Obesity in Pregnancy

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Obesity in Pregnancy

• November 8, 2007

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Overview

• General issues of obesity
• Prevalence of obesity in pregnant women
• Effect of obesity on maternal outcome
• Effect of obesity on neonatal outcome
• Anesthesia considerations
• Issues of clinical care

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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

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General Issues

• Prevalence of obesity
• stable 1960 - 1980
• steadily increasing
• NHANES surveys
• National Health and Nutrition Examination Survey
• Most recent was 2003-4
• Being overweight is now more common than normal
  BMI
• Healthy People 2010 goal 15 obesity

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NHANES data 2003-2004

• Adults 20-74 years
• 32.9 obesity
• Obesity rates in reproductive age women
• Nonhispanic black 50
• Hispanic 38
• Nonhispanic white 31

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How did we get here

• The rise in obesity rates could be explained by
  as little as an average net increase of 50100
  calories per day, which is less than half the
  calories in a 16-ounce carbonated beverage.

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How did we get here

• Complicated
• Cheap food, high density calorie
• Work and lifestyle
• Restaurants
• Infectious
• Racial, socioeconomic effects
• Impact on social mobility

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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

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Bottom line

• More US citizens are overweight or obese than are
  daily smokers, problem drinkers, and living below
  the federal poverty line combined

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Economic cost of obesity

• 117 billion dollars per year in 2000
• 10 of health care cost attributed to obesity
• 6-14 of health care costs attributed to smoking
• Medicare Medicaid
• disproportionate enrollment
• 50 of obese patients

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Economic costs of obesity

• Stronger association with the occurrence of
  chronic medical conditions, reduced physical
  health-related quality of life, and increased
  health care and medication expenditures than
  smoking or problem drinking

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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
• 50 to 100 increase in premature deaths from all
  causes

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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

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Health benefits of weight loss

• 10 kg loss
• ? 20 - 25 total mortality
• ? 30 - 40 diabetes deaths
• ? 40 - 50 cancer deaths
• ? knee osteoarthitis
• 5-10 weight loss raise HDL
• For every two pounds lost, LDL levels are reduced
  by one percent

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Adverse outcomes associated with obesity in
pregnancy

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

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Adverse outcomes associated with obesity in
pregnancy

• Everything except
• placenta previa (so far)
• fetal growth restriction

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Adverse outcomes associated with obesity

• 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

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Outcome studies

• Many
• Different designs
• Different definitions
• Widespread agreement that there is increased
  maternal and fetal morbidity
• Wide variation on range of RR
• Very difficult to compare between studies

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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

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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

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Maternal Morbidity-thromboembolism

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

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Maternal morbidity -Complications of delivery

• ? induction of labor
• ? effect on duration of labor
• ? effect on operative vaginal deliveries
• ? primary cesarean birth
• ? OR time, EBL, infectious morbidity

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Risk of primary cesarean

• Bergholt, et al
• 2007 Observational cohort
• 4341 consecutive term, singeton nulliparas
• OR 3.8 for BMI gt35 compared with BMI lt25 after
  adjustment for variables
• No single explanation

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Cesarean section with abnormal labor

• Increased number of large-for-gestational-age
  infants
• Suboptimal uterine contractions
• Increased fat disposition in the soft tissues of
  the pelvis

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Maternal morbidity -Complications of delivery

• Weiss 2004 (compare normal, obese and morbidly
  obese)
• Induction of labor OR 1.6
• Failed induction
• 7.9, 10.3, 14.6
• Primary cesarean delivery
• 20.7, 33.8, 47.4
• Shoulder dystocia
• 1, 1.8, 1.9
• Increased operative vaginal delivery
• Increased emergency cesarean delivery

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VBAC

• Durnwald, 2004 n 510
• 66 success overall
• 84.7 underweight
• 65.5 overweight
• 54.6 obese
• Chauhan, 2001 n69
• 13 success rate
• indications labor arrestgt fetal distressgt failed
  induction
• ? endometritis, wound breakdown, infectious
  morbidity
• Lower success if interpregnancy weight gain but
  weight loss does not improve outcome

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VBAC

• Edwards, 2003
• Historic cohort n120
• 36 weeks, single prior CS, BMI gt40
• VBAC success gt 45 in all subgroups
• 3X increased infection rate (with VBAC attempt
  no cost saving

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VBAC

• Hibbard et al, 2006 (SMFMU)
• 14,142 TOL 14,304 ERCS
• 4 BMI categories (morbid obesity gt40 BMI)
• No data about counseling, indication for prior
  delivery, intrapartum care. Inadequate data to
  assess death or neurologic damage
• Success of VBAC
• Normal weight 85
• Morbid obesity 60
• Rupture/dehiscence
• Normal weight 0.9
• Morbid obesity 2.1

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VBAC

• Hibbard, 2006
• Compare TOL vs ERCS in morbidly obese

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VBAC

• Hibbard, 2006
• Compare successful and failed VBAC

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Wound infection

• Risks increase with
• Diabetes
• Subcutaneous thickness
• Rupture of membranes
• Multiple vaginal exams
• Chorioamnionitis
• Vermillion, 2000
• SC thickness the only significant variable

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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

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Neonatal morbidity -

• ? Low Apgar scores
• LGA RR 1.4 - 18
• attendant risks of birth trauma, etc
• Structural abnormalities
• Perinatal mortality
• Childhood obesity

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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

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Congenital malformations

• Watkins et al. 2003 state population-based
  case-control study
• RR 3 neural tube defect
• RR 2 cardiac defects
• RR 3 omphalocele
• Multiple abnormalities also increased

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Congenital malformations

• Challenges of diagnosis
• Poor sensitivity of ultrasound
• Heart and spine views
• MSAFP greater false negatives without weight
  correction
• True for other analytes
• Nuchal translucency more likely be obtained
  transvaginally
• Needs to be done later - 13 weeks

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Congenital malformation

• Possible etiology
• Undiagnosed diabetes
• Altered metabolism (increased insulin,
  triglycerides, uric acid, estrogen)
• Increased insulin resistance
• fuel mediated teratogenesis
• Low folate levels
• Supplementation not found to decrease risk

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Macrosomia

• Weiss, et al.
• gt4000 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

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Premature delivery

• Hard to assess with increased rate of indicated
  premature delivery
• e.g. diabetes, hypertension
• OR 1.5
• Preterm birth is more likely associated with low
  prepregnancy weight and poor weight gain

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Fetal death

• Cedergren 2004 n300,00
• 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

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Fetal death

• Partially attributed to co-morbidities. Not
  completely explained
• Increase placental histopathologic abnormality

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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

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Childhood obesity

• Retrospective cohort study 2004
• 8494 low-income children followed until 24 to 59
  months of age.
• Prevalence of obesity at 4 years of age
• 24.1 of children with obese mothers
• 9.0 of children with lean mothers
• Even with controlling for variables there is over
  a 2 fold increased risk of childhood obesity with
  maternal obesity

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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

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Bariatric surgery

• Malabsorptive
• Jejeunoileal bypass
• Pancreaticobiliary diversion
• Restrictive
• Gastric banding
• Vertical gastric gastropathy

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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

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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

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Preconceptual counseling

• Advise risks (all)
• Dietary counseling
• Screen for hypertension
• Screen for diabetes
• Encourage activity, weight loss

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General management

• Dont ignore overweight issues
• Clear, unambiguous message about risks
• Set realistic goals
• Acknowledge difficulty
• Praise success

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Optimal weight gain

• IOM minimum increase of 6.8 kg
• IOM guidelines are under revision
• 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

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Cesarean section techniques

• Panniculus retraction
• Study of 48 women
• incision to delivery time 1.5 to 4 min.
• no wound complications
• Supraumbilical incision requires fundal incision
• case control study no difference in
  postoperative mobidity c/w low transverse
  incisions
• Mobius retractor
• ?Panniculectomy

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Cesarean section technique

• Drains
• 2005 Cochrane review no clear benefit for
  routine use
• 2007 AJOG no evidence for prevention of wound
  complications
• Subcutaneous suture closure of some benefit

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Anesthesia issues

• Difficult IV access
• Airway obstruction
• Rapid desaturation with apnea (?FRC)
• Difficulty with ventilation
• Very increased cardiac output
• Challenging regional anesthesia
• Requires much slower pace of initiating
  anesthesia for cesarean section
• Consider prophylactic epidural

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Labor issues

• Difficulty with external monitors
• Inaccuracy of maternal blood pressure measurement
• Assess ability to flex, external rotation
• Assistance for thigh retraction

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Components of an institutional guideline

• Identification of patients
• BMI measurements in clinic
• Early dating sono prn
• Dietician consultation
• Review access to timely c/s, risks of c/s and
  fetal monitoring issues

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Example consent document

• I have had a prior cesarean section. Women with
  previous cesarean sections often have scar tissue
  which means that future cesarean section take
  longer to perform.
• Because of my body type, a cesarean section will
  take longer to perform in me.
• I have what is called a Class II-III airway.
  This means that it could be difficult to put a
  breathing tube down me, should I need to go
  emergently to sleep to delivery my baby.
• Overall, my doctors state that it could take more
  than 30 minutes from the decision to perform a
  cesarean section to the time the baby is out.
  Thirty minutes may be too long for the baby, and
  there could be neurologic injury due to this
  delay.
• My child is currently coming with its back first.
  If my child stays in this position, a classical
  incision will be needed to deliver my child.
  This means that the upper part of my uterus,
  which is very thick, will need to be cut open.
  This type of incision takes a longer time to
  perform than the typical lower uterine incision.

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Components of an institutional guideline-prenatal
care

• New OB labs including baseline 24 hour urine,
  creatinine, AST
• Cardiology eval if ACOG BMI gt35 and comorbity
• Early glucose challenge!!
• Anesthesiology Consultation
• Review birth control plans

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Delivery considerations

• Type and screen, CBC
• Consider thromboprophylaxis
• Consult anesthesia regarding IV access
• Place a block of wood to support under the toilet
  of the patients bathroom
• Obtain a large wheelchair, a large commode, and
  Big Boy Bed (foot of bed only entry or side or
  foot of bed entry) also need bypass gowns for the
  patient.

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Delivery plan - CS

• OR table extenders if gt 350 pounds
• Venodynes on prior to prep and drape and/or
  heparin
• Consider obtaining extra operative assistants
• Antibiotic prophylaxis before skin incision

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Postpartum care

• Early ambulation after delivery
• Venodynes until ambulatory without assistance
• Or continue heparin until ambulatory without
  assistance
• Assure that patient completely changes position
  in bed q 2 hours

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Contraception

• Combined OC
• Venous and arterial thromboembolism risk
• Increased failure rate especially very low dose
• No data patch, ring, IUD, implants, plan B
• Implanon lower serum etonogestrel levels
• DMPS weight gain, as effective as normal BMI
• IUD Should be as effective, technically
  challenging (ultrasound)
• Essure follicular phase, after DMPA
• Tubal ligation obesity is risk factor for
  complications

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