Obesity in Pregnancy

November 14, 2009

Overview

General issues of obesity Prevalence of obesity in pregnant

women Effect of obesity on maternal outcome Effect of obesity on neonatal outcome Issues of clinical care

Obesity Classifications

BMI = kg/m2

Normal 18.5 – 24.9 Overweight 25-29.9 Obesity ≥ 30

Class I 30 - 34.9 Class II 35 - 39.9 Class III ≥ 40

Recent national data

Is the epidemic leveling out? Prevalence among low-income, preschool-

aged children 12.4% in 1998 to 14.5% in 2003 No further increase:14.6% prevalence in 2008.

Prevalence of adult obesity Dramatic increase1999 to 2006. No significant change between 2003-2004 and

2005-2006

How did we get here

The problem is intake more than energy expense ↑ 10% calorie intake 1985-2000 Mostly carbohydrates Mostly beverages: ~50% increase in fruit juice

and soft drinks More snacking Larger portions

Morbidity from obesity

Metabolic syndrome/insulin resistance syndrome Metabolic core obesity (central obesity)

Elevated waist/hip ratio Insulin resistance

Morbidity from obesity Hypertension Dyslipidemia (for example, high total

cholesterol or high levels of triglycerides)

Type 2 diabetes Coronary heart disease Stroke Gallbladder disease Osteoarthritis Sleep apnea and respiratory problems Some cancers (endometrial, breast,

and colon) Nonalcoholic steatohepatitis (NASH) 50 to 100% increase in premature

deaths from all causes

Pathophysiology of obesity

Cardiac effects Increased oxygen demand, blood

volume, cardiac output, hypertension Longstanding obesity: decreased

diastolic interval and time for myocardial perfusion, diastolic dysfunction

Insulin resistance Diabetes

Direct Arthritis Sleep apnea

Estrogen Endometrial and breast CA

Respiratory pathophysiology

Sleep apnea (snoring, apnea, daytime somnolence

Airway obstruction Rapid desaturation with apnea (↓FRC) Difficulty with ventilation

Infertility/miscarriage

High prevalence of PCOS Negative impact on infertility treatment Miscarriage after infertility Rx

OR 1.77 OI with gonadotropins OR 3 Egg donor cycle OR 4

Miscarriage OR 1.2

Recurrent SAb 3.5

Adverse outcomes associated with obesity in pregnancy

fetal structural abnormalities gestational diabetes macrosomia and childhood obesity preeclampsia/hypertension urinary tract infection thromboembolism perinatal death postdates pregnancy induction of labor cesarean section wound infection postpartum hemorrhage

Metabolic syndrome-like complication of late pregnancy Gestational diabetes Hypertension/preeclampsia

Maternal morbidity - insulin resistance Higher fasting and post absorptive plasma

insulin Most women achieve euglycemia Overweight status: RR of GDM 1.8 to 6.5 Obese: RR GDM 1.4 to 20 Need early diagnosis of diabetes

Maternal morbidity - hypertension

Higher BP: hemoconcentration, altered cardiac function

Even moderate obesity increases risk of HTN/PIH

Obese: RR HTN 2.2 to 21.4 RR Preeclampsia 1.22 to 9.7 Risk of pre-eclampsia doubles with each 5 to

7 kg/m2 increase in pre-pregnancy BMI

Maternal morbidity - hypertension/preeclampsia Diabetes has additional effect

Good control helps Preeclampsia risk

Obese women with well controlled GDM 10% Average weight with well controlled GDM 8% Obese women with poorly controlled GDM 15%

Thromboembolism

Sebine (n= 287,213) Incidence Normal weight 0.04% Overweight 0.07% Obese 0.08%

Macrosomia

Weiss, et al. >4000 grams

8.3% normal weight 13.3% obese 14.6% morbidly obese

Correlation with weight gain, pregravid weight

Fetus of obese women-hyperinsulinemia

Obese women- increase glucose, triglycerides and amino acid turnover

Fetal death

Cedergren 2004 n=~300,00 OR 3 for obese v normal

Kristensen 2005 n= ~25,000 OR for fetal death 2.8 OR for neonatal death 2.6

Meta-analysis Chu, et al. 2007 Overweight v normal OR 1.47 Obese v normal OR 2.07

Fetal death

Partially attributed to co-morbidities. Not completely explained

Increase placental histopathologic abnormality

Maternal death

18% of obstetric causes of maternal death are associated with obesity

80% of anesthesia deaths are associated with obesity

UK Maternal mortality 2000-2002 35% or maternal deaths had obesity

compared with 23% of general population

Maternal long term complications

Urinary stress and urge incontinence

Weight gains correlate with weight retention and worsening obesity

In 15 year follow up after GDM 70% of obese women have type 2

DM 30% of lean women have type 2 DM

Long term weight development after pregnancies

Wide variation in weight loss/gain. Average is 0.5 kg one year postpartum

Very difficult to tease out the factors Most important factor for sustained weight

gain is gain during pregnancy Not predictive: pre pregnancy wt., parity,

socioeconomics, occupation, marital status, dietary advise

Effect of lactation is small

Longterm neonatal impact

Increased risk of infant, childhood and adult obesity

Increased risk of metabolic syndrome in adolescence

Maternal BMI and diabetes account for most of this relationship

Obesity and diabetes likely to be independent risk factors

Much greater impact than IUGR

Bariatric surgery

Malabsorptive Jejeunoileal bypass Pancreaticobiliary diversion

Restrictive Gastric banding Vertical gastric gastropathy

Bariatric surgery

Initial worrisome case reports regarding pregnancy outcome: neonatal nutrition deficiency, IUGR, fetal death

More recent data are reassuring Recommendations give to delay pregnancy for 18

months. Advise patients of increased fertility. Nutrient deficiencies: B12, folate, Fe, Ca, Zinc Monitor nutrients and weight Explain increased calorie, protein and nutrient

demands

Gastric banding

Requires deflation if severe nausea and vomiting

May be increased rate of band complications (migration or leaking)

Recommendation given to wait 12-18 months. Explain improved fertility with weight loss

Nutrient deficiencies still possible: B12, folate, Fe, Ca, Zinc

Monitor nutrients and weight

Psychosocial issues

Depression Poor self-esteem Social discrimination Family support/lack of support for self-care

and weight loss

Preconception care

Assess co morbidity Formal diabetes screen Healthy life style coaching Consider bariatric surgery referral Counseling

Maternal risks Fetal risks Delivery: access to timely c/s, risks of c/s and

fetal monitoring issues

Prenatal considerations

Identification of patients BMI measurements in clinic Keep track of weight gain

Consider early dating ultrasound New OB labs include baseline 24 hour

urine, creatinine, AST (PIH and NASH)

Early glucose challenge!!

Prenatal considerations

Consider cardiology evalulation or echocardiogram BMI >35 and comorbidity Longstanding class III obesity

Dietician consultation Counseling about exercise Anesthesiology Consultation Sleep medicine prn Review birth control plans

Optimal weight gain

Most studies do not show correlation of low weight gain and low birth weight in obese women

High weight gains do lead to macrosomia

Lower weight gain - less retention

IOM guideline 2009

Prepregancy BMI TWG lb Rates of gain 2nd and 3rd trimester

Underweight

<18.5 28–40

1 lb/wk

(1–1.3)

Normal weight

18.5-24.9 25–35

1 lb/wk

(0.8–1)

Overweight

25.0-29.9 15–25

0.6 lb/wk

(0.5–0.7)

Obese

≥30.0 11–20

0.5 lb/wk

(0.4–0.6)

IOM 2009

Provisional guidelines for weight gain for twin pregnancies Normal BMI: 37-54 pounds Overweight: 31-50 pounds Obese women: 25-42 pounds

Surveillance during pregnancy

Growth ultrasound Frequent visits- surveillance for hypertension Fetal kick counts Antenatal testing not yet indicated 12

Contraception

Combined OC Venous and arterial thromboembolism risk Increased failure rate especially very low dose Combined OC: extra 2-4 pregnancies/woman-years Royal College of OB GYN

Risks generally outweigh benefits with BMI 35-39 Contraindicated BMI > 40

Patch: Package insert: Lower effectiveness if weight > 90 kg

No data: ring, implants, plan B Implanon: lower serum etonogestrel levels DMPS – weight gain, as effective as normal BMI

Contraception

IUD – Should be as effective, technically challenging (ultrasound)

Essure: follicular phase, after DMPA Tubal ligation: obesity is risk factor for

complications CREST study 70% increased risk of

complications