The Role of Weight and Obesity Before, During and After Pregnancy

Anna Maria Siega-Riz, PhD, RDProfessor of Epidemiology and Nutrition

Associate Dean for Academic AffairsUNC Gillings School of Global Public Health

Periconceptional

Women

Pregnancy

Infancy

Lactation 

and feeding

Adult Health

Schematic diagram of the life cycle showing the relationships among the life stages

From  March of Dimes Report :Nutrition today matters tomorrow 2002

Obesity Class BMI (kg/m2)Underweight <18.5Normal 18.5 - 24.9Overweight 25.0 - 29.9Obesity I 30.0 - 34.9

II 35.0 - 39.9Extreme obesity III 40+

Classification* of adult underweight, overweight and obesity by BMI

*National Heart Lung and Blood Institute (NHLBI), 1998

Trends in the distribution of BMI* from 1993 to 2003 among prepregnant U.S. women in the total 

population and by race

*1990 cut points. SOURCE: Kim et al., 2007. (IOM Report, 2009)

Distribution of gestational weight gain by race and ethnicity

SOURCE: CDC, Pregnancy Nutrition Surveillance System. (IOM Report 2009)

Independent of Pregnancy:o Cardiovascular diseaseo Type II diabeteso Gallbladder diseaseo Osteoarthritiso Reduced fecundity and fertility

Implications of Obesity on Maternal Health Status

During Pregnancy:◦ Gestational diabetes◦ Gestational hypertension◦ Preeclampsia◦ Cesarean Delivery◦ Fetal macrosomia◦ Late fetal death◦ Early neonatal death◦ Thromboembolic Diseases◦ Birth Defects

Implications of Obesity on Maternal Health Status

Postpartum:•Postpartum weight retention•Anemia•Shorter duration of Breastfeeding

What do we know about the lifestyle behaviors of high BMI women?

Lower quality dietLess likely to participate in physical activityLess likely to take multi‐vitamin/mineral supplementsMore likely to be depressed and have lower scores on various psychosocial scalesMore likely to be food insecure

Balancing the risk and benefits of gestational weight gain

Prepregnancy BMI category

Total weight gain(lb, kg)

Rate of weight gain2nd 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)

New recommendations

*Calculations assume a first-trimester weight gain of 1.1-4.4 lb (0.5-2.0 kg)

Comparison of current GWG* and new guidelines by prepregnancy BMI category

*PRAMS 2002-03

Social‐Ecological Model

Factors Likely to Influence Weight Gain During Pregnancy‐Individual

• Dietary intake• Dieting practices• Attitudes about gaining weight

• Physical activity• Smoking status• Psychosocial status

• Conceive at a normal prepregnancy BMI– Requires preconceptional counseling, contraception, and, 

for some, weight loss• Gain within the 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• Need to address the fact that women live busy lives and many time constraints

What can we do now to help women enter pregnancy healthy and have 

optimal outcomes?

2009 IOM report

Food Calories (kilocalorie)

8 OZ low fat vanilla yogurt + 2 Tb almonds +  ½ C berries

340†

2 OZ cheddar cheese + 5 cherry tomatoes +  5 round crackers

340†

1 medium banana + 1 ½ Tb. peanut butter + 8 FO skim milk

340†

10 medium baby carrots + 1 Tb reduced calorie ranch dressing +

1 medium apple + 2 Tb walnuts

340†

12 FO fruit smoothie(fruit, juice, lowfat yogurt) + 2 Tb trail mix

450

Educate women that they are not eating for two! 

Widen and Siega‐Riz  JMWH 2010