Table 1.

Baseline characteristics and nutritional support in the cohort.

Baseline Characteristics
Gestational age at birth (weeks)	29.1 (2.8)//30.0 (26.4–31.4)
Birthweight (g)	1255 (433)//1337 (839–1588)
Gender: Male	20/45 (44%)
Fetal growth restriction	4/45 (9%)
Multiple (twin or triplet)	15/45 (33%) *
Postnatal age at blood sampling
T1 (days)	46 (26)//41 (15–110)
T2 (days)	150 (52)//150 (69–238)
Nutritional data
Parenteral nutrition
Received	32/45 (71%)
Days **	11.2 (5.6)//10.0 (7.0–14.8)
Enteral feeding
Days at start	1.9 (1.7)//2.0 (1.0–2.0)
Days at full feeds	11.5 (7.2)//10.0 (6.0–15.0)
Oral folic acid supplement
Yes	5/45 (11.1%)
Total days where given	93 (29)//78 (72–100)
Type of feeding
T1
Unfortified breastmilk	7 (16%)
Fortified breastmilk	32 (71%)
Mixed feeding ***	6 (13%)
T2
Breastmilk only	12 (32%)
Mixed feeding	9 (24%)
Formula feeding	16 (43%)

Data are represented by the mean (standard deviation)//median (IQR range) or n (%). T1—time of first blood sample, near discharge. T2—time of second blood sample, on follow-up at 2–3 months’ corrected age. * 2 participants from one set of triplets, 3 from 3 sets of twins in which the other sibling did not participate, and 5 sets of twins. ** Calculated from the group of 32 infants who received PN. *** Includes one infant who switched to formula feeding from recruitment to T1. Among babies receiving mixed feeding, 2/5 had unfortified breastmilk and 3/5 were on fortifier.