title: Vitamin K1 monitoring in pregnancies after bariatric surgery: a prospective cohort study.
abstract: BACKGROUND
  Neonatal intracranial bleedings and birth defects have been reported, possibly related to maternal vitamin K1 deficiency during pregnancy after bariatric surgery. The objective of this study was to investigate the effects of screening and supplementation on K1 serum levels in pregnant women with bariatric surgery, and to compare K1 levels and prothrombin time (PT %) in the first trimester with pregnant women without bariatric surgery.
  
  
  METHODS
  A prospective cohort study including 49 pregnant women with bariatric surgery. Nutritional deficiencies were prospectively screened. In case of observed low K1 serum levels, supplementation was provided. K1 serum levels and PT (%) during the first trimester were compared with a nonsurgical control group of 27 women.
  
  
  RESULTS
  During the first trimester, most women had low K1 serum levels (<0.8 nmol/l). Mean vitamin K1 levels were significantly lower in the surgical group compared to the nonsurgical control group (.44 versus .64 nmol/l; P = .016). PT (%) remained in the normal range, The surgery group showed a higher mean PT compared to the controls (111.3 versus 98.9%; P<.001) Mean K1 serum levels in the study group were higher during the third than during the first trimester (P = .014). PT (%) was significantly higher during the second and third than during the first trimester (P = .004). Most of the coagulation factors, including II, V, VII, IX, and X, remained within normal ranges.
  
  
  CONCLUSIONS
  Low circulating K1 appears to be common in pregnant women with and without bariatric surgery. Supplementation during pregnancy can restore vitamin K1 in women with bariatric surgery, potentially protecting the fetus and newborn against intracranial hemorrhage.
authors.affiliation: Department of Development and Regeneration, Unit Pregnancy, Fetus and Newborn, KU Leuven, Belgium.
authors.forename: Goele
authors.initials: G
authors.lastname: Jans
authors.affiliation: Department of Public Health and Primary Care; Environment and Health, section nutrition, KU Leuven, Belgium.
authors.forename: Isabelle
authors.initials: I
authors.lastname: Guelinckx
authors.affiliation: Jessa Hospital Hasselt, Belgium.
authors.forename: Willy
authors.initials: W
authors.lastname: Voets
authors.affiliation: Department of Development and Regeneration, Unit Pregnancy, Fetus and Newborn, KU Leuven, Belgium; Department of Gynecology and Obstetrics, University Hospitals Leuven, Belgium.
authors.forename: Sander
authors.initials: S
authors.lastname: Galjaard
authors.affiliation: Department of Medical Laboratories/Diagnostic Centre SSDZ, Reinier de Graaf Group of Hospitals, Association of Clinical Chemistry, Delft, the Netherlands.
authors.forename: Paul M M
authors.initials: PM
authors.lastname: Van Haard
authors.affiliation: Department of Public Health and Primary Care; Environment and Health, section nutrition, KU Leuven, Belgium.
authors.forename: Greet M
authors.initials: GM
authors.lastname: Vansant
authors.affiliation: Department of Development and Regeneration, Unit Pregnancy, Fetus and Newborn, KU Leuven, Belgium; Department of Gynecology and Obstetrics, University Hospitals Leuven, Belgium. Electronic address: roland.devlieger@uzleuven.be.
authors.forename: Roland
authors.initials: R
authors.lastname: Devlieger
mesh_terms: D000293:Adolescent; D000328:Adult; D050110:Bariatric Surgery / Q000009:adverse effects*; D016022:Case-Control Studies; D019587:Dietary Supplements; D005260:Female; D006801:Humans; D009765:Obesity / Q000601:surgery; D011247:Pregnancy; D011250:Pregnancy Complications, Hematologic / Q000209:etiology* / Q000517:prevention & control; D011296:Prenatal Diagnosis; D011446:Prospective Studies; D010837:Vitamin K 1 / Q000008:administration & dosage* / Q000378:metabolism; D014813:Vitamin K Deficiency / Q000209:etiology* / Q000517:prevention & control; D014815:Vitamins / Q000008:administration & dosage*; D055815:Young Adult
chemical_list: D014815:Vitamins; D010837:Vitamin K 1
keywords: Bariatric surgery; Obesity surgery; Pregnancy; Vitamin K1