Official Title: “Holotranscobalamin Remains Unchanged During Pregnancy. Longitudinal Changes of Cobalamins and Its Binding Proteins During Pregnancy and Postpartum”

Background and objective: Plasma cobalamins decrease during pregnancy but it is not fully elucidated how this is reflected in the total and cobalamin saturated transport proteins, transcobalamin (total TC, holoTC) and haptocorrin (total HC, holoHC). TC transports cobalamin into the cells. The function of HC is unknown, but in contrast to TC it binds both cobalamins and cobalamin analogues.

Design and methods: Healthy pregnant women (N=141) had blood samples drawn at 18th, 32nd, 39th gestation week and 8 weeks postpartum. The protein moiety of TC and HC (total and holo) was measured by in-house ELISA methods.

Results: During pregnancy, cobalamins and HC (total and holo) decreased, holoTC remained unchanged, while total TC increased. The medians in pmol/L at 18th, (39th) gestation week and [8 weeks postpartum] were: cobalamins 230(170)[310], holoHC 310(260)[380], totalHC 510(450)[450], holoTC 79(79)[93] and total TC 850(950)[810]. The sum of holoTC and holoHC exceeded cobalamins by 150(170)[150] supporting that HC carries both analogues and cobalamins.

Interpretation and conclusions: While cobalamins decrease during pregnancy the active part of the cobalamins, holoTC, remains unchanged. The decrease in cobalamins can be explained by a decrease in holoHC suggesting that holoTC is more useful than cobalamins as a marker of vitamin B12 deficiency during pregnancy.

Study Type: Observational

Study Design: Natural History, Longitudinal, Defined Population, Prospective Study

Background and objective: Plasma cobalamins decrease during pregnancy but it is not fully elucidated how this is reflected in the total and cobalamin saturated transport proteins, transcobalamin (total TC, holoTC) and haptocorrin (total HC, holoHC). TC transports cobalamin into the cells. The function of HC is unknown, but in contrast to TC it binds both cobalamins and cobalamin analogues.

Design and methods: Healthy pregnant women (N=141) had blood samples drawn at 18th, 32nd, 39th gestation week and 8 weeks postpartum. The protein moiety of TC and HC (total and holo) was measured by in-house ELISA methods.

Results: During pregnancy, cobalamins and HC (total and holo) decreased, holoTC remained unchanged, while total TC increased. The medians in pmol/L at 18th, (39th) gestation week and [8 weeks postpartum] were: cobalamins 230(170)[310], holoHC 310(260)[380], totalHC 510(450)[450], holoTC 79(79)[93] and total TC 850(950)[810]. The sum of holoTC and holoHC exceeded cobalamins by 150(170)[150] supporting that HC carries both analogues and cobalamins.

Interpretation and conclusions: While cobalamins decrease during pregnancy the active part of the cobalamins, holoTC, remains unchanged. The decrease in cobalamins can be explained by a decrease in holoHC suggesting that holoTC is more useful than cobalamins as a marker of vitamin B12 deficiency during pregnancy.

Inclusion Criteria:

• Danish healthy Caucasian women >18 years of age with previous uncomplicated pregnancies and deliveries and presently with a normal pregnancy.

Exclusion Criteria:

• >4 cigarettes smoked per day,
• Treatment with vitamin B12, folic acid or acetyl salicylic acid,
• Impaired renal function and clinically significant vaginal haemorrhage before first visit as well as blood haemoglobin <6.4 mmol/L at first visit.

Gender Eligibility for this Clinical Trial: Female

Minimum Age for this Clinical Trial: 18 Years

Maximum Age for this Clinical Trial: 45 Years

Are Healthy Volunteers Accepted for this Clinical Trial?: Accepts Healthy Volunteers

Lead Sponsor: University of Aarhus

Overall Clinical Trial Officials and Contacts

Nils Milman, MD Principal Investigator University of Copenhagen  

Information obtained from ClinicalTrials.gov on October 10, 2008

Link to the current ClinicalTrials.gov record. http://clinicaltrials.gov/show/NCT00467623

Study ID Number: KA-93140

ClinicalTrials.gov Identifier: NCT00467623

Health Authority: Denmark: Ethics Committee