, Jenkinson C, Reynolds DJ, Gavaghan DJ,
et al. Assessing the quality of reports of randomized clinical trials: is blinding
necessary? Control Clin Trials 1996; 17:1-12.
4. Wells GA, Shea B, O’Connell D, Peterson J, Welch V, Losos M, et al. The
Newcastle-Ottawa Scale (NOS) for assessing the quality of nonrandomised