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ORIGINAL ARTICLE
Year : 2015  |  Volume : 28  |  Issue : 1  |  Page : 239-244

Comparison of oral misoprostol and oxytocin for labor induction in prelabor rupture of membranes at term


1 Department of Obstetrics and Gynecology, Faculty of Medicine, Menoufia University, Menoufia, Egypt
2 Department of Obstetrics and Gynecology, El-Mahalla General Hospital, El-Mahalla, Gharbia, Egypt

Date of Submission11-Mar-2014
Date of Acceptance18-May-2014
Date of Web Publication29-Apr-2015

Correspondence Address:
Shereen M Tayel
Department of Obstetrics and Gynecology, El-Mahalla General Hospital, Tanta University, El-Mahalla, Gharbia
Egypt
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/1110-2098.156001

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  Abstract 

Objective
This study aims to compare the efficacy and safety of oral misoprostol with oxytocin infusion for induction of labor in women with prelabor rupture of membranes (PROM) at term.
Background
PROM at term is one of the most common complications of pregnancy. It is an important cause of perinatal morbidity and mortality, particularly if it is associated with a prolonged latency period from membranes rupture to delivery.
Patients and methods
This prospective randomized study included 100 pregnant women admitted to the Department of Obstetrics and Gynecology at El-Mahalla General Hospital presenting with PROM at term. The women were assigned randomly to one of the two equal groups (groups A or B): group A, which received 100 mg oral misoprostol every 4 h for a maximum of three doses, and group B, which received an intravenous infusion of oxytocin starting with a dose of 4 mU/min with an incremental increase of 4 mU/min every 30 min until a maximum dose of 32 mU/min. The primary outcome variable was time from induction to vaginal delivery. The secondary outcomes were mode of delivery, maternal, and neonatal outcomes.
Results
The study showed that the time intervals from induction to delivery were significantly shorter in the misoprostol group than in the oxytocin group (6.59 ± 1.91 and 9.30 ± 2.58 h, respectively; P < 0.001). Also, there were no significant differences in maternal and neonatal outcomes between both groups.
Conclusion
Oral misoprostol at a dose of 100 mg every 4 h was not only as successful as oxytocin for labor induction in women presenting with PROM at term but also reduced the duration of labor in nulliparous women. Oral misoprostol was safe in terms of maternal and neonatal outcomes.

Keywords: Induction of labor, misoprostol, oxytocin, prelabor rupture of membranes


How to cite this article:
Shabana AA, El Kilani OA, El Khouly NI, Tayel SM. Comparison of oral misoprostol and oxytocin for labor induction in prelabor rupture of membranes at term. Menoufia Med J 2015;28:239-44

How to cite this URL:
Shabana AA, El Kilani OA, El Khouly NI, Tayel SM. Comparison of oral misoprostol and oxytocin for labor induction in prelabor rupture of membranes at term. Menoufia Med J [serial online] 2015 [cited 2019 Nov 22];28:239-44. Available from: http://www.mmj.eg.net/text.asp?2015/28/1/239/156001


  Introduction Top


Prelabor rupture of membranes (PROM) at term is one of the most common complications of pregnancy. It is defined as rupture of fetal membranes before the onset of labor [1].

PROM occurs in 8-10% of pregnant women at term. A prolonged interval from rupture of membranes to delivery is associated with an increase in the incidence of chorioamnionitis and neonatal sepsis. The management of term patients with PROM, especially those with an unfavorable cervix, remains controversial; management options range from an immediate induction of labor to delayed induction or expectant management. Active management leads to a shorter interval from PROM to delivery, reducing the risk of postnatal infection. In addition, active management is preferred by patients [2].

Oxytocin and prostaglandins are the most frequently used pharmacological agents for induction of labor [3]. Oxytocin is the standard agent for labor induction. It is produced endogenously chiefly in the hypothalamus and released from the posterior pituitary gland [4].

Although oxytocin infusion is accepted widely as a safe and effective labor induction method, its success is highly dependent on the condition of the cervix at the beginning of the induction [3].

Misoprostol is a prostaglandin E1 analogue that is absorbed rapidly orally, and has been shown to have both safety and efficacy for cervical ripening and labor induction. Misoprostol has the advantage of being inexpensive and stable at room temperature and requires no refrigeration for its storage as other prostaglandins. These features make it ideal for use in the third-world countries [5].

The advantage of misoprostol orally with particular reference to PROM is avoidance of repeated vaginal examinations, resulting in a lower risk of sepsis for the mother and the baby [6].


  Patients and methods Top


This prospective controlled-randomized study included 100 pregnant women admitted to the Department of Obstetrics and Gynecology at El-Mahalla General Hospital presenting with PROM at term in the period from April 2012 to January 2013. After obtaining approval from ethical committees, all women were informed about the nature of the study and they signed an informed consent before starting the study.

The inclusion criteria were as follows: singleton living fetus, gestational age of at least 37 weeks, vertex presentation, no evidence of active labor, normal fetal heart rate pattern, nulliparous and multiparous (not>para 5), and Bishop score of at least 6. The exclusion criteria were as follows: previous uterine scar, chorioamnionitis, contraindications to prostaglandins use, for example, bronchial asthma, cardiac disorders, thick or dark meconium-stained liquor, placenta previa or active vaginal bleeding, or any condition that contraindicated vaginal delivery.

Finally, a local examination (P/V) was performed to confirm the diagnosis of rupture of membranes using a sterile speculum, presentation, position, station, and assessment of the Bishop score. An obstetric ultrasound examination was then performed to determine the fetal cardiac activity, gestational age, lie, presentation, and AFI. Women who agreed to participate in the study were assigned randomly to one of the two equal groups (groups A or B).

Group A received 100 mg oral misoprostol every 4 h for a maximum of three doses [7].

Group B received an intravenous infusion of oxytocin starting at a dose of 4 mU/min (eight drops/min), with an incremental increase of 4 mU/min every 30 min. We started with a solution of 500 ml Ringer's solution that contained 5 IU oxytocin/ml at a rate of 4 mU/min (eight drops/min). Oxytocin infusion was administered by an intravenous set using the gravity-fed counting drops technique. The starting dose was 4 mU/min (eight drops/min) and it was increased every 30 min until there were adequate uterine contractions (three contractions within 10 min lasting 40-60 s) or to a maximum of 32 mU/min [8].

Women admitted to the delivery room underwent monitoring of fetal heart rate and uterine activity. For every woman, a partogram was initiated to evaluate the progress of labor. The induction process was stopped whenever any fetal or maternal complications developed and cesarean section was performed, for example, fetal distress, thick or dark meconium passage, and failed induction, which is defined as an active labor failing to occur within 12 h of oxytocin and misoprostol administration.

Patients who developed hyperstimulation were treated by stopping oxytocin infusion, intravenous fluids, supplementation of oxygen mask, and changing their position to the left lateral position. If the hyperstimulation did not reverse and the fetal heart rate not improving to the normal level, emergency cesarean section was indicated.

The primary study outcome was induction to delivery interval (IDI). The secondary study outcomes were mode of delivery, maternal side effects, including abnormal uterine activity pattern (such as tachysystole, uterine hypertonus, uterine hyperstimulation), nausea and vomiting, pyrexia (maternal temperature ≥38°C), and postpartum hemorrhage. The secondary fetal outcomes such as Apgar score at 5 min, birth weight, and NICU admissions were documented.

Statistical analysis

Data were collected, tabulated, coded, and then analyzed using a computer software SPSS version 17.

Analysis of data was carried out as follows: quantitative variables were described as mean, SD, and range, and qualitative variables were described as number (n) and percentage (%). A difference in variables was expressed by the P value (>0.05 was considered nonsignificant, <0.05 was considered significant, and <0.001 was considered highly significant).


  Results Top


The results of this study showed that there was no significant difference between the study groups in demographic and antepartum variables. Maternal age, gestational age, parity, PROM duration, admission temperature, and Bishop score were similar in both groups as shown in [Table 1].
Table 1: Demographic data of the patients in the two groups

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There was a statistically significant difference between the two groups in the time of IDI as the mean was lower in the misoprostol group than in the oxytocin group (6.59 ± 1.91and 9.30 ± 2.58; P < 0.001), respectively. Also, there was a highly statistically significant difference between the study groups in the mean IDI in nulliparity and multiparity as shown in [Table 2].
Table 2: Induction to delivery interval according to parity

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In the misoprostol group, 47 women (94%) were delivered vaginally and three women (6%) were delivered by cesarean section, whereas in the oxytocin group, 44 women (88%) were delivered vaginally and six women (12%) were delivered by cesarean section, with a nonsignificant difference in the mode of delivery (P = 0.487) as shown in [Table 3].
Table 3: Mode of delivery of the patients in the study groups

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The indication for cesarean section in the misoprostol group was two cases (4%) because of fetal distress in the form of fetal tachycardia and one case (2%) because of failed induction, whereas in the oxytocin group, one case (2%) was because of fetal distress, one case (2%) because of failed induction, and four cases (8%) because of failed progress.

One patient in the misoprostol group showed gastrointestinal tract complications in the form of nausea, vomiting; no complications were encountered in the oxytocin group. Two patients (4%) in the misoprostol group experienced uterine hypertonus and one of the patients in the oxytocin group experienced uterine hypertonus, which is defined as a contraction lasting at least 2 min without a normal fetal heart rate. No cases of chorioamnionitis were detected in the two study groups, with a nonsignificant difference in intrapartum complications (P = 0.503) as shown in [Table 4].
Table 4: Intrapartum complications in the study groups

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One patient (2%) in the misoprostol group experienced atonic postpartum hemorrhage and two patients (4%) in the oxytocin group experienced atonic postpartum hemorrhage who did not require blood transfusion, with a nonsignificant difference (P = 0.558), as shown in [Table 5].
Table 5: Incidence of postpartum hemorrhage in the study groups

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There were no significant differences between the two groups in the neonatal outcome measures, Apgar score, and birth weight as shown in [Table 6]. The number of neonatal ICU admissions was slightly higher in the oxytocin group, four cases (8%), compared with the misoprostol group, two cases (4%), with a nonsignificant difference (P = 0.678) as shown in [Table 6].
Table 6: Neonatal outcome between both groups

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  Discussion Top


The study showed that the time intervals from IDI were reduced in the misoprostol group compared with the oxytocin group (6.59 ± 1.91 and 9.30 ± 2.58 h, respectively; P < 0.001) and the difference between both groups was statistically significant.

Our result was in agreement with the study of Ngai et al. [7], who found that the IDI was significant longer in the oxytocin group than in the misoprostol group (11.1 ± 4.9 and 7.3 ± 3.1 h, respectively). In the study of Al-Hussaini et al. [9] the IDI was significantly shorter in the misoprostol group than in the oxytocin group (5.5 ± 2.9 and 10 ± 4.8 h, respectively). Also, in the study of Nigam et al. [10], it was found that the IDI was shorter with misoprostol (7.7 ± 2.8 h) than (14.3 ± 4.8 h) with oxytocin.

However, a study by Mozurkewich [11] found that the time interval from IDI was similar: 11.9 h in the misoprostol group and 11.8 h in the oxytocin group.

Our result was not in agreement with the study of Crane et al. [12], who found a significant difference between the misoprostol and the oxytocin group, with longer IDI in the misoprostol group (737 ± 426 min) compared with oxytocin (573 ± 318 min) (P < 0.05). This may be explained by the higher percentage of nullipara in their study in the misoprostol group (67.3%) and their use of an oral dose of misoprostol (75 mg).

There was no significant difference between the two groups in the mode of delivery as 47 women (94%) delivered vaginally in the misoprostol group and 44 women (88%) delivered vaginally in the oxytocin group. The incidence of cesarean section in the misoprostol group was 6% (three cases) compared with 12% (six cases) in the oxytocin group. These findings were in agreement with those of previous studies, for example, Ngai et al. [7], (5% in the oral misoprostol group and 7.5% in the oxytocin group); Mozurkewich [11], (20.1% in the oral misoprostol group and 19.9% in the oxytocin group). Butt et al. [13], (14.5% in the oral misoprostol group vs. 13.2% in the oxytocin group), with a nonsignificant difference in the mode of delivery between the misoprostol group and the oxytocin group.

Failed progression in the oxytocin group accounted for the most indications of cesarean section, four cases (8%), with nonoccurrence of failed progression in the misoprostol group. This finding was in agreement with that of Tarik [1], who found that all cesarean sections performed in the oxytocin group were because of failure to progress (7.4%). However, Butt et al. [13], found that failed progression in both the misoprostol group and the oxytocin group was the most common indication for cesarean section in both groups: six cases (10.9%) in the misoprostol group and 11.3% in the oxytocin group. The emergency cesarean section rate because of fetal distress in this study was not statistically significant in the two groups [two cases (4%) in the misoprostol group, and only one case (2%) in the oxytocin group]. Mozurkewich [11], found no significant difference between the misoprostol group and the oxytocin group in the occurrence of fetal distress and the percentage of fetal distress in the misoprostol group was 6.9 versus 2.7% in the oxytocin group.

In the misoprostol group, 30 women (60%) required a single dose of misoprostol (100 mg) whereas the rest, 20 women (40%), required more than one dose. Our findings in the misoprostol group are in agreement with those of Ngai et al. [7], who found that 60% of women required a single dose of oral misoprostol.

There were no differences between the two groups in the occurrence of hypertonus, tachysystole, and hyperstimulation (4% of women in the misoprostol group and 2% of women in the oxytocin group had hypertonus). Similarly, Crane et al. [12] found no difference between the misoprostol and oxytocin groups in the occurrence of hypertonus (6 vs. 4.1%, respectively). In addition, this result was in agreement with that of Mozurkewich [11], who found that there was a nonsignificant difference trend toward the occurrence of hypertonus in the misoprostol group compared with the oxytocin group (10.7 vs. 8.8%, respectively). There was no occurrence of tachysystole in the two groups in this study; this was in agreement with Rath et al. [11], who did not encounter any incidence of tachysystole in their study.

Mozurkewich [11] found a higher rate of occurrence of tachysystole in both the misoprostol group and the oxytocin group (10.1 vs. 8.1), respectively, with a greater occurrence in the misoprostol group, with a nonsignificant difference between the two groups. Unfortunately, the sample size was not sufficient in the two groups to detect the occurrence of this common outcome.

No cases of chorioamnionitis were detected in the two study groups. Many studies found that there was no significant difference between misoprostol and oxytocin groups in the occurrence of chorioamnionitis [7, 14, 15].

Our study also found no significant difference between the two groups in the occurrence of specific drug gastrointestinal side effects such as diarrhea, nausea, and vomiting as only one patient in the misoprostol group (2%) developed nausea and vomiting, with no occurrence of diarrhea in the two study groups. These results were similar to the results of Al-Hussaini et al. [9], who found no significant difference in the occurrence of specific drug side effects, for example, nausea, vomiting, and diarrhea between the two study groups.

No significant difference was found between the study groups in the occurrence of atonic postpartum hemorrhage as there was only one case (2%) in the misoprostol group and two cases (4%) in the oxytocin group. This is similar to the results of Crane et al. [12], who found no significant difference in both misoprostol and oxytocin groups (two cases) out of 52 cases (3.8%) in the misoprostol group, with no occurrence of this complication in the oxytocin group.

Apgar score at 5 min is an important neonatal outcome that must be considered in labor induction. There was no significant difference between the study groups in the 5-min Apgar score. The incidence of babies with Apgar score less than 7 in both misoprostol and oxytocin groups was 4 and 8%, respectively (P = 0.678).

These results were in agreement with those of Crane et al. [12], who found no significant difference between misoprostol and oxytocin groups in the Apgar score at 5 min (10 for each at 5 min). Also, Rath and Kabiraj [5] found no significant difference in the incidence of Apgar score less than 7 in both groups (6.6 and 6%, respectively).

In our study, although the two groups were similar in terms of neonatal admission to the ICU (NICU), there was a tendency toward greater NICU admissions in the oxytocin group: four cases (8%) in the oxytocin group versus two cases (4%) in the misoprostol group. Our results were in agreement with those of Crane et al. [12], who found that the misoprostol and oxytocin groups were similar in terms of admission to NICU, with greater incidence of admission in the oxytocin group: 3.8 versus 5.7%, respectively.

However, a study by Mozurkewich [11] found a nonsignificant trend toward greater NICU admission among infants born to mothers receiving misoprostol compared with the oxytocin group (20.1 vs. 12.4%), respectively. The higher incidence of admission to NICU in their study in the misoprostol group than in our misoprostol group may be because of the higher incidence of occurrence of hyperstimulation in their misoprostol group (13.8%) versus (0%) in our misoprostol group.

Our sample size was not sufficient to detect differences in uncommon outcomes; thus, it is recommended that further studies include large numbers of patients. This can lead to better evaluation of the rare complications and side effects of the drugs and may also enable identification of the ideal dose of misoprostol.


  Conclusion Top


Oral misoprostol at a dose of 100 mg every 4 h was not only as successful as oxytocin for labor induction in women presenting with PROM at term but also reduced the duration of labor in nulliparous women. Oral misoprostol was safe in terms of maternal and neonatal outcomes.

Oral misoprostol may be an alternative to oxytocin for labor induction in women with PROM at term where repeated vaginal examination is not recommended. Thus, oral misoprostol is still an option for term PROM.


  Acknowledgements Top


Conflicts of interest

There are no conflicts of interest.

 
  References Top

1.
Zamzami TY. Prelabor rupture of membranes at term in low-risk women: induce or wait?. Arch Gynecol Obstet 2006; 273 : 278-282.  Back to cited text no. 1
    
2.
Nagpal MB, Raghunandan C, Saili A. Oral misoprostol versus intracervical prostaglandin E 2 gel for active management of premature rupture of membranes at term. Int J Gynaecol Obstet 2009; 106 : 23-26.  Back to cited text no. 2
    
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Ozden S, Delikara MN, Avci A, Fiçicioglu C. Intravaginal misoprostol vs. expectant management in premature rupture of membranes with low Bishop scores at term. Int J Gynaecol Obstet 2002; 77 : 109-115.  Back to cited text no. 3
    
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American College of Obstetricians and Gynecologists (ACOG). Technical bulletin no. 127. Washington, DC: Induction of Labor; 1995.  Back to cited text no. 4
    
5.
Rath D, Kabiraj M. Induction of labor with oral misoprostol in women with prelabor rupture of membranes at term. J Obstet Gynecol 2007; 57 :505-508.  Back to cited text no. 5
    
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Ara J, Noorani M. Induction of labour with oral misoprostol for prelabour rupture of membranes at term. J Pak Med Assoc 2005; 55 : 180-183.  Back to cited text no. 6
    
7.
Ngai S, Chan Y, Lam S. Labor characteristics and uterine activity: misoprostol compared with oxytocin in women at term with prelabor rupture of the membranes. BJOG 2000; 107 :222-227.  Back to cited text no. 7
    
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Ade-Ojo IP, Kuti O, Loto OM, Ogunniyi SO. Prospective comparison of the 30-min and 60-min oxytocin dose incremental schedules for induction of labor at term. NJOG 2011; 6 :35-40.  Back to cited text no. 8
    
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Al-Hussaini TK, Abdel-Aal SA, Youssef MA. Oral misoprostol vs. intravenous oxytocin for labor induction in women with prelabor rupture of membranes at term. Int J Gynaecol Obstet 2003; 82 : 73-75.  Back to cited text no. 9
    
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Nigam A, Singh VK, Dubay P, Pandey K, Bhagoliwal A, Prakash A. Misoprostol vs. oxytocin for induction of labor at term. Int J Gynaecol Obstet 2004; 86 : 398-400.  Back to cited text no. 10
    
11.
Mozurkewich E. Prelabor rupture of membranes at term: induction techniques. Clin Obstet Gynecol 2006; 49 : 672-683.  Back to cited text no. 11
    
12.
Crane JM, Delaney T, Hutchens D. Oral misoprostol for premature rupture of membranes at term. Am J Obstet Gynecol 2003; 189 : 720-724.  Back to cited text no. 12
    
13.
Butt KD, Bennett KA, Crane JM, Hutchens D, Young DC. Randomized comparison of oral misoprostol and oxytocin for labor induction in term prelabor membrane rupture. Obstet Gynecol 1999; 94 : 994-999.  Back to cited text no. 13
    
14.
Shetty A, Stewart K, Stewart G. Active management of term prelabor rupture of membranes with oral misoprostol. Br J Obstet Gynecol 2002; 109 :1354-1358.  Back to cited text no. 14
    
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Cheung PC, Yeo EL, Wong KS, Tang LC. Oral misoprostol for induction of labor in prelabor rupture of membranes (PROM) at term: a randomized control trial. Acta Obstet Gynecol Scand 2006; 85: 1128-1133.  Back to cited text no. 15
    



 
 
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