Table I.

Comparison of MZ and DZ twin pairs

Variable	MZ (N=170)	DZ (N=665)	p
GA (weeks)	31.0 ± 3.1*	31.1 ± 3.3	0.883
BW (grams)	1579 ± 572	1652 ± 688	0.045
Male gender	180 (52.9)**	691 (52.0)	0.812
5-minute Apgar score	9†	9	0.091
RDS	148 (44.4)	534 (40.8)	0.252
VENT (days)	6.9 ± 15.5	7.5 ± 20.1	0.563
TPN (days)	9.9 ± 17.3	10.2 ± 18.4	0.811
Length of stay (days)	39.6 ± 33.9	36.9 ± 36.2	0.201
Late-onset sepsis	38 (11.2)	111 (8.3)	0.127

^*Mean ± SD

^**N (%)

^†Median

GA: gestational age; BW: birth weight; RDS: respiratory distress syndrome; VENT: duration of (invasive) mechanical ventilation; TPN: duration of total parenteral nutrition