Obesity, Bariatric Surgery & Pregnancy

Pat O’Brien

Institute for Women’s Health

University College London Hospitals

Obesity & Pregnancy

Bariatric Surgery Adjustable Gastric Banding Proximal Gastric Bypass Sleeve Gastrectomy

Bariatric Surgery

United States • x 8 from 1998 to 2005 (12,000 113,000) • Of those aged 18-45 years old, 83% women Maggard et al, 2009

United Kingdom • 40% from 2006 to 2007 in NHS (1951 2724)

– 78% women Information Centre for Health & Social Care, 2009

• Private: 74% from 2008 to 2009 (to 12,848)

Singleton births in Sweden 1992-2009

Roos N et al. BMJ 2013;347:f6460

Bariatric Surgery • BMI > 40 or • BMI 35 – 40 with health

problems • Type 2 DM • Cardiovascular

NICE (2006)

If BMI ≥ 38 (♀): surgery better than non-surgical measures

Bariatric Surgery

Profound effects on glucose homeostasis

• 50% complete ‘remission’ of T2DM = HbA1c <6.0% off all drugs for at least 1year (ADA consensus criteria, Buse et al, Diabetes Care 2011)

• Majority discontinue anti-DM drugs prior to leaving hospital

• Improvement occurs before significant weight loss

Bariatric Surgery

Restrictive versus Malabsorptive

Reversible versus Irreversible

Gastric Banding Laparoscopic Adjustable Gastric Banding (LAGB)

• First described in mid-1980’s

• First laparoscopic insertion Belgium 1993

• Pouch 20-40 mls = mouthful

Gastric Banding Laparoscopic Adjustable Gastric Banding (LAGB)

• Restrictive • Reversible • No effect on absorption

– though intake may be ↓ (e.g. Iron)

• Calorie intake ↓ by 50 – 60% • No ‘feeling of fullness’

Gastric Banding Management in pregnancy

• Deflate in first trimester food intake

• heartburn – deflation may help • Deflate before delivery - ? pressure

Gastric Banding Complications

• Obstruction: fundus moves through band • Erosion • Slips • Tube leaks • Port problems • If removed, may be scarring

– Subsequent bypass more difficult – Tend to gain weight again

(no psychological change)

25% will need removal “Expect it to last 10 years”

Gastric Bypass Roux-en-Y (RYGBP)

• Originally ulcers/cancer • Combination of restriction and

malabsorption • Stomach pouch 20-40mls restrictive

empties into mid-jejunum (bypasses 50-100 cm) Also delayed mixing with bile & pancreatic juices

Note: Amount of bowel bypassed does not seem to be α weight loss

Another powerful effect: • Early satiety ↓↓ appetite ↓ food cravings

Secondary to intestinal hormone Peptide YY-36 (PYY)

Gastric Bypass Roux-en-Y (RYGBP)

Gastric Bypass Micronutrient effects

• Iron – ↓ stomach acid ↓ ferric ferrous

• Vitamin B12 – ↓ intrinsic factor

• Calcium – Duodenal exclusion absorption ↓↓

• Vitamin D – Fat soluble (may be deficient even before surgery)

• Vitamin A – Difficult to process samples false low measurements

Biliopancreatic Diversion (BPD)

• Introduced in 1979 • Part of stomach resected • Distal small intestine

connected to stomach • Restriction not major

– Normal diet possible • Bypasses duodenum &

jejunum

Biliopancreatic Diversion (BPD)

• Alimentary limb • Biliopancreatic limb • Food meets bile & pancreatic juices

in “Common channel” truly malabsorptive • ↓ absorption

• Fats • CHO • Fat-soluble vitamins (A,D,E,K)

Proteins absorbed by mass effect, even in ascending colon

Laparoscopic Sleeve Gastrectomy

• Small reservoir • Cardiac sphincter intact

Ghrelin • hunger • α time since last food • Gastric peptide • Produced mainly in fundus

• Swedish registry 1992 - 2009 • 1.7 million singleton pregnancies • Bariatric surgery 2,562 • Matched controls 5:1

Singleton births in Sweden 1992-2009

Roos N et al. BMJ 2013;347:f6460

Control Group 1

Roos N et al. BMJ 2013;347:f6460

Pregnancy outcomes after Bariatric surgery

PTB < 37 weeks Iatrogenic PTB Spontaneous PTB PTB 32-37 weeks PTB < 32 weeks SGA (<2.5th centile) LGA (>97.5th centile)

9.7 4.5 5.2 7.7 2.2 5.2 4.2

6.1 2.5 3.6 5.1 1.0 3.0 7.3

1.7 1.8 1.5 1.6 2.0 2.0 0.6

Bariatric Controls OR

All p values <0.001

Control group Normal

Subgroup analysis

Mortality: No difference

Stillbirth Neonatal mortality

0.79 0.28

0.60 0.26

0.32 0.86

Bariatric Controls P value

Control Group 2

Matched with women eligible for bariatric surgery (BMI ≥ 35)

Post-surgery No surgery P-value n 2,496 12,126 Mean BMI 32.5 38.5 <0.001 Preterm Birth 236 (9.5%) 863 (7.2%) <0.001 SGA 128 (5.2%) 313 (2.6%) <0.001

Conclusions

• Increasingly common in pregnancy • High risk group • Risk of Preterm Birth and SGA • Mechanism unknown - ?micronutrients • Does micronutrient supplementation help?

• Band: deflate in early pregnancy • Bypass: malabsorption

Thank you