Post on 18-Dec-2014
description
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
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
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
REEXAMINING GWG GUIDELINES
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
REEXAMINING GWG GUIDELINES
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
Bodnar L; Am J Clin Nutr 2010;91:1642–8.
GWL ∞ elevated risk of SGA, iPTB, and sPTB; High GWG ∞ elevated risk of LGA and iPTB
CLASS 2 OBESITY
Bodnar L; Am J Clin Nutr 2010;91:1642–8.
GWL ∞ elevated risk of sPTB; High GWG ∞ elevated risk of LGA and iPTB
CLASS 3 OBESITY: WHITE & BLACK WOMEN
Bodnar L; Am J Clin Nutr 2010;91:1642–8.
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