Assessing nutritional needs in pregnant patients with prior bariatric surgery

Overview: Patients who undergo bariatric surgery, especially malabsorptive procedures, are at increased risk of nutritional deficiencies. Pregnancy may make some of these nutritional deficiencies more severe by increasing demand or decreasing intake, especially if a patient has nausea and vomiting.

Objective: To describe the nutritional deficiencies frequently encountered in patients who have undergone bariatric surgery.

Definition: The 2 most common bariatric procedures performed in the United States are Roux-en-Y gastric bypass (65%) and adjustable gastric banding (24%). Roux-en-Y gastric bypass restricts intake and food absorption, whereas adjustable gastric banding limits only food intake. Risks: Types of nutritional deficiencies seen are: malnutrition, malabsorption of fat, vitamin B12, folate, vitamin B1, iron and fat soluable vitamins (AEDK). Nutritional deficiencies are more frequently encountered in patients who have undergone malabsoprtive procedures compared to restrictive procedures. Pregnancy may make some of these nutritional deficiencies more severe by increasing demand or decreasing intake.

Management: Nonpregnant patients who have had bariatric surgery are commonly prescribed a variety of nutritional supplements because of nutritional deficiencies. Common supplements prescribed are multi-vitamins, calcium citrate, folic acid, iron, and vitamin B12. In patients who have had bariatric surgery, stomach pH is altered and the surface area for absorption decreases. These changes may warrant manipulation in the preparation, route, or dose of nutrient replacements. Liquid or chewable vitamins are better absorbed than tablets. The evidence for routine supplementation of nutritional deficiencies in pregnancy is insufficient to make any strong recommendation. Patients should continue to receive monitoring and supplementation as needed, in collaboration with the bariatric surgery team and medical specialists, and the ob/gyn should remain vigilant for signs and symptoms of nutritional deficiencies. 

Screening/Work-up: Current guidelines suggest checking serum levels of vitamin B12 and folate during pregnancy in women with prior bariatric surgery, along with a complete blood count, iron, ferritin, calcium, and vitamin D levels. The evidence for monitoring of nutritional deficiencies is insufficient to make any strong recommendation.Prenatal care: Care should be taken when administering screening tests for gestational diabetes. In about 50% of patients who have Roux-en-Y gastric bypass, dumping syndrome can occur. Alternative methods, such as home glucose monitoring or hemoglobin A1C measurement, may be considered.