Misoprostol vs. oxytocin for induction of labor at term.

Efficacy of misoprostol was studied for induction of labor at term. Seventy patients were randomized to Group A (n = 36, oral misoprostol 50 microg four hourly to maximum of 5 doses) and B (n = 34, continuous oxytocin infusion). Induction-delivery interval was shorter with misoprostol (7.7 +/- 2.8 h against 14.3 +/- 4.8 h with oxytocin) but the rates of vaginal delivery, cesarean, neonatal outcome variables were similar. Hence, misoprostol is an effective agent for induction of labor at term.     

Rate of increase in oxytocin dose on the outcome of labor induction.

OBJECTIVE: To compare the efficacy and safety of arithmetic and geometric increases in oxytocin infusion dosage during induction of labor. METHODS: A total of 120 pregnant women requiring induction of labor at term were randomly assigned to receive oxytocin at dosages increasing arithmetically or geometrically. Maternal demographics, labor delivery data, and newborn outcomes were compared. The setting was the maternity unit of the Obafemi Awolowo University Teaching Hospitals Complex, Ile-Ife, Nigeria. RESULTS: The mean maximum rates of oxytocin delivery needed to achieve adequate uterine contractions were similar in the 2 groups (24.66+/-8.34 mU/min vs. 26.38+/-8.77 mU/min, P=0.24). Labor duration was significantly shorter in the geometric progression group (496.33+/-54.77 min vs. 421.34+/-63.91 min, P<0.001). There were no differences in the rates of cesarean sections, vaginal deliveries, or uterine hyperstimulation, or in neonatal outcomes. CONCLUSION: A geometric rise in the rate of oxytocin infusion delivery reduced the duration of labor without affecting the rates of cesarean sections and uterine hyperstimulation, or newborn outcomes.     

Randomized comparison of oral misoprostol and oxytocin for labor induction in term prelabor membrane rupture

OBJECTIVES: To compare labor induction intervals between oral misoprostol and intravenous oxytocin in women who present at term with premature rupture of membranes. METHODS: One hundred eight women were randomly assigned to misoprostol 50 microg orally every 4 hours as needed or intravenous oxytocin. The primary outcome measure was time from induction to vaginal delivery. Sample size was calculated using a two-tailed alpha of 0.05 and power of 80%. RESULTS: Baseline demographic data, including maternal age, gestation, parity, Bishop score, birth weight, and group B streptococcal status, were similar. The mean time +/-standard deviation to vaginal birth with oral misoprostol was 720+/-382 minutes compared with 501+/-389 minutes with oxytocin (P = .007). The durations of the first, second, and third stages of labor were similar. There were no differences in maternal secondary outcomes, including cesarean birth (eight and seven, respectively), infection, maternal satisfaction with labor, epidural use, perineal trauma, manual placental removal, or gastrointestinal side effects. Neonatal outcomes including cord pH, Apgar scores, infection, and admission to neonatal intensive care unit were not different. CONCLUSION: Although labor induction with oral misoprostol was effective, oxytocin resulted in a shorter induction-to-delivery interval. Active labor intervals and other maternal and neonatal outcomes were similar.     

A comparison of obstetrical outcomes with labor induction agents used at term

Abstract

Objective: To compare the obstetrical outcomes of term pregnancies induced with one of four commonly used labor induction agents.

Methods: This is a retrospective cohort study of induced deliveries between 1 August 1995 and 31 December 2007 occurring at the Los Angeles County?+?University of Southern California Medical Center. Viable, singleton, term pregnancies undergoing induction were identified. Exclusion criteria included gestational age less than 37 weeks, previous cesarean delivery, breech presentation, stillbirth, premature rupture of membranes, and fetal anomaly. Induction methods studied were oxytocin, misoprostol, dinoprostone and Foley catheter. Our primary outcome was cesarean delivery rate among the four induction agents. Secondary outcomes included rate of failed induction, obstetrical complications, and immediate neonatal complications.

Results: A total of 3707 women were included in the study (1486 nulliparous; 2221 multiparous). Outcomes were compared across induction methods using Chi-square Tests (Pearson or Fisher’s, as appropriate). Among the nulliparous patients, there was no statistical difference among the four induction agents with regards to cesarean delivery rate (p?=?0.51), frequency of failed inductions (p?=?0.49), the cesarean delivery frequency for “fetal distress” (p?=?0.82) and five minute Apgar score <7 (p?=?0.24). Among parous patients, the cesarean delivery rate varied significantly by induction method (p?<?0.001), being lowest among those receiving misoprostol (10%). Those receiving oxytocin and transcervical Foley catheter had cesarean rates of 22%, followed by dinoprostone at 18%. The rate of failed inductions was 2% among those receiving misoprostol, compared to 7–8% among those in the other groups (p?<?0.01). Although cases of “fetal distress” between the four induction agents was not significantly different amongst multipara women, the cesarean delivery indication for “fetal distress” was higher among multipara receiving misoprostol (p?=?0.004). There was no difference among the different induction agents with regards to five minute Apgar <7 (p?=?0.34).

Conclusion: Among nulliparous women, all induction methods have similar rate of cesarean delivery. The use of misoprostol appears to be associated with a lower risk of cesarean birth among parous women induced at our institution.     

A comparison of two dosage regimens of oral misoprostol for labor induction at term

METHODS: 251 women with indications for labor induction at term were randomised to receive either 50 or 100 microgs of oral misoprostol, repeated every 4 h to a maximum of 5 doses. Parous women in the higher dose group received 50 microgs as their first dose, subsequent doses being 100 microgs. Women who failed to respond to the 5 doses of misoprostol had the option of having vaginal PGE2 gel. The primary outcome measure was the induction to delivery interval in those who delivered vaginally. Patient satisfaction was assessed by postnatal questionnaire. RESULTS: The induction to vaginal delivery interval, although shorter in the 100 microgs group was not statistically significant (26.8 versus 33.7 h, mean difference 6.9 h, 95% CI 0.4-13). There were, however, more failed inductions with misoprostol in the 50 microgs group (12.7% Vs 4.8%, RR 2.6, 95% CI 1.07-6.5). There were no differences in the modes of delivery, number of caesarean sections for fetal distress or in the neonatal outcomes in the two groups. Most patients, 83% and 92% in the 50 and 100 microgs, respectively, were satisfied with their inductions, and 64% of patients would prefer to have the inducing agent given orally if they were to have another induction. CONCLUSION: Oral misoprostol is effective in inducing labor and seems acceptable to patients. Both the 50 and 100 microgs dose regimens have a reasonable safety profile, but in view of the higher incidence of failed inductions with the 50 microgs dosage, the 100 microgs dose regimen may be the preferred dose regimen.     

Pulsatile oxytocin for induction of labor: a randomized prospective controlled study

In a prospective randomized study, 20 patients with term pregnancies underwent induction of labor with either continuous or pulsed (every 8 minutes) intravenous oxytocin infusion. There were no significant differences with respect to induction-labor interval, induction-delivery interval, cesarean section rates, need for pain relief and Apgar scores. Sixty percent of patients receiving continuous oxytocin infusion developed uterine hyperstimulation but only 10% receiving pulsed oxytocin did so. However, the difference was not significant. The mean +/- SEM total amount of oxytocin given by continuous infusion was 4237 +/- 1066 mU which was 70% more than by pulsatile infusion (2454 +/- 808 mU). The highest rate of oxytocin infused was significantly lower by pulsatile administration (5.2 +/- 0.8 mU/min) than by continuous infusion (9.2 +/- 1.8 mU/min, p = less than 0.05). Our study demonstrates that pulsed administration of oxytocin every 8 minutes is as effective and safe as continuous intravenous infusion of oxytocin for induction of labor, requires less oxytocin with therefore, a wider margin of safety and is consistent with the pulsatile release of oxytocin during normal labor.     

Randomized trial of concurrent oxytocin with a sustained-release dinoprostone vaginal insert for labor induction at term.

OBJECTIVE: The purpose of this study was to determine whether the concurrent administration of oxytocin with sustained-release dinoprostone results in shorter induction times when compared with oxytocin after the removal of the dinoprostone insert. STUDY DESIGN: Women with singleton pregnancies at > or = 36 weeks, vertex presentations, reactive nonstress tests, no prior uterine scar, intact membranes, and Bishop scores of < or = 6 were randomly assigned to receive oxytocin either immediately after placement of a sustained-release dinoprostone insert (immediate) or 30 minutes after its removal (delayed). The primary outcome was the time interval from induction to delivery. RESULTS: Seventy-one patients were enrolled (immediate, 34 patients; delayed, 37 patients). There were no differences between treatment groups in non-reassuring fetal heart tracings, excess uterine activity, and epidural use. The mean time from dinoprostone placement until delivery was 544 minutes, shorter in the immediate group (972 vs 1516 minutes; P =.001). The proportion of deliveries within 24 hours was higher (90% vs 53%; P =.002) in the immediate group. Cesarean delivery rates were similar between the immediate and delayed groups (16% vs 13%; P =.73). No adverse maternal or neonatal outcomes were observed with concurrent therapy. CONCLUSION: Oxytocin that is administered concurrently with sustained-release dinoprostone significantly shortens induction-to-delivery times and results in a higher proportion of vaginal deliveries of < or = 24 hours with no apparent adverse effects.     

Sublingual misoprostol for the induction of labor at term.

OBJECTIVE: To evaluate the efficacy, safety, and patient acceptability of sublingual misoprostol compared with an equivalent dose administered orally for labor induction at term. STUDY DESIGN: One hundred women with medical or obstetric indications for induction of labor after 37 weeks of gestation and unfavorable cervices were randomized to receive 50 microg of misoprostol either orally or sublingually. The dose was repeated every 4 hours to a maximum of 5 doses if indicated. Previous cesarean delivery was a criteria for exclusion. Our primary outcome measure was the number of patients who went on to have a vaginal delivery within 24 hours of the induction. The need for oxytocin, mode of delivery, number of cesarean deliveries for fetal distress, uterine hyperstimulation rates, and neonatal outcomes were secondary outcome measures. Patient acceptability was assessed by questionnaires completed after delivery. RESULTS: Significantly more patients were delivered of infants within 24 hours (73.8% versus 45.7%; relative risk, 1.6; 95% confidence interval, 1.1 to 2.4) and the induction to delivery intervals were significantly shorter (20 hours versus 28.3 hours; mean difference, 8.3 hours; 95% confidence interval, 1.2 to 15.4) in the sublingual group compared with the oral group. There was 1 case of uterine hyperstimulation in the sublingual group. There were no significant differences in the mode of delivery, interventions for fetal distress, or neonatal outcomes in the 2 groups. The satisfaction rates were 82.5% and 85.7% in the oral and sublingual groups respectively, and 9.5% of patients thought that the sublingual tablets did not dissolve completely. CONCLUSION: There has been no previous report in the literature of misoprostol given sublingually for labor induction. Sublingual misoprostol seems to have better efficacy than oral misoprostol, seems to be acceptable to patients, and is an option to be considered to induce labor at term.     

Pulsatile administration enhances the effect and reduces the dose of oxytocin required for induction of labor

Pulsatile administration of oxytocin was compared with continuous infusion of oxytocin for induction of labor in pregnant rats. The dosages consisted of intravenous injections of 0, 2.5, and 5 mU oxytocin every 10 minutes and intravenous infusion of 1 mU/minute of oxytocin in 0.9% sodium chloride. These doses are within the range of endogenously secreted pulses. All treatments began on day 22 at 2 p.m. and continued for 8 hours. Pulsatile administration resulted in a marked reduction in the dose of oxytocin required to induce labor. Using 5 mU pulses, birth was induced with 18.4%, and using 2.5 mU pulses, with 24% of the dose needed using continuous infusion. Parturition was advanced by 12 hours on the average by oxytocin treatment, but no significant differences were observed between the various oxytocin dosage regimens in this regard or in regard to gestation length, induction-delivery interval, duration of delivery, or the proportion of living or dead pups. Significantly more uterine activity was induced with each mU of oxytocin using pulsatile administration than using continuous infusion. There was no evidence for down-regulation of oxytocin receptors during a continuous infusion of oxytocin. We postulate that the greater efficacy of oxytocin pulses to induce uterine activity and delivery in comparison to continuous infusions is due to a more effective stimulation of prostaglandin F2 alpha release from the decidua. The amount of oxytocin needed for induction of labor with 2.5 mU pulses was similar to the decrease in neurohypophyseal oxytocin content during the first stage of spontaneous labor, and uterine activity elicited was also similar to that observed during spontaneous labor.(ABSTRACT TRUNCATED AT 250 WORDS)     

A comparison of early and delayed induction of labor with spontaneous rupture of membranes at term

The management of women with spontaneous rupture of membranes at term in the absence of labor and with a cervix unfavorable for induction of labor is controversial. In this randomized study of 182 patients, we report the effects of delayed versus early induction of labor on maternal and neonatal outcome. Qualifying patients not in labor at 6 hours after spontaneous rupture of membranes were randomized to either immediate oxytocin induction (86 women) or expectant management with oxytocin induction at 24 hours if labor had not occurred spontaneously (96 women). The cesarean section rate did not differ between the two groups. Women in the delayed group had significantly longer hospitalization (P less than .003), and their infants were significantly more likely to receive antibiotics (P = .006). Infectious morbidity (positive cultures or x-ray-documented pneumonia) occurred in five of the neonates in the delayed group, all of whose mothers had an initial digital cervical examination, but in none of the neonates in the early group, a difference that did not reach statistical significance (P = .061). Five (28%) of 18 infants from the delayed group whose mothers had received an initial digital cervical examination became infected, compared with none of the 78 infants from the delayed group whose mothers did not have digital examinations (P less than .001). We conclude that there is no advantage to delaying induction of labor when women present at term with spontaneous rupture of membranes.     

Comparison of induction of labor with vaginal misoprostol plus oxytocin versus oxytocin alone in term primigravidae

Objective.?To compare the efficacy and complications of intravaginal misoprostol application before starting oxytocin infusion with oxytocin infusion alone for labor induction in term primigravidae pregnancies with low-Bishop score.

Methods.?This randomized study included 101 primigravidae women with singleton pregnancies >38 weeks and a Bishop score of <6. Group 1 (50 patients) received a 50-μg dose of intravaginal misoprostol, with an oxytocin infusion started 3?h later. Group 2 (51 patients) received only an oxytocin infusion for labor induction. The time from induction to delivery, the route of delivery and complications were analyzed.

Results.?The mean time from induction to delivery was 10.4?±?2.1?h in Group 1 and 13.7?±?3.4 in Group 2 (p?<?0.001). The rates of vaginal delivery, Apgar scores at 1st and 5th min, placental abruption, and postpartum hemorrhage were similar between the two groups.

Conclusion.?Intravaginal application of 50-μg misoprostol before starting oxytocin infusion is a more effective method of labor induction than oxytocin infusion alone in term primigravidae pregnant women with low-Bishop scores.     

A prospective randomized study comparing misoprostol and oxytocin for premature rupture of membranes at term

Objective.?The aim of this randomized trial was to compare the efficacy and safety of vaginal misoprostol and oxytocin for cervical ripening and labor induction in patients with premature rupture of membrane (PROM) at term.

Methods.?Ninety-seven women with PROM at term were assigned randomly to receive intravaginal misoprostol or oxytocin. The primary outcome measure was the induction–delivery interval. Secondary outcomes included the number of women who delivered vaginally within 12 hours of the start of the induction in the two groups, the cesarean, hyperstimulation, and failed induction rates, the mode of delivery, and the neonatal outcome.

Results.?Forty-eight women were assigned to intravaginal misoprostol and 49 to oxytocin administration. The mean interval from induction to delivery was 10.61 ± 2.45 hours in the misoprostol group and 11.57 ± 1.91 hours in the oxytocin group (p = 0.063). The rates of vaginal delivery were 83.3% and 87.7% and cesarean delivery were 16.7% and 8.2% in the misoprostol and oxytocin groups, respectively. Neonatal outcomes were not significantly different. Of the cases, 8.3% in the misoprostol group and 8.2% in the oxytocin group revealed uterine contraction abnormalities.

Conclusion.?Our study demonstrates that, intravaginally, misoprostol results in a similar interval from induction of labor to delivery when compared to oxytocin.