pico caecar

7/23/2019 PICO Caecar

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Perspective

TheNEW ENGLAND JOURNAL ofMEDICINE

march 1, 2007

n engl j med 356;9 www.nejm.org march 1, 2007 885

show that contemporary rates are

10 times as high, having climbed

above 30% (see graph).2 Indeed,

of the 20th centurys many chang-

es in obstetrical care the whole-

sale move from home to hospital

delivery, increasing use of anes-

thesia, the advent of in vitro fer-

tilization few have generated

more attention and debate or had

a greater effect on the process of

delivery than this seemingly in-exorable rise.

To be sure, the same period has

seen similarly substantial chang-

es in maternal and neonatal mor-

bidity and mortality. In 1937, 6%

of primiparous patients died after

cesarean delivery, a risk that has

decreased by a factor of nearly

1000 thanks to modern antibiot-

ics, anesthetic techniques, blood

banks, and critical care units. Cer-

tainly, in earlier eras, the specter

of death during childbirth hov-

ered over each decision to proceed

to cesarean delivery, and everyone

involved tolerated a greater degree

of risk of maternal or neonatal

complications from vaginal de-

livery than we accept today. As

the risk associated with cesarean

delivery decreased, practitioners

and patients felt more comfort-

able choosing this option, even in

situations in which there was less

potential benefit (i.e., the number

Cesarean Delivery and the RiskBenefit CalculusJeffrey L. Ecker, M.D., and Fredric D. Frigoletto, Jr., M.D.

In 1937, an article in the Journaldescribing 10years of births at Boston City Hospital revealedan overall rate of cesarean delivery of about 3%.1

Recently released 2005 data on cesarean deliveries

l

Rateper100

LiveBirths

25

30

20

15

5

10

01989 1991 1993 1995 1997 2001 20031999 2004 2005

Year

VBAC

Total cesarean

Primary cesarean

35

Primary Cesarean Rate and Rate of Vaginal Birth after Previous Cesarean Delivery(VBAC) in the United States, 19892004, and Data for Total Cesarean Rate, 1989

2005.

The New England Journal of Medicine

Downloaded from nejm.org on September 21, 2011. For personal use only. No other uses without permission.

Copyright 2007 Massachusetts Medical Society. All rights reserved.


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PERSPECTIVE

n engl j med 356;9 www.nejm.org march 1, 2007886

needed to treat in order to prevent

one adverse outcome was larger).

The second half of the 20th cen-tury saw many other changes in

perinatal care, including the devel-

opment of technologies for both

visualizing the fetus (ultrasonog-

raphy) and tracing its heart rate

before and during labor, as well

as the development of neonatal

intensive care units and the evo-

lution of neonatology into a dis-

tinct subspecialty. As more could

be known about and done for the

fetus and the newborn, more preg-

nancies were identified as poten-

tially benefiting from cesarean

delivery.

Critics decry the cesarean num-

bers and argue that obstetricians

have been too quick to abandon

possible vaginal deliveries for rea-

sons related to profit or their own

convenience. A more dispassion-

ate analysis, however, reveals that

the trend is widespread, crossing

state and national boundaries, and

suggests that multiple, convergent

factors are responsible, includingchanges in patients and their preg-

nancies, in options and recom-

mendations for delivery, and in

patients and providers expecta-

tions and evaluation of risk.

Indeed, 21st-century pregnant

women and their pregnancies dif-

fer from those of previous eras.

Parturients are now heavier than

they used to be (one 21-year study

found a doubling of obesity rates),

and they are older (there has been

a 3.8-year increase since 1970 in

the mean age at first delivery, and

since 1990, births to women 35 to

39 years of age and 40 to 44 years

of age have increased by 43% and

62%, respectively). In addition, the

number of premature and low-

birth-weight neonates has in-

creased, in part as a function of

the increasing number of multi-

ple gestations (121,246 in 2001 vs.

68,339 in 1980), many of which

have resulted, in turn, from the

use of assisted reproductive tech-nology assistance necessitated

in many cases by advancing ma-

ternal age. All these changes have

been associated with an increased

risk of cesarean delivery.

Evidence-based recommenda-

tions founded on outcomes data

are increasingly influencing ob-

stetrical care and changing prac-

tice. Vaginal breech deliveries are

no longer recommended, since the

3% associated neonatal morbidity

has been judged excessive, and

such deliveries have been aban-

doned. Careful and repeated study

of a trial of labor after prior ce-

sarean delivery has led some to

conclude that elective repeated ce-

sarean delivery, because it is as-

sociated with lower rates of major

complications (including uterine

rupture) and lower rates of poor

perinatal outcome (including hy-

Cesarean Delivery and the RiskBenefit Calculus

B.D.

Colen





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PERSPECTIVE

887

poxicischemic encephalopathy),

is safest,3 and among women

who have had a cesarean delivery,

fewer now choose a trial of labor

in their next pregnancy (see graph).

Furthermore, better data describ-

ing the complications associated

with the use of forceps or vacu-um extraction neonatal birth

injury and maternal perineal trau-

ma and incontinence have led

to a decrease in the number of

operative vaginal deliveries (from

9.5% in 1994 to 5.6% in 2003)

that parallels the increase in ce-

sarean deliveries; as obstetricians

perform fewer operative vaginal

deliveries, they grow less comfort-

able with the methods, and the

decrease becomes self-perpetuat-ing. Finally, in 2003, 20.6% of la-

bors were induced, as compared

with 9.5% in 1990. Some induc-

tions result from increased use of

antenatal fetal surveillance and

the real or perceived fetal jeop-

ardy that is detected. Inductions

may also be scheduled for con-

venience for example, to allow

parents to organize work and

child-care schedules or to allow

providers to be on call when their

patients deliver. Most studies link

inductions to increased use of ce-

sarean delivery.

More difficult to quantify than

changes in patients and practice

are changes in provider behavior.

Many currently practicing obste-

tricians believe they are delivering

care amidst a malpractice crisis.

U.S. obstetricians average three

lawsuits over the course of their






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PERSPECTIVE


careers, and at least one study

found that physicians malpractice

premiums, the number of claims

against physicians and hospitals,

and the physicians perception of

the risk of being sued were all

positively correlated with the like-

lihood of cesarean delivery.4Many in the f ield defend the ris-

ing cesarean rates by citing con-

cern about legal jeopardy, and in-

deed lawsuits often allege a failure

to perform a timely cesarean de-

livery.

Balanced against all these in-

fluences pushing the cesarean

rates higher are the methods as-

sociated risks and consequences.

Apart from the immediate oper-

ative risks including infection,the need for blood transfusion,

damage to pelvic organs, and post-

operative pain specific objec-

tions to cesarean delivery include

concern regarding a mothers

future reproductive health, since

later pregnancies are associated

with increased risks of miscar-

riage, ectopic gestation, placenta

previa, and placenta accreta. These

risks are real and have been well

described, yet when making de-

cisions, patients and their pro-

viders often think only within the

context of the current pregnancy,

especially since future reproduc-

tive plans may be uncertain.

More generally, to critics of the

rising cesarean rate, many cesar-

ean deliveries seem unnecessary

unlikely, in their evaluation, to

meaningfully improve neonatal or

maternal outcome. And many ce-

sarean deliveries do appear at first

glance to be unnecessary. For

example, among women without

gestational diabetes whose fetus-

es have an ultrasound-predicted

weight of more than 4500 g (10

lb), it has been estimated that

3695 cesarean deliveries are need-ed to prevent one permanent bra-

chial plexus injury a number

that reflects both the imprecision

of in utero estimations of fetal

weight and the realit y that most

large infants will undergo vaginal

delivery without injury.5 To cite

another example, only 3% of

infants with breech presentation

who are delivered vaginally will

have traumatic injury. And most

babies delivered by cesarean sec-tion because of a nonreassuring

fetal heart-rate tracing are born

healthy and vigorous, reinforcing

the perception that cesarean de-

liveries are not needed in such

circumstances.

But the key question centers on

both the number needed to treat

to avoid one adverse neonatal out-

come and the level of risk that is

currently considered acceptable.

As practicing obstetricians, we

find that the risk that women

are now willing to assume in ex-

change for a measure of potential

benefit, especially for the neonate,

has changed: for many, the level

of risk of an adverse outcome that

was tolerated in the past to avoid

cesarean delivery is no longer ac-

ceptable, and the threshold num-

ber needed to treat has thus been

reset.

In the face of the resulting con-

tinued increase in cesarean deliv-

eries, our obligation as providers

is to educate patients about the

trade-offs entailed in choosing a

particular course or intervention

and to ensure that their choices

are congruent with their own phi-losophy, plans, and tolerance of

risk. In areas in which there is still

uncertainty, we must organize

clinical trials that will produce the

data we require for counseling pa-

tients. For the moment, however,

few of the relevant factors seem

likely to change, and the cesarean

rate can be predicted to continue

its climb.

An interview with Dr. Ecker can beheard and a slide show can be seen

at www.nejm.org.

Dr. Ecker is an associate professor and Dr.Frigoletto a professor of obstetrics, gyne-cology, and reproductive biology at HarvardMedical School, and both are obstetriciansat Massachusetts General Hospital, Boston.

Duncan CJ, Doyle JB. Cesarean section:a ten-year study of 703 cases at the BostonCity Hospital. N Engl J Med 1937;216:1-5.

Hamilton BE, Martin JA, Ventura SJ.Births: preliminary data for 2005. Healthe-stats. Hyattsville, MD: National Center forHealth Statistics, November 21, 2006. (Ac-cessed February 8, 2007, at http://www.cdc.gov/nchs/products/pubs/pubd/hestats/prelimbirths05/prelimbirths05.htm.)

Greene MF. Vaginal delivery after priorcesarean section is the risk acceptable?N Engl J Med 2001;345:54-5.

Localio AR, Lawthers AG, Bengston JM,et al. Relationship between malpracticeclaims and cesarean delivery. JAMA 1993;269:366-73.

Rouse DR, Owen J, Goldenberg RL, CliverSP. The effectiveness and costs of electivecesarean delivery for fetal macrosomia diag-nosed by ultrasound. JAMA 1996;276:1480-6.

Copyright 2007 Massachusetts Medical Society.

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