Objective: To assess the influence of pre-pregnancy body mass index (BMI), total gestational weight gain (TGWG), and pre-pregnancy surgical success on the nutritional status of vitamin D, calcium, and parathyroid hormone (PTH) in the trimesters of pregnancy of women who previously underwent Roux-en-Y gastric bypass (RYGB).
Methodology: This is an analytical, longitudinal, and retrospective study comprising 42 pregnant women who previously underwent RYGB. Concentrations of vitamin D3, calcium, and PTH were assessed in all trimesters. Anthropometric variables necessary for calculating TGWG, surgical success, and BMI were collected preoperatively and over the trimesters of pregnancy.
Results: A total of 97.1% had vitamin D3 inadequacy at some point in pregnancy. Pre-pregnancy BMI, even when classified as overweight, may have exacerbated the serum concentrations of this vitamin in the third trimester (p = 0.011), and it was significantly lower in women with normal weight and/or obesity (p = 0.039). It was evidenced that both pre-pregnancy BMI and TGWG above the recommended optimal weight can be associated with calcium homeostasis, especially early in pregnancy. It was also shown that surgical success in the pre-pregnancy period may have influenced the serum concentrations of vitamin D in the second trimester of pregnancy (p = 0.013).
Conclusion: This study draws attention to the importance of monitoring the nutritional status of vitamin D3 and calcium in the prenatal period due to its relationship with pre-pregnancy BMI, TGWG, and surgical success.
Keywords: Bariatric surgery; Body mass index; Calcium; Obesity; Pregnancy; Roux-en-Y gastric bypass; Vitamin D.