Guidelines on Pregnancy After Bariatric Surgery

As the prevalence of obesity increases in the United States, physicians are more often caring for patients who have undergone bariatric surgery and have become pregnant.  Women who have undergone bariatric surgery generally have lower risk pregnancies compared to morbidly obese women.  Obesity is associated with increased risk of gestational diabetes, preeclampsia, cesarean delivery and infectious morbidity.  Operative morbidity is also increased.  Although outcomes are generally good, nutritional and surgical complications can arise. 

After bariatric surgery, a woman should wait 12-24 months before conceiving so that the fetus is not affected by rapid maternal weight loss and allowing the patient to achieve her weight loss goals.  If pregnancy occurs before this recommended period, there may be an increased risk for maternal nutritional deficiencies, subsequent miscarriage or intrauterine growth restriction (IUGR).  Closer surveillance of maternal weight and nutritional status is indicated, and serial ultrasound monitoring of fetal growth should be considered.

There are two approaches to bariatric surgery: restrictive and restrictive/malabsorptive surgeries.  The most common restrictive procedure is adjustable gastric banding and the most common restrictive/malabsorptive procedure is the Roux-en-Y gastric bypass.  Rapid weight loss is typical after either procedure.

Antenatal Period Considerations

Dumping syndrome can occur after ingestion of refined sugars and high glycemic carbohydrates in patients who have had the Roux-en-Y gastric bypass surgery.  Oral GTT (1 and 3 hour) is not recommended in gastric bypass patients.  Alternative screening methods such as home blood glucose monitoring should be considered.  We recommend one week of testing, fasting and 2 hr postprandial.  The 2 hr is recommended rather than the 1 hr since the peak blood glucose occurs closer to two hours.  Target ranges are fasting less than 95 mg/dl and 2 hr PP less than 120 mg/dl.  If 20% or more of the values are elevated, the patient should be followed for gestational diabetes. 

Because there is no alteration of the GI –tract in the LapBand™, Oral GTT may be administered as recommended.

Because of the risk of malabsorption, oral drug administration must be carefully monitored.  Extended release preparations are not recommended, oral solution or rapid-release preparations are preferred.  Nonsteroidal anti-inflammatory drugs should be used with caution during the postpartum period to avoid gastric ulceration. When prescribing medications for which the drug level is critical, physicians may need to test drug levels to ensure a therapeutic effect.

Nutritional Status Monitoring
It is highly recommended that if the patient has access to the weight management program that serviced the patient for surgery, they be referred back to the program for close monitoring of their nutritional status.  Most programs provide ongoing follow up after surgery especially during pregnancy.

Weight gain:  Follow the Institute of Medicine’s Guidelines for Weight Gain based on BMI.

Protein:  There are no current industry standards
     ? if patient is < 6 months post-op 1.5 grams/kg IBW
     ? if patient is weight stable 1.2 grams/kg IBW or 60-80 grams daily

Multivitamin/Prenatal:  There are no specific recommendations but common practice is to recommend doubling the MVI/PN intake. 

Vitamin A:  Vitamin A (retinyl acetate and retinyl palmitate) in doses of > 10,000 IU/day may be teratogenic. There has been no toxicity or danger demonstrated with the preform of Vitamin A, beta-carotene.   Choose prenatal vitamins that have Vitamin A in the form of beta-carotene.  Two PNV would give 8000 IU.  Consider  doubling the MVI/PN after the first trimester when major organ development has already occurred.
    
Fat Soluble Vitamins:  Avoid prescribing more than twice the recommended daily allowance of fat soluble vitamins,  A, D, E, K.  

Folic Acid:  Does not differ from conventional recommendations.

Vitamin B12:  Risk for deficiency in this nutrient is low if patients are following the prescribed post-op protocol. 
     ? Gastric Bypass: There is limited gastric acid and intrinsic factor necessary for the adequate absorption
         of B12.  Post-op patients are usually prescribed 500-1000 mcg daily in sublingual or spray form.
     ? LapBand™:  These patients still have an intact GI-tract.  They may continue to take conventional
         forms of B12.

Iron:  Due to altered anatomy of the gastric bypass patient, additional iron supplementation is recommended.  Supplementation should be based on red blood cell indices, serum iron, and/or ferritin levels.  Ferrous fumerate is better tolerated than ferrous gluconate or ferrous sulfate.  1st trimester additional iron needs may be reduced secondary to amenorrhea.  2nd and 3rd trimesters may require iron supplementation due to dilutional anemia.

Recommend
     ? 30 mg ferrous fumerate daily during 2nd and 3rd trimester
     ? check ferritin and iron levels prior to second trimester to catch anemia or decreases in ferritin.  Iron
         stores should be > 300.  If ferritin level is low, start extra iron supplementation.  60 mg ferrous
         fumerate daily for those with iron deficiency or low ferritin. 

Calcium:  For gastric bypass patients, calcium supplementation should be in the form of calcium citrate as reduced gastric acid limits calcium absorption.  LapBand™ patients can still use other forms of calcium. 

Recommend:
     ? 1500-2000 mg calcium citrate with Vitamin D daily
     ? Not to be taken at the same time with iron or thyroid medication as they inhibit absorption.

DHA/Omega-3 fatty acids:  Recommend supplementing DHAs (Expecta) 300mg/day.

 

References:
ACOG Guidelines on Pregnancy After Bariatric Surgery

The Queen’s Medical Center Comprehensive Weight Management Program

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