Up to 80% of patients who undergo bariatric surgery are women of childbearing age. Coupled with improved fertility in women with obesity after bariatric surgery, pregnancy postbariatric surgery has become increasingly more common. Although numerous studies have evaluated associations of bariatric surgery with pregnancy outcomes, the effect of maternal nutritional status on maternal and perinatal outcomes is not well established. We used Medline and Embase databases and a manual search of references for articles published until June 2018 to conduct a systematic review on nutritional status after bariatric surgery and its association with maternal and perinatal outcomes. Of the 306 initially identified articles, 27 met the study inclusion criteria, comprising 2056 women with pregnancies after bariatric surgery. Deficiencies were reported in maternal concentrations of vitamins A, B1, B6, B12, C, D, K, iron, calcium, selenium, and phosphorous. The only adverse events documented for these deficiencies encountered during pregnancy were anemia (vitamin B12, iron), night blindness (vitamin A), and urinary tract infections (vitamin A, D). This systematic review suggests that various micronutrient deficiencies are common among pregnant postbariatric surgery patients. Nevertheless, despite the concern that these deficiencies could adversely affect pregnancy outcomes (e.g., lower neonatal birth weight), evidence of such is lacking. Further prospective studies are warranted to confirm our findings and better delineate the optimal supplementation regimen during pregnancy after bariatric surgery.