Pregnancy post weight loss surgery is a common and generally safe occurrence.

Just like the workup that occurs prior to the surgery, it is important to include all the team members in the management of the pregnant, post-bariatric patient. It is especially vital to include the bariatric surgeon and the dietician early so as to help avoid or easily identify and treat any nutritional or structural problems that are more common in pregnancy. It may be necessary to perform extra blood tests to ensure nutritional sufficiency as well as potentially increase vitamin supplementation. It is also common for reflux and gallstones to arise in pregnancy, both of which should be considered and screened for in the setting of new abdominal discomfort. In extremely rare circumstances issues can arise from adhesions and internal hernias, especially post bypass surgery. This can lead to small bowel obstruction and ischemia and must be considered in the event of any non-resolving abdominal pain as delays to treatment for have dire consequences.

Vitamin deficiencies do not only effect the mother. Consideration of the infant needs to be taken when screening the post-surgery patient for vitamin deficiency. Specifically vitamin K may be low after bypass surgery which increases an infants risk of heamorrhage. B12 deficiency can contribute to failure to thrive in a breastfed baby. Any gastric surgery can decrease the production of acid due to decreased parietal cells, which is essential for the absorption of folic acid and calcium. There is no standard approach to screening for and managing deficiencies in pregnancy post weight loss surgery. The approach should closely resemble that of the non-bariatric population with more frequent screening and supplementation considered depending on results.

The following recommendations are evidence-based recommendations for the nutritional management of the post-bariatric surgery patient from a task force of the American Association of Clinical Endocrinologists, The Obesity Society, and American Society for Metabolic and Bariatric Surgery.

Guidelines for Supplementation and Laboratory Testing in a Pregnancy after Bariatric Surgery


Laboratory Testing

Treatment ifDeficient or NotResponsive to OralSupplements

Routine Supplementationin Pregnancy


Serum albumin

Protein supplements

60g protein/day inbalanced diet


Total and ionizedcalcium, Parathyroidhormone

1200 mg/d calciumcitrate in addition toprenatal vitamin

Folic acid

Complete blood count,folic acid level

Oral folate 1000 μg/d

400 μg/d containedin prenatal vitamin


Complete blood count,serum iron, ferritin, totaliron binding capacity

Parenteral iron;Consult withnutritionist orheamatologist

Ferrous sulfate300mg 2-3times/day withvitamin C inaddition to prenatalvitamin

Vitamin A

Vitamin A levels

Vitamin Asupplements shouldnot exceed 10,000IU/d in pregnancy

4000 IU/d containedin prenatal vitamin

Vitamin B12

Complete blood count,vitamin B12 levels

Oral crystalline B12350 μg/d or 1000-2000 μg IM every 2-3months; Consult withnutritionist

4 μg/d contained inprenatal vitamin

Vitamin D

25-hydroxy vitamin D

Calcitriol oral vitaminD 1,000 IU/d

400-800 IU/dcontained inprenatal vitamin

*Adapted from Macmillan Publishers Ltd: Mechanick JI, Kushner RF, Sugerman HJ, et al. American Association of Clinical Endocrinologists, The Obesity Society, and American Society for Metabolic and Bariatric Surgery Medical Guidelines for Clinical Practice for the Perioperative Nutritional, Metabolic, and Nonsurgical Support of the Bariatric Surgery Patient. Perioperative bariatric guidelines. Obesity. 2009;17:s1-s70.


Other specific considerations include:

 1. Fetal Growth Assessment

There is a theoretical risk of low-for-birthweight infants. Therefore serial ultrasound every 4 weeks is recommended in the final trimester. It may need to be more frequent if there is poor weight gain or conception occurs within 24 months post-surgery.

 2. Gestational Diabetes

There is a risk dumping syndrome, especially in malabsorptive procedures like a bypass. This occurs when a large glucose load travels directly to the midgut. This causes a rapid spike in blood glucose followed by a reactive increase in insulin secretion. This eventually leads to transient hypoglycemia. It is so named due to the ‘dump’ of sugar and is unrelated to bowel actions (a common misconception). This can thereby be easily triggered by a glucose tolerance test. It is best to consider fasting BSL’s for 1 week if the patient cannot tolerate a large glucose load.

3. Hyperemesis gravidarum

This condition can exacerbate all deficiencies. It is essential to consider thiamine replacement to prevent Wernicke’s encephalopathy.

Please reach out to us if you are looking to become pregnant or are pregnant post bariatric surgery. We are here to help!