Obesity Flashcards
Ref: IOM 2009 guidelines
2009 IOM guidelines for weight gain in twin pregnancy
BMI 18.5-24.9 - 37-54 lbs
BMI 25-29.9 - 31-50 lbs
BMI 30 or greater - 25- 42 lbs
2009 IOM Weight Gain Guidelines
Prepreg BMI - Total Wt - lbs/wk in 2/3 Trim <18.5 - 28-40 - 1 lb/wk 18.5-24.9 - 25-35 - 1 lb/wk 25-29.9 - 15-25 - 0.6 lb/wk 30.0 - 11-20 lbs - 0.5 lb/w
Micronutrient supplementation after Roux-en-Y gastric bypass (RYGB)
Vitamin B1 (thiamine) 1.4 mg Vitamin D 400 IU Vitamin K 120 mcg Zinc 11 mg Biotin 30 mcg Iron 65 mg Folate 800 mcg Calcium citrate 1200 mg Vitamin B12: oral or sublingual: 350 to 500 mcg/day, intramuscular: 1000 mcg/week, intranasal: 500 mcg/week.
These daily requirements can typically be met with a prenatal vitamin in addition to calcium and vitamin B12 supplementation. Additional iron and folate may also be required with certain prenatal vitamins. Chewable and liquid prenatal vitamins are an option for women who cannot take a large prenatal vitamin.
Screening for micronutrient deficiencies in pts s/p RYGB
We suggest screening for micronutrient deficiencies to individualize therapy and adjust doses as needed. The importance of monitoring was illustrated by a study that observed various micronutrient deficiencies during pregnancy in spite of prophylactic supplementation [56]. We obtain the following laboratory tests preconceptionally or at the first prenatal visit [57]:
Complete blood count Ferritin Iron Vitamin B12 Thiamine Folate Calcium Vitamin D
Identified deficiencies should be corrected and monitored with monthly assessments. Further surveillance of blood count, iron, ferritin, vitamin B12, calcium and vitamin D is performed every trimester [25,57]. Persistent deficiencies should be corrected with increased oral dosages or parenteral forms of iron, vitamin B12 and vitamin D.
Supplementation and screening should continue following delivery in women who breastfeed (see ‘Postpartum’ below).
Early screening for GDM
Screening for gestational diabetes is optimally performed at 24 to 28 weeks of gestation. However, it should be done as early as the first prenatal visit if there is a high degree of suspicion that the pregnant woman has undiagnosed type 2 diabetes (eg, marked obesity, personal history of gestational diabetes, glycosuria, or strong family history of diabetes).
Screening for GDM if s/p RYGB
The glucose challenge test used to screen for gestational diabetes is typically not well tolerated in women with prior Roux-en-Y gastric bypass (RYGB) due to dumping syndrome, which occurs in approximately 50 percent of these patients [58]. This phenomenon follows ingestion of food or drinks containing high amounts of refined sugars. As a result of the hyperosmolar environment, fluid shifts rapidly from the intravascular compartment to the small bowel lumen causing distension, cramping, nausea, vomiting, and diarrhea. Tachycardia, palpitations and diaphoresis are also common, and may be related to intravascular depletion or a hyperinsulinemic response and reactive hypoglycemia.
To avoid the possible occurrence of dumping syndrome, we generally recommend that women with RYGB avoid the standard 50-g glucose challenge test used to screen for gestational diabetes. We, along with others, suggest following fasting and post-breakfast blood sugars for one week as an alternative [25,59]. Patients who regularly drink and tolerate sugared soft drinks are an exception; these women probably can tolerate a standard glucose challenge test. A third option is to measure glycated hemoglobin (A1C) and assume overt diabetes is present if it is elevated (≥6.5 percent); women with a normal A1C should undergo screening as described.
Dumping syndrome typically does not occur in women who have undergone restrictive-type bariatric procedures such as gastric banding. These women can undergo standard testing for GDM.
Treatment of GDM in women s/p RYGB
Although conventional treatment of GDM involves nutritional therapy and insulin, some clinicians use oral anti-hyperglycemic agents, such as glyburide or metformin. If these agents are used, it should be noted that oral agents may not be absorbed completely after RYGB due to bypass of the duodenum
Complications of bariatric surgery
The most common late sequelae of bariatric surgery are mild nutritional deficiencies, which are readily treated with replacement therapy. (See ‘Micronutrient supplementation’ above.) Small bowel obstruction after RYGB is an uncommon but life-threatening complication that requires a high index of suspicion and early evaluation for the disorder when patients present with often nonspecific abdominal symptoms.
We recommend a low threshold for obtaining abdominal computed tomography (CT) in women post-RYGB with abdominal pain. Radiologic studies, including abdominal CT, may not reveal obvious bowel obstruction in patients with internal herniation; therefore, maintaining a high index of suspicion and early consultation with a bariatric surgeon are warranted in patients with gastrointestinal complaints, and possibly fever and/or leukocytosis [71]. Exploratory surgery may be necessary. Two reported maternal deaths were associated, in part, with a delay in diagnosis and surgical intervention
Fetal growth assessment in pts s/p bariatric surgery
Given the inconsistent data regarding the risk of IUGR and SGA in post-bariatric surgery pregnancies (see ‘Growth restriction’ above), we suggest performing one or two ultrasound examinations to evaluate fetal growth in the third trimester, especially in women with poor weight gain.
Pregnancy interval after bariatric surgery
We suggest delaying pregnancy for 12 months following bariatric surgery (Grade 2C). This provides time to optimize weight loss and reduce potential adverse effects of nutritional deficiencies. However, women who conceive proximate to their bariatric surgery can be reassured of a likely favorable pregnancy outcome with optimization of nutrition and careful monitoring and follow-up.
Observational studies have found that the time to conception after surgery does not affect the risk of obstetrical and neonatal complications [13,19-23]. As an example, a study that stratified 52 post-gastric bypass patients into groups by surgery-to-conception intervals of ≤18 months versus >18 months and ≤12 months versus >12 months found no statistically significant differences between these groups in terms of adverse obstetric or neonatal outcomes. There was no difference in growth restriction, preterm delivery, preterm premature rupture of membranes, gestational diabetes, hypertension, cesarean delivery, Apgar scores, or birth defects [19].
