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Elective
Cesarean Sections
The New
England Journal of Medicine just published a study which found
"significantly increased risks" for babies when elective (no medical
reason) cesareans are performed before 39 weeks of gestation,
accounting for more than one third of cesarean
sections.
"In this large, multi-center study in the United States, more than
one third of elective repeat cesarean deliveries at term were
performed before 39 weeks of gestation. As compared with deliveries
at 39 weeks, these early deliveries were associated with a
significantly increased risk of composite outcomes that included
neonatal death, as well as individual neonatal adverse outcomes that included
respiratory complications and admission to the neonatal ICU." ~NEJM
abstract
There
are alarming implications due to the rise in elective cesareans
prior to 39 weeks in the US accompanied by vast surprise that OBs
have not followed ACOG's own recommendation to wait until 39 weeks
for elective cesareans. Following is an expert commenting on
the impact and implications of this study by Michael F. Green, M.D.
Is it a small risk? Read his editorial and the full
NEJM abstract. There's nothing "small" about the numbers of babies ending up in NICU's across the country.
~Susan Oshel, director of midwifery studies, Charis
Childbirth
Visit
The New England Journal of Medicine January 08, 2009 full abstract:
January 8, 2009 NEJM
-
Timing of Elective
Repeat Cesarean Delivery at Term and Neonatal Outcomes -
(Adobe
Acrobat Required)
The NEW ENGLAND JOURNAL of
MEDICINE
E D I T O R I A L
Making Small Risks Even Smaller
Michael F.
Greene, M.D.
Cesarean
sections performed without antecedent labor are associated with a
higher risk of respiratory distress than those performed after the
onset of labor, despite the fact that they may have been done at
full term (at least 37 weeks of gestation). This respiratory
distress is usually transient tachypnea of the newborn, which is
generally milder in both severity and duration than respiratory
distress syndrome due to hyaline membrane disease in premature
babies. Unlike hyaline membrane disease, which results from a
surfactant deficiency, transient tachypnea of the newborn results
from delayed clearance of fetal alveolar fluid. The volume of fetal
alveolar fluid decreases progressively but not linearly with
advancing gestational age. In fetal guinea pigs, oxytocininduced
labor induces elevated levels of catecholamines, which stimulate
β-adrenergic sodium channels that clear fluid from fetal lung
alveoli to permit gas exchange in the neonate.2
In this
issue of the Journal, Tita et al.3 report the results of an
observational study of 13,258 women with viable singleton
pregnancies who underwent elective repeat cesarean section at term
(37 weeks or greater) at 19 academic medical centers in the United
States. The primary outcome was a composite measure of neonatal
mortality and morbidity, which included respiratory distress
syndrome, transient tachypnea of the newborn, hypoglycemia, newborn
sepsis (suspected and proved), seizures, necrotizing enterocolitis,
hypoxic–ischemic encephalopathy, cardiopulmonary resuscitation or
ventilator support within 24 hours after birth, cord-blood arterial
pH below 7.0, a 5-minute Apgar score of 3 or below, admission to the
neonatal intensive care unit (ICU), and prolonged hospitalization (5
days or longer).
Tita et
al. found that 35.8% of the elective repeat cesarean deliveries were
performed at less than 39 completed weeks of gestation, despite
best-obstetrical-practice recommendations to deliver after 39
weeks.4 No babies had necrotizing enterocolitis or hypoxic–ischemic
encephalopathy, and only one baby died (after delivery at 39 weeks
of gestation). However, the risk of neonatal complications increased
with decreasing gestational age before 39 weeks and was increased
even among babies delivered in the last 3 to 4 days of the 38th week
of gestation. The higher risk of composite neonatal complications in
babies delivered before 39 weeks of gestation was driven by adverse
respiratory outcomes, hypoglycemia, suspected sepsis, and medical
interventions (admission to the ICU, mechanical ventilation, and
prolonged hospitalization) in response to these clinical conditions.
There was no increase in proved sepsis at earlier gestational ages.
Since
signs that lead pediatricians to suspect newborn sepsis include
tachypnea, grunting, flaring of the nasal alae, intercostal
retractions, decreased breath sounds, and apnea, it could reasonably
be said that the composite outcome measure largely reflects clinical
respiratory distress and hypoglycemia. The incidence of the primary
outcome declined after 39 weeks of gestation but rose again after 41
weeks, leaving a relatively narrow 2-week window of minimal risk in
which elective repeat cesarean deliveries could optimally be
performed.
The
differences between the women who delivered before 39 weeks of
gestation and those who delivered at or after 39 weeks are
revealing. The women who delivered earlier were more likely to be
married, to be white, to have had a first or second-trimester
ultrasound examination, and to be privately insured. In short, a
woman in this group was more likely to be a private patient and to
place a premium on her own doctor’s performing the delivery. The
physicians probably reciprocated, wanting to deliver their own
patients to foster the doctor–patient relationship and improve
patient satisfaction. To accommodate busy schedules and to minimize
the chance that a patient will begin labor and require a non-elective
procedure when her doctor might not be available, procedures are
frequently scheduled just before 39 weeks of gestation.
As
desirable as it is to minimize neonatal complications, it is
imperative to avoid perinatal death. This study was not a treatment
trial to assess overall perinatal death resulting from alternative
strategies of elective delivery at term. Such a trial would include
an accounting of fetal deaths among women waiting to deliver at
later gestational ages. Enrollment in the current observational
study required a living fetus and did not include any fetal deaths.
Among the 4743 viable babies delivered at less than 39 weeks of
gestation in the current study, there were no neonatal deaths and
there was no assessment of potential long term complications. As the
investigators correctly note, all the complications observed after
delivery at 37 to 39 weeks of gestation must be weighed against the
risk of fetal death while awaiting completion of the 38th week of
gestation. That risk has been estimated at 1 in 10005,6 and could be
greater than the risk of neonatal death associated with delivery
during this 2-week gestational period. Antenatal surveillance of
fetal well-being to prevent fetal death is unlikely to reduce the
risk of fetal death below 0.8 in 1000.7
Some
have suggested that amniocentesis should be performed to determine
fetal lung maturity before elective delivery earlier than 39 weeks
of gestation. In two small case series of women undergoing
amniocentesis in the third trimester, several patients required
emergency deliveries, but there were no perinatal deaths.8,9 The
combined size of the two series (1475 patients), however, does not
rule out a procedure-related risk of perinatal death that is
potentially greater than the risk of neonatal death among babies
delivered at less than 39 weeks. Tita et al. point out that they had
no information regarding the results of amniocenteses to determine
fetal lung maturity that may have been performed for women in their
study. Therefore, it is unknown whether testing for fetal lung
maturity may have reduced the incidence of complications or death in
the babies delivered at 37 to 39 weeks of gestation and whether some
complications occurred despite reassuring results of testing.
Given
the small risk of perinatal death at term (probably less than 1 in
1000), a randomized trial to demonstrate the elective delivery
strategy resulting in the least risk of perinatal death and
long-term complications would have daunting power and sample-size
challenges. Even if the optimal strategy could be defined, its
implementation might require overcoming the dread of late stillbirth
and convincing patients (and their doctors) that having “their
doctor” perform the delivery is less important than avoiding the
complications associated with early term birth.
No potential conflict of interest relevant to this article was
reported.
From the Department of Obstetrics and Gynecology, Massachusetts
General Hospital, Boston.
1. van den Berg A, van Elburg RM, van Geijn HP, Fetter WPF.
Neonatal respiratory morbidity following elective caesarean section
in term infants: a 5-year retrospective study and a review of the
literature. Eur J Obstet Gynecol Reprod Biol 2001;98:9-13.
2. Norlin A, Folkesson HG. Alveolar fluid clearance in
late-gestational guinea pigs after labor induction: mechanisms and
regulation. Am J Physiol Lung Cell Mol Physiol 2001;280:L606-L616.
3. Tita ATN, Landon MB, Spong CY, et al. Timing of elective
repeat cesarean delivery at term and neonatal outcomes. N Engl J Med
2009;360:111-20.
4. ACOG Practice Bulletin No. 97: fetal lung maturity. Obstet
Gynecol 2008;112:717-26.
5. Landon MB, Hauth JC, Leveno KJ, et al. Maternal and peri-natal
outcomes associated with a trial of labor after prior cesarean
delivery. N Engl J Med 2004;351:2581-9.
6. Smith CG, Pell JP, Dobbie R. Cesarean section and risk of
unexplained stillbirth in subsequent pregnancy. Lancet 2003;362:
1779-84.
7. Dayal AK, Manning FA, Berck DJ, et al. Fetal death after
normal biophysical profile score: an eighteen-year experience. Am J
Obstet Gynecol 1999;181:1231-6.
8. Stark CM, Smith RS, Lagrandeur RM, Batton DG, Lorenz RP.
Need for urgent delivery after third-trimester amniocentesis. Obstet
Gynecol 2000;95:48-50.
9. Gordon MC, Narula K, O’Shaughnessy R, Barth WH Jr. Com-plications
of third-trimester amniocentesis using continuous ultrasound
guidance. Obstet Gynecol 2002;99:255-9.
Copyright © 2009 Massachusetts Medical Society.
n engl j med 360;2 nejm.org january 8, 2009
Downloaded from www.nejm.org at VA LIBRARY NETWORK on January 8,
2009
'Behold, I will bring them from the north country, And gather them
from the ends of the earth,
Among them the blind and the lame,
The woman with child and The one who labors with child, together,
A
great throng shall return there...And My people shall be satisfied with My goodness, says the LORD.'
Jeremiah 31:8, 14~~~
©2009 Charis Childbirth
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January 2009
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