Table 1.

Perinatal Information for Infants Born in the NICHD Neonatal Research Network Between January 1, 1995 and December 31, 1996*

Perinatal Data501 to
750 Grams
n = 1002
751 to
1000 Grams
n = 1084
1001 to
1250 Grams
n = 1053
1251 to
1500 Grams
n = 1299
501 to
1500 Grams
n = 4438
Antenatal steroids63 (30–92)76 (52–100)74 (54–94)70 (53–93)71 (49–95)
Antenatal antibiotics62 (49–82)65 (54–85)60 (45–88)61 (44–79)62 (52–84)
ROM>24 h27 (17–35)30 (22–44)23 (5–30)24 (13–35)26 (17–33)
Multiple births21 (10–36)19 (10–50)21 (10–33)25 (14–50)22 (13–42)
Small for gestational age16 (11–12)17 (11–29)24 (16–41)29 (17–36)22 (19–29)
Mode of delivery
Vaginal vertex36 (15–45)34 (23–47)39 (28–50)47 (40–55)40 (31–46)
Vaginal breech20 (0–35)6 (0–13)1 (0–4)3 (0–6)7 (1–10)
Cesarean section44 (27–69)60 (49–72)60 (46–72)50 (43–60)53 (45–64)
Delivery room resuscitation
Endotracheal intubation82 (51–96)79 (43–97)54 (19–86)32 (4–59)60 (30–79)
Resuscitation medications15 (2–31)8 (1–21)5 (0–17)3 (0–17)7 (2–18)
Apgar ≤3 at 1 min57 (29–71)33 (20–44)21 (8–28)13 (2–30)30 (15–43)
Apgar ≤3 at 5 min27 (0–49)7 (3–15)4 (0–11)3 (0–5)10 (1–13)
  • ROM indicates rupture of membranes.

  • * Data expressed as percent with center ranges in parentheses.

  • Time between rupture of membranes and delivery.

  • Small for gestational age as weight <10th percentile at birth.