Butte o&p2013

GUIDELINES FOR GESTATIONAL WEIGHT GAIN IN THE OBESE

Nancy F. Butte, PhD

OBESITY AND GESTATIONAL WEIGHT GAIN (GWG)• Obesity among reproductive-aged women (20-39 y) in the US

(Flegal, 2012)

Overweight BMI≥25 50.7% Class II BMI≥35 17.2%

Class I BMI≥30 31.9% Class III BMI≥40 4.3%

• Obese women at increased risk for congenital anomalies, stillbirths, miscarriage, GDM, hypertension, preeclampsia, complications L&D, macrosomia

• Majority of obese women gain weight outside guidelines

• Low and high GWG in obese women associated with substantial risks for mother and her child

• Intentional or unintentional weight loss in some pregnant obese women, yet benefits/risks uncertain

PREVALENCE OF OVERWEIGHT, OBESITY AND EXTREME OBESITY AMONG WOMEN20-39 Y, US 1963-2004

RISKS ASSOCIATED WITH LOW AND HIGH GWG IN OBESE

Low GWG

Infant RisksPreterm birthLow birth weight /SGAFetal distress

High GWG

Maternal Risks PreeclampsiaGestational diabetesC-sectionPostpartum weight retentionAbdominal adiposity Insulin resistanceDepression

Infant RisksHigh birth weight /LGAFetal distressOverweight later childhood

WEIGHT GAIN DURING PREGNANCY REEXAMINING THE GUIDELINES

Institute of Medicine andNational Research Council, 2009 National Academy of Sciences

STUDY OBJECTIVES

Review evidence on the relationship between weight gain patterns before, during and after pregnancy and maternal and child health outcomes

Recommend revisions to the existing guidelines, where necessary, including the need for specific pregnancy weight guidelines for underweight, normal weight, and overweight and obese women and adolescents and women carrying twins or higher-order multiples

Consider a range of approaches to promote appropriate weight gain

Identify gaps in knowledge and recommend research priorities

50% 59% 73% 70%

DISTRIBUTION OF GWG RELATIVE TO 1990 GUIDELINES BY PREPREGNANCY BMI CATEGORY (PRAMS, 2002-3)

Outside Guidelines:

THEORETICAL COMPONENTS OF GWG

Component Increase at term (kg)

Fetus 3.40 (2.5 – 5.0)

Placenta 0.65

Amniotic fluid 0.80

Maternal tissue (uterus, mammary glands) 1.38

Blood (plasma and red cell volume) 1.45

Maternal stores (fat) 3.35 (loss – gain)

Extracellular extravascular fluid 1.48 (with edema, 4.7)

TOTAL 12.5

Hytten and Chamberlain (1991)

MATERNAL OUTCOMES OF GWGOutcome category Evidence rating

Antepartum outcomes

Maternal discomforts of pregnancy, hyperemesis, abnormal glucose metabolism, hypertensive disorders, gallstones

Weak

Intrapartum outcomes

PROM, preterm labor, post-term pregnancy, induction of labor, length of labor, mode of delivery, VBAC, vaginal lacerations, shoulder dystocia, cephalopelvic disproportion, labor/delivery complications

Weak (except moderate for cesarean delivery)

Postpartum outcomes

Lactation, fat accrual, short-, intermediate- and long-term weight retention, interpregnancy weight retention, premenopausal breast cancer

Weak or no evidence (except moderate for intermediate-term weight retention)

Viswanathan M, et al. AHRQ Publ. No. 08-E09, 2008

INFANT OUTCOMES OF GWG

Outcome category Evidence rating

Birth outcomes

Preterm birth, birth weight, low birth weight, macrosomia, large-for-gestational age, small-for-gestational age, Apgar score

Strong (except weak for Apgar score)

Postnatal outcomes

Perinatal mortality, neonatal hypoglycemia, neonatal distress, hyperbilirubinemia, neonatal hospitalization, other infant morbidity, infant BMI, other infant growth

Weak

Viswanathan M, et al. AHRQ Publ. No. 08-E09, 2008

REEXAMINING GWG GUIDELINES

Considered outcomes for the mother, not just the infant, and the inevitable trade-offs between them

Commissioned new analyses• Ellen Nohr: DNBC (1996-2002), extension of trade-off

analyses• Amy Herring: NIMHS (1988), black and

white women• Cheryl Stein: NYC subsample (1995-2003), black and white

women• Jim Hammitt: quantitative risk analysis


Considered outcomes for the mother, not just the infant, and the inevitable trade-offs between them

Commissioned new analyses• Ellen Nohr: Danish National Birth Cohort (1996-2002),

extension of trade-off analyses• Amy Herring: National Maternal and Infant Health Survey

(1988), black and white women• Cheryl Stein: New York City subsample (1995-2003), black

and white women• Jim Hammitt: quantitative risk analysis


Balanced the trade-offs between maternal and infant outcomes

• Maternal outcomes • Postpartum weight retention• Unscheduled cesarean delivery

• Infant outcomes• SGA • LGA • Preterm birth • Childhood obesity

GWG-SPECIFIC RISKS FOR PREGNANCY OUTCOMES BY PREPREGNANCY BMI CATEGORY AMONG PRIMIPAROUS WOMEN

IOM 2009 GWG RECOMMENDATIONS

Prepregnancy BMI category

Total weight gain

(lb, kg)

Rate of weight gain

2nd and 3rd trimester

(lb/wk, kg/wk)

Underweight

(< 18.5 kg/m2)

28-40, 12.5-18 1.0 (1.0-1.3),

0.51 (0.44-0.58)

Normal-weight

(18.5-24.9 kg/m2)

25-35, 11.5-16 1.0 (0.8-1.0),

0.42 (0.35-0.50)

Overweight

(25.0-29.9 kg/m2)

15-25, 7-11.5 0.6 (0.5-0.7),

0.28 (0.23-0.33)

Obese**

(≥ 30.0 kg/m2)

11-20, 5-9 0.5 (0.4-0.6),

0.22 (0.17-0.27)*Calculations assume a first-trimester weight gain of 1.1-4.4 lb (0.5-2.0 kg)** 1990 IOM Recommendation: for obese women (BMI>29), weight gain at least 6.8 kg (15 lb)

PROVISIONAL GWG GUIDELINES FOR TWIN PREGNANCY

Prepregnancy BMI category Weight gain at term

Normal-weight 37-54 lb,17-25 kg

Overweight 31-50 lb,14-23 kg

Obese 25-42 lb,11-19 kg

*Based on the interquartile (25th-75th percentile) of gains of women who delivered twins at term (37-42 wk gestation) with birth weights ≥ 2,500 gNote: Insufficient data are available to offer a guideline for underweight women

GWG-SPECIFIC RISKS PREGNANCY OUTCOMES AMONG SUBTYPESOF NORMAL-WEIGHT WOMEN

RECOMMENDATIONS FOR SPECIAL POPULATIONS

Short stature: no modification

Young age: no modification; use adult BMI tables

Racial/ethnic subgroups: no modification

Primiparity: no modification, but trade-off should be studied further

Smokers: no modification, but stop smoking

COMPARISON OF NATIONAL GWG GUIDELINES

Alavi N et al.; Obesity Rev 14:68-85, 2013

COMPARISON OF NATIONAL GWG GUIDELINES

Alavi N et al.; Obesity Rev 14:68-85, 2013

Search 70 countries

18% (13) countries had GWG guidelines

31% (4) adopted the 2009 IOM guidelines

Canada, Finland, Australia, New Zealand

23% (3) similar to IOM guidelines

46% (6) different GWG guidelines

No guidelines specify for obesity severity

COMPARISON OF PRAMS GWG* AND 2009 IOM GUIDELINES BY PREPREGNANCY BMI

*PRAMS: Pregnancy Risk Assessment Monitoring System (CDC) and state health departments

DISTRIBUTION OF GWG BY OBESE CLASS MAGEE OBSTETRIC MEDICAL ANDINFANT (MOMI) DATABASE 2003-2008.

Bodnar L; Am J Clin Nutr 2010;91:1642–8.

Excessive GWG declined and GWL increased with obesity severity

CLASS 1 OBESITY


GWL ∞ elevated risk of SGA, iPTB, and sPTB; High GWG ∞ elevated risk of LGA and iPTB

CLASS 2 OBESITY


GWL ∞ elevated risk of sPTB; High GWG ∞ elevated risk of LGA and iPTB

CLASS 3 OBESITY: WHITE & BLACK WOMEN


GWL ∞ elevated risk of SGA (white women only)High GWG ∞ elevated risk of LGA and iPTB

GESTATIONAL WEIGHT LOSS (GWL) IN OBESE

Obese pregnant women lose weight more often than normal-weight women

11% vs. 0.1% (Edwards 1996)9% vs. 0.2% (Bianco 1998)8.3% obese, 19% morbidly obese vs. 1.9% (Dietz 2006)

Incidence of GWL increases with obesity severity

Observations studies (Beyerlein 2011, Blomberg 2011, Hinkle 2010)Decreased risks: pre-eclampsia,C-section, LGA Increased risks: SGA infants

MATERNAL AND NEONATAL OUTCOMES AMONG OBESE WOMEN WITH GWL (BLOMBERG 2011)

Database: Swedish Medical Birth Registry 1993-2008 data on 46,595 obese women

Outcomes: C-section, SGA, LGA, pre-eclampsia, delivery complications, Apgar scores, fetal distress

Findings: GWL compared with women gaining 5-9 kg

Class I: GWL ∞ decreased risk of C-section, LGA & increased risk of SGA

Class II: GWL ∞ decreased risk of C-section, LGA

Class III: GWL ∞ decreased risk of C-section, LGA & increased risk of SGA

GWL/GWG IN OBESE AND ASSOCIATION WITH FETAL GROWTH (HINKLE 2010)

Database: 2004–2006 Pregnancy Nutrition Surveillance System data from 122,327 obese mothers

Outcomes: GWG and SGA, LGA, sPTB, iPTB by severity of obesity

Findings:

Class I:GWL ∞ increased risk of SGA

GWG (0.1 to 4.9 kg) not ∞ SGA2SD

Class II/ III: GWL∞ decreased risk of LGA

GWL/GWG ∞ (-4.9 to +4.9 kg) not ∞ SGA2SD

ASSOCIATION OF GWL/GWG WITH SGA (HINKLE 2010)

ASSOCIATION OF GWL/GWG WITH LGA (HINKLE 2010)

ASSOCIATION OF GWL AND PREGNANCY OUTCOMES (BEYERLEIN 2011)

Database: Bavarian obstetric records from 2000–2007 on 709,575 singleton births

Outcomes: Pre-eclampsia, nonelective C-section, preterm delivery, SGA/LGA, perinatal mortality

Findings:

Class I: GWL ∞decreased risk of C-section

Class II: GWL ∞ decreased risk pre-eclampsia, LGA

Class III: GWL ∞ decreased risk LGA, pre-eclampsia, C-section

GWL ∞ increased risks of SGA births in obese class I/II (NS class III)

COCHRANE REVIEW

Antenatal interventions for reducing weight in obese women for improving pregnancy outcome (Furber 2013)

Objective: To evaluate effectiveness of interventions that reduce weight in obese pregnant women

Results: no RCT or quasi-random studies identified

Conclusion: Until the safety of weight loss in obese pregnant women can

be established, there can be no practice recommendations for these women to intentionally lose weight during the pregnancy period.

Further study is required to explore the potential benefits, or harm, of weight loss in pregnancy when obese before weight loss interventions in pregnancy can be designed.

THE CHALLENGES AHEAD

Conceive at a normal prepregnancy BMI

• Requires preconceptional counseling, contraception, and, for some women, weight loss

Gain within the IOM Guidelines

• Inform women and their health care providers of the guidelines

• Provide individualized assistance with meeting the guidelines

• Monitor GWG, guidance on diet and exercise

MODEL CHARTS THAT CAN BE ADAPTED FOR USE IN COUNSELING WOMEN

GWG CALCULATORDynamic energy-balance model to predict GWG that results from changes in energy intake

Diana M Thomas et al. AmJClinNutr 2012;95:115-22.

www.pbrc.edu/the-research/tools/gwg-predictor/

EDUCATIONAL MATERIALS

IMPLEMENTATION OF WEIGHT GAIN & PREGNANCY GUIDELINES

WEIGHT GAIN TRACKER

CONCLUSIONSIn contrast to the 1990 IOM GWG recommendations of at least 6.8 kg, the new 2009 IOM recommendations provide a GWG range of 5 to 9 kg for obese women

Insufficient evidence to provide specific recommendations by obese severity

Data are emerging on child/maternal outcomes associated with minimal weight gain 0.1-4.9 kg in obese women (class II/III);

Weight loss in obese pregnant women may have some benefits, yet a small increased risk for SGA

In the absence of RCT and robust evidence of benefits or harms, weight loss during pregnancy in obese is not recommended

Given the profound effect of maternal obesity on fetal outcomes, effective weight management prior to conception is needed

• Kathleen Rasmussen, ChairCornell University• Barbara AbramsUniversity of California-Berkeley• Lisa BodnarUniversity of Pittsburgh• Claude BouchardPennington Biomedical Research

Center• Nancy ButteBaylor College of Medicine• Patrick CatalanoCase Western Reserve University• Matthew GillmanHarvard University

• Fernando GuerraSan Antonio Metropolitan Health District• Paula JohnsonBrigham and Women’s Hospital• Michael LuUniversity of California-Los Angeles• Elizabeth McAnarneyUniversity of Rochester• Rafael Perez-EscamillaUniversity of Connecticut• David SavitzMount Sinai School of Medicine• Anna Maria Siega-RizUniversity of North Carolina-Chapel Hill

Staff: Ann Yaktine, Study Director, Heather Del Valle, Research Associate, Jenny Datiles, Senior Project Assistant, Linda Meyers, Director FNB, Rosemary Chalk, Director BCY&F, Anton Bandy, Financial Associate

COMMITTEE TO REEXAMINE IOM PREGNANCY WEIGHT GUIDELINES

Butte o&p2013

Health & Medicine

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