olume Number September rends in Cesarean Rates for - PDF document

Volume 54, Number 4 September 22, 2005 Trends in Cesarean Rates for First Births and Repeat Cesarean Rates for Low-Risk Women: United States, 1990–2003 by Fay Menacker, Dr. P.H., Division of Vital Statistics Abstract Objectives—This report presents trends in cesarean rates for first births and repeat cesarean rates for low-risk women, in relation to the Healthy People 2010 (HP 2010) objectives. Data for the U.S. showing trends by maternal age and race and Hispanic origin are presented. Methods—Cesarean rates were computed based on the information reported on birth certificates. Results—With a decrease between 1990 and 1996 and an increase between 1996 and 2003, the trend in the cesarean rate for low-risk women having a first birth paralleled trends in the primary (regardless of parity) and total cesarean rates. During 1996–2003 the cesarean rate for low-risk women having a first birth has consistently been at least 13 percent lower than the rate for all women having a first birth. For 2003 the cesarean rate for all primiparous women was 27.1 percent; for low-risk women the rate was 23.6 percent. The trend in the repeat cesarean rate for low-risk women was similar to the trend in the repeat rate for all women, i.e., a decrease from 1990 to 1996 and an increase from 1996 to 2003. The repeat cesarean rate for low-risk women has consistently been slightly lower than the rate for all women. For 2003 the repeat rate for all women was 89.4; the rate for low-risk women was 88.7. These trends were found for low-risk women of all ages and racial or ethnic groups. Therefore, low-risk women giving birth for the first time who have a cesarean delivery are more likely to have a subsequent cesarean delivery. Keywords: cesarean c low risk c repeat cesarean c VBAC c primary cesarean c birth certificate Introduction Lowering the cesarean rate in the United States has been a goal for the past 25 years (1). In response to growing concerns in the 1980s about the rising cesarean rate, the U.S. Department of Health and Human Services established decreasing the cesarean rate as one of the Healthy People Year 2000 objectives (2). When objectives were evaluated for HP 2010, lowering the cesarean rate was again included (3). However, for HP 2010, the focus of the objective was changed from all women giving birth to low-risk women. A low-risk woman is defined as one with a full-term (at least 37 completed weeks of gestation), singleton pregnancy (not a multiple pregnancy), with vertex fetal presentation (head facing in a downward position in the birth canal). Separate objectives were formulated for low-risk women giving birth for the first time (a subset of all women having a first birth) and for low-risk women who had a prior cesarean birth. The objectives set a target of 15 percent for cesarean delivery and 63 percent for repeat cesarean delivery (table A). This report pre sents detailed tabular data on trends for low-risk women, in relation to the HP 2010 objectives. Cesarean rates for low-risk women and for all women are shown in figure 1 a nd table B Figure 1. Cesarean rates for first births and repeat cesarean rates, for all women and low-risk women: United States, 1990–2003 Thedecreasefrom1990to1996intherateforwomenwithnopreviouscesareanregardlessofparity(theprimarycesareanrate)andtheincreasefrom1996to2003(thecurrentrateis19.1percent)havebeenreportedindetailelsewhere(4).Morethan680,000deliveriesin2003wereprimarycesareans.Althoughthetotalcesareanrate(thepercentofalllivebirthsbycesareandelivery)isshowninthisreporttoprovidecontext,inkeepingwiththeHP2010objectives,weconcentrateonthecesareanrateforfirstbirthstolow-riskwomenandtherepeatcesareanrate,andfocusonthetrendssince1996.DatainthisreportarefrombirthcertificatesfiledforallinfantsbornintheUnitedStatesduringtheyears1996–2003(see‘‘TechnicalNotes’’).Theannualnumberofbirthsrangedfrom3.9millionto4.1million.Cesareanratesincreased1996–2003forallwomenandforlow-riskwomenForallwomentotalandprimarycesareanratesincreasedsubstantiallyfrom1996to2003,asdidtheratesforallwomengivingbirthforthefirsttime.However,comparedwithcesareanratesforallwomengivingbirthforthefirsttime,ratesforlow-riskwomenhavingafirstbirthhavebeenconsistentlylower.Nevertheless,forthesewomen,thecesareanrateincreasedbyone-thirdbetween1996and2003(to23.6percent)(tablesBfigure1).Atthesametime,thecesareanrateforwomengivingbirthforthefirsttimewhowerenotlow-risk,increasedfrom41.7to47.1percent(tabulardatanotshown).In2003outof363,924cesareandeliveriestowomenhavingafirstbirth,265,423(73percent)weretolow-riskwomen.Outofthetotalnumberofcesareandeliveries(1,119,388),24percentweretolow-riskwomenhavingafirstbirth.ThetrendsforallwomenaregenerallyreplicatedinthetrendsbyageandraceandHispanicorigin(seetable1figure2Repeatcesareanbirthsincrease1996to2003Forwomenwhohaveafirstcesareandelivery,thenextdeliverywillbeeitherarepeatcesareanoravaginalbirthaftercesarean(VBAC).Therepeatrateincreasedbymorethanone-fourthfrom1996to2003,from69.8to88.7per100birthstolow-riskwomenwithapreviouscesarean(figure1tableBtable2).In2003therewere434,699repeatcesareandeliveries(4);348,550(80percent)weretolow-riskwomen.Althoughfollowingthetrendforallwomen,repeatratesforlow-riskwomenhaveconsistentlybeenslightlylowerthanratesforallwomen(by1percentsince2001).Ofallcesareandeliveries,31.1percentweretolow-riskwomenhavingarepeatThisincreaseintherepeatrateindicatesacorrespondingdecreaseintherateofVBACdeliveries.Accordingly,theVBACratedeclinedby63percentbetween1996and2003(from30.2to11.3per-centforlow-riskwomen).Toputthisanotherway,onlyabout11percentwomenwhohadapreviouscesareandeliverywentontohaveasubsequentvaginaldelivery(tableB).In2003ofallVBACdeliveries(51,602)(4),86percent(44,380)weretolow-riskwomen(tabulardatanotshown).ThetrendsinrepeatcesareandeliverybyageandraceandHispanicoriginaresimilartothoseforallwomen;variationsareshowntable2figure3DiscussionandConclusionsSincethelate1970s,theU.S.cesareanratehasreceivedconsiderableattention(5–10).Nationaleffortstodecreasethecesareanratenowfocusonlow-riskwomenasdefinedintheHP2010objectives.Despitethisfocus,thetrendsintheratesforlow-riskwomencontinuetoparallelthetrendsforallwomen.PrimaryandrepeatcesareanratesforallwomenhavenowreachedtheirhighestlevelsandVBACrateshavedroppedtotheirlowestlevelssincethesedatawerefirstreportedonthebirthcertificatein1989(4).Thecesareanrateforlow-riskwomenhavingafirstbirthhasbeenconsistentlylower(by13to16percentsince1996)thanthecesareanrateforallfirst-timemothers.However,therateforlow-riskprimipa-rouswomenthathaddecreasedby15percentbetween1990and1996,thenincreasedduringthenext7years,reaching23.6percentin2003,thehighestrateeverreportedintheUnitedStates.TableAshowstheHP2010objectivesforcesareanbirths,the1998baselineandthedatafor2003.Bothratescontinuetomoveawayfromthestatedobjectives.Forlow-riskwomengivingbirthforthefirsttime,theobjectiveisforacesareanrateofnomorethan15per100births.Giventhe2003cesareanrateforbirthstothesewomen(23.6percent),a36percentdropinthisratewillbenecessarytoachievetheobjective.Forlow-riskwomenwhohavehadapriorcesarean,theobjectiveisforacesareanrateof63per100births.Giventhe2003repeatrateforlow-riskwomenof88.7percent,therepeatratewouldhavetodecreaseby29percenttoreachtheobjective.Theclassificationofwomenbyriskstatusisbasedoninformationgenerallywellreportedonbirthcertificates,namelybirthorderorparity,plurality,gestationalage,andpresentation(position)ofthefetusinutero.However,awoman’sriskisalsoinfluencedbythepresenceofmedicalriskfactorsandcomplicationsoflaborand/ordelivery,whicharelesswellreportedonbirthcertificates,orarenotcollectedonbirthcertificatesatall(11,12).Nevertheless,anincreaseinthecesareanrateof67percentbetween1991and2001hasbeenreportedamongevenlower-riskmothers(i.e.,womenwithsingleton,full-term,vertexpre-sentationbirthswithnoriskfactorsorcomplicationsoflaborand/ordeliveryreportedonthebirthcertificate)(13).Thereisstillconsiderabledebateinthemedicalcommunityastotheappropriatelevelforthecesareanrate;controversycontinuesregardingelectivecesareandelivery,thewoman’schoicetoundergo TableA.HealthyPeopleObjectivesregardingcesareanTargetandbaselineReducecesareanbirthsamonglow-riskwomenBaseline2003TargetPercentoflivebirths....Womengivingbirthforthefirsttime1823.615....Womenwhohadapriorcesareanbirth7288.763 U.S.DepartmentofHealthandHumanServices.TrackingHealthyPeople2010.Washington,DC.U.S.GovernmentPrintingOffice.November2000.Alow-riskwomanisdefinedasonewithafull-term(atleast37completedweeksofgestation),singleton(notamultiplepregnancy),andvertexfetus(headfacinginadownwardpositioninthebirthcanal).http://www.healthypeople.gov/Document/HTML/Volume16MICH.htm#_Toc494699664.NationalVitalStatisticsReports,Vol.54,No.4,September22,2005 anelectiveprimarycesarean,thesafetyofVBACdeliveries,andtherisksandbenefitsofvaginaldelivery(9,14–17).Thefactthattheincreaseincesareanrateshasbeenwidespreadandincreasingyearlyforlow-riskwomenofallagesandracialorethnicgroupssupportstheideathatthecriteriaorindicationsforcesareandeliveryintheUnitedStateshavechanged.1.U.S.DepartmentofHealthandHumanServices.CesareanChildbirth.ReportofaconsensusdevelopmentconferencesponsoredbytheNationalInstituteofChildHealthandHumanDevelopmentinconjunc-tionwiththeNationalCenterforHealthCareTechnology.September22–24,1980.NIHPublicationNo.82–2067.U.S.DepartmentofHealthandHumanServices.October1981.2.U.S.DepartmentofHealthandHumanServices.HealthyPeople2000.Nationalhealthpromotionanddiseasepreventionobjectives.Wash-ington:PublicHealthService.1990.3.U.S.DepartmentofHealthandHumanServices.HealthyPeople2010.2nded.WithUnderstandingandImprovingHealthandObjectivesforImprovingHealth.Twovols.Washington:U.S.GovernmentPrintingOffice.November2000.Availableat:http://www.health.gov/4.MartinJA,HamiltonBE,VenturaSJ,etal.Births:Finaldatafor2003.Nationalvitalstatisticsreports;vol54no2.Hyattsville,MD.NationalCenterforHealthStatistics.2005.Availablehttp://www.cdc.gov/5.FlammBL.Onceacesarean,alwaysacontroversy.ObstetGynecol90(2):312–5.1997.6.SachsBP,KobelinC,CastroMA,FrigolettoF.Therisksofloweringthecesarean-deliveryrate.NEnglJMed340(1):54–7.1999.7.HarerWBJr.Patientchoicecesarean.ACOGClinicalReview5(2):1,13–6.2000.8.GreeneMF.Vaginaldeliveryaftercesareansection—istheriskacceptable?NEnglJMed345(1):54–5.2001.9.Lydon-RochelleM,HoltVL,EasterlingTR,MartinDP.Riskofuterineruptureduringlaboramongwomenwithapriorcesareandelivery.NEnglJMed345(1):3–8.2001.10.AmericanCollegeofObstetriciansandGynecologists.Evaluationofcesareandelivery.ACOGGuidelines.Washington:AmericanCollegeofObstetriciansandGynecologists.2000.11.ReichmanNE,HadeEM.Validationofbirthcertificatedata:AstudyofwomeninNewJersey’sHealthstartprogram.AnnEpidemiol.11:186–93.2001.12.DobieSA,BaldwinL-M,RogerA,etal.Howwelldobirthcertificatesdescribethepregnanciestheyreport?TheWashingtonStateexperi-encewithlow-riskpregnancies.MaternChildHealthJ2(3):145–54.13.DeclercqE,MenackerF,MacDormanMF.Risein‘‘noindicatedrisk’’primarycesareansintheUnitedStates,1991–2001:Crosssectionalanalysis.BritishMedicalJ330:71–2.2005.14.MinkoffH,PowderlyKR,ChervenakF,McCulloughLB.Ethicaldimensionsofelectiveprimarycesareandelivery.ObstetGynecol103(2):387–92.2004. Figure3.Repeatcesareanratesforlow-riskwomenbyageandraceandHispanicoriginofmother:UnitedStates,1996and2003NationalVitalStatisticsReports,Vol.54,No.4,September22,2005