OBSTETRICS

Effect of physical ac nof deliveryIris Domenjoz, MBBS; Bengt Kayser, MD

OBJECTIVE: The purpose of this study was tostructured physical exercise programs during preof labor and delivery.

STUDY DESIGN:We conducted a systematic revTalari

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Research www.AJOG.orgwere not powered to show a differencein obstetric outcomes. A metaanalysisof these studies may increase the like-lihood to identify a benet from exerciseprograms.

We performed a systematic reviewof randomized controlled trials to de-termine whether structured physicaltraining programs during pregnancycan improve the course of labor and

domized controlled trials (ie, men-tioned as randomized in title, abstract,or full text), (2) included women of anyage, parity, and body mass index (BMI)with a singleton pregnancy and noneof the absolute obstetrics contraindi-cations to exercise according to theAmerican College of Obstetricians andGynecologists (ACOG),11 (3) compari-son of exercise program vs no exercise

(Dr Kayser), Switzerland.

Received Dec. 14, 2013; revised Feb. 3, 2014;accepted March 10, 2014.

The authors report no conict of interest.

Reprints: Iris Domenjoz, MBBS, UniversityHospital of Geneva, Gabrielle perret gentil 4,Geneve, Geneve 1205, Switzerland.domenjozi@bluewin.ch.

0002-9378/$36.00 2014 Mosby, Inc. All rights reserved.http://dx.doi.org/10.1016/j.ajog.2014.03.030and her child.3 Short-term maternalrisks include infection, thromboembo-lism and hemorrhage, sometimes severeenough to be life threatening.4 The in-crease of cesarean deliveries also raisesconcerns about longer term morbiditysuch as uterine rupture and placentaprevia and/or accreta during subsequentpregnancies and adhesions with chronic

Observational stuthat regular exercisreduces the risk of cSeveral randomizehave attempted to mstructured exerciseoutcomes, includingmellitus and preeclwere conducted torelation between pcesarean delivery risa signicant effect.8

were of relatively sm

From the Faculty of Medicine of Geneva(Dr Boulvain and Ms Domenjoz) and the Instituteof Sports Sciences, University of Lausannedelivery.

FLA 5.2.0 DTD YMOB9730_prooies have suggestedduring pregnancyarean deliveries.5-7

controlled trialseasure the effect ofograms on variousgestational diabetesmpsia. Some trialsaluate directly theysical activity and; only 1 trial foundost of the studies

all sample size and

Search strategyWe searched electronic databases, Med-line (PubMed), and the Cochrane Li-brary, using the words: pregnancy ANDexercise AND (randomized OR ran-domized). We scanned the referencelists of identied relevant articles. Weimposed neither language nor publica-tion date restrictions. The last search wasrun in March 2013.

Eligibility criteriaThe eligibility criteria were (1) ran-delivery has become safer, it remains aninvasive procedure with potentialmorbidity and death for both mother

livery for sound medical reasons only,and interventions effective in decreasingthe risk would be welcome.

items for systematic reviews and meta-analyses statement.9,10T deliveries increased steadily duringthe last decades.1,2 Although cesareanusing the following data sources: Medline andIn our study, we used randomized controlled trithe effects of exercise programs during pregnlivery. The results are summarized as relative

RESULTS: In the 16 RCTs that were incluwomen. Women in exercise groups had a sigcesarean delivery (relative risk, 0.85; 95% c0.73e0.99). Birthweight was not significantgroups. The risk of instrumental delivery was

Cite this article as: Domenjoz I, Kayser B, Boulvain M

he number of cesarean deliverytivity during pregna

, PhD; Michel Boulvain, MD, PhD

evaluate the effect ofgnancy on the course

iew and metaanalysishe Cochrane Library.s (RCT) that evaluatedncy on labor and de-sks.

d there were 3359ificantly lower risk offidence interval [CI],reduced in exerciseimilar among groups

(relative risk, 1.00;episiotomy, epiduralinduction of labor weuse of data from 11 stwomen in the exerciswomen in control gre1.49 to e0.78).

CONCLUSION: Structuthe risk of cesarean dwomen to be activephysician to recommethis is not contraindic

Key words: cesarean

ffect of physical activity during pregnancy on mode o

pain as a consequence of the surgicalprocedure.4 Obstetricians thereforeshould restrict the use of cesarean de-MONTH 2014 Am

f 6 May 2014 6:26cy on mode

% CI, 0.82e1.22). Data on Apgar score,esthesia, perineal tear, length of labor, andinsufficient to draw conclusions. With theies (1668 women), our analysis showed thatgroups gained significantly less weight thanps (mean difference, e1.13 kg; 95% CI,

d physical exercise during pregnancy reducesivery. This is an important finding to convinceuring their pregnancy and should lead thephysical exercise to pregnant women, when

ed.

elivery, physical activity, pregnancy

elivery. Am J Obstet Gynecol 2014;210:.

MATERIALS AND METHODSThis review was conducted in accor-dance with the preferred reportingprogram (the exercise program should

erican Journal of Obstetrics& Gynecology 1.e1pm ce

Research Obstetrics www.AJOG.orgFIGURE 1Diagram flow chartinclude resistance or aerobic exercise;minimum 1 session per week, super-vised, to ensure it was carried out with aminimum level of intensity and regu-larly, thus providing some homogeneityin the intervention group; studies withan intervention limited to pelvic oorexercises, stretching, or relaxation wereexcluded), (4) trials that reported themode of delivery, that included thepercentage of cesarean and instrumental

RCT, randomized controlled trial.

Domenjoz. Physical activity reduces cesarean delivery. Am J Ob

1.e2 American Journal of Obstetrics& GynecologyFLA 5.2.0 Ddelivery and/or any of the followingoutcomes: Apgar score, duration of la-bor, episiotomy, epidural anesthesia,induced labor, and delivery lacerations.

Contact was attempted with authorsof articles that included an adequateintervention but that did not reportthe prespecied outcomes. Among 17authors who we contacted, 13 authorsresponded, and 1 author provided ad-ditional unpublished data.12 Barakat

stet Gynecol 2014.

MONTH 2014

TD YMOB9730_proof 6 May 2014 6:26et al13-19 assured us that there was nooverlap of participants in their reports.

Data collectionTwo of the authors (I.D. and M.B.) per-formed the rst screening, studiesappraisal, and data extraction; the thirdauthor (B.K.) veried the data collection.We extracted data on (1) type of partic-ipants: inclusion and exclusion criteria,age, BMI, parity, prepregnancy level ofphysical activity, type of recruitment,percentage of dropout, and pregnancyweight gain; (2) type of intervention inthe exercise group: number of hoursper training and per week, when theintervention started and nished, typeof exercise, how the women were su-pervised, and compliance; (3) controlgroup: if asked not to exercise and howany exercise habits were assessed; and (4)outcomes mentioned earlier and birth-weight (which could be considered as apotential effect of the intervention or asconfounding factor).

The ACOG recommends 30 minutesof exercise on most days of the week,which means a minimum of 2 hours perweek. An intervention that follows theseguidelines during 2 trimesters wouldtotal approximately 50 hours of exercise.For each study, we calculated the num-ber of hours of exercise planned andused the percentage of compliance(available for 11 studies) to estimate theamount of exercise carried out.

Risk of biasTo ascertain the validity of eligible ran-domized trials, we determined adequacyof concealment of allocation, sequencegeneration, blinding of the obstetricianand data collector, and percentage of lossto follow up. We used the Jadad score,which is a scale that ranges from 0e5points to assess the quality of randomi-zation.20 Because blinding of the womenwas impossible, a maximum of 3 pointscould be obtained.

Statistical analysisOur primary analysis was a comparisonof the risk of cesarean delivery inwomen who participated in a structuredphysical activity program compared

with women in the control groups. We

pm ce

TABLE 1Characteristics of studies included in metaanalysis

StudyEachgroup, n

Drop-outs, n

Lost tofollow up, n Primiparas, %

Pregestational bodymass index, kg/m2a Pregestational inactivity

Adequateallocationconcealment

Adequatesequencegeneration

Barakat et al, 201216 EG: 160 22 (14%) 0 60.9 24.0 4.3 Not participating in another physicalactivity program or exercising>4 times/wk

Yes Yes

CG: 160 8 (5%) 0 54.6 23.6 4.0 One-third of the women had anactive profession

Barakat et al, 201213 EG: 50 10 (20%) 0 65.0 22.7 2.8 One-half of the women were activeor very active before pregnancy

Unclear Unclear

CG: 50 7 (14%) 0 48.8 23.0 2.9 One-third of the women had anactive profession

Barakat et al, 201117 EG: 40 6 (15%) 0 76.5 23.9 3.0 No information Unclear YesCG: 40 7 (17%) 0 36.4 24.8 4.0 One-half of the women had an

active profession

Price et al, 20128 EG: 43 12 (28%) 0 58.1 26.6 3.1 No aerobic exercise >1 time/wkfor at least 6 mo

Yes Unclear

CG: 48 17 (35%) 0 58.1 28.7 5.4 No information about their professionMarquez-Sterlinget al, 200023

EG: 10 1 (10%) 0 100 22.8 4.0 No exercise on regular basis for atleast 1 year before conception

Yes Unclear

CG: 10 2 (20%) 2 (20%) 100 24.5 4.5 No information about their professionStafne et al, 201224 EG: 429 33 (8%) 21 (5%) 58.0 24.7 3.0 One-third of the women exercised

3 times/wkYes Yes

CG: 426 49 (11%) 50 (12%) 56.0 25.0 3.4 No information about their professionBarakat et al, 200914 EG: 80 8 (10%) 0 72.2 24.3 0.5 Not exercising >20 min on >3 d/wk Yes Unclear

CG: 80 5 (6%) 5 (6%) 57.1 23.4 0.5 24% of the women had an activeprofession

Kihlstrand et al, 199925 EG: 129 5 (3%) 1 (1%) 35.4 No information Yes Unclear

CG: 129 11 (8%) 0 26.6

Baciuk et al, 200821 EG: 34 12 (35%) 1 (3%) 47.1 24.1 4.5 Not exercising regularly Unclear YesCG: 37 10 (27%) 0 62.2 23.4 3.8

Ramirez-Velezet al, 201112

EG: 33 0 9 (27%) 100 No information Yes Unclear

CG: 31 0 5 (16%) 100

Domenjoz. Physical activity reduces cesarean delivery. Am J Obstet Gynecol 2014. (continued)

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1.e4 American Journal of Obstetrics& Gynecology MONTH 2014FLA 5.2.0 DTD YMOB9730_proof 6 May 2014 6:26also assessed the risk ratio for the otheroutcomes. Statistical analysis was per-formed with Review Manager software(version 5.2; US Cochrane Collabora-tion, Baltimore, MD); we entered thedata that were collected in each report.We have not made attempts to obtainraw data from the authors of the originalstudies to perform individual patientsdata metaanalysis. Risk ratios werecalculated with 95% CI with theMantel-Haenszel method. We used axed effects model. Heterogeneity wasevaluated with I2, and we would haveused a random effect model in case of I2

to indicate heterogeneity (I2 >50%)Sensitivity analysis was done excluding2 studies in which there was a markedimbalance in parity and 5 studies thathad a dropout proportion of >25%.Publication bias was assessed by theexamination of a funnel plot.

RESULTSStudy selectionWe screened the abstracts of the 376identied articles and excluded 203clearly irrelevant references and 92observational studies (Figure 1).

The full text of the 81 potentiallyrelevant articles were obtained andassessed with the use of the eligibilitycriteria. Twenty-six articles wereexcluded because they reported none ofthe outcomes, even after attemptedcontact with the authors; 33 articles re-ported interventions that did not corre-spond to the inclusion criteria. A total of19 reports of 16 studies were identied(Table 1). The study by Barakatet al14,18,19 was reported in 3 differentarticles, and the study by Baciuk et al21

and Cavalcante et al22 were reported in2 articles.We used the information of the19 reports8,12-19,21-31 to assess the qualityof the studies and used the data of the 16studies for the metaanalysis. The studiesconducted by Brankston et al32 andJovanovic-Peterson et al,33 which wereincluded in the Cochrane Review onexercise in pregnant women with dia-betes mellitus,34 were not includedbecause they did not report the cesareanpercentage; the study by Bung et al35 wasnot included because the comparison

was exercise vs insulin. No additional

pm ce

TABLE 2Interventions in included studies

StudyPeriod ofexercise

Hours ofexercise

Hours 3compliance

Compliance,%

Intervention

Control groupExercise Length

Barakatet al, 201216

From wk 6-9to wk 38-39

57 49 87 Light aerobic and resistance exercises(7-8 min warm-up walking and staticstretching, 25 min of aerobics andmuscle strengthening exercises, 7-8 mincool-down walking);

TABLE 2Interventions in included studies (continued)

StudyPeriod ofexercise

Hours ofexercise

Hours 3compliance

Compliance,%

Intervention

Control groupExercise Length

Baciuket al, 200821

From wk 20to wk 40

50 21 Aquatic aerobic exercise (no specificsgiven);

nwww.AJOG.org Obstetrics ResearchFIGURE 2Cesarean delivery

Risk ratio of cesarean delivery in exercise and costudy was found by screening of refer-ence lists.

Study characteristicsThe 16 identied studies were random-ized controlled trials that were publishedin English and included a total of 3359participants.

Three studies included only primipa-rous women. The studies including bothprimiparous and multiparous womenwere balanced, with the exception of 2.In the 2011 study of Barakat et al,17

26 primiparous women were assignedrandomly to the exercise group, and only12 women were in the control group. Inthe study by Avery et al,28 the meanparity was 1.5 in the exercise group and0.4 in the control group. In most studies,mean BMI was normal (BMI, 25 kg/m2)8,28 orobese (BMI >30 kg/m2).27,29 Despitethose differences among studies, therewere no signicant differences betweengroups for a given study. The studiesincluded mostly women without specic

Domenjoz. Physical activity reduces cesarean delivery. Am J Ob

FLA 5.2.0 Dtrol groups.conditions, except the study by Averyet al,28 in which all women had gesta-tional diabetes mellitus. The mean age ofparticipants in the studies ranged from25-32 years, except for the study byRamirez-Velez et al12 (mean, 19.5 years).

Most authors chose tomix aerobic andresistance exercise (Table 2). One study(Barakat et al14,18,19) planned trainingthat was composed exclusively of resis-tance exercise; 4 studies focused on aer-obic exercise.21-23,28,31 The training tookplace in swimming pools, in sports halls,or outdoors. The study by Barakat et al13

in 2012 mixed aquatic and land-basedactivities. Exercise sessions were super-vised by a physiotherapist or a tnessspecialist. The intervention startedduring the rst trimester in somestudies13,15-17,27 and at the end of thesecond trimester in others.21,22,24-26,31

This led to substantial differences in thenumber of weeks of intervention andin the number of hours of exercise be-tween studies. Seven of the selectedstudies planned an intervention of 50hours of exercise.8,13,15-17,21,22,31

stet Gynecol 2014.

MONTH 2014 Am

TD YMOB9730_proof 6 May 2014 6:26Most studies chose to control the in-tensity of exercise with a heart-ratemonitor and kept the heart rate at

Price et al,8 reported the percentage of

FIGURE 3Instrumental delivery

Risk ratio of cesarean delivery in exercise and control groups.

Domenjoz. Physical activity reduces cesarean delivery. Am J Obstet Gynecol 2014.

Research Obstetrics www.AJOG.orgin 3 studies each but with different criteriato dene those outcomes. Therefore,except for cesarean deliveries, it was notpossible to perform a metaanalysis ofthose outcomes because of the scarcity ofthe data that could be obtained, even aftercontact with the authors of those studies.

Few details were reported on thecontext of the decision to perform acesarean delivery. Only Kihlstrand et al25FIGURE 4Weight gain

Mean weight gain of women during pregnancy.

Domenjoz. Physical activity reduces cesarean delivery. Am J Ob

1.e8 American Journal of Obstetrics& GynecologyFLA 5.2.0 Dprimary vs repeated cesarean deliveries.

Risk of biasThe quality assessment is presented inTable 1.and Lee31 reported whether the cesareandeliveries were elective or performed inemergency. None of the studies, exceptstet Gynecol 2014.

MONTH 2014

TD YMOB9730_proof 6 May 2014 6:26All selected articles obtained 3 pointsaccording to the Jadad scale, except forthe Marquez-Sterling et al23 and Lee31

studies. Those studies provided no in-formation about blinding, allocationconcealment, and sequence generationand presented a high percentage ofloss of follow up. Ten studies reportedadequate concealment of alloca-tion.8,12,14-16,23-25,27,28 Only Baciukpm ce

et al21 and Cavalcante et al22 clearly re-ported the blinding of the obstetrician.As described in the Table 1, the propor-tion of dropout and lost to follow up was

3359 participants and reported data for3037 patients (9.7% dropout rate).

The exercise group had a signicantlylower cesarean delivery risk (relative risk[RR], 0.85; 95%CI, 0.73e0.99) comparedwith the control group (Figure 2). Therewere 14.2% cesarean deliveries in theexercise group and 17.8% in the controlgroup. The risk difference was e0.03(95% CI, e0.06 to e0.00), which gave anumber needed to treat of 33. There wasno evidence of heterogeneity (I2 0%).Separate analysis of the studies with anintervention of 50 hours8,13,15-17 showsan even greater reduction of cesareandelivery risk (RR, 0.76; 95% CI,0.58e0.99; Figure 2). Removal from theanalysis of the studies with an interven-tion of

Research Obstetrics www.AJOG.orgthe identication of a benet from ex-ercise programs on a relatively infre-quent outcome.

A limitation of our study is that,because the focus of the authors was noton the mode of delivery, details on theindications for performing the cesareandelivery or the inclusion of women witha history of cesarean delivery rarely werereported.

Only 1 study reported the blinding ofthe caregiver in charge of delivery.21,22

This lack of information concerningthe blinding of the obstetrician maybe due to the fact that the main out-comes ofmost studies were not related tothe delivery. However, this actually mayhave decreased the risk of performancebias, because the obstetrician in chargeof the delivery had no interest in modi-fying his decision to perform a cesareandelivery depending on his knowledge ofthe group allocation. We used a funnelplot to assess the risk of publication bias(Figure 5). It was symmetric, whichmade such bias unlikely.

There were differences among studiesregarding the population, the type andintensity of the intervention, compli-ance, and percentage of dropouts. Thismay increase external validity of theeffect that was observed in this review.Every woman without pregnancy com-plications may benet from physical ac-tivity, regardless of her weight, previoustness, or parity. Most studies includedwomen with habitual low levels of exer-cise. This increased the difference inexercise level between groups, at leastcomparing control subjects with thewomen who were complying with theintervention. Even the studies withrelatively few hours of exercise contrib-uted to the reduction of the cesareandelivery risk. Every pregnant womantherefore should be encouraged toperform physical activity, even inmodestamounts.

Despite heterogeneity in the design ofexercise programs, there was no signi-cant heterogeneity in the results for theoutcomes that we evaluated. We there-fore used a xed effect model for theanalysis.

Only 2 studies showed a difference

between the groups regarding parity, 1 in

1.e10 American Journal of Obstetrics& GynecoloFLA 5.2.0 Dfavor of the exercise group and 1 in favorof the control group. The number ofprimiparous women is of clinical sig-nicance because they have at least a3-fold increased risk of having a cesareandelivery compared with multiparouswomen.37 The result of our analysisremained the same when excluding these2 studies.

The nding of the inuence of struc-tured physical exercise programs on thepercentage of cesarean birth is of greatclinical signicance, given the importantcomplications of this intervention andits rising incidence.38 The ability of suchprograms to reduce the risk of cesareandelivery by almost 15% is substantial andlikely difcult to obtain by any othersingle intervention.

One may hypothesize that physicalexercise reduces birthweight, therebyreducing cesarean delivery risk. How-ever, data on this are controversial.39,40

There was a small, but not signicant,effect of the intervention on birthweightin our analysis (Figure 6), which madethis effect an unlikely explanation of thereduction of the rate of cesarean delivery.On the other hand, we observed thatwomen in the exercise group had a sig-nicant reduction in their overall weightgain. Reduction of weight gain duringpregnancy may have longer term bene-ts on womens health. This partly couldexplain the effect of physical exerciseon the cesarean delivery percentage, be-cause studies have shown that the risein cesarean delivery rates correlates withthe rise in BMI.41

It would be important to conduct largerandomized trials to evaluate structuredexercise programs, to report all laboroutcomes, and to assess any benet ofexercising during pregnancy on the otheroutcomes of labor. It is important to havesolid evidence in favor of exercise toconvince obstetricians and women of thebenet of physical exercise during preg-nancy. Currently a minority of pregnantwomen report exercising according toACOG guidelines (ie, 16% in theUnited States; 21% in Ireland, 20% inSpain).37-39 For many women, it is dif-cult to nd themotivation to start regularphysical exercise, and pregnancy could be

a decisive moment to cease sedentary

gy MONTH 2014

TD YMOB9730_proof 6 May 2014 6:26behavior if exercise is proved to bebenecial for pregnancy outcomes. It isimportant that future studies on thistopic maximize compliance of the par-ticipants, because the effect of the inter-vention depends largely on compliance.

In conclusion, this systematic reviewand metaanalysis shows that the practiceof a structured physical activity programby pregnant women decreases the risk ofcesarean deliveries by 15% and reducesmaternal weight gain on average by 1 kg.Therefore, pregnant women should beencouraged to exercise according to theACOG recommendations. -

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Effect of physical activity during pregnancy on mode of deliveryMaterials and MethodsSearch strategyEligibility criteriaData collectionRisk of biasStatistical analysis

ResultsStudy selectionStudy characteristicsRisk of biasSynthesis of results

CommentReferences