Vitamin K1 monitoring in pregnancies after bariatric surgery: a prospective cohort study

Area of Science:

• Obstetrics and Gynecology
• Maternal-Fetal Medicine
• Nutritional Science

Background:

• Maternal vitamin K1 deficiency during pregnancy after bariatric surgery is linked to neonatal intracranial bleeding and birth defects.
• Screening and supplementation strategies are crucial for managing vitamin K1 levels in this high-risk population.

Purpose of the Study:

• To investigate the impact of screening and vitamin K1 supplementation on serum K1 levels in pregnant women who have undergone bariatric surgery.
• To compare first-trimester vitamin K1 levels and prothrombin time (PT) between pregnant women with and without a history of bariatric surgery.

Main Methods:

• A prospective cohort study involving 49 pregnant women with a history of bariatric surgery.
• Nutritional deficiencies were screened, and vitamin K1 supplementation was administered for low serum levels.
• Vitamin K1 levels and PT were compared with a control group of 27 non-surgical pregnant women during the first trimester.

Main Results:

• Most pregnant women, regardless of bariatric surgery history, exhibited low vitamin K1 levels (<0.8 nmol/l) in the first trimester.
• Significantly lower mean vitamin K1 levels were observed in the bariatric surgery group compared to controls (0.44 vs. 0.64 nmol/l; P = .016).
• While PT remained within normal ranges, the bariatric surgery group had higher mean PT (111.3% vs. 98.9%; P<.001). Vitamin K1 levels increased by the third trimester in the surgical group, and PT also increased significantly across trimesters.

Conclusions:

• Low circulating vitamin K1 is prevalent in pregnant women, with or without bariatric surgery.
• Vitamin K1 supplementation effectively restores levels in pregnant women with bariatric surgery.
• Supplementation may mitigate the risk of fetal and neonatal intracranial hemorrhage.