The Impact of Bariatric Surgery on Obesity-Related Infertility and Pregnancy Outcomes - Article Example

?The Impact of Bariatric Surgery on Obesity-Related Infertility and Pregnancy Outcomes INTRODUCTION There has been a significant increase in prevalence of obesity in the United States. More than one-third of women in the United States are obese and fall under the category of having a body mass index (BMI) of thirty or more.14 Obesity is a condition which is very difficult to manage. Diet, exercise and behavioral modifications are ideal but gaining weight even after that is quite common. In 1991 the NIH conference on gastrointestinal surgery for obesity recommended bariatric surgery as the only effective treatment for those with BMI >40 as well as those over 35 with significant comorbidities.5 Women of reproductive age account for 49% of patients undergoing bariatric surgery. Obese women are more likely to face infertility than women with a normal BMI. Although it has been shown that bariatric surgery is a good treatment for obesity, the effect on fertility and pregnancy outcomes has been questioned. Evidence is beginning to mount that some there are improvements in these areas after weight loss induced by bariatric surgery. FERTILITY IN OBESE WOMEN The relation of fertility to the nutritional status of the mother is important. The nutritional effects on pregnancy during and before conception have serious impact on the general health of the baby and the mother. The Body mass Index (BMI) analysis, of a woman before pregnancy, is used to determine her nutritional status. A BMI count of 18.5 could indicate serious nutritional deficiency making the mother unfit to carry a baby. If the BMI is above 25, it will also have an effect on conception.23 The presence of excess adipose layer in obese women affects the regulation and a control of sex hormones availability which determines fertility and conception. This is because sex hormones such as androgens are stored in this fat layer. Moreover, production of estrogen and the release of hormone binding globulin are also affected by the amount of body fats.23 Obesity has also been shown to cause insulin resistance which is associated with increase in infertility. Body weight is very crucial in puberty. Teenagers with high body weight mature faster and are more likely to get their first menstrual flow earlier than those who have absolute weight or are underweight. Obesity in adolescent years is also likely to result in oligomenorrhea, long menstrual cycles and amenorrhea.23 Many women are not at an ideal weight and nutritional status before attempting to conceive. Women need a certain minimal amount of body fat to be able to reproduce, but fat in excess has been linked to oligoannovulation, annovulation, polycystic ovarian syndrome (PCOS), infertility and poor response to assisted fertility treatments.19 Many obese women are hyperinsulemic and have endocrine reports characteristic of PCOS, one of the leading causes of female infertility.4 Insulin and luteinizing hormones are increased, the follicle-stimulating hormone and luteinizing hormone ratio is abnormal and the midluteal progesterone is low. These hormone profiles demonstrate annovulation. Annovulation is a major problem in obese women but it has been shown that even obese women with regular cycles have an increased time to achieve pregnancy than women of normal weight.21 Obese women exhibit abnormal LH pulsatility, which may affect ovarian follicular steroid development.7 This may lead to poor oocyte quality and a change in endometrial development by affecting the function of the corpus luteum in the luteal phase. It has also been shown that a high-fat diet is associated with lipid accumulation in oocytes, which leads to poorer oocyte quality.8 MATERNAL AND FETAL EFECTS OF OBESITY Apart from the fertility related issues of obesity, there are other issues impacting the mother and the fetus. Women who are obese and pregnant are at increased risk of pregnancy induced hypertension, gestational diabetes, labor induction, cesarean delivery, postpartum hemorrhage, post-operative infections and thromboembolic events.2,3,9,10,14,Obesity also increases the rate of spontaneous abortions.12 Miscarriages in obese women can be caused by impaired progesterone release due to low insulin resistance and this can inhibit normal corpus luteum function. An obese mother places the fetus at risk of stillbirth, macrosomia, birth trauma, and birth defects and childhood obesity. 13 Conception causes numerous changes in the mother’s metabolism to increase oxygen, nutrient and energy supply to the growing fetus. In women with normal body weight, these changes do not create any risk to the mother or the fetus. However, in obese women, who already have excess glucose in their body, these metabolic changes can lead to complications such as pre-eclampsia and gestational diabetes mellitus. The risk of getting these two disorders increases with the level of obesity. Gestational hypertension is also common with pregnant mothers. During gestation, obese mothers may have to undergo a cesarean delivery which increases the risk of maternal or fetal death. Gestation period for obese women is longer than that of normal women.23 They also develop some complications such as infected wounds, venous thrombophlebitis, endometritis and excessive blood loss compared to the normal women.3,19,20,21,23. Due to hemorrhage, most of these women experience post partum anemia which exposes them at higher risk of infections.23 Effects of Obesity on Birth Outcomes Obesity in pregnant mothers increases the risk of congenital defects in their fetus compared to those borne of women with normal weight.13,23 This is because, the amount of fat in the adipose tissues of the mother, alters the development of the fetus in the sensitive embryonic stage.13,23 Neural tube defects have been reported to have an occurrence as twice as much as that found in normal women.13 Spinal bifida is also the most common disorder associated with Obesity.23 Other abnormalities common in children born of obese mothers include cleft lips, hydrocephaly, heart anomalies and abdominal wall abnormalities.13,24 It is speculated that the deficiencies in glycemic control could be partly responsible for these conditions. A diet with high glycemic index can be a predisposing factor. A study revealed that obesity is also a risk factor for still births and intrauterine fetal deaths.11 High level of maternal BMI has been cited to cause increase in the weight of the newborns which again comes with its own complications. The complications that are experienced during birth, prolongs the time of their first lactation, and also compromise with lactogenesis.23 BARIATRIC SURGICAL PROCEDURES Bariatric Surgery or Weight Loss Surgery is considered the most successful treatment for morbid obesity in obese adults. Patients are eligible for weight loss surgeries when they have a Body Mass Index > 40kg/m2 or a Body Mass Index > 35kg/m2 when having co-morbid conditions like diabetes. The patient should also exhibit a history of failed sustained weight loss on supervised weight – reduction programmes. Bariatric Surgery promotes weight loss via restriction (it limits the amount of food ingested), inducing malabsorption ( bypassing parts of the small intestine) or a combination of both. 11 There are several different types of bariatric surgery performed worldwide in open procedures and laparoscopically. The most common procedures that are performed today are the Roux-en-Y gastric bypass (RYGB) , adjustable gastric banding(AGB), vertical sleeve gastrectomy (VSG) and biliopancreatic diversion (BPD).The most common restrictive procedure is the AGB, and the most common restrictive and malabsorptive procedure is the RYGB. In restrictive procedures weight loss is predominantly due to the restriction of nutrient intake. Restrictive and malabsorptive procedures restrict nutrient intake as well but also create a physiological condition of malabsorption. A laproscopic adjustable gastric band(AGB), commonly called a Lap-Band is an adjustable silicone device that is placed around the top of the stomach. The band squeezes to form a pouch and after banding the stomach can hold approximately one ounce of food. A silicone tube attaches the band to a device under the skin and by injecting saline the band can be adjusted to control weight loss. Gastric banding is considered the least invasive and the only reversible weight loss surgery. The band adjustability is an appealing aspect that allows room for adaptation to the nutritional requirements necessary for a healthy pregnancy. Average weight loss at two years is 50% of excess body weight or 25% of BMI. Gastric banding is generally a very safe operative procedure but the revision rates due to a band that has moved or broken is considerable. Long-term complications of the gastric band include vomiting, gastric prolapse, stomal obstruction, esophageal and gastric pouch dilatation, gastric erosion and necrosis, and access port problems.6 For pregnancies after AGB, one of the issues is to manage the band. A common practice is to deflate the band either prior to or early in pregnancy to lessen complications such as band migration and nausea in pregnancy.6 RYGB combines food restriction with a degree of malabsorption by decreasing the length of the intestinal tract. The procedure starts with the creation of a gastric pouch that is separated from the remaining stomach. The pouch empties directly into the distal jejunum through a gastrojejunostomy. Bypassing the remaining stomach, the duodenum and a portion of the proximal jejunum reduces the absorptive area. This procedure can be performed laparoscopically or by an open technique. Weight loss averages at 65-70% of excess body weight or 35% BMI one to two years after the surgery. RYGB can be complicated due to stomal stenosis, marginal ulcers, staple lie disruption, internal hernias and nutrient deficiencies including folate, calcium and vitamin B12. 1 One of the routine recommendations after bariatric surgery is to minimize or eliminate the intake of simple carbohydrate- dense foods and beverages after RYGB as this can precipitate dumping syndrome ( a group of symptoms which includes abdominal pain, cramping, nausea, diarrhea, flushing, tachycardia, light headedness and syncope). It s caused due to the release of gut peptides released when food bypasses the stomach and enters the small intestine directly. As such, an alternative method to the 50g glucose test conducted at the 24th week for gestational diabetes screening is therefore recommended. One such example includes home glucose monitoring with fasting and post prandial values during one week in the 24-28 week period.11 . Outcomes of Bariatric Surgery Several studies have compared outcomes between the pregnancies conceived early ( less than 12 months of surgery) versus the late periods ( between 12 and 18 months after surgery). The largest study conducted under this point included 104 pregnancies conceived during and 384 pregnancies conceived after the post operative year of Bariatric Surgery elucidated that hypertension, diabetes, or bariatric complications were not different between the two groups. The neonatal outcomes like the malformations and mean birth weight [3048grams (12months of surgery) versus 3123 grams (> 12 months of surgery)] were statistically insignificant (p=0.181).11,24 A small percentage of early pregnancies occurred after infertility treatments (4.8% after clomiphene and 1.9% after in vitro fertilization) suggesting that there is no need to wait for 12 months after bariatric surgery for attempting conception.11 Following bariatric surgery there is often resolution of conditions that leads to improved fertility. Weight loss after bariatric surgery improves the hormonal changes related to polycystic ovary syndrome (PCOS) reducing anovulation and increasing fertility. 4 In a study of 142 women with infertility related to their weight, 69 became pregnant after having one of these procedures in the following 2.5 years and all of the pregnancies proceeded without complications and ended in live births.12 There was no significant difference in the pregnancy rate among patients that had gastric lap bands or RYGB. The patients that lost more than 5 BMI were more successful in getting pregnant.24,25 Study results have shown that pregnancy after bariatric surgery is safe and that the overall outcomes are similar to women that are not obese. The rates of morbidities including macrosomia, pregnancy-induced hypertension, preeclampsia, and gestational diabetes are lower in patients who have undergone bariatric surgery than those of obese women and are similar to those of non obese women in the general population. Studies have also shown improvements in neonatal outcomes. Obese women are more likely to experience intrauterine demise and early neonatal death. 11,24,25 The greatest concern after a bariatric surgery is the maternal nutrition. Anemia is a common complication after RYGB surgery (10.2% ) and the reason is the iron deficiency.24 In some cases nutritional deficiencies are also common in pregnancies after bariatric surgery.24 A report revealed that 39 pregnancies indicated protein and micronutrient deficiencies- 53.4% vitamin B12, 16.1% folic acid, 6.7% iron, 41.7% ferritin, 16.7% calcium and 10.3% albumin.24 Most literatures support the fact that the risk of pregnancies are not increased after a bariatric surgery.24,25 However published articles have smaller numbers ( largest to date is 298 deliveries after bariatric surgery) and had varying control groups including obese women without prior bariatric surgery. The common observations in these studies reflect are less hypertension (gestational and preeclampsia combined) and diabetes in pregnancies after bariatric surgery with low occurrences than compared to their obese counterparts who did not have a bariatric surgery.11,24,25 Cesarean delivery data have been found to be conflicting but the overall trend is that of increased cesarean sections after bariatric surgery ( For example, more than 2/3 rd of the 39 pregnancies conceived after a bariatric surgery in a single centre were delivered by cesarean sections).11 Lapolla et al reported 28.2% cesarean in normal weight pregnancies versus 65.8% cesareans in 120 obese pregnancies and 45.9% cesareans in 83 pregnancies after AGB.25 An improvement in obesity related co-morbidities during a pregnancy after bariatric surgery is not surprising in the view that weight control has occurred. Reports of infant birth weight should be interpreted with caution as because there is a trend for more small for gestational age infants(SGA) and fewer large for gestational age infants(LGA) with a lower mean birth weight in pregnancies after bariatric surgical procedures. This might be a concern given the potential for smaller weight being attributed to nutritional deprivations.24 There were no significant differences in the SGA infants when pregnancies after bariatric surgeries were compared to normal groups. This was also true in a group of patients that lost weight during pregnancy-0% SGA in weight loss group compared to 2.9% in the group that gained 0-10 kg.24 If a decrease in birth weight represents a loss of nutrition from metabolic changes or it increases risk of future complications like adult chronic diseases of hypertension, or diabetes in the offspring than this would be a matter of concern. 11,24,25 The perinatal outcomes after bariatric surgical procedures must be interpreted in the light of the BMI of the patient at the time of pregnancy. It is noted that many patients are still obese after the intervention of bariatric surgery. For example, Lapolla et al reported a mean pre-pregnancy BMI of 35kg/m2 and around 41% of patients were still obese after bariatric surgery.25 This finding may be due to the persistent high rates of complications like hypertension and diabetes and also impact pregnancy counselling regarding the risk for adverse outcomes. 24 A conventional weight loss program including diet modification, exercise, and therapy should have been attempted. When the conventional attempts fail then bariatric surgery is the most successful method of weight loss. Bariatric surgery provides lasting and significant reductions in body weight (>60% long-term excess weight loss), correction of many comorbidities, and improved survival.17 It increases fertility, reduces maternal and neonatal complications compared to that of obese women. Evidence has demonstrated that women are able to tolerate pregnancy and have minimal complications after bariatric surgery procedures. Long term follow up studies indicated that rate of obesity in children decreased by 52% after bariatric surgery of mother and also there was a reduction of 42% of severe obesity.24 RECCOMENDATIONS FOR PREGNANCY AFTER BARIATRIC SURGERY 23,24,11,25 Although bariatric surgery decreases many adverse obstetric outcomes it is important that the patient and provider be educated about possible complications. An informed patient is able to minimize risks and improve outcomes. A two-year interval is recommended before attempting to get pregnant.16 Contraception is important during this period because this is the period when maternal nutritional status is not optimal and there is a period of very rapid weight loss. Contraception and preconception counselling should be provided for all women of the reproductive age undergoing bariatric surgery. This is important because pregnancy rates following bariatric surgery are twice those in the general adolescents (12.8% versus 6.4%) which indicate chances of oral contraceptive failure and hence non oral contraceptive measures should be considered. Pregnancy during this interval will also affect the amount of weight a person can lose from the surgery. By the time the rapid weight loss has passed and the patient is stabilized on supplementation the pregnancy and delivery is less risky to the mother and fetus. The patient’s nutritional status should be closely monitored following the procedure. In particular RYGB patients are at risk of nutritional deficiencies because of the malabsorptive mechanism. Anemia and changes in hemoglobin levels are complications of bariatric surgery. Iron is absorbed in the duodenum that is bypassed in RYGB procedures. Iron deficiency is most likely to be of clinical significance in menstruating women. Vitamin B12 absorption requires stomach acid to dissociate it from foods, and R and intrinsic factors secreted by the gastric mucosa to permit its absorption in the distal ileum. This can be disrupted by gastric bypass surgery resulting in B12 deficiency. There may also be deficiencies of folic acid and calcium. It is recommended that women post-bariatric surgery be prescribed lifetime replacement therapy that includes ferrous sulfate, 500 to 1000 mg B12 daily, and 1200 mg of oral calcium citrate daily. All reproductive-age women should receive at least 400 mg of folic acid daily but it is unclear whether gastric bypass patients require greater folic acid doses to achieve the same protective effects as the general population. With folic acid supplementation it appears that post-op women are not at a high risk for fetuses with neural tube defects. 22 It is important for all pregnant women that have had a weight loss surgery to be screened through second trimester maternal serum alpha-fetoprotein and ultrasound. Protein needs will go up to about 60 grams per day. A nutritionist in post-op clinics can monitor most post-bariatric surgery patients. Close evaluation by the bariatric surgeon to diagnose nutritional deficiencies or wound complications plays an important role in achieving positive outcomes during pregnancy. If deficiencies are present they should be corrected preconceptionally. Due to the risk of malabsorption , oral drug administration must be carefully monitored in women having a gastric bypass surgery. Extended release preparations are not at all recommended, oral solutions or rapid release preparations are preferred. Non steroidal anti-inflammatory drugs should be used with caution during the post partum period to avoid gastric ulceration. It is always advisable to test the drug levels of a patient to ensure a therapeutic effect before prescribing a drug to any such patient who have undergone bariatric surgery CONCLUSION In conclusion, evidence suggests pregnancy after bariatric surgery is safe and has good outcomes. Rates of many adverse fetal and maternal outcomes are decreased in women who become pregnant after having had bariatric surgery compared with pregnant women who are obese. Efforts should be made to educate and counsel pregnant women about weight gain and healthy lifestyle during pregnancy. Both non-surgical and surgical weight loss can improve fertility and outcomes. Lifestyle modifications might be a better approach for an overweight individual. However for an obese patient that has attempted lifestyle modifications in the past or for a patient older than thirty-five it may not be the best option. Preconception interventions may offer more potential for an impact on subsequent reproductive and pregnancy outcomes. KEY POINTS Bariatric surgery provides lasting and significant reductions in body weight, correction of many comorbidities, and improved survival. Bariatric surgery improves obesity-related PCOS, annovulation and irregular menses. Rates of negative outcomes are believed to be lower in women who become pregnant after bariatric surgery compared with pregnant women who are obese. It is recommended that a woman wait 2 years post bariatric surgery before attempting to get pregnant to maximize weight loss and minimize negative outcomes. REFERENCES 1.Buchwald H.(2005) Consensus conference statement bariatric surgery for morbid obesity: health implications for patients, health professionals, and third-party payers. 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Maria Grazia Dalfra, Luca Busetto, Nino Cristiano Chilelli & Annunziata Lapolla.(2012) Pregnancy and foetal outcome after bariatric surgery: a review of recent studies Journal of Maternal-Fetal and Neonatal Medicine; Early Online: 1–7 25. Lapolla A, Marangon M, Dalfra MG, et al.(2010): Pregnancy outcome in morbidly obese women before and after laparoscopic gastric banding. Obes Surg 20:1251-1257. Read More