2. 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
4. RISKS ASSOCIATED WITH LOW
AND HIGH GWG IN OBESE
Low GWG
Infant Risks
Preterm birth
Low birth weight /SGA
Fetal distress
High GWG
Maternal Risks
Preeclampsia
Gestational diabetes
C-section
Postpartum weight retention
Abdominal adiposity
Insulin resistance
Depression
Infant Risks
High birth weight /LGA
Fetal distress
Overweight later childhood
5. WEIGHT GAIN DURING
PREGNANCY REEXAMINING
THE GUIDELINES
Institute of Medicine and
National Research Council,
2009 National Academy
of Sciences
6. 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
7. 50% 59% 73% 70%
DISTRIBUTION OF GWG RELATIVE TO
1990 GUIDELINES BY PREPREGNANCY
BMI CATEGORY (PRAMS, 2002-3)
Outside Guidelines:
8. 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)
9. MATERNAL OUTCOMES OF GWG
Outcome 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
10. MATERNAL OUTCOMES OF GWG
Outcome 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
11. MATERNAL OUTCOMES OF GWG
Outcome 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
13. 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
14. 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
16. GWG-SPECIFIC RISKS FOR PREGNANCY
OUTCOMES BY PREPREGNANCY BMI CATEGORY
AMONG PRIMIPAROUS WOMEN
17. 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)
18. 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 g
Note: Insufficient data are available to offer a guideline for underweight women
20. 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
22. 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
23. COMPARISON OF PRAMS GWG* AND
2009 IOM GUIDELINES BY
PREPREGNANCY BMI
*PRAMS: Pregnancy Risk Assessment Monitoring System (CDC) and state health departments
24. DISTRIBUTION OF GWG BY OBESE CLASS
MAGEE OBSTETRIC MEDICAL AND
INFANT (MOMI) DATABASE 2003-2008.
Bodnar L; Am J Clin Nutr 2010;91:1642–8.
Excessive GWG declined
and GWL increased with
obesity severity
25. 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
26. 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
27. 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
28. 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
29. 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
30. 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
33. 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)
34. 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.
35. 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
37. GWG CALCULATOR
Dynamic 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/
41. CONCLUSIONS
In 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
42. • Kathleen Rasmussen, Chair
Cornell University
• Barbara Abrams
University of California-Berkeley
• Lisa Bodnar
University of Pittsburgh
• Claude Bouchard
Pennington Biomedical Research
Center
• Nancy Butte
Baylor College of Medicine
• Patrick Catalano
Case Western Reserve University
• Matthew Gillman
Harvard University
• Fernando Guerra
San Antonio Metropolitan Health District
• Paula Johnson
Brigham and Women’s Hospital
• Michael Lu
University of California-Los Angeles
• Elizabeth McAnarney
University of Rochester
• Rafael Perez-Escamilla
University of Connecticut
• David Savitz
Mount Sinai School of Medicine
• Anna Maria Siega-Riz
University 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
