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.     

High and low dose oxytocin in augmentation of labor.

OBJECTIVE: To compare the efficacy and safety of high dose oxytocin in the augmentation of labor. METHOD: Two hundred pregnant women requiring augmentation of labor were randomly assigned to receive oxytocin by either a low dose protocol (1.5 microm/min initially, increased by 1.5 microm/min every 30 min) or a high dose protocol (4.5 microm/min initially, increased by 4.5 microm/min every 30 min). RESULTS: High dose of oxytocin was associated with a significant shortening of labor 4 (1.10-10) vs. 6 (1-10) h, p<0.0001 without a significant difference in cesarean delivery rate, neonatal and maternal outcome. CONCLUSION: The use of high dose oxytocin is associated with significantly shorter labor without any adverse fetal and maternal effects.     

Randomized, double-blind trial of prostaglandin E2 intravaginal gel versus low-dose oxytocin for cervical ripening before induction of labor

OBJECTIVE: Our purpose was to compare two methods of preinduction cervical ripening in a randomized, double-blind clinical trial. STUDY DESIGN: Two intravaginal, 4 mg prostaglandin E₂ gel applications administered 4 hours apart were compared with 10 hours of low-dose oxytocin (2 mU/min) in 200 patients undergoing preinduction cervical ripening. RESULTS: There were no differences in parity, initial Bishop scores, estimated gestational ages, indications for induction, or birth weights. Prostaglandin E₂ gel was significantly better (p < 0.0001) at achieving a change in the Bishop score of 3 or more. The number of successful inductions was significantly greater (p < 0.0003) and the mean time to active labor was significantly shorter (p < 0.0002) in the prostaglandin E₂ group than in the oxytocin group. More multiple-day inductions (p < 001) occurred in the oxytocin group, and fewer discharged patients who did not deliver infants (p < 003) were seen in the prostaglandin E₂ gel group. There were no differences between patient groups in the cesarean section rate, meconium staining, hyperstimulation, and Apgar scores. CONCLUSION: Two 4 mg doses of prostaglandin E₂ intravaginal gel applied 4 hours apart are superior to low-dose oxytocin in producing cervical ripening and preparing for successful induction. (Am J Obstet Gynecol 1996;174:1910-6.)     

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.     

Clinicians' guide to the use of oxytocin for labor induction and augmentation

Oxytocin is commonly used in obstetrics for labor induction and augmentation. Careful assessment of the individual clinical situation based on indications and contraindications is essential to enhancing safe and effective use. Counseling the woman and her partner regarding potential risks and benefits before use is necessary to promote informed consent. At least 39 weeks of gestation is required for elective labor induction. Recent research has shown that deferring elective induction until cervical readiness has been achieved without the use of pharmacologic agents can be beneficial in reducing the risk of cesarean birth associated with elective induction. A conservative physiologic oxytocin protocol for labor induction and augmentation is recommended to minimize the risk of side effects. Although treatment of excessive uterine activity related to oxytocin has not been studied prospectively, several interventions such as maternal repositioning, an intravenous fluid bolus, and discontinuation of the oxytocin infusion are beneficial in returning uterine activity to normal, based on retrospective review of oxytocin-induced tachysystole. Perinatal quality measures from the National Quality Forum and the Joint Commission can be useful in monitoring care related to induction of labor. These include elective births before 39 weeks of pregnancy and cesarean births for low-risk, first-birth mothers.     

Elective induction of labor conducted under lumbar epidural block. I. Labor induction by amniotomy and intravenous oxytocin.

Epidural analgesia (bupivacaine) was administered during labor after amniotomy, in some cases supplemented by intravenous oxytocin. A higher incidence of transient uterine hypertonus was seen after blocking. Fetal heart rate changes mainly took the form of bradycardia (in association with uterine hypertonus). At birth, the maternal biochemical condition was characterized by a lower degree of metabolic acidosis, compared to normal unanesthetized controls. The fetuses displayed a slight degree of hypoxia and hypercapnia. The mechanisms underlying these modifications are discussed. Epidural blockade in combination with elective induction of labor, whether or not supplemented by intravenous oxytocin, may carry a risk. Its magnitude is considered acceptable for both mother and fetus provided they are constantly under close surveillance, limited amounts of bupivacaine are administered and the second stage of labor is kept short. However, some warnings against epidural analgesia apply to patients with placental insufficiency and very active labor.     

Effect of oxytocin discontinuation during the active phase of labor

Objective: To observe the progression of labor when oxytocin use is limited to the onset of the active stage of labor.

Methods: A randomized, prospective controlled study was performed to address the issue of oxytocin infusion after the onset of active labor in 140 patients. In the study group, infusion of oxytocin was discontinued at the onset of the active phase of labor, which was accepted as a cervical dilatation of 5?cm. In the control group, incremental oxytocin infusion was administered until 5?cm cervical dilatation, and then was maintained at the same level until delivery.

Results: The primary outcome variable was duration from the beginning of the active phase to delivery. In the study group, the duration of the active phase of labor was about 30?min longer than in the control group and this difference was significant. The secondary outcomes of the study were maternal–fetal complications of oxytocin and in both groups there were no significant differences.

Conclusion: It is not reasonable to discontinue oxytocin infusion at the beginning of active labor. Nevertheless, for an accurate conclusion expanded investigations are needed.     

An appraisal of oral prostaglandin E2 and intravenous oxytocin in the induction of labor

Oral prostaglandin E₂ (PGE₂) was used to induce labor in 39 patients. These were matched closely with a similar number of patients induced with intravenous oxytocin. The induction-full dilatation interval was significantly shorter in the oxytocin group than in the group on oral PGE₂. Possible explanations for the difference are offered. The rest of the results showed no significant difference.     

Comparison of oral prostaglandin E2 and intravenous oxytocin for induction of labor in hypertensive pregnancies

Labor was induced with oral prostaglandin (PGE₂) without amniotomy in 20 patients (10 nulliparae and 10 multiparae) with hypertension, whether or not associated with edema and/or proteinuria. An average dose of 8 mg was required to achieve effective uterine contractility in both nulliparae and multiparae. Multiparae required only a mean dose of 12 mg but nulliparae a dose of 18 mg to achieve delivery. The mean duration of labor was slightly longer in both nulliparae and multiparae than that achieved with fast escalating doses of i.v. oxytocin. The need for analgesia was greater in oxytocin-induced patients than in the prostaglandin-induced patients. Otherwise no differences were found between the two groups.     

Foley catheter with simultaneous oxytocin on labor induction: a meta-analysis of randomized controlled trials

Objective: It is unclear that whether Foley catheter with simultaneous oxytocin could improve the efficacy of induction outcome.

Method: To conduct a meta-analysis of randomized controlled trial (RCT) studies to evaluate the effect of Foley catheter with simultaneous oxytocin on labor induction. PubMed, Embase, and other databases were searched from their inception to July 2017. We included all RCTs comparing Foley catheter with simultaneous oxytocin (i.e. intervention group) with Foley catheter followed by oxytocin (i.e. control group) in the three kinds of women (nulliparas and multiparas/only nulliparas/only multiparas). We estimate summarized relative risk (RR) and 95% confidence intervals (CIs) for dichotomous outcomes, standard mean difference for continuous outcomes. Fixed- and random-effects models were used, depending on heterogeneity.

Results: After application of our inclusion and exclusion criteria, six RCTs with a total of 1133 participants were identified. We found that only nulliparas had significant RR of delivery within 24?h (RR?=?1.32, 95% CI: 1.12, 1.55, I²?=?46.5%). Meanwhile, there was no statistically significant difference between intervention and control groups in vaginal delivery in 24?h, cesarean delivery, time to delivery, and Apgar score at 5?min less than 7. Foley catheter with simultaneous oxytocin did not increase the risk of side effects, included chorioamnionitis, postpartum hemorrhage, uterine hyperstimulation, and neonatal intensive care unit admission.

Conclusion: The results seem to support the use of oxytocin to a Foley catheter at the initiation of labor induction, as it might lead to increases the rate of delivery within 24?h in nulliparas.     

A prospective comparison of hourly and quarter-hourly oxytocin dose increase intervals for the induction of labor at term

Fifty-two women undergoing labor induction and vaginal delivery at term were randomized between two oxytocin infusion protocols, involving hourly versus quarter-hourly increases in dose. Potential differences were sought of duration of labor, amount of uterine activity generated, and amount of oxytocin required. Starting at 0.5 mU/minute, oxytocin infusion was increased regularly in small increments every hour or every 15 minutes, according to group assignment. No differences were observed in potentially confounding clinical and demographic factors between the groups, including time to ruptured membranes. There were no clinically or statistically significant differences found for the duration of any phase or stage of labor, quantitative assessment of uterine activity, incidence of hyperstimulation, or neonatal outcome. The average dose of oxytocin used was lower in the hourly than in the quarter-hourly, protocol (4.4 versus 6.7 mU/minute; P less than .005). Significantly fewer patients on the hourly protocol required a maximum infusion rate exceeding 8 mU/minute (P less than .05). More patients on the hourly protocol either had oxytocin discontinued completely or were maintained at 4 mU/minute or less during the active phase of labor (P less than .05 and P less than .001, respectively). We conclude that a slower rate of increase in oxytocin administration via continuous infusion results in no prolongation of any phase of induced labor, while permitting lower infusion rates of the drug.     

The impact of labor at term on measures of neonatal outcome

OBJECTIVE: The purpose of this study was to determine risk assessments for a spectrum of neonatal outcomes with elective cesarean delivery versus a trial of labor for previous cesarean section and otherwise healthy patients who deliver at term. STUDY DESIGN: The perinatal/neonatal database of St. Joseph's Health Care, London, Ontario, Canada, was used to obtain the umbilical cord pH and base excess values, incidence of adverse neonatal outcomes, and patient demographics for all term (> or =37 weeks of gestation), singleton, liveborn, or intrapartum demise infants with no major anomalies who were delivered between January 1992 and March 2002 (n = 33,709 infants). Patient groupings (all patient, patient with previous cesarean delivery, and low-risk patient) with no labor versus labor were studied by a comparison of mean values/incidences for those neonatal outcomes that were available from the database with the use of linear and logistic regression analysis and controlling for potentially confounding variables. RESULTS: Labor was associated with a small drop in umbilical artery pH from approximately 7.27 to 7.25 and base excess from approximately -3.1 to -5.4 mmol/L, but this was generally well tolerated, with no difference in the incidence of 5-minute Apgar scores of <7 for any of the patient population groupings. Neonatal respiratory morbidity was increased generally in the group of elective cesarean delivery patients, which resulted in increased neonatal intensive care unit triage/admission even out to 7 days; some of this risk was likely to persist even with a policy of elective cesarean delivery after 39 weeks of gestation. Although we found no significant difference in the incidence of pathologic acidemia at birth with an umbilical artery pH <7.00, there was a risk for intrapartum/neonatal death that could be attributed to labor events per se that ranged from 1 of 882 for the patients with previous cesarean delivery to 1 of 3406 for the low-risk patients. CONCLUSION: For otherwise healthy patients at term, the risk of adverse neonatal outcomes is low, with the choice between elective cesarean delivery and trial of labor in general balancing the low risk of increased respiratory morbidity and thereby neonatal intensive care unit triage/admission against the extremely low risk of labor-related infant death and severe morbidity. However, this balance for the patients with previous cesarean delivery appears shifted, with less benefit from a trial of labor in terms of reduced respiratory morbidity and neonatal intensive care unit triage/admission and with increased labor-related severe morbidity/death, albeit with all of these still at a low level.     

Prediction of adverse outcome associated with vaginal misoprostol for labor induction

Objective: To identify predictors of adverse outcome in pregnant women at term receiving 50 μg of intravaginal misoprostol for labor induction. Study design: A prospective observational study was conducted of 720 pregnant women at term with an unfavorable cervix and a medical or obstetric indication for labor induction. All patients received 50 μg of intravaginal misoprostol every 4 h up to three doses. The primary outcome measure was “adverse outcome” defined as: neonatal death, fetal acidemia and emergent cesarean delivery performed for non-reassuring fetal heart rate tracings. A stepwise logistic regression analysis was used to identify predictors of adverse outcome. Results: Tachysystole (frequent uterine contractions) (odds ratio (OR), 3.7; 95% confidence interval (CI), 1.2–10.8) and fetal tachycardia (OR, 4.8; 95% CI, 1.4–16.2) were determined as significant predictors of adverse outcome. The specificity of the model was 94.2%, whereas the sensitivity was 20.4%. Conclusion: In the absence of tachysystole and fetal tachycardia, an uneventful delivery might be expected for women receiving 50 μg of intravaginal misoprostol.     

Ambulatory epidural anesthesia and the duration of labor.

OBJECTIVES: Ambulatory epidural analgesia has become a common option for women in labor in France. We tested the hypothesis that a method of epidural analgesia that allowed women to walk had specific advantages regarding mode of delivery, consumption of local anesthetic, oxytocin requirement, and labor duration. METHODS: Two hundred and twenty-one women with uncomplicated pregnancies who presented in spontaneous labor between 36 and 42 weeks of gestation or who were scheduled for induced labor were randomly divided into two groups, ambulatory and non-ambulatory. All were given intermittent epidural injections of 0.1% ropivacaine with 0.6 microg/ml sufentanil for analgesia during labor (P<0.05 was considered significant). None of the women had previous cesarean delivery. RESULTS: There were no significant differences between the two groups in mode of delivery, consumption of local anesthetic, or oxytocin requirement. However, a significant difference was noted in labor duration (173.4+/-109.9 min vs. 236.4+/-130.6 min; P=0.001). CONCLUSIONS: Walking with ambulatory labor analgesia shortens labor duration but has no other effect on the progress and outcome of labor.     

Effect of oxytocin during labor on neonatal acidemia

Objective: To assess the factors affecting neonatal acidemia, including occurrence of tachysystole/hypertonus in fetuses exposed to oxytocin during labour and with continuously-monitored fetal heart rate (FHR) tracings.

Methods: Prospective observational study of all women with term pregnancies who received oxytocin for induction/augmentation of labour. FHR tracings were prospectively classified using ACOG classification. Independent predictors of neonatal acidemia were identified using multivariate linear regression with p?<?0.05 considered significant.

Results: We included 430 women, 236 of whom (54.9%) had spontaneous onset of labour. The duration of active phase of the second stage of labour and the presence of abnormal FHR tracing during labour were significantly associated with UA pH (p?<?0.001) and BE (p?<?0.001), while maximum dose of oxytocin (p?<?0.17; p?<?0.7) and tachysystole (p?<?0.9; p?<?0.8) were not. At logistic regression, the duration of active phase of the second stage of labour was independently predictive of neonatal acidemia (p?<?0.009) while abnormal FHR tracing approached significance (p?<?0.088).

Conclusions: In women receiving oxytocin during labour, the duration of active phase of the second stage of labour correlates with neonatal acidemia, whereas maximum dose of oxytocin, duration of oxytocin administration and occurrence of tachysystole during labour do not.