Bariatric surgery is a major treatment option for morbidly obese patients when lifestyle modifications of diet and increased physical activity do not result in weight loss. Bariatric surgeries have increased, especially among obese women in the reproductive age range. A significant aspect of weight loss after bariatric surgery is increased fertility. Weight loss following bariatric surgery, especially with gastric bypass, can be quite rapid and many previously fertility-challenged women become pregnant soon after. It is necessary for clinicians to appreciate the specific nutritional needs of pregnant women after bariatric surgery.

Nutritional deficiencies in the post bariatric surgery pregnant women are a complex problem. Even before surgery, many have some macro and micro nutritional deficiencies. Different types of procedures result in differing nutritional deficiencies. Timing of pregnancy, lab testing, clinical presentation, and supplementation need to be evaluated. It is critical that women who become pregnant within the first or second year post bariatric surgery are managed through a team approach.

Identification of the type of bariatric procedure: gastric band, gastric sleeve, Roux-en-Y-Gastric Bypass (RYGB), or biliopancreatic diversion (gastric bypass) is important. The Band is a placement of an adjustable gastric band that does not bypass the small intestines. Gastric band surgery results in slower weight loss. Similarly, the sleeve gastrectomy reduces the gastric volume. In the RYGB, however, the stomach and duodenum are bypassed completely. There are also newer procedures currently being used and more being developed with the goal of more rapid and sustained weight loss. For all types, the primary basis of weight loss is malabsorption, and so, with increasingly more rapid weight loss there is a corresponding increase in nutritional deficiencies.

Protein deficiency is the major macronutrient concern in all types of bariatric procedures. Consumption of adequate protein intake is difficult after surgery and is managed in a variety of ways such as increased dietary intake, liquid supplements, and parental nutrition. Clinical presentation of protein deficiency is hair loss and edema. Laboratory values will show anemia and hypoalbuminemia. Micronutrient deficiencies can occur. Micronutrients are essential minerals (calcium, iodine, iron, and magnesium), trace elements (copper, selenium, zinc), and water- and fat-soluble vitamins. These deficiencies may be present even before surgery, and last up to 18 months post procedure; iron deficiency and anemia up to 5 years after surgery (Bal, Finelli, Shope, & Koch, 2012). Many bariatric nutritionists prescribe prenatal vitamins, which must be given in chewable form (no large pills can be swallowed). Of particular concern in pregnancy are deficiencies in folate, Vitamin K, Vitamin B12, iron, zinc, and calcium, although all micronutrients may be deficient and should be monitored. Patient education on dietary sources of these nutrients is problematic at best and supplementation may be inadequate due to reduced bioavailability in a multivitamin source (e.g., B12 is degraded by copper; calcium inhibits iron absorption). Vitamin and mineral intake likely have greater efficacy than a multivitamin supplement. Attention to route and type of supplement is critical.

Assessing deficiencies by clinical symptoms can be a challenge as some deficiencies' symptoms overlay with those of pregnancy: Vitamin B1-nausea, vomiting; B5-depression, hypotension; B12-depression, paresthesia; Vitamin C-malaise, gum disease; Vitamin E-anemia, muscle weakness; Vitamin K-bleeding disorder; Iron-fatigue, shortness of breath; Zinc-hair loss; Selenium-fatigue, leg swelling. It is important to know the baseline post bariatric surgery and prepregnancy micronutrient status. Meticulous attention must be given to laboratory testing and be done according to recommended guidelines. Recent evidence shows that although the prevalence of micronutrient deficiencies is increasing (due to type of procedure), monitoring of patients at follow-up is decreasing (Parrott et al., 2017). Understanding the potential nutritional deficiencies, the importance of monitoring, and supplementation issues in the post bariatric surgical pregnant women is important to provide the best care.

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