The optimal induction timing in prelabor rupture of membranes: a retrospective study

Figures & data

Figure 1. Study population.

Table 1. Maternal baseline characteristics, by oxytocin administration timing.

	0-12 h following PROM N = 1127	12-24 h following PROM N = 285	24+ hours following PROM N = 264	p-value
Age, y, N [range]	29.7 [18.1-46.7]	29.4 [18.2-44.6]	28.7 [18.8-47.8]	NS
Ethnicity, N (%)				NS
Jewish	788 (69.92%)	193 (67.72%)	174 (65.91%)
Muslim	198 (17.57%)	52 (18.25%)	62 (23.48%)
Christian	41 (3.64%)	10 (3.51%)	9 (3.41%)
Other	100 (8.87%)	30 (10.52%)	19 (7.20%)
Parity, N [range]	1.8 [1–11]	1.6 [1–9]	1.5 [1, 1–6]	NS
Gestational age at delivery, N [range]	39.2 [37–43.3]	39.2 [37–42.2]	39.3 [37–41.5]	NS
Background diseases, N (%)				NS
Hypertension	10 (0.89%)	5 (1.75%)	2 (0.76%)
Diabetes	86 (7.63%)	16 (5.61%)	19 (7.2%)
Smoking	13 (1.15%)	1 (0.35%)	3 (1.14%)
Cervical dilation at time of PROM, cm, mean ± SD	1.2 + 0.5	1.3 + 0.3	1.1 + 0.6	NS

Data are presented as mean ± SD or N (%) or N [range]; n: number; SD: standard deviation; PROM: prelabor rupture of membranes; NS: no significance.

Table 2. Delivery outcomes, by oxytocin administration timing.

	0–12 h following PROM N = 1127	12–24 h following PROM N = 285	24+ hours following PROM N = 264	p-value
Interval from membrane	23.2 [8–80]	28.2 [12.2–61.4]	45 [25.8–78]	*<.0001
rupture to delivery, hours, mean [range]				**<.0001
				***<.0001
Delivery mode, N (%)				NS
Spontaneous	809 (71.78%)	194 (68.07%)	188 (71.21%)
Cesarean	174 (15.44%)	42 (14.74%)	31 (11.74%)
Vacuum/Forceps	144 (12.78%)	49 (17.19%)	45 (17.05%)
Episiotomy, N (%)	340 (30.17%)	103 (36.14%)	92 (34.85%)	NS
				*NS
PPH, N (%)	23 (2.04%)	9 (3.16%)	12 (4.55%)	**0.034
				***NS
Intrapartum fever, N (%)	64 (5.68%)	21 (7.37%)	13 (4.92%)	NS
Days of hospitalization, mean [median, range]	3.5 [3, 1–17]	3.7 [4, 2–9]	3.6 [3, 1–7]	*= .002
				**NS
				***NS
Maternal composite outcome^a, N (%)	66 (5.86%)	21 (7.37%)	14 (5.3%)	NS

Data are presented as mean ± SD or n (%) or N [range]; PROM: prelabor rupture of membranes; NS: no significance; PPH: postpartum hemorrhage.

* Comparison between 0–12 h group and 12–24 h group.

** Comparison between 0–12 h group and 24 h + group.

*** Comparison between 12–24 h group and 24 h + group.

^aMaternal composite outcome included one of the following: PPH, intrapartum fever, chorioamnionitis, endometritis.

Table 3. Newborn characteristics and outcomes, by oxytocin intake.

	0–12 h following PROM N = 1127	12–24 h following PROM N = 285	24+ h following PROM N = 264	p-value
Gender – male, N (%)	591 (52.44%)	140 (49.12%)	141 (53.41%)	NS
Weight, g, mean [range]	3245.2 [1899–4715]	3256.3 [2200–4505]	3229 [2130–4400]	NS
Apgar score, mean [range]
1 min	8.7 [1–10]	8.6 [1–10]	8.8 [2–10]	NS
5 min	9.8 [4–10]	9.8 [4–10]	9.9 [7–10]
NICU admission, N (%)	4 (0.35%)	0 (0%)	3 (1.14%)	NS
				*<.0001
Antibiotic administration, N (%)	302 (26.8%)	110 (38.6%)	88 (33.33%)	**NS
				***NS
Complications, N (%)				NS
CP	0 (0%)	0 (0%)	0 (0%)
Apnea	3 (0.27%)	0 (0%)	0 (0%)
Hypotonia	1 (0.09%)	0 (0%)	0 (0%)
Seizures	2 (0.18%)	1 (0.35%)	0 (0%)
Resuscitation	1 (0.09%)	0 (0%)	0 (0%)
				*<.0001
Neonatal composite outcome^a, N (%)	309 (27.42%)	111 (38.95%)	91 (34.47%)	**NS
				***NS
Days of hospitalization, mean [range]	3.2 [1.4–23.4]	3.2 [1.6–16.9]	3.2 [1.8–12.4]	NS

Data are presented as mean ± SD or N (%) or N [range]; PROM: prelabor rupture of membranes; NS: no significance.

*Comparison between 0–12 h group and 12–24 h group.

**Comparison between 0–12 h group and 24 h + group.

**Comparison between 12–24 h group and 24 h + group.

^aNeonatal composite outcome includes one of the following – Apgar score at 5 min < 7, NICU admission, antibiotic administration, cerebral palsy, apnea, hypotonia, seizures, resuscitation.

Table 4. Multivariable log-binomial regression for the study outcomes.

	Multivariable regression
	Adj. RR	95% CI		p-value
		Low	Up
Maternal composite outcome^a
Age ≥ 35	1.04	0.66	1.63	.8683
Interval from membrane rupture to delivery	1.016	1.011	1.021	<.0001
Oxytocin
Oxytocin 0–12 h after PROM	1
Oxytocin 12–24 h after PROM	1.07	0.65	1.75	.7876
Oxytocin 24+ h after PROM	0.43	0.23	0.81	.0086
Neonatal composite outcome^b
Age ≥ 35	1.00	0.82	1.22	.9982
Interval from membrane rupture to delivery	1.024	1.019	1.028	<.0001
Oxytocin
Oxytocin 0–12 h after PROM	1
Oxytocin 12–24 h after PROM	1.27	1.02	1.58	.0307
Oxytocin 24+ h after PROM	0.78	0.60	1.02	.0716

PROM: prelabor rupture of membranes; Adj. RR: adjusted relative risk.

^aMaternal composite outcome includes one of the following – PPH, intrapartum fever, chorioamnionitis or endometritis.

^bNeonatal composite outcome includes one of the following – Apgar score at 5 min < 7, NICU admission, antibiotic administration, cerebral palsy, apnea, hypotonia, seizures, resuscitation. .