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Research www.AJOG.org

OBSTETRICS

Morbidity following primary cesarean deliveryin the Danish National Birth CohortSherri Jackson, MD, MPH; Laura Fleege, MPH; Moshe Fridman, PhD;Kimberly Gregory, MD, MPH; Carolyn Zelop, MD; Jorn Olsen, MD, PhD

OBJECTIVE: Cesarean delivery rates are on the rise in many countries,including the United States. There is mounting evidence that cesareandelivery is associated with adverse reproductive outcomes in subse-quent pregnancies. The purpose of this article is to review those out-comes in a well-defined cohort of pregnant women.

STUDY DESIGN: In a cohort of primigravid women from the Danish Na-tional Birth Cohort with known baseline exposure characteristics, we strati-fied women by method of first delivery, vaginal or cesarean, and evaluatedfor appearance of adverse reproductive events in subsequent pregnancies.

RESULTS: After adjusting for age, body mass index, alcohol, smok-

ing, and socioeconomic status, women who underwent cesarean

2012;206:139.e1-5.

tnsbpdcp

(DNBC). Based on prdoi: 10.1016/j.ajog.2011.09.023

delivery at first birth were at increased risk in their subsequent preg-nancy for anemia (odds ratio [OR], 2.8; 95% confidence interval [CI],2.3–3.4), placental abruption (OR, 2.3; 95% CI, 1.5–3.6), uterinerupture (OR, 268; 95% CI, 65.6 –999), and hysterectomy (OR, 28.8;95% CI, 3.1–263.8).

CONCLUSION: Women who deliver their first baby with a cesarean areat increased risk of adverse reproductive outcomes in subsequent preg-nancies and should be counseled accordingly.

Key words: Danish National Birth Cohort, morbidity following

cesarean, primary cesarean

Cite this article as: Jackson S, Fleege L, Fridman M, et al. Morbidity following primary cesarean delivery in the Danish National Birth Cohort. Am J Obstet Gynecol

iWcpto

Cesarean delivery rates in developedcountries are on the rise, with a

ean of 21% and ranging from 6.2% to6% of births.1 In 2007, cesarean births

represented 31.8% of all births in theUnited States—an all-time high.2 In

From the Division of Maternal FetalMedicine, Department of Obstetrics andGynecology, Cedars-Sinai Medical Center(Drs Jackson and Gregory and Ms Fleege);AMF Consulting Incorporated (DrFridman); and the Department ofEpidemiology, School of Public Health,University of California, Los Angeles, Schoolof Medicine (Dr Olsen), Los Angeles, CA;the Division of Maternal-Fetal Medicine,Department of Obstetrics and Gynecology,Beth Israel Deaconess Medical Center,Boston, MA (Dr Zelop); and the DanishEpidemiology and Science Center, Aarhus,Denmark (Dr Olsen).

Received May 9, 2011; revised Aug. 4, 2011;accepted Sept. 20, 2011.

The authors report no conflict of interest.

Reprints: Sherri Jackson, MD, MPH, 8635 W. 3St., Suite 160 W., Los Angeles, CA 90048.jacksonsherri@me.com.

0002-9378/$36.00© 2012 Mosby, Inc. All rights reserved.

contrast, only 19.1% of births were de-livered by cesarean in Denmark in 2005.1

Currently, there is no consensus regard-ing what the “ideal” cesarean rate shouldbe; however, many researchers, clini-cians, and women purport that when ce-sarean rates rise too high, “the risks toreproductive health may outweigh thebenefits.”1,3 There is mounting evidencehat cesarean delivery is associated withot only short-term health consequencesuch as bleeding, infection, impairedreast-feeding, and infant bonding, buterhaps more important, adverse repro-uctive outcomes in subsequent pregnan-ies such as ectopic pregnancy, abnormallacentation, and hysterectomy.4-13 The

rising trend in cesarean delivery ratesacross the world suggests that women andtheir health care providers are unaware ofthese risks or perhaps consider these risksto be negligible.

To evaluate the role of cesarean onsubsequent reproductive outcomes, ourstudy examined the long-term repro-ductive outcomes in women who had aninitial vaginal delivery compared tothose with an initial cesarean delivery us-ing the Danish National Birth Cohort

evious studies, we

FEBRUARY 2012 Americ

hypothesize that even after control ofbaseline confounders, women who havea cesarean delivery in their first pregnancyare at increased risk for adverse short- andlong-term reproductive events thanwomen who have a vaginal delivery in thefirst pregnancy.

MATERIALS AND METHODSThe DNBC has been described exten-sively.14,15 The main features of the reg-stry are repeated here for convenience.

omen are recruited at their first healthare visit during early pregnancy. Ap-roximately 30% of Danish women par-icipate in the DNBC, representing 60%f those invited.16 This cohort has been

validated to produce similar associationswith those who do not participate in thecohort.16

After approval from the Danish DataProtection Agency, we identified a co-hort of 26,059 primigravid women whoparticipated in the DNBC during theirfirst pregnancy and had at least 1 subse-quent pregnancy with documented out-comes during the study period, October1994 through August 2010. We excluded1220 women (1061 women who had

codes for vaginal delivery and cesarean at

an Journal of Obstetrics & Gynecology 139.e1

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Jackson. Morbidity following primary cesarean. Am J Obstet Gynecol 2012. (continued )

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139.e2 American Journal of Obstetrics & Gynecology FEBRUARY 2012

the same time, 94 women who had anabortion as the first outcome, 30 womenwho were gravida 2 at initiation of co-hort, 4 women who had codes for deliv-ery and abortion at the same time, and 31women who were missing key back-ground variables). The remaining 24,839women comprised the study populationfor this analysis.

Baseline exposure characteristics werecollected via interview and included dataon lifestyle factors, health problems, andsocial conditions. Our primary outcomeswere chosen based on literature review andanalysis of risk and were stratified acrossthe reproductive continuum and includedthe following: pregnancy loss (spontane-ous abortion [SAB], ectopic pregnancy, in-trauterine fetal demise [IUFD]) and ante-partum or labor complications (pretermbirth, anemia, postpartum hemorrhage,placenta previa, placenta accreta, abrup-tion, uterine rupture, and hysterectomy).

International Statistical Classificationof Diseases, 10th Revision coding as wellas Danish procedure codes were used toidentify delivery type and primary out-comes. The codes are listed in the Ap-pendix. Categorical and continuous test-ing was performed with �2 and Studentt test, respectively, with a significancelevel of P � .05 for all outcomes after the

rst delivery. Multiple logistic regressionodels were fitted to estimate the ad-

usted odds ratio of the first delivery byesarean on each outcome. The presencef each outcome was then examined us-

ng the second delivery only as around0% of women in this cohort deliverednly 1 or 2 infants and to avoid oversam-ling the more fecund. Poisson regres-ion models were used to estimate thedjusted effect of first delivery by cesar-an on the number of SAB and ectopicregnancies after the initial delivery andefore the second delivery. Baseline ad-

ustment for possible confounders in-luded age, body mass index (BMI), al-ohol use, tobacco use, and a marker forocioeconomic status based on incomend occupation of both partners androuped into 3 levels. Statistical analysisas performed with software (SAS, ver-

TABLE 1Background characteristics at enrollment

Category at interviewVaginal,n � 21,499

Cesarean,n � 3340 P value

Physical.....................................................................................................................................................................................................................................

Mean age, y 27.4 28.2 � .0001.....................................................................................................................................................................................................................................

Mean weight, kg 66.55 68.34 � .0001.....................................................................................................................................................................................................................................

Mean height, cm 169.2 167.5 � .0001.....................................................................................................................................................................................................................................

Mean BMI 23.23 24.35 � .0001..............................................................................................................................................................................................................................................

Pregnancy status.....................................................................................................................................................................................................................................

Oral contraceptive pills in 4 mo prior 35% 31% � .0001.....................................................................................................................................................................................................................................

Infertility treatment prior to pregnancy 22% 25% .0063..............................................................................................................................................................................................................................................

Pregnancy planning.....................................................................................................................................................................................................................................

Planned 77% 78%.....................................................................................................................................................................................................................................

Partly 13% 13%.....................................................................................................................................................................................................................................

No 10% 9%..............................................................................................................................................................................................................................................

Medical conditions.....................................................................................................................................................................................................................................

Vaginal bleeding in pregnancy 19% 18% .5639.....................................................................................................................................................................................................................................

Vaginal infection in pregnancy 10% 10% .3670.....................................................................................................................................................................................................................................

Metabolic disorder 1.4% 1.4% .2331.....................................................................................................................................................................................................................................

Asthma 9.4% 10.4% .0147.....................................................................................................................................................................................................................................

Mental disorder, neurosis 6.5% 6.2% .8238.....................................................................................................................................................................................................................................

Anemia 9.5% 9.7% .4025.....................................................................................................................................................................................................................................

Urinary tract disease 39% 42% .0061.....................................................................................................................................................................................................................................

Urinary tract disease in pregnancy 37% 40% .0136..............................................................................................................................................................................................................................................

Hypertension.....................................................................................................................................................................................................................................

Yes 4% 5%.....................................................................................................................................................................................................................................

Only in pregnancy 0.4% 0.6%.....................................................................................................................................................................................................................................

No 96% 94%..............................................................................................................................................................................................................................................

Social behaviors.....................................................................................................................................................................................................................................

Tobacco in pregnancy 24% 25% .2392.....................................................................................................................................................................................................................................

Exercise 47% 44% .0010.....................................................................................................................................................................................................................................

In school/training 19% 16% � .0001.....................................................................................................................................................................................................................................

Have spouse/partner 98% 98% .8942.....................................................................................................................................................................................................................................

Mean tobacco/d (cigarettes) 7.6 8.1 .0126.....................................................................................................................................................................................................................................

Alcohol (any) 21% 20% .4789.....................................................................................................................................................................................................................................

Median beer/wk 0 0 .8579.....................................................................................................................................................................................................................................

Median wine/wk 0 0 .9710.....................................................................................................................................................................................................................................

Median spirits/wk 0 0 .1337.....................................................................................................................................................................................................................................

Mean fish in meal/wk 2.1 2.1 .9029.....................................................................................................................................................................................................................................

Median fish in meal/wk 2.9 2.9 .5198..............................................................................................................................................................................................................................................

ion 9.2; SAS Institute Inc, Cary, NC.

ofSfinaitt

tet G

www.AJOG.org Obstetrics Research

RESULTSTable 1 lists the background characteris-tics of the cohort identified at the initialinterview by first delivery route. Womenwho experienced a cesarean delivery atthe time of their first pregnancy wereolder, heavier, more likely to have un-dergone treatment for infertility, and lesslikely to have been on oral contraceptivesprior to pregnancy. They were more likelyto have asthma, hypertension during preg-nancy, and urinary tract disease. With re-gard to social behaviors, women undergo-ingcesareanweremorelikelytobeemployedand were less likely to exercise or be in schoolor vocational training.

The cesarean rate in the first preg-nancy was 17% and in the second preg-nancy, it was 16%. Table 2 displays the

TABLE 1Background characteristics at enro

Category at interview

Of those smoking currently..........................................................................................................

Yes, daily..........................................................................................................

Yes, �daily..........................................................................................................

No...................................................................................................................

Employed..........................................................................................................

Yes, 1 job..........................................................................................................

Yes, 2 jobs..........................................................................................................

Yes, �2 jobs..........................................................................................................

No...................................................................................................................

Partner supported..........................................................................................................

Unemployed..........................................................................................................

Rehabilitation..........................................................................................................

Social benefit..........................................................................................................

Pension..........................................................................................................

Wife..........................................................................................................

Grant/education/training..........................................................................................................

Leave..........................................................................................................

Sick...................................................................................................................

Socioeconomic status..........................................................................................................

High..........................................................................................................

Mid..........................................................................................................

Low...................................................................................................................

BMI, body mass index.

Jackson. Morbidity following primary cesarean. Am J Obs

unadjusted rates of the primary out-

comes after the first delivery. With re-gard to pregnancy loss, only SAB was sig-nificantly associated with first cesareandelivery; however, almost all antepartumand labor complications evaluated werestatistically significantlyassociatedwithce-sarean delivery except placenta accreta. Werepeated the analysis for women who onlyunderwent all vaginal deliveries (vaginaldelivery for all pregnancy outcomes) vswomen who had a primary cesarean andthe results were similar to those in Table 2except that placenta accreta was statisti-cally significantly associated with cesareandelivery in first pregnancy (data notshown).

Table 3 shows the adjusted odds ratiosand 95% confidence intervals for each ofthe outcomes of interest in the second

ent (continued)

aginal,� 21,499

Cesarean,n � 3340 P value

..................................................................................................................

7% 44%..................................................................................................................

7% 6%..................................................................................................................

7% 50%..................................................................................................................

..................................................................................................................

9% 82%..................................................................................................................

0.2% 0.3%..................................................................................................................

0.02% 0..................................................................................................................

1% 18%..................................................................................................................

..................................................................................................................

8% 18%..................................................................................................................

4% 3%..................................................................................................................

5% 4%..................................................................................................................

1% 2%..................................................................................................................

4% 4%..................................................................................................................

1% 61%..................................................................................................................

2% 1%..................................................................................................................

2% 3%..................................................................................................................

..................................................................................................................

6.52% 54.94%..................................................................................................................

6.34% 37.35%..................................................................................................................

7.14% 7.72%..................................................................................................................

ynecol 2012.

pregnancy only with the odds of cesarean

FEBRUARY 2012 Americ

relative to vaginal delivery. After adjust-ing for age, BMI, alcohol, smoking, andsocioeconomic status, there was no sig-nificant difference in pregnancy lossrates (SABs, ectopics, IUFD). Womenwho delivered by cesarean in their firstpregnancy were at increased risk for ane-mia, placental abruption, uterine rup-ture, and hysterectomy and were lesslikely to deliver preterm.

Table 4 shows the live births of womenin each arm of the study, by route of firstdelivery. Most women had 2 deliveries.However, women who had a vaginal de-livery at their first pregnancy were morelikely to have a third or fourth deliveryduring the follow-up period.

COMMENT

In a group of women having their firstpregnancy result in a cesarean delivery,subsequent deliveries were more likely tohave anemia, placental abruption, uter-ine rupture, and hysterectomy after ad-justing for age, BMI, and social condi-tions at baseline. First-time cesarean wasassociated with decreased risk of pretermbirth.

Our findings are similar to previousliterature regarding risk of anemia, uter-ine rupture, hysterectomy, and abrup-tion.4-6,8,9,11,12,17 The absolute number

f these events occurring was low; there-ore, our confidence intervals were wide.imilar to Kendrick et al,18 we did notnd an increased risk of ectopic preg-ancy that had been reported by otheruthors.6,13 Further, we did not find anncrease in risk of IUFD after cesareanhat has been inconsistently reported inhe literature.9,10,17 Hemminki7 reported

an increased risk of SAB; however, thiswas not supported by our study after ad-justing for baseline risk factors. We eval-uated SAB and ectopic pregnancy whenthey occurred after the initial deliveryand prior to the second delivery. Ananalysis of all subsequent pregnancieswould likely capture more first-trimesterlosses. Similar to previous studies, wefound an increased risk in abnormal pla-centation but did not find an increasedrisk in accreta. This is surprising in light

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Jackson. Morbidity following primary cesarean. Am J Obstet Gynecol 2012.

Jackson. Morbidity following primary cesarean. Am J Obstet Gynecol 2012.

Research Obstetrics www.AJOG.org

139.e4 American Journal of Obstetrics & Gynecology FEBRUARY 2012

may be related to the very low numbersof accreta in our cohort overall (16);more than the actual association of ce-sarean delivery with accreta. In addition,other investigators have demonstratedthat accreta is strongly associated withthe number of cesareans and/or abnor-mal placentation and this analysis waslimited to second pregnancy.

Although several investigators havedemonstrated an association betweencesarean delivery and subsequent pre-term birth,5,8,10 we found a decrease inhe risk of preterm birth in women whonderwent an initial cesarean even afterdjusting for age, smoking, alcohol, so-ioeconomics, and BMI. This findingay be related to other confounders not

nown or addressed here. The DNBC ineneral represents a healthy study cohortf relative high socioeconomic statusith a low risk of preterm birth when

ompared to standards in the Unitedtates. The strengths of this study are inhe design of the cohort and the ability toapture many confounding factors ataseline and follow up these women overime for development of any complica-ions through the linked hospital registryystem.

The analysis does not take into ac-ount the following protective effects ofesarean in first delivery: if cesarean hadhigher rate of hysterectomy in first de-

ivery they would not have adverse out-omes for any subsequent reproductivevent. These women will not be includedn the analysis as our study group pur-osely included women with �1 preg-ancy. However, the rate of hysterec-

omy is very low and the bias is expectedo be small. A larger potential effect ofsing only women with �2 deliveries in

he analysis is the potential tendency ofomen first delivered with a cesarean to

void a second pregnancy, as we knowomen with previous cesarean have a

onger time to subsequent pregnancynd fewer subsequent pregnancies thanhose with initial vaginal deliveries.13

And in fact, in this study, women whodelivered their first baby vaginally weremore likely to have �2 deliveries com-

ared to women who delivered their first

TABLE 2Unadjusted rates of all outcomes afterfirst delivery by route of first delivery

Outcome

Vaginal,(n � 27,543)

Cesarean,(n � 4030)

P value% n % n

Pregnancy loss.....................................................................................................................................................................................................................................

Spontaneous abortion 10.66 3691 13.08 675 � .0001.....................................................................................................................................................................................................................................

Ectopic pregnancy 0.84 291 1.01 52 .2249.....................................................................................................................................................................................................................................

IUFD 0.15 41 0.10 4 .4356..............................................................................................................................................................................................................................................

Antepartum or labor complications.....................................................................................................................................................................................................................................

Uterine rupture 0.04 12 1.86 75 � .0001.....................................................................................................................................................................................................................................

Preterm birth 0.78 216 0.32 13 .0013.....................................................................................................................................................................................................................................

Placenta accreta 0.04 12 0.10 4 .1424.....................................................................................................................................................................................................................................

Placental abruption 0.38 105 0.82 33 � .0001.....................................................................................................................................................................................................................................

Placenta previa 0.30 82 0.55 22 .0102.....................................................................................................................................................................................................................................

Hysterectomy 0.01 4 0.12 5 .0001.....................................................................................................................................................................................................................................

Anemia 1.58 434 4.19 169 � .0001.....................................................................................................................................................................................................................................

Postpartum hemorrhage 4.11 1132 3.47 140 .0551..............................................................................................................................................................................................................................................

IUFD, intrauterine fetal demise.

TABLE 3Adjusted cesarean vs vaginal odds ratiosfor birth complications in second delivery

Variable n OR 95% CI

Pregnancy loss.....................................................................................................................................................................................................................................

Spontaneous abortiona 2271 0.98 (IRR) 0.88–1.26.....................................................................................................................................................................................................................................

Ectopic pregnancya 155 0.82 (IRR) 0.54–1.26.....................................................................................................................................................................................................................................

IUFDb 32 0.7 0.2–2.2..............................................................................................................................................................................................................................................

Antepartum or labor complications.....................................................................................................................................................................................................................................

Uterine ruptureb 71 268 65.6–999.....................................................................................................................................................................................................................................

Preterm birthb 179 0.5 0.3–0.9.....................................................................................................................................................................................................................................

Placenta accretac 6 1.5 0.2–12.9.....................................................................................................................................................................................................................................

Placenta abruptionb 102 2.3 1.5–3.6.....................................................................................................................................................................................................................................

Placenta previab 72 1.5 0.8–2.6.....................................................................................................................................................................................................................................

Hysterectomyd 5 28.8 3.1–263.8.....................................................................................................................................................................................................................................

Anemiab 483 2.8 2.3–3.4.....................................................................................................................................................................................................................................

Postpartum hemorrhageb 947 0.89 0.73–1.09..............................................................................................................................................................................................................................................

CI, confidence interval; IRR, incidence rate ratio; IUFD, intrauterine fetal demise; OR, odds ratio.a Poisson regression for number of occurrences between first and second delivery; b Controlled for age, body mass index, tobacco,

alcohol, socioeconomic status; c Controlled for age, body mass index, tobacco, alcohol; d Controlled for age and body massindex.

aby by cesarean (Table 4). Whether this is

www.AJOG.org Obstetrics Research

caused by a reduction in fecundability or awish for smaller family size is unknown.

Additionally, cesarean delivery is notprovided by a random process and ourresults may thus contain risks associatedwith cesarean delivery. As cesarean deliv-ery can be both an exposure and an out-come, we have kept in mind that con-founding by indication may occur andmay overestimate the effects. The out-come of the first delivery was purposelyexcluded as some outcomes could lead toa cesarean delivery such as placental ab-ruption or uterine rupture making thisdifferentiation between cesarean as anexposure or an outcome even moredifficult.

In conclusion, a primary cesarean de-livery does appear to increase risk of fu-ture reproductive adverse events, specif-ically abnormal placentation and relatedbleeding complications (anemia, uterinerupture, hysterectomy). This should bediscussed with patients in addition to theshort-term operative risks so that womenand their providers can make appropriateinformed decisions–especially when thefirst cesarean is performed for “elective” ornonmedically indicated reasons. Futurestudies in this area should look to capturewomen across all demographic and racial/ethnic groups and include those baseline

TABLE 4Parity by route of first delivery

Live births witheach pregnancy

Firstvaginal

Firstcesarean

First 21,499 3340...........................................................................................................

Second 20,762 3147...........................................................................................................

Third 6135 807...........................................................................................................

Fourth 602 70...........................................................................................................

Fifth 37 5...........................................................................................................

Sixth 6 1...........................................................................................................

Seventh 1 0...........................................................................................................

Jackson. Morbidity following primary cesarean. Am JObstet Gynecol 2012.

factors outlined prior to occurrence of de-

livery and any delivery complications tobetter outline risks following cesareandelivery. f

REFERENCES1. Betrán AP, Merialdi M, Lauer JA, et al. Ratesof cesarean section: analysis of global, regionaland national estimates. Paediatr Perinat Epide-miol 2007;21:98-113.2. Martin JA, Hamilton BE, Sutton PD, et al.Births: final data for 2007. Natl Vital Stat Rep2010;58:1-85.3. Childbirth connection. Available at: http://www.childbirthconnection.org. Accessed May2, 2011.4. Ananth CV, Smulian JC, Vintzileos AM. Theassociation of placenta previa with history ofcesarean delivery and abortion: a metaanalysis.Am J Obstet Gynecol 1997;177:1071-8.5. Kennare R, Tucker G, Heard A, Chan A.Risks of adverse outcomes in the next birth aftera first cesarean delivery. Obstet Gynecol 2007;109:270-6.6. Hemminki E, Meriläinen J. Long-term effectsof cesarean sections: ectopic pregnancies andplacental problems. Am J Obstet Gynecol1996;174:1569-74.7. Hemminki E. Impact of caesarean section onfuture pregnancy–a review of cohort studies.Paediatr Perinat Epidemiol 1996;10:366-79.8. Hemminki E, Shelley J, Gissler M. Mode ofdelivery and problems in subsequent births: aregister-based study from Finland. Am J ObstetGynecol 2005;193:169-77.9. Silver RM. Delivery after previous cesarean:long-term maternal outcomes. Semin Perinatol2010;34:258-66.10. Smith GC, Pell JP, Dobbie R. Caesarean sec-tion and risk of unexplained stillbirth in subsequentpregnancy. Lancet 2003;362:1779-84.11. Lydon-Rochelle M, Holt VL, Easterling TR,Martin DP. First-birth cesarean and placentalabruption or previa at second birth. Obstet Gy-necol 2001;97:765-9.12. Daltveit AK, Tollånes MC, Pihlstrøm H, IrgensLM. Cesarean delivery and subsequent pregnan-cies. Obstet Gynecol 2008;111:1327-34.13. Mollison J, Porter M, Campbell D, Bhat-tacharya S. Primary mode of delivery and sub-sequent pregnancy. BJOG 2005;112:1061-5.14. Olsen J, Melbye M, Olsen SF, et al. TheDanish National Birth Cohort–its background,structure and aim. Scand J Public Health2001;29:300-7.15. Danish National Birth Cohort. Available at:

http://www.bsmb.dk. Accessed May 2, 2011.

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16. Nohr EA, Frydenberg M, Henriksen TB, Ol-sen J. Does low participation in cohort studiesinduce bias? Epidemiology 2006;17:413-8.17. Taylor LK, Simpson JM, Roberts CL, OliveEC, Henderson-Smart DJ. Risk of complica-tions in a second pregnancy following caesar-ean section in the first pregnancy: a population-based study. Med J Aust 2005;183:515-9.18. Kendrick JS, Tierney EF, Lawson HW,Strauss LT, Klein L, Atrash HK. Previous cesar-ean delivery and the risk of ectopic pregnancy.Obstet Gynecol 1996;87:297-301.

APPENDIXInternational Statistical Classification ofDiseases, 10th Revision and Danish Pro-cedure Codes

Vaginal: DO800, DO840, DO841,DO844A, DO845, DO801, DO802, DO803,DO814, DO815, DO810, DO813, DO700,DO701, DO702, DO703, DO714, BKXA1,BKZB, KMAE00, KMAE03, DO757

Cesarean: DO820, DO821, DO821A,DO821B, DO821C, DO842, DO843,DO843A, DO843B, DO843C, DO844B,KMCA10, KMCA10A, KMCA10B,KMCA10D, KMCA10E, KMCA11,KMCA12, KMCA12A, KMCA12B

Uterine rupture: DO710, DO711, DO711A

Preterm birth: DO609

Intrauterine fetal demise: DO364

Accreta: DO722E, DO432

Placental abruption: DO452, DO458,DO459

Placenta previa: DO440–DO449

Hysterectomy: DO822, KLCD00

Blood transfusion: BOQA0

Anemia: DO908, DO990, DO990A

Postpartum hemorrhage: DO720, DO721,DO721A, DO721B, DO721C, DO721D,DO722

Missed abortion and spontaneous abor-tion: DO020–DO029, DO030–DO039

Ectopic: DO000–DO009

an Journal of Obstetrics & Gynecology 139.e5