WEIGHTY ISSUES IN PREGNANCY
| MANAGEMENT OF THE OBESE PATIENT IN PREGNANCY —William E. Scorza, MD, Professor and Vice Chair,
Division of Maternal-Fetal Medicine, Department of Obstetrics, Gynecology, and Reproductive Sciences, University of
Medicine and Dentistry of New Jersey, Robert Wood Johnson Medical School, New Brunswick
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| General considerations: obesity complicates 10% of pregnancies; massive obesity complicates 0.5% to 3% of pregnancies;
statistics from 1994 to 1998 show 28% of women >25 yr of age overweight and 27% obese
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| Obesity complications and contributors: hypertension, hypercholesterolemia, gallbladder disease (≈33%-50% of obese
people have gallbladder disease), diabetes mellitus, osteoarthritis, pulmonary disease, sleep apnea, infertility, and depression;
contributors—“fast food,” larger portions, consumption of high-glycemic index foods (leads to overeating; causes
surges in blood glucose followed by drop in blood glucose signaling feeding activity; sensation of satiety occurs earlier
with high-protein meal), and sedentary lifestyle; higher birth weights result in increased body mass index (BMI) in adulthood
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| Body mass index: most commonly used to define body habitus; calculation based on person’s weight and height;
normal—18.5 to 24.9; overweight—25 to 29.9; obese—>30; morbid obesity—>35; massive obesity—>40; defining
obesity by weight—≈200 lb obese; ≈250 lb morbid obesity; >300 lb massive obesity
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| Pathophysiology of obesity: fetal life—growth-restricted babies in utero use nutrients more efficiently; thrifty phenotype
develops; postnatal catch-up growth occurs; ≈80% chance obese child will become obese adult; large babies and
growth-restricted babies tend to develop visceral fat (contributor to cardiac disease); genes associated with obesity—
ob/ob gene codes for leptin protein; ob-r codes for leptin receptor; fat gene involved in formation of proinsulin; at least
4 or 5 genes associated with obesity and diabetes; leptin—word derived from Greek leptos, meaning thin; cytokine involved
in regulating body weight, metabolism, and reproductive function; expressed in adipocytes (major site), stomach,
placenta, bone and brain; affects hypothalamic control of feeding behavior, hunger, body temperature, and energy
expenditure; abnormalities can occur in leptin receptors and production; ob/ob gene causes secretion of leptin; experiments
show mice become obese with deletion of ob/ob gene; weight loss occurs when leptin injected into obese mice;
leptin regulates fat deposits in body; leptin and pregnancy—produced by mother and fetal placenta; increases dramatically
in pregnancy; concentrations decrease immediately after delivery; increase in fetal body fat causes increase in secretion
of leptin; babies with intrauterine growth retardation (IUGR) have less leptin and decreased fat; increased
placental leptin in pregnancy-induced hypertension (PIH), hypoxic conditions, and diabetes; leptin may be marker for
fetal hypoxia; maternal leptin levels do not affect fetal leptin levels; endocrine causes of obesity—resistin causes tissues
to be insensitive to action of insulin; enhanced secretion in large fat cells of mice; hypothyroidism, polycystic
ovary syndrome, and Cushing’s disease; caloric intake and expenditure—set point theory proposes energy expenditure
declines 15% more than percentage decline in body weight (body begins to adjust metabolic rate); genetics of humans
reflects long history of scarcity of food; now in age of surfeit, cannot adapt; increased food intake does not signal
satiety, leading to gradual increase in energy stores as intake of energy outpaces need
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| Risks and complications: maternal—in obese patients, chronic hypertension 25% to 35% (2%-3% in nonobese patients);
with obesity, PIH/preeclampsia 25% (≈5% in nonobese population); gestational diabetes 10% to 15% (≈5% in
nonobese population; ≈30% of gestational diabetes attributed to obesity); with morbid obesity, pregestational diabetes
≈19% (<1% in nonobese patient); altered pulmonary function, reduced vital capacity, reduced total lung capacity, decreased
chest wall compliance, increased airway resistance, exacerbated asthma, and exacerbated sleep apnea; primary
cesarean delivery 32%; emergency cesarean delivery 32% to 48% (consider elective cesarean delivery to help avoid potential
risks associated with emergency cesarean delivery); excessive blood loss (>1000 mL blood loss in >33% of
obese patients), prolonged delivery interval, prolonged operative time (50% longer, compared to 10% in nonobese population),
postoperative endometritis (≈33% of patients), wound infection, breakdown, and dehiscence (26%); anesthesia
risks and complications—failed epidural catheter placement (requiring multiple attempts to place catheter),
difficult tracheal intubation and failed intubation leading to maternal death; fetal—macrosomia and birth trauma, stillbirth
(1.5-2.5 times higher than in nonobese population), neural tube defects (estimated risk increased ≈7% for each
unit of increase in BMI); risk for prematurity controversial
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| Antepartum management: American College of Obstetricians and Gynecologists (AGOG) recommends 15- to 25-lb
weight gain in pregnancy for overweight or obese women; 5 or 10 lb for morbidly or massively obese women; good
pregnancy outcomes reported in obese patients who gained no weight during pregnancy; glucose challenge test at first
prenatal visit (unless patient has undergone gastric bypass surgery); weighing patient—counterweights available from
medical supply company that allow weighing of patients >300 lb; may be necessary to find alternative way of weighing
massively obese patient, eg, loading dock (have someone sensitive to patient’s feelings accompany them); blood pressure
cuff—bladder of cuff should encircle arm ≈80% and cover ≈40% in width; laboratory values—baseline 24-hr
urine, complete blood count (CBC), electrolytes and liver function tests (LFTs); anesthesia consult; first-trimester ultrasonography
for dating; 12- to 14-wk vaginal probe scan for fetal anatomy; assess feasibility of follow-up abdominal examinations;
think and plan ahead for potential medical and surgical problems
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| Intrapartum issues: percutaneous intravenous catheter may be required; fetal assessment; pelvimetry useful tool in deciding
whether to perform cesarean delivery or to allow patient trial of labor; most operating tables accommodate patients
≤500 lb; bariatric operating tables, hospital beds, and chairs can be rented on daily or weekly basis to
accommodate obese patients; early intravenous (IV) catheter placement recommended; combined spinal epidural anesthesia
needles specifically designed for obese patients available; consult with anesthesiologist about possible intubation
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| Cesarean delivery: Pfannenstiel incision most common in United States for cesarean delivery; also may be used in obese
patients; respiratory function can be compromised when panniculus retracted caudad; increased risk for wound complication
in moist area colonized with bacteria and yeast; use caution to avoid bisecting panniculus when doing vertical midline
incision; low uterine segment transverse incision possible when large panniculus mobilized inferiorly; higher tension on
wound can pose problem; patient with umbilicus at least at level of pubis symphysis good candidate for incision (not good
candidate if umbilicus near to or at normal level); decreasing wound complications—wound breakdown, infection and
dehiscence reduced if subcutaneous tissue closed (running suture using plain surgical gut or Monocryl recommended);
closed suction drains beneficial (but not adjunctive to subcutaneous tissue closure); prophylactic antibiotics decrease risk
for endometritis and wound infections; delayed absorbable suture material recommended, eg, polydiaxonone [PDS] or
Panacryl for closing peritoneum; Vicryl or Mono-cryl for closure of soft tissue; permanent sutures recommended for patient
at risk for wound dehiscence (eg, from coughing)
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| Pregnancy after bariatric surgery: nutritional status generally not optimal after surgery (patient generally in ketotic state);
pregnancy should be avoided until patient’s nutritional status stabilizes (12-18 mo after surgery); pregnancy outcomes
good after patient’s nutritional status improves; nutritional concerns more likely with malabsorptive-type surgeries; adjustable
gastric banding—gastric band can be adjusted during pregnancy (consult with bariatric surgeon who performed
patient’s surgery); pregnancy generally well tolerated; gastric bypass—successful pregnancy outcomes
reported; nutritional supplementation (vitamin B12 , folate, iron, calcium) required; do not perform glucose challenge test
(patient cannot eat concentrated sugars, prone to dumping syndrome); obtain fasting blood glucose and 2-hr postprandial
blood glucose instead
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| Conclusion: increased physical fitness should be encouraged beginning in childhood; weight loss prior to pregnancy improves
pregnancy outcome; development of referral centers that meet needs of obese pregnant patients should be considered
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| WEIGHT GAIN IN PREGNANCY —Naomi E. Stotland, MD, Assistant Professor, Department of Obstetrics, Gynecology,
and Reproductive Sciences, University of California, San Francisco, School of Medicine
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| Why it matters: excessive and inadequate weight gain associated with multiple adverse outcomes for mother and neonate;
currently, cesarean delivery accounts for 29% of all deliveries (unclear whether obesity epidemic contributing);
women concerned about weight gain in pregnancy; 25% of women 20 to 39 yr of age in United States overweight and
29% obese
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| Components of gestational weight gain: breast hypertrophy 1 to 2 lb; baby 6 to 8 lb; placenta 1 to 2 lb; uterine hypertrophy
1 to 2 lb; amniotic fluid 2 to 3 lb; protein and fat storage 8 to 10 lb; increase in blood volume important predictor of
birth outcome; current research looking at amount of weight gain in pregnancy as well as components of weight gain
(components of weight gain may be more predictive of outcome)
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| Institute of Medicine (IOM) recommended gestational weight gain: low BMI (<18) 28 to 40 lb; normal BMI (19.8-26.0)
25 to 35 lb; high BMI (26.1-29.0) 15 to 25 lb; BMI >29.0 (obese) ≥15 lb
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| Trends in pregnancy weight gain in United States: average gain 20 lb in 1930s; current average gain 30 lb; no increase in average
weight gain since 1990s, but percentage of women gaining above IOM guidelines has increased; from 1989 to 2003
(among term births) percentage of women who gained <16 lb increased and percentage gaining >40 lb increased by ≈30%
(≈20% of women gain >40 lb); statistics not sorted by BMI (percentage gaining above IOM guidelines would be much
higher)
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| Outcomes associated with excessive and inadequate pregnancy weight gain: excessive weight gain—macrosomia and
large-for-gestational-age neonates, prolonged labor (independent of birth weight), primary cesarean delivery, failure of
vaginal birth after cesarean delivery (VBAC), preeclampsia, gestational diabetes, postdate pregnancy, preterm birth
(only with extremely high weight gain), neonatal morbidity, postpartum weight retention, and failure to initiate and/or
sustain breast-feeding; relationship between weight gain and outcome varies by prepregnancy BMI; risks associated
with inadequate weight gain—IUGR and small for gestational age, spontaneous preterm birth and neonatal morbidity
(only with extremely low weight gain); relationship between weight gain and outcome varies by prepregnancy BMI; low
weight gain in pregnancy associated most strongly with low birth weight and preterm birth among women with low
prepregnancy BMI; excessive weight gain associated most strongly with postpartum weight retention among overweight
women
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| Efficacy of interventions: controversial area; some feel weighing women in office increases anxiety; amount of weight
woman told to gain in pregnancy shown to correlate with actual amount of weight gained; few trials of interventions to
prevent abnormal weight gain; Olson et al conducted intervention study to reduce excessive weight gain in pregnancy;
showed significant results only in low-income group; tools used in intervention study available at www.nutritionworks.cornell.edu;
Stotland et al showed 24% of overweight women reported target weight gain above IOM guidelines
compared with 4% of normal-weight women; underweight women more likely than normal-weight women to have target
that was too low; 33% of women reported receiving no advice about gestational weight gain; study concluded that
many women report incorrect target weight gains and incorrect or absent advice from provider; Coswell et al showed
target weight gain and advised weight gain predictive of actual weight gain; high or low prepregnancy BMI (patients at
most risk) predictor of incorrect target weight gain
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| Daily nutritional recommendations: pregnancy requires 300 additional calories per day (ie, small snack); 7 servings of
fruits and vegetables; 6 to 9 servings of whole-grain breads or cereals; 4 servings of low-fat or non-fat dairy products;
60 g of protein; limit or avoid high-calorie nonnutritive foods (eg, candy, soda)
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| Physical activity: ACOG recommends moderate exercise (30 min) on most or all days of week for low-risk pregnancies;
conflicting data and poor-quality studies on impact of exercise on pregnancy weight gain and birth outcomes; moderate
exercise not associated with adverse outcomes such as preterm birth; exercise during pregnancy associated with improved
maternal fitness and well-being
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| Clinical recommendations: record BMI prominently in medical chart at first prenatal visit; do not “eyeball” patient’s
weight (BMI often higher than thought); track gestational weight gain using charts; discuss weight at each visit; utilize
nutritionists, but important that patient hear advice (in nonjudgmental manner) from clinician providing obstetric care;
become knowledgeable about nutrition and exercise in pregnancy; appropriate amount of gestational weight gain for
overweight and obese women remains unclear; IOM guidelines recommend at least 15 lb; conflicting data whether restriction
of weight gain in pregnancy for obese patient safe, and if inadequate gestational weight gain places obese
women at higher risk for preterm birth and delivery of low birth weight infants
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Educational Objectives
| The goal of this program is to educate the listener about the issue of weight in pregnancy. After hearing and assimilating
this program, the clinician will be better able to:
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 | 1. Discuss the pathophysiology of obesity and environmental factors that contribute to it.
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| 2. Identify the risks and complications that obesity presents in pregnancy.
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| 3. Implement a plan of care for the obese pregnant patient.
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| 4. Counsel pregnant patients about the appropriate amount of weight gain in pregnancy.
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| 5. State interventions for monitoring gestational weight gain.
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Resources
www.nutritionworks.cornell.edu
Suggested Reading
Caughey AB: Obesity, weight loss, and pregnancy outcomes. Lancet 368:1136, 2006; Olson CM et al: Efficacy of an intervention
to prevent excessive gestational weight gain. Am J Obstet Gynecol 191:530, 2004; Pathi A et al: A comparison
of complications of pregnancy and delivery in morbidly obese and non-obese women. J Obstet Gynaecol 26:527,
2006; Smith GC et al: Maternal obesity in early pregnancy and risk of spontaneous and elective preterm deliveries: A retrospective
cohort study. Am J Public Health 97:157, 2007 (Epub 2006 Nov 30); Stotland NE et al: Weight gain and
spontaneous preterm birth: the role of race or ethnicity and previous preterm birth. Obstet Gynecol 108:1448, 2006.
Faculty Disclosure
In adherence to ACCME guidelines, the Audio-Digest Foundation requests all lecturers to disclose any significant financial
relationship with the manufacturer or provider of any commercial product or service discussed. For this issue, the faculty
reported nothing to disclose.
Dr. Scorza was recorded at the 21st annual Issues & Controversies in OB/GYN, sponsored by the University of Medicine
& Dentistry of New Jersey, Robert Wood Johnson Medical School, held on November 9-11, 2006, in Lake Buena Vista,
FL. Dr. Stotland was recorded at Antepartum & Intrapartum Management, sponsored by the University of California,
San Francisco, School of Medicine, held on June 8-10, 2006, in San Francisco. The Audio-Digest Foundation thanks the
speakers and the sponsors for their cooperation in the production of this program.
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