The authors have declared that no competing interests exist.
The rate of morbid obesity among women of reproductive age continues to rise worldwide. Surgical treatment remains the most effective mean to face it. Anatomical, physiological and nutritional modifications lead to several challenges for pregnancy after bariatric procedures. In spite of routine supplementation after bariatric surgery, vitamin and mineral deficiency frequently appear in bariatric pregnancies. The aim of this review is to summarize the existing data on the prevalence and management of nutritional deficiencies in pregnancy after bariatric surgery.
A comprehensive search of Pubmed Database was conducted for English-language studies using a list of key words.
The most common post-operative deficiencies in pregnancy include iron, vitamin B12, folate, vitamin D and magnesium deficiency. Less common are selenium, vitamin A, vitamin B6 and vitamin C deficiency. Finally, copper, vitamin K, vitamin B1, vitamin E and albumin deficiencies are considered to be relatively rare.
Pregnancy after bariatric surgery has been proven to be safe for both the mother and the fetus. However, there is still the risk of significant nutritional deficiencies with adverse effects on pregnancy and lactation. As a result, a thorough customized nutritional assessment is mandatory for every woman in reproductive age who has undergone a bariatric operation, with strict regular follow-up during pregnancy and lactation.
Obesity has taken an epidemic form during the last two decades. The World Health Organization (WHO) assessed than in 2008 there were more than 1.4 billion overweight and more than half a billion obese adults. Excess body weight is the 5th leading risk factor for global deaths. More than 2.8 million adults die each year due to being overweight or obese
Maternal obesity has turned out to be one of the most commonly occurring risk factors for pregnancy, delivery and postpartum complications, not to mention the negative effects on fertility as it is characterized by polycystic ovarian syndrome leading to oligo- or amennorhea
Maternal risks associated with obesity include increased prevalence of stillbirth and intrauterine fetal death, preterm labor, miscarriage, fetal chromosomal anomalies and macrosomia. Obese women are more likely to suffer from thromboembolism, gestational diabetes and pre-eclampsia. Moreover dysfunctional labour, cesarian section, perioperative complications and postpartum hemorrhage are more common in these women
Therefore, weight loss, ideally before conception, appears imperative. Bariatric surgery (BS) remains the only effective means of treatment for morbid obesity
Two of the most common bariatric procedures are Roux-en -Y gastric bypass (RYGBP) and the vertical sleeve gastrectomy (VSG). During RYGBP, the stomach is divided and a small gastric pouch that can hold approximately 30ml is created, thus inducing a restriction of the amount of food the recipient can ingest. Subsequently, the jejunum is divided 0.6 -1 meter distally to the ligament of Treitz with the distal segment anastomosed to the gastric pouch (gastro-jejunal anastomosis, GJ), thus reducing the absorbing capacity of the alimentary tract. Eventually, the continuity of the alimentary tract is restored with the construction of a jejuno-jejunal anastomosis (JJ) 1-1.5 meters distally to the gastro-jejunal anastomosis. So RYGBP is a combined restrictive and malabsorptive procedure. The VSG on the other hand is a purely restrictive procedure. The greater curvature of the stomach is resected, leaving a narrow vertical tube that can hold a volume of approximately 150 ml
Nevertheless, in both techniques the anatomy of the gastrointestinal tract is modified and this leads to micronutrient deficiencies. Risk factors for this include preoperative malnutrition, decreased food intake, food intolerances, excessive vomiting, inadequate nutrient supplementation and nutrient malabsorbtion. All of these problems are amplified for women in pregnancy or lactation since during both of these conditions the demands for micronutrients are increased
A comprehensive search of Pubmed Database was conducted between April and May 2014. The review covered a period from 1991 to 2014. The keywords which were used individually or in combination were: bariatric surgery (BS), obstetric outcome, nutritional deficiencies, iron, Vitamin D, B12, B6, B1, C, A, E, K, folate, albumin, zinc, magnesium, calcium, biotin, copper, selenium and supplementation.
Many studies have shown that iron deficiency exists already pre-operatively in obese patients and more particularly in female bariatric surgery patients of childbearing age due to heavy menstrual periods. Even more, all patients after bariatric surgery face a decrease in the production of hydrochloric acid, subsequently contributing to a lower iron uptake, since the Fe3+ to Fe2+ conversion is reduced, due to the resection of 75-80% of the stomach and the administration of PPIs (proton pumps inhibitors). Futhermore red meat, which is rich in iron, is less well-tolerated after BS
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Van Rutte et al. |
200 | 1 | 18.5 | 8 | |
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Alexandoru et al. |
40 | 4 | 30 | 7 | |
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Coupaye et al. |
30 | 1 | NR | 30 | |
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Eltweri et al. |
41 | NR | NR | 8 | |
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Saif et al. |
82 | 1 / 3 / 5 | 3 / 10.5 / 0 | 8.6 / 15.8 / 5.6 | |
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Damms-Machado et al. |
54 | 1 | 4.3 | NR | |
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Aarts et al. |
60 | 1 | 43 | NR | |
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Gehrer et al. |
50 | 3 | 18 | NR | |
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Hakeam et al. |
61 | 1 | 4.9 | NR | |
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Toh et al. |
64 | 1 | 11 | 0 |
NR: Not Reported
The main cause of anemia in pregnancy is iron deficiency. Pregnancy anemia can be aggravated by various conditions such as uterine or placental bleedings, gastrointestinal bleedings, and peripartum blood loss. In addition to the general consequences of anemia, there are specific risks during pregnancy for the mother and the fetus such as intrauterine growth retardation, prematurity, feto-placental miss ratio, and higher risk for peripartum blood transfusion
Vitamin B12 deficiency is also very common before and after bariatric surgery
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Van Rutte et al. |
200 | 1 | 11.5 |
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Alexandrou et al. |
95 | 4 | 5 |
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Eltweri et al. |
41 | NR | 20 |
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Moizẽ et al. |
61 | 5 | 12.5 |
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Saif et al. |
82 | 1 / 3 / 5 | 2.9 / 0 / 0 |
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Damms-Machado et al. |
54 | 1 | 17.2 |
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Aarts et al. |
60 | 1 | 9 |
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Gehrer et al. |
50 | 3 | 18 |
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Toh et al. |
64 | 1 | 0 |
NR: Not Reported
Folate absorption occurs along most of the small intestine, mainly in the duodenum and in the jejenum, and depends on pH level, mechanisms of the intestinal wall which have to do with nutrient’s transport, and saturation points
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Van Rutte et al. |
200 | 1 | 12.5 |
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Eltweri et al. |
41 | NR | 3 |
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Saif et al. |
82 | 1 / 3 / 5 | 8.8 / 5.5 / 0 |
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Damms-Machado et al. |
54 | 1 | 13.8 |
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Ruiz-Tovar et al. |
30 | 2 | 0 |
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Aarts et al. |
60 | 1 | 15 |
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Gehrer et al. |
50 | 3 | 22 |
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Toh et al. |
64 | 1 | 0 |
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Hakeam et al. |
61 | 1 | 9.8 |
NR: Not Reported
The mechanisms which affect calcium metabolsim afterbariatric procedures are not clearly understood. Lower Vitamin D - mediated absorption of calcium due to Vitamin-D deficiency, changes in HCl (hydrochloric acid) secretion and intolerance of calcium-rich food after bariatric procedures are pathways which can influence calcium nutrient status. Moreover, hypovitaminosis D may occur due to less sun exposure, increased uptake of Vitamin D in adipose tissue and vitamin D malabsorption caused by bypassing segments of the intestine where it is naturally absorbed. Because of the inverse relationship between the levels of serum Vitamin D/serum calcium and the levels of serum PTH, vitamin D deficiency provoking secondary hyperparathyroidism is frequently observed post-operatively. However, serum calcium levels are usually within the normal ranges
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Coupaye et al. |
43 | 1 | 70 | 0 | NR |
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Van Rutte et al. |
200 | 1 | 36 | 2 | 18 |
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Alexandrou et al. |
40 | 4 | 56.3 | NR | 43.3 |
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Saif et al. |
82 | 1 / 3 / 5 | 34.3 / 55.6 / 42 | 0 / 0 / 0 | 23.2 / 7.7 / 58.3 |
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Moizẽ et al. |
61 | 4 / 5 | 44.4 / 0 | 4.8 / 12.5 | 57.1 / 87.5 |
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Damms-Machado etal. |
54 | 1 | 70.4 | 0 | NR |
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Ruiz-Tovar et al. |
30 | 2 | 3.3 | NR | 3.3 |
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Aarts et al. |
60 | 1 | 39 | 0 | 39 |
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Gehrer et al. |
50 | 3 | 32 | 0 | 14 |
NR: Not Reported
Pregnancy is characterized by many hormonological and metabolic changes
Zinc is a trace element which is only second to iron in concentration in the human body
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Van Rutte et al. |
200 | 1 | 5 |
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Saif et al. |
82 | 5 | 14.3 |
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Moizẽ et al. |
61 | 4 / 5 | 47.6 / 12.5 |
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Pech et al. |
100 | 2 | 14 |
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Salle et al. |
33 | 1 | 18.8 |
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Gehrer et al. |
50 | 3 | 34 |
Since magnesium is an essential trace element for optimal metabolic function, magnesium deficiency may be a risk factor not only for neurological and cardiovascular complaints but also for metabolic syndrome
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Van Rutte et al. |
200 | 1 | 3 |
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Eltweri et al. |
41 | NR | 0 |
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Saif et al. |
82 | 5 | 0 |
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Moizẽ et al. |
61 | 5 | 12.5 |
NR: Not Reported
There are no reports referring to chromium or vanadium deficiency in pregnant women after bariatric surgery.
it is not common, maternal magnesium deficiency has been associated with premature labor, small-for-gestational-age (SGA) neonates, pre-eclamsia and the pathogenesis of the sudden infant death syndrom (SIDS). Tayaka et. al., showed a significant lower level of Mg concentrations in umbilical cord blood in SGA neonates compared to that of control group
Selenium is a trace element with an essential role in human biology
Vitamin A is included in the fat-solube vitamins and its absorption occurs in the small intestine either as retinol (animal sources) or qas caroten (plants and vegetables). Vitamin A plays an important role in cells’ reproduction, differentiation and proliferation and its’ requirements during pregnancy and lactation are higher by 20%
After a bariatric procedure Vitamin A deficiency can arise due to the bypassing of intestinal segments, reduced dietary intake, oxidative stress, lipid malabsoption and excessive vomiting, which can be even more profound during pregnancy
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Coupaye et al. |
43 | 1 | 20 | NR |
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Van Rutte et al. |
200 | 1 | NR | 55.5 |
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Saif et al. |
82 | 5 | 0 | NR |
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Damms-Machado et al. |
54 | 1 | NR | 7.9 |
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Aarts et al. |
60 | 1 | 4 | 48 |
NR: Not Reported
Vitamin K is another fat-solube vitamin which is absorbed primarily in the ileum. It is notable that vitamin K has an already limited placental transfer during pregnancy, but its deficiency is rare. The excessive vomiting or fat malabsorption affecting pregnant women, particularly after bariatric surgery, may lead to a higher risk of vitamin K deficiency and concomitant disorders such as clotting abnormalities and an increased bleeding tendency
Vitamin E, being also a fat-solube vitamin, is mainly absorbed in the small intestine, especially in the terminal ileum. Since the intestinal segment which is bypassed in malabsoptive procedures such as RYGBP is jejunum and not the distal ileum, vitamin E deficiency seems to be uncommon after bariatric surgery. One study reported that hypovitaminosis E was found in 3% of 43 patients who underwent BS one year after the procedure
Water-soluble vitamin B1 is absorbed in the proximal small intestine (mainly in the ileum) and its deficiency may occur due to persistent vomiting, from which pregnant women commonly suffer, reduced intake and malabsorption. Thiamine deficiency has been associated with encephalopathies, namely Wernicke’s encepalopathy and Korsakoff’s syndrome, dry Beri-Beri, ataxia and mental status changes
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Coupaye et al. |
43 | 1 | 23 | NR |
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Van Rutte et al. |
200 | 1 | 9 | 4.5 |
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Moizẽ et al. |
61 | 5 | 0 | NR |
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Saif et al. |
82 | 5 | 30.8 | NR |
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Aarts et al. |
60 | 1 | 11 | 31 |
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Gehrer et al. |
50 | 3 | 0 | NR |
NR: Not Reported
Vitamin B6 concetrations decline during pregnancy as a physiologic adjustment secondary to increased blood volume or as a result of increased requirements for active transport across the placenta
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Coupaye et al. |
43 | 1 | 17 | NR |
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Van Rutte et al. |
200 | 1 | 4 | 47.5 |
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Damms-Machado et al. |
54 | 1 | 17.2 | 9.2 |
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Moizẽ et al. |
61 | 5 | 0 | NR |
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Aarts et al. |
60 | 1 | 0 | 30 |
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Gehrer et al. |
50 | 3 | 0 | NR |
NR: Not Reported
Riboflavin deficiency during pregnancy can result in pre-eclamsia and birth defects including congenital heart deffect and limb deformities
For pregnant women who have undergone bariatric surgery the risk of those deficiencies is greater due to malabsorbtion but there are no specific data referring to these water-soluble vitamins either after RYGBP or after VSG.
Vitamin C is an essential water-soluble vitamin, involved in many biological mechanisms. During pregnancy, serum levels of vitamin C progressively decrease almost by 50%, because of the extra uptake by the fetus and the hemodilution. It’s deficiency except from fatigue, bleeding gums, petechia, crockscrew hair, hyperceratosis, myalgias/arthralgias is also associated with pre-eclampsia, poor fetal growth and premature birth
The evaluation of protein status includes the assessment of the following parameters: 1) total protein, 2) prealbumin and 3) albumin. The majority of the proteins are absorbed in the duodeum. Protein deficiency after BS may occur due to the ensuing anorexia, lower protein uptake, reduced protein digestion caused by poor HCl secretion, and malabsorption. It is associated with loss of muscle, oedema and hypoalbuminaemia. Prealbumin is considered to be an indicative parameter of adequacy of protein intake
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Coupaye et al. |
43 | 1 | 3 | 3 | NR |
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Eltweri et al. |
41 | NR | 0 | NR | NR |
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Saif et al. |
82 | 1 / 3 / 5 | 5.5 | NR | NR |
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Moizẽ et al. |
61 | 4 / 5 | 0 | 0 | NR |
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Damms-Machado et al. |
54 | 1 | 0 | NR | NR |
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Ruiz-Tovar et al. |
30 | 2 | 0 | NR | NR |
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Aarts et al. |
60 | 1 | 15 | NR | NR |
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Gehrer et al. |
50 | 3 | 0 | NR | 4 |
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Toh et al. |
64 | 1 | 0 | NR | NR |
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Hamoui et al. |
118 | 1 | 0 | NR | NR |
NR: Not Reported
The above mentioned research data have shown that obese women in reproductive age suffer quite often from several nutritional deficiencies, even prior to bariatric surgery, and there is a high risk of aggravation of these defeciencies after either RYGBP or VSG for various reasons. Pregnancy can further amplify some of these nutritional deficiencies either by increasing the demand or by decreasing the intake
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65 mg | 30 mg | 40-65 mg |
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5 mg | 3 mg | 4-5 mg |
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4 mg | 4 mg | |
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1200-2000mg oral | - | 2000mg calcium citrate |
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800-1000iu | - | 2000-6000iu |
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8-15mg | - | 15mg |
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- | - | 200-1000mg (if states of deficiency or symptoms occur) |
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300mg | - | Close follow up |
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2-8mg | - | 2-8mg |
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10.000 iu | - | 5.000 iu |
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500mg | - | 500-1000mg |
Further testing should be conducted for the evaluation of more nutrient markers, namely magnesium, PTH, copper and other water-soluble vitamins
The authors have no interest to disclose.