A meta-analysis of 22,094 patients compared both restrictive and malabsorptive procedures, noting a significant impact in resolution of diabetes mellitus, hypertension, and sleep apnea. Ninety-five percent of AGB patients experienced a resolution in sleep apnea. Thirty-eight percent noted resolution of hypertension, and 48% experienced resolution of type 2 diabetes mellitus (T2DM). Eighty-four percent of patients who underwent the RYGB experienced resolution of hypertension, and 75% experienced resolution of T2DM. The mortality among the procedures is lower in the AGB at 0.1% compared with 0.5% for the RYGB.11
SG is a restrictive procedure that removes an estimated 80% of the stomach, resulting in a tubular-shaped gastric pouch. This small gastric pouch significantly impacts the amount of food that can be consumed. The procedure also seems to alter the hormones that assist in absorbing and metabolizing the food consumed.10 Complications or risks associated with SG include, but are not limited to, weight regain, ulcers, esophageal dilatation, dumping syndrome, and nutritional deficiencies.12
A randomized control trial showed an estimated excess weight loss of up to 66% for SG compared with 48% with AGB at 3-year post- op follow-up. Case studies have shown that RYGB is superior to SG in regards to weight loss and decreasing comorbidities. However, randomized controlled studies show that SG induces weight loss greater or equal to the RYGB.11
The ASMBS considers RYGB the gold standard of weight loss surgery.2,10 RYGB combines restrictive and malabsorptive techniques to induce weight loss.8,11 It is the most commonly performed bariatric procedure, accounting for up to 65% of bariatric surgeries.5 The weight loss induced by gastric bypass can be up to three-fourths of the excess weight and up to a third of the patient's BMI. RYGB consists of the sectioning of a small pouch with surgical staples or cutting.
The pouch is then connected to the distal jejunum through a surgically constructed gastrojejunostomy.5 This results in the remaining stomach and duodenum being bypassed. Some of the complications that may occur with RYGB are similar to SG, including weight regain, ulcers, esophageal dilatation, dumping syndrome, and nutritional deficiencies.12
Several meta-analyses and randomized controlled trials show promising data regarding RYGB. A meta-analysis of 28 studies involving 7,383 patients showed gastric bypass induced an excess weight loss of 62% compared with 49% with laparoscopic AGB. A prospective randomized control trial compared 250 patients who were randomly assigned to have RYGB or AGB. At 4 years postsurgery, RYGB patients showed a 68.4% excess weight loss compared with 45.4% in AGB patients. This confirms findings in a smaller randomized trial that showed excess weight loss up to 66.6% in RYGB and 47.5% in AGB patients.11
The majority of the studies show that RYGB induces greater weight loss when compared with laparoscopic SG and AGB. However, there are a few studies that show the laparoscopic SG to be superior or equal to RYGB in regards to inducing weight loss. All three of the above bariatric surgeries induce weight loss and reduce or resolve comorbidities, improving the quality of life for many patients.10,11
BPD/DS is a malabsorptive procedure that consists of a partial gastrectomy in which a portion of the stomach is attached to the distal segment of the small intestines. This technique bypasses approximately 75% of the small intestines, decreases the stomach's capacity, and decreases the absorption of calories and nutrients, contributing to an excess weight loss of up to 70%.11 BPD/DS is restricted to patients with a BMI above 50 kg/m2 and contributes to approximately 2% of all bariatric surgeries performed in the United States.10,11
BPD/DS is considered by the ASMBS to be the most effective in resolving a patient's diabetes. However, despite the effectiveness of BPD/DS, the procedure is associated with high complications compared to other bariatric procedures. There is also increased risk of protein and vitamin deficiencies, leaks and ulcerations at surgical attachment sites, chronic loose stools, and anemia.10,11
Research is ongoing to additionally evaluate all of these methods. Further detailed discussion of each procedure (risks and benefits) is beyond the scope of this article and should be discussed with a board-certified bariatric surgeon.10,11
Nutritional deficiencies and nutritional guidance during pregnancy
Healthcare providers need to be aware of the types of bariatric surgeries, the process for each, and potential complications so they can properly monitor and advise patients. The techniques used in bariatric surgery alter the structure and function of the gastrointestinal tract. These changes affect how vital nutrients are absorbed and processed. AGB decreases the size of the stomach by the adjustment of the silicon band around the superior portion of the stomach. SG requires the removal of at least 80% of the fundus or top of the stomach.10
The remaining portions of the stomach consist of the antrum and pylorus. The antrum is where food is mixed with gastric fluid. The pylorus serves as a valve (or gatekeeper), controlling the passage of food into the small intestines. The removal of the distal stomach in SG causes the loss of parietal cells (which produce intrinsic factor, promoting absorption of vitamin B12 in the terminal ileum).13
In RYGB, a small gastric pouch approximately 1 oz in volume is created. Then the proximal end of the small intestines (the duodenum) is divided, and the distal end (the jejunum) is attached to the gastric pouch. The duodenum is where enzymes break down food, and the jejunum is where the food particles broken down by digestive enzymes are absorbed.13
Key nutrients, such as iron, calcium, and vitamin B12, are processed or absorbed in the duodenum and jejunum. The decreased gastric area in RYGB results in decreased hydrochloric acid and pepsin production, also contributing to vitamin B12 deficiency. The above-mentioned deficiencies are some of the more common nutritional abnormalities that may be noted in bariatric surgery patients.8 (See Nutritional deficiencies.)14-16
Contraception, family planning, screening for nutritional deficiencies, nutritional counseling, and psychological support are key components to preconception counseling after bariatric surgery. Women who have undergone bariatric surgery are recommended to wait at least 12 months before planning a pregnancy. This recommendation is based on the concern for fetal development during a period of rapid weight loss.17
When selecting a contraceptive method, the patient's age, health history, surgical history, and family planning need to be taken into consideration. Women with heart disease or those who continue to smoke 15 cigarettes or more a day and are age 35 or older should not use combined hormonal contraceptive methods, which increase the risk of adverse cardiovascular events.18 As a result, the World Health Organization (WHO) advises against the use of combined oral contraceptives in women who are less than 42 days postpartum and who smoke.19
The American College of Obstetricians and Gynecologists strongly recommends nonoral methods of contraception for bariatric patients. This is largely due to malabsorptive changes that have been observed with certain bariatric procedures.17,20 The CDC adopted the WHO's Medical Eligibility Criteria for Contraceptive Use, which further outlines recommendations on contraception after bariatric surgery.18 In 2015, the WHO updated the Medical eligibility criteria for contraceptive use.19 (See Contraceptive recommendations after bariatric surgery.)
Close monitoring and referral to a nutritionist should be considered in caring for the postbariatric surgery patient. Nutritional screening and counseling during the preconception period are paramount to decreasing the incidence and severity of nutritional deficiencies. At a minimum, women need to take a prenatal vitamin with 400 mcg of folic acid, 1,200 mg of calcium citrate, 800 international units of vitamin D, 65 mg elemental iron, and 350 mcg vitamin B12.21 PCPs need to assess women for their sequence of eating; proteins should be consumed before fats and carbohydrates. The goal for protein consumption is up to 60 g per day, which may be challenging in patients with a history of RYGB.21
The journey to and through weight loss surgery can be a roller coaster of emotions. Many patients experience a renewed sense of well-being and a reduction of comorbidities. However, some patients, despite having bariatric surgery, continue to struggle with the perception of their body image and maintaining the weight loss. The incorporation of psychological assessments and counseling can help the patient prepare for and adapt to the changes in their bodies and lifestyle.22 Pregnancy, whether planned or unplanned, can trigger the fluctuation of a wide range of emotions.
Women typically experience weight gain during pregnancy, and this may trigger some adverse emotions regarding body image. The healthcare team, including behavioral health specialists, can be a critical source of support. Referral to a behavioral health specialist can be instrumental in helping the patient adjust to the changes and result in continued physical and psychological health.22,23
Bariatric surgery provides an effective method of weight loss for obese women. Surgery substantially lowers the risk of heart disease, diabetes, and cancer as well as pregnancy-related complications. The increased rates of obesity directly coincide with the increased rates of bariatric surgery. As a result, PCPs, in conjunction with other members of the healthcare team, are key to maintaining a woman's health after bariatric surgery and throughout the reproductive years.
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20. Robinson JA, Burke AE. Obesity and hormonal contraceptive efficacy. Womens Health (Lond Engl)
21. Johnson D. Assessing nutritional needs in pregnant patients with prior bariatric surgery. Contemporary OB/GYN
22. Kubik JF, Gill RS, Laffin M, Karmali S. The impact of bariatric surgery on psychological health. J Obes
23. Farahi N, Zolotor A. Recommendations for preconception counseling and care. Am Fam Physician
Keywords:Copyright © 2016 Wolters Kluwer Health, Inc. All rights reserved.
bariatric surgery; obesity; preconception counseling