Effectiveness of nifedipine in threatened preterm labor: a randomized trial

Figures & data

Figure 1 Consort diagram.

Table 1 Comparison of epidemiological characteristics

Data	Nifedipine group (N=103)	Placebo group (N=103)
Maternal age (years; mean)	27.1 (SD 5.73)	25.6 (SD 5.85)
Gravid (mean)	2.28 (SD 1.17)	1.87 (SD 0.89)
Parity (mean)	0.89 (SD 0.76)	0.70 (SD 0.79)
Previous abortion, n (%)	28 (27.1%)	15 (14.5%)
Previous cesarean section, n (%)	27 (25.9%)	17 (16.5%)
History of preterm birth, n (%)	13 (12.5%)	8 (7.7%)
Smoking, n (%)	4 (1.94%)	2 (3.85%)
Infection, n (%)	15 (14.0%)	17 (16.5%)
Mean gestational age (weeks)	33.6 (SD 2.48)	33.4 (SD 2.52)
Body weight (kg)	67.1 (SD 14.25)	64.0 (SD 10.19)
Body mass index (kg/m^2)	26.9 (SD 0.53)	26.2 (SD 0.39)
Initial dilatation of cervix (cm)	0.20 (SD 0.40)	0.17 (SD 0.37)

Abbreviation: SD, standard deviation.

Table 2 Numbers of successful patients with regard to inhibition and delivery data in nifedipine and placebo groups

Outcome	Nifedipine	Placebo	RR	Adjusted RRa	95% CI	NNT
Successful at 90 minutes, n (%)	91/103 (88.3%)	72/103 (69.9%)	1.18	1.27	1.10–1.47b	5.6
Successful after 48 hours, n (%)	80/103 (77.6%)	51/103 (49.5%)	1.57	1.52	1.22–1.91b	3.6
Delayed delivery ≥48 hours, n (%)	93/103 (90.3%)	90/103 (87.4%)	1.03	1.05	0.95–1.15	34.3
Delivery ≥37 weeks, n (%)	73/99 (76.7%)	77/103 (74.8%)	0.99	1.01	0.91–1.12	98.8

Notes:

a Adjusted for gravid and previous abortion.

b Statistically significant.

Abbreviations: CI, confidence interval; RR, relative risk; NNT, number needed to treat.

Figure 2 Flow diagram of the pregnancies with threatened preterm labor between nifedipine and placebo groups.

Table 3 Delivery and newborn data

Outcome	Nifedipine (N=99)	Placebo (N=103)	P-value
Gestational age at delivery (weeks) (mean)	37.26 (SD 1.56)	37.17 (SD 1.84)	0.71
Duration for delaying delivery (weeks) (mean)	3.56 (SD 2.70)	3.71 (SD 2.88)	0.70
Mode of delivery
Vaginal delivery, n (%)	46 (46.5%)	72 (69.9%)	–
Cesarean section, n (%)	53 (53.5%)	31 (30.1%)	–
Maternal complication at delivery, n (%)
Preeclampsia	2 (2.02%)	2 (1.94%)	–
Chorioamnionitis	0	2 (1.94%)	–
Postpartum hemorrhage	3 (3.03%)	3 (2.91%)	–
Fetal distress	8 (8.08%)	5 (4.85%)	–
Cephalopelvic disproportion	6 (6.06%)	1 (0.97%)	–
Neonatal birth weight (g) (mean)	2,999.3 (SD 541.5)	2,920.9 (SD 394.2)	0.24
APGAR score
1 minute	8.76 (SD 1.21)	9.06 (SD 0.82)	0.04a
5 minutes	9.80 (SD 1.48)	9.91 (SD 0.31)	0.45
Neonatal complication, n (%)
Respiratory distress syndrome	10 (10.10%)	7 (6.80%)	–
Jaundice	1 (1.01%)	0	–
Sepsis	1 (1.01%)	1 (0.97%)	–
Death	1 (1.01%)	0	–

Note:

a Statistically significant.

Abbreviation: SD, standard deviation.