Gestational weight gain and obesity: is 20 pounds too much?

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OBSTETRICS

Gestational weight gain and obesity: is 20 pounds too much?Michelle A. Kominiarek, MD; Neil S. Seligman, MS, MD; Cara Dolin, MD; Weihua Gao, MS; Vincenzo Berghella, MD;Matthew Hoffman, MD; Judith U. Hibbard, MD

OBJECTIVE: To compare maternal and neonatal outcomes in obese gestational age infants (class I OR, 2.4; 95% CI, 1.9e2.9; class II OR,
women according to weight change and obesity class.
STUDY DESIGN: Cohort study from the Consortium on Safe Labor of20,950 obese women with a singleton, term live birth from 2002-2008. Risk for adverse outcomes was calculated by multiple logisticregression analysis for weight change categories (weight loss [<0 kg],low [0-4.9 kg], normal [5.0-9.0 kg], high weight gain [>9.0 kg])in each obesity class (I 30.0-34.9 kg/m2, II 35.0-39.9 kg/m2, and III�40 kg/m2) and by predicted probabilities with weight change as acontinuous variable.

RESULTS: Weight loss was associated with decreased cesareans forclass I women (nulliparas odds ratio [OR], 0.21; 95% confidence in-terval [CI], 0.11e0.42; multiparas OR, 0.61; 95% CI, 0.45e0.83) andincreased small for gestational age infants (class I OR, 1.8; 95% CI,1.3e2.5; class II OR, 2.2; 95% CI, 1.5e3.2; class III OR, 1.7; 95% CI,1.1e2.6). High weight gain was associated with increased large for

From the Division of Maternal-Fetal Medicine, Department of Obstetrics and GMedicine (Drs Kominiarek andHibbard), and the School of Public Health (MsGat Chicago, Chicago, IL; the Division of Maternal-Fetal Medicine, DepartmenGynecology (Dr Seligman), University of Rochester Medical Center, Rochesteof Obstetrics and Gynecology (Dr Dolin), New York University School of MedicDivision of Maternal-Fetal Medicine, Department of Obstetrics and GynecoloJefferson Medical College of Thomas Jefferson University, Philadelphia, PA;Obstetrics andGynecology (Dr Hoffman), ChristianaHospital, Newark, DE. InsConsortium are listed in the Acknowledgments.

Received Jan. 30, 2013; revised April 9, 2013; accepted April 26, 2013.

This research was supported by the Intramural Research Program of the EuNational Institute of Child Health andHumanDevelopment (NICHD), National In(MAK, MH, JH), through contract number HHSN267200603425C; by grant nfrom the NICHD and NIH Office of Research on Women’s Health (ORWH) (MUniversity of Illinois at Chicago (UIC) Center for Clinical and Translational ScieNumber UL1RR029879 from the National Center for Research Resources (W

The authors report no conflict of interest.

Presented in oral format at the Eighth Annual Interdisciplinary Women’s HeaSymposium, Bethesda, MD, Nov. 17, 2011, and (in part) in poster format atmeeting of the Society for Maternal-Fetal Medicine, Chicago, IL, Feb. 7-12, 2

Reprints not available from the authors.

0002-9378/$36.00 � ª 2013 Mosby, Inc. All rights reserved. � http://dx.doi.org/10.1

214.e1 American Journal of Obstetrics & Gynecology SEPTEMBER 2013

1.7; 95% CI, 1.3e2.1; class III OR, 1.6; 95% CI, 1.3e2.1). As weightchange increased, the predicted probability for cesareans and large forgestational age infants increased. The predicted probability of lowbirthweight never exceeded 4% for all obesity classes, but small forgestational age infants increased with decreased weight change. Thelowest average predicted probability of adverse outcomes (cesarean,postpartum hemorrhage, small for gestational age, large for gesta-tional age, neonatal care unit admission) occurred when women (classI, II, III) lost weight.

CONCLUSION: Optimal maternal and neonatal outcomes appear tooccur when weight gain is less than current Institute of Medicinerecommendations for obese women. Further study of long-term out-comes is needed with respect to gestational weight changes.

Key words: gestational weight gain, maternal, neonatal outcomes,obesity, pregnancy

Cite this article as: Kominiarek MA, Seligman NS, Dolin C, et al. Gestational weight gain and obesity: is 20 pounds too much? Am J Obstet Gynecol 2013;209:214.e1-11.

besity has reached epidemic pro-
O portions, estimated at 35.7% foradults in the United States.1 The preva-lence of obese reproductive age women(20-39 years) increased by 64% between
1988-1994 and 2007-2008, accountingfor the greatest increase in obesity forwomen of any age category.2 The obesityepidemic and its associated obstetric andneonatal complications has highlighted

ynecology, College ofao), University of Illinoist of Obstetrics andr, and the Departmentine, New York, NY; thegy (Dr Berghella),and the Department oftitutions involved in the

nice Kennedy Shriverstitutes of Health (NIH)umber K12HD055892AK); and by thence (CCTS), AwardG).

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016/j.ajog.2013.04.035

the issue of gestational weight gain(GWG). Regardless of maternal weightstatus, high GWG has been associatedwith both maternal (eg, cesarean de-liveries, long-termweight retention) andoffspring risks (eg, larger infants, child-hood obesity).3-8 Although the evidenceis less consistent, an association betweenhigher GWG and gestational diabetesand preeclampsia has also been re-ported.9-12 On the other hand, lowGWGand weight loss have also been associatedwith maternal ketonemia and fetalgrowth restriction.13

According to conventional wisdom,pregnancy is a time for weight gain, notfor dieting or weight loss. Typically, anadditional 300 calories per day is rec-ommended for appropriate fetal growthand this was reflected in the 1990 Insti-tute of Medicine report on NutritionDuring Pregnancy.14 More recently, in2009, the Institute of Medicine pub-lished revised guidelines for GWG.Important updates included a range of5e9 kg (or 11-20 lbs) for GWG in obesewomen, defined by a prepregnancybody mass index (BMI)�30 kg/m2. This

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FIGURE 1Flow diagram for participant selection

BMI, body mass index.

Kominiarek. Weight gain obesity. Am J Obstet Gynecol 2013.

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differed from the prior recommenda-tion of “at least 15 pounds.”13 Notably,all obese women, were grouped into 1category as a result of insufficient datafrom women in individual obesity clas-ses (ie, obesity classes I-III) and theinability to draw statistically soundconclusions for GWG for the separateobesity classes. Behavioral interventionsfor women who are obese at conceptionhave shown some success at meetingGWG recommendations,15 but limitedevidence suggests that lower GWG orweight loss (ie, gestational weightchange) in this population may improvematernal and neonatal outcomes.12,16,17

Given the nationwide rise in obesity aswell as the influence of GWG onmaternal and neonatal outcomes, wehypothesized that the current recom-mendations (up to a 20 pound weightgain) were too high for obese womenand required closer scrutiny into eachof the obesity classes. The objectiveof our investigation was to evaluatematernal and neonatal outcomes atbirth in obese women by weight changeand BMI class.

MATERIALS AND METHODS

The Consortium on Safe Labor is aretrospective, observational, electronicdatabase acquired from 12 institutions(19 hospitals) across 9 American Collegeof Obstetricians and Gynecologists(ACOG) districts in the United States.The complete database contains 233,730births resulting from 228,562 deliveries.Although the data were collected from2002 to 2008, 87% of the births in thedatabase occurred between 2005 and2007. Extensive data were collected oneach delivery including demographics,prenatal complications, labor and de-livery information, and maternal andneonatal outcomes. Validation studieson 4 outcomes (shoulder dystocia, ce-sarean delivery for nonreassuring fetalheart rate, neonatal intensive care unit[NICU] admission for respiratory con-ditions, and neonatal asphyxia) wereperformed by hand-abstraction of el-igible charts. Most variables reviewedwere highly accurate when comparingdata from the electronic database andthe hand-abstraction. Further detailregarding the database is available.18,19

SEPTEMBER 2013 Ameri

Inclusion criteria for the current studywere a prepregnancy BMI �30 kg/m2

and known gestational weight change ina singleton, term (�37.0 weeks), live-born gestation. If a woman contributedmore than 1 pregnancy to the database,only the first pregnancy was analyzed tomaintain the independence of the ob-servations. Class I-III obesity was definedaccording to the World Health Organi-zation (WHO) criteria as class I 30.0-34.9 kg/m2, class II 35.0-39.9 kg/m2, andclass III�40 kg/m2.20Weight change wasdefined as the difference between theself-reported prepregnancy weight anddelivery weight. The weight changecategories were defined as weight loss,low (0-4.9 kg), normal (5.0-9.0 kg), andhigh (> 9.0 kg). The weight change cat-egories were chosen for their simplicity,ease of clinical use, and were alsomodeled after those of another investi-gation.21 Although the range of gesta-tional weight change was�55 kg to 77 kgin the current cohort, this range wasrestricted to �20 kg to 50 kg to reflect amore clinically plausible value, alsosimilar to the range chosen in anotherstudy.22 In doing so, only 70 women or0.3% of the cohort was excluded.

Maternal demographics and charac-teristics included age, race/ethnicity,marital status, insurance, parity, smokingstatus, prior cesarean delivery, pregesta-tional diabetes, chronic hypertension,and gestational age at delivery. The pri-mary maternal outcomes were operativevaginal delivery, cesarean delivery, andpostpartum hemorrhage. The primaryneonatal outcomes were birthweight,shoulder dystocia, 5 minute Apgar score<7, and NICU admission. Small andlarge for gestational age infants (SGA,LGA) were defined by birthweights<10th% or>90th%, respectively, for thegestational age at birth.23 Low birth-weight (LBW) and macrosomia weredefined by birthweights <2500 g or>4500 g, respectively.

All analyses were stratified by obesityclass (I, II, III). For the maternal de-mographics and characteristics, Pearsonc2, and analysis of variance tests wereused to statistically compare the asso-ciation between categorical and con-tinuous variables, respectively, and

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TABLE 1Maternal demographics and characteristics by weight change categories

Variablen (%) or mean (SD)

Weight change categoriesa

P valueLossn [ 1182

Lown [ 3028

Normaln [ 3613

Highn [ 13,127

Age, y 28.1 � 5.7 28.8 � 5.7 28.7 � 5.8 27.7 � 5.9 < .001b

Race/Ethnicity < .001c

Non-Hispanic white 555 (48.3) 1419 (48.38) 1582 (44.9) 5710 (44.8)

Non-Hispanic black 405 (35.2) 848 (28.9) 988 (28.0) 3943 (30.9)

Hispanic 161 (14.0) 556 (18.9)‘ 826 (23.4) 2555 (20.0)

Other 28 (2.4) 114 (3.9) 128 (3.6) 544 (4.3)

Insurance < .001c

Private 576 (48.7) 1597 (52.7) 1798 (49.8) 6412 (48.8)

Public 540 (45.7) 1167 (38.5) 1416 (39.2) 5288 (40.3)

Other 66 (5.6) 264 (8.7) 399 (11.0) 1427 (10.9)

Married 637 (53.9) 1808 (59.7) 2124 (58.9) 7011 (53.4) < .001c

Parity < .001c

0 305 (25.8) 743 (24.5) 983 (27.2) 4908 (37.4)

�1 877 (74.2) 2285 (75.5) 2630 (72.8) 8219 (62.6)

Smoker 138 (11.7) 248 (8.2) 259 (7.2) 1025 (7.8) < .001c

Prior cesarean 232 (21.0) 641 (22.6) 826 (24.2) 2552 (20.4) < .001c

Pregestational diabetes 59 (5.4) 143 (5.0) 153 (4.6) 505 (4.1) .05c

Chronic hypertension 69 (6.7) 173 (6.6) 210 (6.6) 872 (7.6) .11c

Weight change, kg �5.0 � 4.4 2.8 � 1.6 7.1 � 1.1 16.0 � 5.8 < .001b

Gestational age at delivery, wks 39.1 � 1.1 39.1 � 1.1 39.1 � 1.1 39.2 � 1.1 < .001b

SD, standard deviation.

a Weight loss (<0 kg), low (0-4.9 kg weight gain), normal (5.0-9.0 kg weight gain), and high (>9.0 kg weight gain); b Analysis of variance; c c2.


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weight change category. A P value < .05was considered statistically significant.Through multiple logistic regressionanalysis, adjusted odds ratios (aORs)with 95% confidence intervals (CIs) weregenerated for eachmaternal and neonataloutcome in each of the weight changecategories, using 5.0-9.0 kg as thereferent, for each obesity class andadjusting for age, race/ethnicity, maritalstatus, insurance, parity, smoking, andgestational age. To clarify the potentialmaternal and neonatal risks and benefitsof weight change, logistic regressionmodels were created with weight changeas a continuous variable (kg) for eachBMI class. The estimated logistic regres-sion coefficients then determined thepredicted probabilities for each of the

214.e3 American Journal of Obstetrics & Gynecol

maternal and neonatal outcomes, similarto the analysis approach of anotherstudy.24 The average predicted probabil-ity of 5 outcomes (cesarean, postpartumhemorrhage, SGA, LGA, and NICU) wasthen calculated over a weight changeof �20 kg to þ50 kg. These outcomeswere chosen for their clinical relevance orthe apparent association between gesta-tional weight change in the logisticregression models and the individualpredicted probabilities. Given that eachof these 5 outcomes increased withincreased weight change except for SGA,we performed a sensitivity analysisweighting SGA (2-5 times) to determinehow varying the importance of thisoutcome would influence the averagepredicted probability.

ogy SEPTEMBER 2013

To further determine the potentialimmediate neonatal risk associated witheither weight loss or low GWG, weanalyzed neonatal outcomes for SGAinfants born to women with weight lossor low (0-4.9 kg) weight gain andcompared them with SGA infants bornto women with normal (5.0-9.0 kg)weight gain using c2 or Fisher exact tests.The following neonatal outcomes werereported for this analysis: respiratorydistress syndrome (RDS), transienttachypnea of the newborn (TTN), use ofventilators, oxygen or CPAP (continuouspositive airway pressure), pneumonia,meconium aspiration, anemia, sepsis,asphyxia, congenital anomalies, NICUadmission, and death. All statistical an-alyses were performed with SAS software

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TABLE 2Maternal outcomes for each obesity class by weight change categories

Variable


Loss Low Normal High

Operative vaginal delivery

Class I n (%) 24 (6.2) 62 (4.6) 80 (4.1) 460 (5.5)

aOR (95% CI) 1.5 (0.93e2.5) 1.1 (0.80e1.6) 1 1.3 (0.98e1.6)

Class II n (%) 16 (4.6) 43 (4.7) 41 (4.0) 133 (4.4)

aOR (95% CI) 1.2 (0.64e2.2) 1.1 (0.68e1.7) 1 1.0 (0.70e1.4)

Class III n (%) 18 (4.0) 37 (4.9) 27 (4.1) 82 (4.6)

aOR (95% CI) 0.97 (0.52e1.8) 1.2 (0.69e1.9) 1 1.1 (0.73e1.8)

Nulliparas cesarean delivery

Class I n (%) 15 (14.7) 111 (34.6) 195 (37.7) 1279 (41.8)

aOR (95% CI) 0.21 (0.11e0.42) 0.85 (0.62e1.2) 1 1.2 (1.0e1.5)

Class II n (%) 30 (34.9) 90 (41.7) 115 (39.4) 565 (48.2)

aOR (95% CI) 0.81 (0.48e1.4) 1.1 (0.74e1.6) 1 1.5 (1.1e2.0)

Class III n (%) 58 (43.9) 105 (51.0) 79 (45.4) 401 (58.6)

aOR (95% CI) 0.79 (0.49e1.3) 1.1 (0.71e1.7) 1 1.7 (1.2e2.4)

Multiparas cesarean delivery

Class I n (%) 64 (21.6) 292 (28.1) 425 (30.1) 1816 (34.5)

aOR (95% CI) 0.61 (0.44e0.83) 0.88 (0.74e1.1) 1 1.3 (1.1e1.4)

Class II n (%) 86 (32.0) 237 (33.8) 277 (38.1) 754 (40.6)

aOR (95% CI) 0.82 (0.60e1.1) 0.82 (0.66e1.0) 1 1.1 (0.93e1.3)

Class III n (%) 144 (41.0) 222 (40.7) 233 (47.5) 562 (50.5)

aOR (95% CI) 0.76 (0.56e1.0) 0.77 (0.59e.99) 1 1.1 (0.94e1.5)

Postpartum hemorrhage

Class I n (%) 4 (1.5) 25 (2.7) 38 (2.7) 185 (3.1)

aOR (95% CI) 0.55 (0.19e1.6) 0.96 (0.57e1.6) 1 1.1 (0.75e1.5)

Class II n (%) 6 (2.6) 20 (3.2) 33 (4.5) 81 (3.7)

aOR (95% CI) 0.54 (0.22e1.3) 0.67 (0.38e1.2) 1 0.74 (0.49e1.1)

Class III n (%) 15 (4.5) 20 (3.8) 19 (3.8) 90 (6.6)

aOR (95% CI) 1.1 (0.55e2.2) 0.94 (0.49e1.8) 1 1.6 (0.97e2.7)

aOR, adjusted odds ratio after controlling for age, race/ethnicity, marital status, insurance, parity, smoking, and gestational age; CI, confidence interval.

a Weight loss (<0 kg), low (0-4.9 kg weight gain), normal (5.0-9.0 kg weight gain, referent), and high (>9.0 kg weight gain).



(version 9.2; SAS Institute, Cary, NC)using primarily LOGSTIC and GLMprocedures. Appropriate institutionalreview board approval was obtainedfrom all the participating institutions.

RESULTS

From the 228,562 deliveries in the entiredatabase, 20,950 obese women (11,984class I, 5307 class II, and 3659 class III)

were studied (Figure 1). Of the 57 still-births, which were excluded from theremainder of the analysis, 70% occurredin those with high weight gain andnone occurred in those who lost weight.There were differences among theweight change categories with respect toage, race/ethnicity, marital status, in-surance, parity, smoking, and prior ce-sarean, P � .001 (Table 1). This analysis


was stratified by obesity class and thedifferences in the comparisons persist-ed for each obesity class, P < .02 (datanot shown). The mean (� SD) GWGwas 12.5 � 7.6 kg class I, 10.6 � 8.1 kgclass II, and 8.9 � 8.9 kg class III, P <.001. Weight loss was most common inclass III (12%) and high weight gainwas most common in class I women(69%). For women who lost weight, the


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TABLE 3Neonatal outcomes for each obesity class by weight change categories

Variable



SGA infants

Class I n (%) 66 (17.3) 135 (10.0) 187 (9.7) 549 (6.6)

aOR (95% CI) 1.8 (1.3e2.5) 1.0 (0.82e1.3) 1 0.60 (0.50e0.72)

Class II n (%) 57 (16.6) 100 (10.9) 85 (8.4) 193 (6.4)

aOR (95% CI) 2.2 (1.5e3.2) 1.4 (1.0e1.9) 1 0.66 (0.51e0.87)

Class III n (%) 57 (12.8) 72 (9.6) 51 (7.7) 119 (6.7)

aOR (95% CI) 1.7 (1.1e2.6) 1.4 (0.93e2.0) 1 0.73 (0.51e1.0)

LGA infants

Class I n (%) 13 (3.4) 76 (5.6) 119 (6.2) 1029 (12.5)

aOR (95% CI) 0.59 (0.33e1.1) 0.92 (0.68e1.2) 1 2.4 (1.9e2.9)

Class II n (%) 17 (5.0) 67 (7.3) 101 (9.9) 435 (14.5)

aOR (95% CI) 0.51 (0.30e0.86) 0.71 (0.51e0.98) 1 1.7 (1.3e2.1)

Class III n (%) 31 (6.9) 77 (10.3) 85 (12.8) 315 (17.7)

aOR (95% CI) 0.48 (0.31e0.75) 0.76 (0.54e1.1) 1 1.6 (1.3e2.1)

LBW

Class I n (%) 17 (4.4) 28 (2.1) 46 (2.4) 133 (1.6)

aOR (95% CI) 1.6 (0.85e3.0) 0.90 (0.55e1.5) 1 0.65 (0.46e0.94)

Class II n (%) 15 (4.4) 22 (2.4) 19 (1.8) 61 (2.1)

aOR (95% CI) 2.4 (1.1e4.9) 1.3 (0.69e2.5) 1 1.0 (0.59e1.7)

Class III n (%) 9 (2.0) 16 (2.1) 12 (1.8) 33 (1.9)

aOR (95% CI) 1.1 (0.45e2.8) 1.3 (0.60e3.0) 1 0.91 (0.45e1.9)

Macrosomia

Class I n (%) 2 (0.52) 7 (0.52) 15 (0.78) 191 (2.3)

aOR (95% CI) 0.83 (0.19e3.6) 0.73 (0.30e1.8) 1 3.1 (1.9e5.4)

Class II n (%) 1 (0.29) 8 (0.88) 13 (1.3) 87 (2.9)

aOR (95% CI) 0.24 (0.03e1.9) 0.66 (0.27e1.6) 1 2.4 (1.3e4.4)

Class III n (%) 7 (1.6) 11 (1.5) 19 (2.9) 66 (3.7)

aOR (95% CI) 0.58 (0.24e1.4) 0.51 (0.24e1.1) 1 1.5 (0.86e2.5)

Shoulder dystocia

Class I n (%) 1 (0.28) 13 (1.0) 32 (1.8) 156 (2.0)

aOR (95% CI) 0.16 (0.02e1.2) 0.60 (0.31e1.1) 1 1.1 (0.76e1.7)

Class II n (%) 3 (0.93) 17 (2.0) 15 (1.6) 43 (1.5)

aOR (95% CI) 0.58 (0.17e2.0) 1.3 (0.64e2.6) 1 0.91 (0.50e1.7)

Class III n (%) 6 (1.5) 6 (0.9) 8 (1.3) 30 (1.8)

aOR (95% CI) 1.1 (0.37e3.2) 0.69 (0.24e2.0) 1 1.4 (0.63e3.1)

5 min Apgar <7

Class I n (%) 2 (0.52) 5 (0.37) 16 (0.83) 78 (0.94)

aOR (95% CI) 0.56 (0.13e2.4) 0.43 (0.16e1.2) 1 0.98 (0.57e1.7)

Kominiarek. Weight gain obesity. Am J Obstet Gynecol 2013. (continued)



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TABLE 3Neonatal outcomes for each obesity class by weight change categories (continued)

Variable



Class II n (%) 3 (0.87) 8 (0.87) 9 (0.89) 28 (0.93)

aOR (95% CI) 1.0 (0.28e3.9) 1.0 (0.40e2.7) 1 0.96 (0.45e2.1)

Class III n (%) 4 (0.89) 3 (0.40) 6 (0.90) 23 (1.3)

aOR (95% CI) 0.91 (0.26e3.3) 0.15 (0.02e1.2) 1 1.3 (0.52e3.2)

NICU admission

Class I n (%) 33 (8.5) 79 (5.8) 146 (7.6) 715 (8.6)

aOR (95% CI) 1.1 (0.72e1.6) 0.75 (0.56e1.0) 1 1.1 (0.92e1.3)

Class II n (%) 28 (8.1) 92 (10.0) 81 (8.0) 307 (10.1)

aOR (95% CI) 1.0 (0.64e1.6) 1.3 (0.92e1.7) 1 1.3 (0.99e1.7)

Class III n (%) 51 (10.8) 57 (7.7) 83 (12.8) 196 (11.0)

aOR (95% CI) 0.83 (0.57e1.2) 0.56 (0.39e0.80) 1 0.85 (0.64e1.1)

aOR, adjusted odds ratio after controlling for age, race/ethnicity, marital status, insurance, parity, smoking, and gestational age; CI, confidence interval; LBW, low birthweight; LGA, large forgestational age; NICU, neonatal intensive care unit; SGA, small for gestational age.

a Weight loss (<0 kg), low (0-4.9 kg weight gain), normal (5.0-9.0 kg weight gain, referent), and high (>9.0 kg weight gain).



mean (� SD) weight loss was �4.8 �4.5 kg,�4.6� 4.3 kg, and�5.6� 4.2 kgfor class I, II, and III, respectively. Theproportion of women gaining within the2009 Institute of Medicine recom-mended guidelines (5-9 kg) was 17% forall obesity classes.

The aORs for the maternal andneonatal outcomes from the multiple

FIGURE 2Predicted probabilities of maternal o

A, Class I obese women (BMI 30.0-34.9 kg/m2), BBMI, body mass index.


logistic regression analysis are pre-sented in Tables 2 and 3, respectively.Cesareans decreased for class I womenwho lost weight, but increased inwomen with high weight gain in mostBMI classes, compared with normalweight gain. Operative vaginal deliveryand postpartum hemorrhage did notdiffer from normal weight gain in all

utcomes

, Class II obese women (BMI 35.0-39.9 kg/m2), an


obesity classes. SGA infants increasedfor women in all obesity classes wholost weight, whereas LGA and macro-somia increased with high weight gainin most obesity classes, compared withnormal weight gain. Shoulder dystociaand 5 minute Apgar <7 did not differfrom normal weight gain in all obesityclasses.

d C, Class III obese women (BMI �40.0 kg/m2).


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FIGURE 3Predicted probabilities of neonatal outcomes

A, Class I obese women (BMI 30.0-34.9 kg/m2), B, Class II obese women (BMI 35.0-39.9 kg/m2), and C, Class III obese women (BMI �40.0 kg/m2).

BMI, body mass index; LGA, large for gestational age; NICU, neonatal intensive care unit; SGA, small for gestational age.


FIGURE 4Average predicted probability of 5 outcomes for each obesity class

Cesarean delivery, postpartum hemorrhage, SGA, LGA, and NICU admission for Class I obese women

(BMI 30.0-34.9 kg/m2), Class II obese women (BMI 35.0-39.9 kg/m2), and Class III obese women

(BMI �40.0 kg/m2).

BMI, body mass index; LGA, large for gestational age; NICU, neonatal intensive care unit; SGA, small for gestational age.



The predicted probability of cesareanincreased linearly as weight changeincreased for all obesity classes, whereasoperative vaginal delivery and postpartumhemorrhage did not vary significantlywith weight change (Figure 2, A-C). Thepredicted probabilities of SGA decreasedas weight change increased, whereasLGA and macrosomia increased expo-nentially with increased weight change.Shoulder dystocia, 5 minute Apgar <7,and NICU admissions showed a lesspronounced increase as weight changeincreased for all obesity classes (Figure 3,A-C). The predicted probability of LBWwas always <4% for all the obesity clas-ses. The average predicted probability of5 maternal and neonatal outcomes(Figure 4) shows that the lowest proba-bility of these outcomes occurred atweight loss in all obesity classes. In thesensitivity analysis of varying weights forSGA, weight gain was associated with thelowest average predicted probability onlywhen SGAwas weighted 4 times for classI (lowest predicted probability of 10.6%at 5.0 kg), 3 times for class II (lowestpredicted probability of 12.4% at 4.5 kg),and 5 times for class III (lowest predictedprobability of 13.1% at 2.9 kg) obesewomen (Figure 5).

There were no differences in neonataloutcomes for SGA infants born towomen with either low weight gain orweight loss for each BMI class compared


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FIGURE 5Average predicted probabilities ofmaternal and neonatal outcomes

Cesarean delivery, postpartum hemorrhage,

SGA, LGA, and NICU admission for A, Class I

obese women (BMI 30.0-34.9 kg/m2), B, Class

II obese women (BMI 35.0-39.9 kg/m2), and C,

Class III Obese women (BMI �40.0 kg/m2) with

weighting of SGA.

BMI, body mass index; LGA, large for gestational age; NICU,neonatal intensive care unit; SGA, small for gestational age.



with those with normal weight gain,P � .05 (Table 4). The occurrence ofthese outcomes was rare and the num-bers were too small to perform statisticalanalysis within each obesity class, socomparisons were reported for all obe-sity classes combined.

COMMENT

In our investigation of 20,950 obesewomen, several maternal and neonataloutcomes improved for obese womenwho lost weight during pregnancy, withup to 77% reduction in cesarean de-liveries and up to 52% reduction in LGAinfants compared with women whogained 5-9 kg. However, a prepregnancyBMI �30 kg/m2 does not appear toprotect these women from having a SGAinfant given that the odds for a SGA in-fant nearly doubled in all women wholost weight. It is noteworthy that lowweight gain was not associated with SGAin obese women. Our data also confirmthe risks of high GWG in obese women(eg, increased cesareans, LGA infants,macrosomia).12,21,24-26 Based on theaverage predicted probabilities, imme-diate adverse outcomes are lowest whenweight loss occurs for all obesity classes,with the effect most pronounced forclass III women.According to the sensitivity analysis

which weighted SGA differently, SGAwould need to be weighted 3-5 times inthe predicted probability models tomake any weight gain better than weightloss when evaluating the outcomes ofcesarean delivery, postpartum hemor-rhage, SGA, LGA, and NICU admissionin obese women. The analysis of weightchange as a categorical and continuousvariable in a large heterogeneous popu-lation from the United States is unique inderiving these findings.This information is timely with the

Institute ofMedicine’s shift in focus frompreventing LBW (1990 Nutrition DuringPregnancy) to addressing contemporaryissues related to perinatal outcomes inthe United States such as increasedmaternal age, complications duringpregnancy, racial diversity, the globalincrease in BMI, and very importantly,increased GWG (2009 Reexamining theGuidelines).13,14 However, our data


suggest that the existing guidelinesshould be further refined for obesewomen. Since the publication of the2009 IOM guidelines, several studieshave also suggested that obese womenand their neonates may benefit fromlimiting weight gain21,24-27 or even losingweight21,23,24,26 during pregnancy. In onestudy, a weight loss of 0.19 kg/week wasassociated with the lowest predictedoccurrence of adverse maternal andneonatal outcomes (preterm delivery,SGA, LGA, childhood obesity, maternallong-term weight retention) for obesewomen, which translates to a weight lossof 7.6 kg at term for obese women.27

Beyerlein et al22 noted that optimalneonatal outcomes (eg, SGA, LGA)occurred with aweight loss of up to 15 kgin obese women. Similar to our study,Blomberg showed a 23-44% decrease incesareans for obese women who lostweight during pregnancy.21 Given thatthe cesarean delivery rate reached an all-time high of 32.9% in 200928 and obesewomen are at very high risk for cesareandelivery,29 the public health implicationsof reducing GWG may include curbingthe cesarean delivery rate in obesewomen.

Because lower GWG may result inlower birthweights (eg, LBWor SGA), itis important to balance the maternalbenefits with neonatal risks especially ifthe etiology for the lower birthweightcould be attributed to nutritional depri-vation or metabolic changes in utero.One investigation reported only 4% SGAinfants in women with a BMI>35 kg/m2

who either lost weight or did not gainweight during pregnancy.30 Further-more, Lapolla et al reported no differ-ences in the number of SGA infants whencomparing pregnancies after bariatricsurgery to either obese women withoutbariatric surgery or normal weightwomen. This was also true in a group ofwomen who lost weight during thepregnancy after bariatric surgery e0%SGA in the weight loss group comparedwith 2.9% in the group gaining 0-10 kg.31

In a randomized clinical trial of abalanced nutritional regimen (eg, nutri-tional counseling, food diaries) for 232obese women, 57 women in the inter-vention arm who gained <10 pounds


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TABLE 4Neonatal outcomes in small for gestational age infants with <5.0 kg gestational weight gain

Variable, n (%)

<5.0 kg weight gain 5.0-9.0 kg weight gain

P valuea

30-34.9 kg/m2

Class In [ 201

35.0-39.9 kg/m2

Class IIn [ 157

‡40.0 kg/m2

Class IIIn [ 129

All obesityclassesn [ 487

All obesityclassesn [ 323

RDS 2 (1.0) 3 (1.9) 0 5 (1.0) 4 (1.2) .74

TTN 4 (2.0) 6 (3.1) 2 (1.5) 12 (2.5) 14 (4.3) .14

Ventilator use 2 (1.0) 4 (2.7) 1 (0.77) 7 (1.4) 2 (0.62) .33

Oxygen use 11 (5.5) 9 (5.8) 1 (0.78) 21 (4.3) 12 (3.8) .72

CPAP use 4 (2.0) 2 (1.3) 1 (0.78) 7 (1.5) 3 (0.95) .75

Pneumonia 2 (1.0) 2 (1.3) 0 4 (0.82) 0 .16

Meconium aspiration 4 (2.0) 2 (1.3) 2 (1.6) 8 (1.6) 3 (0.93) .54

Composite respiratory morbidityb 13 (6.5) 14 (8.9) 5 (3.9) 32 (6.6) 24 (7.4) .64

Anemia 3 (1.5) 2 (1.3) 1 (0.78) 6 (1.2) 4 (1.2) .99

Sepsis 2 (1.0) 4 (2.6) 3 (2.3) 9 (1.8) 6 (1.9) .99

Asphyxia 1 (0.5) 2 (1.3) 0 3 (0.62) 2 (0.62) .99

Congenital anomaly 16 (8.0) 6 (3.8) 7 (5.4) 29 (6.0) 22 (6.8) .62

NICU admission 19 (9.4) 21 (13.4) 7 (5.4) 47 (9.6) 37 (11.5) .41

Death before discharge 1 (0.57) 0 0 1 (0.24) 2 (0.77) .56

CPAP, continuous positive airway pressure; NICU, neonatal intensive care unit; RDS, respiratory distress syndrome; TTN, transient tachypnea of the newborn.

a Comparisons (either c2 or Fisher exact test) are between <5.0 kg (n ¼ 487) gestational weight gain vs 5.0-9.0 kg (n ¼ 323) gestational weight change for all obesity classes combined;b Composite respiratory morbidity was calculated as an occurrence of any respiratory morbidity (respiratory distress syndrome, transient tachypnea of the newborn, ventilator use, oxygen use,CPAP use, pneumonia, and/or meconium aspiration) per neonate.



during pregnancy had fewer occurrencesof gestational diabetes (5.3% vs 15.4%,P < .05) and similar mean birthweights(3437 � 475 vs 3594 � 612 g, P ¼ .06)compared with the control group.17

Maternal and neonatal outcomes werenot reported separately for the 23 womenwho lost weight during the pregnancy.Our data, as well as others, suggest thatimmediate neonatal outcomes are notadversely affected with lower weightgains or a small amount of weight loss.

We recognize several limitations to thestudy. Our database did not contain in-formation about the circumstances ofthe weight loss (eg, intentional, a resultof a pregnancy complication, or severematernal illness) or data about the long-term physical or neurocognitive devel-opment of infants after discharge fromthe hospital. We have documented thatstillbirths were absent in obese womenwho lost weight and that other neonatalmorbidities and mortality were rare in

214.e9 American Journal of Obstetrics & Gynecol

SGA infants of women with low weightgain or weight loss (Table 4). If lowGWG or weight loss were to increase therisk for future complications (eg, adultchronic diseases such as hypertension ordiabetes in the offspring), these conse-quences would impact GWG guidelinesas well; however, data on these types oflong-term outcomes are not currentlyavailable. Further study of long-termoutcomes including childhood and ad-olescent obesity in offspring of obesewomen with low GWG or weight loss(and its quantity) during pregnancy, isneeded.This database uses self-reported

weight, which is more likely to be inac-curate in women with higher BMIswho might underestimate prepregnancyweight resulting in information biasincluding underrepresentation of womenwho lost weight and overreporting ofwomen with high weight gains.32 Giventhe number of women missing either

ogy SEPTEMBER 2013

prepregnancy weight or height data(Figure 1), we performed a sensitivityanalysis that compared maternal de-mographics and characteristics betweenthose with a missing and nonmissingBMI. There were no significant differ-ences between age, parity, smoking, priorcesarean, pregestational diabetes, chronichypertension, or weight change betweenthese 2 groups. However, nonHispanicblacks had the most missing BMIs (39%)compared with nonHispanic whites(30%) and Hispanics (27%), P < .001.Because the prevalence of obesity ishighest in nonHispanic black women,12

we may have introduced bias in ex-cluding women with a missing BMI.However, there was no systematic expla-nation for the missing data (eg, not spe-cific to a single site). The pregnancies inthis retrospective observational databasealso occurred before the publication of2009 Institute of Medicine guidelines.As such, obese women may have been

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counseled to gain weight according to theprevious guidelines (ie, “at least 15pounds”). Furthermore, we were notable to ascertain prenatal care contentincluding nutritional counseling andwhether women were advised on weightgain goals. We also restricted the analysisto full-term, singleton live births, sothe results may not be applicable to allpregnancies. Because of reverse causality,preeclampsia and gestational diabeteswere not studied as outcomes as only atotal GWG instead of a weight gain at thetime of the diagnosis of the outcome wasavailable in our database.14 Finally, thestudy may have been underpoweredto detect differences in several of thematernal and neonatal outcomes such aspostpartum hemorrhage, should dys-tocia, and 5 minute Apgar <7.

Obesity in pregnancy is an importantpublic health issue. We recognize thedifficulty in recommending a lowerweight gain or even weight loss in aculture where weight gain is expectedand considered to be “healthy” in preg-nancy. Furthermore, there may be risksto weight loss in pregnancy. Basedon the 2009 IOM guidelines, 63% ofobese women would have exceeded thecurrent weight gain recommendations(>9 kg), consistent with other reports(59-64%),26,33 highlighting the ur-gency of interventions that are not onlyeffective, but feasible in modifyingweight change. Based on this obser-vational data, future research shoulddevelop interventions that assist obesewomen in reaching weight goalsthrough a combination of behavioralchanges, diet monitoring with propernutritional counseling, and physical ac-tivity and then ultimately determinewhether the interventions improvematernal and neonatal outcomes in arandomized controlled trial. This typeof research could address many unre-solved issues including the lower limit ofgestational weight change for each of theobesity classes, the influence of weightchange on outcomes specific to preg-nancy such as gestational diabetes andpreeclampsia, and the long-term impli-cations for the offspring of obesewomen who lose weight during preg-nancy. Future research should also

evaluate weight change and perinataloutcomes among women in the highestobesity class (�40 kg/m2). -

ACKNOWLEDGMENTS

Institutions involved in the Consortium include, inalphabetical order: Baystate Medical Center,Springfield, MA; Cedars-Sinai Medical CenterBurnesAllenResearchCenter, LosAngeles, CA;Christiana Care Health System, Newark, DE;Georgetown University Hospital, MedStarHealth, Washington, DC; Indiana UniversityClarian Health, Indianapolis, IN; IntermountainHealthcare and the University of Utah, Salt LakeCity, UT; Maimonides Medical Center, Brooklyn,NY; MetroHealth Medical Center, Case WesternUniversity, Cleveland, OH; Summa HealthSystem, Akron City Hospital, Akron, OH; TheEMMES Corporation, Rockville, MD (DataCoordinating Center); University of Illinois atChicago, Chicago, IL; University of Miami,Miami, FL; and University of Texas HealthScience Center at Houston, Houston, TX.

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Gestational weight gain and obesity: is 20 pounds too much?