Maternal vitamin D supplementation during pregnancy and lactation to promote infant growth in Dhaka, Bangladesh (MDIG trial): study protocol for a randomized controlled trial

Table 3 Biological specimen collection schedule and planned laboratory analyses in the Maternal Vitamin D for Infant Growth (MDIG) trial in Dhaka, Bangladesh

		Maternal-fetal						Infant			Father
		Baseline	30 wk gestation	Delivery	Cord blood	3 mo postpartum	6 mo postpartum	3 mo	6 mo	12 and 24 mo	Father
Blood/serum/plasma	Calcium	R^a	R	R	R	R	R	R	R
	Phosphate, alkaline phosphatase, creatinine								S^a
	25(OH)D	R		S	S		S	S	S
	1,25(OH)₂D, whole/bioactive PTH(1–84), C-terminal PTH(73–84), intact PTH, FGF-23	S		S	S			S	S
	PTHrP	S		S	S	S	S	S	S
	IGF-1, IGFBP-1, IGFBP-3				S				S
	Ferritin								S
	Retinol, folate, cadmium			S
	C-reactive protein, IL-6, IL-8, TNF-α			S	S
	Epigenetic studies			S	S						S
	Collection for future analyses	R	R	R	R	R	R	R	R	R	R
Placenta	Epigenetic studies			R
Urine	Calcium:creatinine ratio			R					S
	Calcium, phosphate, fluoride, cyclic AMP								S
	Collection for future analyses	R		R					R
Breast milk	PTHrP					S		S
Breast milk	Collection for future analyses					R		R
Nasal swab^b	PCR for respiratory viruses							R^b	R^b
Nasal swab^b	PCR for Streptococcus carriage density							R^b	R^b

FGF fibroblast growth factor, IGF insulin-like growth factor, IGFBP insulin-like growth factor-binding protein, IL interleukin; PTHrP parathyroid hormone–related protein, R routine, S subset, TNF tumor necrosis factor
^aRoutine analyses to be performed in all specimens collected; subset analyses to be performed in a sub-set of stored specimen aliquots
^bNasal swabbing is performed at any time from 1 wk to 6 mo of age if criteria for acute respiratory infection are met

ISSN: 1745-6215