Nutritional deficiencies in pregnancy after bariatric surgery
Since bariatric surgery is becoming more prevalent due to the increase of adult obesity in the U.S., obstetricians must be aware of their patients’ history and the risks of pregnancy. Bariatric surgery can reduce the complications that obesity brings but increase the risk of nutritional deficiencies in pregnancy. In a recent national survey, it has been estimated that more than 60 percent of women age 20-39 are overweight - half of which are obese. Obesity has been associated with decreased fertility and patients who become pregnant have higher risk of hypertension, gestational diabetes mellitus, birth defects, death and stillbirth. The two most common types of bariatric procedures are restrictive (gastric banding) and restrictive/malabsorptive (gastric bypass). The results of both types of procedures lead to rapid weight loss, improvement of polycystic ovarian syndrome, ovulation and irregular periods, and can result in higher fertility rates. It is generally recommended that a patient not get pregnant for at least one to two years after bariatric surgery. After bariatric surgery the typical caloric intake generally drops to 700-900 calories per day.
What are the nutritional deficiencies noted in pregnancy after bariatric surgery?
- Protein deficiency − often produced by intolerance of protein-rich foods and diary foods. In the patient, low protein can lead to hair loss and poor wound healing. Studies have suggested that protein deficiencies in pregnancy might worsen nausea and vomiting in early pregnancy and play a significant role in anemia in pregnancy.
- Calcium − deficiency produced by inadequate consumption or absorption. Inadequate calcium levels can lead to maternal bone loss, reduced breast milk calcium levels and inadequate fetal skeletal mineralization. Studies show that the concentration of calcium should be 2000 mg daily during pregnancy.
- Vitamin D − inadequate levels of vitamin D can lead to rickets in childhood and decreased immune system function in adulthood. Dysfunction of the immune system has been associated with increased risk of cancers, diabetes and heart disease. In pregnancy, studies have suggested an increased risk of premature labor and decreased fetal growth. Supplementation should be 1000-2000 IU daily throughout pregnancy.
- Iron − iron deficiency anemia is common after bariatric surgery and may be exaggerated in pregnancy. If the mother is iron deficient, the baby may not be able to absorb iron from the mother and may be anemic. Pregnant women are recommended to consume 40-65 mg of a ferrous form of iron daily.
- Vitamin B12 − absorption is impaired and should be supplemented. Low B12 can lead to anemia in the mother and her fetus. Studies have shown that low B12 levels can lead to neurological disorders in the child including decreased ability to concentrate, problems with forming abstract thoughts, depression and memory impairment. At present, B12 supplementation during pregnancy should be 3-10 mcg sublingual daily or 1000 cg injection monthly.
- Folic acid − inadequate levels of folic acid have been associated with birth defects including spina bifida, improper development of the skull, brain and spinal column, and premature birth. After bariatric surgery, the recommended dose is 4 mg of folic acid daily.
- Vitamin K − decreased vitamin K absorption and fat malabsorption during pregnancy after bariatric surgery can lead to increased risk of skeletal malformations and intracranial bleeding.
- Vitamin A − occurs in over 10 percent of patients after bariatric surgery and can be worsened during pregnancy. Vitamin A deficiencies have been associated with bronchopulmonary dysplasias, increased susceptibility to infections and increased mortality. Current recommendations are to use beta-carotene supplementation during pregnancy.
- Zinc − levels often decrease by 30 percent after bariatric surgery. Low levels of zinc have been associated with premature delivery, low birth weight, spina bifida and abnormal fetal development. Current dosage is 15 mg each day.
- Magnesium − low levels in pregnancy are associated with reduced fetal growth and premature labor. Current recommendations are 200-1000 mg daily.
- Iodine − deficiencies occur often in normal pregnancies as well as after bariatric surgery. Iodine is essential in normal development of the thyroid gland in the fetus. The World Health Organization recommends 250 mcg of iodine daily.
- Antioxidants − vitamin C, E, selenium and lycopene – can lead to decreased fetal growth and premature deliveries. Deficiencies in selenium have been associated with higher risk of miscarriages.
If you have had bariatric surgery and are planning to get pregnant, a preconception consult can help establish needs prior to pregnancy. Talk with your physician about pregnancy and the manner in which monitoring of the pregnancy can be accomplished. Listen to the recommendations of your physician and let your physician monitor you as he or she feels best, both for your safety and the safety of your baby.