Table 2

Comparison of ampicillin concentrations in umbilical cord and peripheral blood according to study groups:

(a) Analyses include all neonates
Ampicillin concentration, median Group 1
(<1 hour)
Group 2
(≥1 and <2 hours)
Group 3
(≥2 and <4 hours)
Group 4
(≥4 hours)
p*
Umbilical cord blood, µg/mL16.36† (14.23–19.49)11.92‡ (8.97–14.8)7.72§ (5.33–11.07)6.44 (4.87–7.92)<0.001
Peripheral blood, at age 4 hours, µg/mL4.21 (2.55–5.58)5.52 (4.21–6.97)4.96 (3.04–6.56)4.29 (2.52–6.74)0.06
(b) Analyses include 115 neonates exposed to IAP>15 min prior to delivery
Ampicillin concentration, median Group 1
(>15 min<1 hour)
Group 2
(≥1 and<2 hours)
Group 3
(≥2 and<4 hours)
Group 4
(≥4 hours)
p*
Umbilical cord blood, µg/mL16.74† (14.57–19.49)11.92‡ (8.97–14.8)7.72§ (5.33–11.07)6.44 (4.87–7.92)<0.001
Peripheral blood, at age 4 hours, µg/mL4.47 (3.59–5.60)5.52 (4.21–6.97)4.96 (3.04–6.56)4.29 (2.52–6.74)0.24
  • Values are expressed as median (25–75 percentiles).

  • *p value from Kruskal-Wallis test; p<0.05 adjusted for multiple comparisons.

  • †Group 1 versus groups 2, 3 and 4.

  • ‡Group 2 versus groups 1, 3 and 4.

  • §Group 3 versus groups 1 and 2.

  • IAP, intrapartum antibiotic prophylaxis.