16583
Fasting serum total vitamin B12 ( TB12 ) , holotranscobalamin ( HoloTC ) , a marker of functional B12 status and plasma Hcy concentrations were measured at 20 - 34 weeks ( at randomization ) and 36 weeks gestation , then at 6 - 8 weeks postpartum .
 Chemical: vitamin B12; Chemical: Hcy
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
 Chemical: vitamin B12; Chemical: Hcy