Current Medical Research and Opinion
Curr Med Res Opin 1975.3:397-406. Downloaded from informahealthcare.com by CDL-UC Davis on 01/07/15. For personal use only.
The role of amniotomy in induction of labour with oral administration of prostaglandin E2
Vol. 3, No. 6, 1975
H.K. Basu,Ph. D.,F.R.C.S.(Ed.), M.R.C.O.G. and
K.T. J. Rajan, M.B., B.S., D.Obst.R.C.0.G West Hill Hospital Dartford, England
Cum. med. Res. Opin., (1975), 3, 397.
Received: 26th June 1975
Summary Prostagland~nE2 was administered orally in doses of 0.5 mg. to 2.0 mg. every 2 hours to 169 women for induction of labour. Induction was successful in 153 women (90%). In 99 of these women, low amniotomy was performed at the beginning. Performance of amniotomy at the beginning of induction did not alter the incidence of successful induction but did lead to a mean induction-delivery interval shorter than that in women who had amniotomy performed in the active phase of labour. Vomiting andlor diarrhoea occurred in 34 women (20 %). Uterine hypertonus of only transient nature occurred in 3 women. One woman suffered from atonic post-partum haemorrhage. No adverse effects on the fetus were apparent. The presence of fetopelvic disproportion was associated with a slow rate of cervicaldilatation andunsuccessful induction. Key words: Prostaglandins - labour, induced- amniotomy
Introduction Prostaglandin E2 and Fzcradministered intravenously have been proved to be an effectivemethod of inducing labour, particularly following a m n i ~ t o m y .It~ has . ~ been shown that prostaglandin E2 administered orally in 0.5 to 1.0 mg. doses stimulates effective uterine contractions at or near term without producing undesirable gastrointestinal or cardiovascular side-effectsand that the oxytocic effect of a single dose lasts for 2 to 3 hours.10 Karim and Sharma,” Barr and Naismith,’ and Yip et aI.13 induced labour successfully in a high proportion of cases by oral administration of prostaglandin E2without prior amniotomy. Membranes were ruptured artificially during the active phase of labour, corresponding to a cervical dilatation of 3 to 6 cm. Craft5 reported on the successful induction of labour by oral administration of prostaglandin E2 of 0.5 mg. to 3.0 mg. given every 2 hours following amniotomy. He compared the induction-delivery interval following oral administration of prostaglandin E2 and amniotomy performed in multigravid patients and that of a nonselected group in whom labour was induced by amniotomy alone. He found that the induction-delivery interval was shorter in the group who had prostaglandin orally along with amniotomy, than in the group who had amniotomy as the only method of inducing labour.6 Kelly et a1.12 observed that the success rate and mean inductiondelivery interval in women given prostaglandin E2orally following amniotomy was not different from that in women given oxytocin intravenously following amniotomy for induction of labour. 397
Curr Med Res Opin 1975.3:397-406. Downloaded from informahealthcare.com by CDL-UC Davis on 01/07/15. For personal use only.
The role of amniotomy in induction of labour with oral administration of prostaglandin E,
The present study was undertaken to compare the efficacy of performing amniotomy at the beginning of induction of labour with that of delaying amniotomy until the labour is established in pregnant women receiving prostaglandin E2 orally for induction of labour. Furthermore, as it has been previously suggested that a dose of prostaglandin E2 of up to 1.5 mg. given orally every 2 hours may be adequate for the purpose of induction of labour,2 it was decided to continue with this dose regime to assess its efficacy and the incidence of side-effects. This was done in preference to gradually increasing the dose on a titration basis as was done in the study reported by Craft.5
Patients and method Induction of labour was undertaken in 169 women for a variety of reasons, the major indications being as follows : prolonged pregnancy- 79 patients ;hypertensive complications - 54 patients; antepartum haemorrhage - 10 patients; uterine growth retardation- 16patients; blood group incompatibility-4 patients; and other reasons in 6 patients. Of the 169 women, 83 were primigravidae and 86 were multigravidae. The maturity at induction varied between 37 and 42 weeks (average 39.1 weeks). Patients were excluded from the study if they (a) were grand multiparae, (b) had Caesarian section or hysterotomy in a previous pregnancy, (c) had cardiac or respiratory diseases, (d) did not wish to participate in the study after an adequate explanation was given, or (e) had premature rupture of membranes, abdominal pain or irritableuterus. During the first half of the study period, doses of prostaglandin E2 were administered orally, as described below. Membranes were intact at the beginning of the induction procedure in all the cases. They either ruptured spontaneously or were ruptured artificially in the active phase of labour corresponding to a cervical dilatation of approximately 5 cm. A total of 70patients were thus treated. During the second half of the study period, 99 patients had low amniotomy performed at the beginning of induction of labour. Women started taking doses of prostaglandin E2 simultaneously as described below. The only element of selection as to whether the women had prior amniotomy or not was determined by the policy in force at the time the induction was carried out. Cervical assessment Prior to the administration of prostaglandin E2, a pelvic examination was performed by one of us. The condition of the cervix was recorded by the Bishop scoring method,3 as shown in Table I. Scores of 0 to 5 were considered as unfavourable, whilst scores of 6 to 13 were considered favourable for a successful outcome. The individual and the total score for all five parameters were recorded for each patient. The distribution of patients according to age, gravidity, body weight and cervical score is given in Table 11. 398
H. K. Basu and K. T. J. Rajan
Table I. Clinical assessment of cervix: Bishop scoring
Curr Med Res Opin 1975.3:397-406. Downloaded from informahealthcare.com by CDL-UC Davis on 01/07/15. For personal use only.
~
~
~~~~
Parameter
Score
Dilatation of 0s (cm.)
0 0
1to2 1
3 to4 2
5 to 6 3
Effacement of cervix (%)
0 to 30 0
40 to 50 1
60 to 70 2
80+ 3
Station
-3 0
-2 1
-1 t o o 2
3
Firm 0
Medium 1
Soft 2
Posterior
Middle 1
Anterior 2
Consistency Position
0
$ 1 to + 2
-
Total score: 0 to 5 = unfavourable; 6 to 13 = favourable Table 11. Details of patients studied Data
Prostaglandin E, alone
Amniotomy and prostaglandin E,
Total
No. of patients Age (years) : Range Average Weight (Ibs): Range Average
70 16 to 40 24 96 to 21 1 147
99 16to44 25 76 to 193 135
169 16 to 44 25 76 to 21 1 140
Cervical score 0 to 5 Cervical score 6 to 13
14 17
13 39
27 56
Total primigravidae
31
52
83
Cervical score 0 to 5 Cervical score 6 to 13
19 20
10 37
29 57
Total multigravidae
39
47
86
Primigravidae
Multigravidae
Prostaglandin E2 A solution of prostaglandin E2 (‘Prostin E2’) in either N:N dimethylacetamide (DMA) or ethanol was diluted in distilled water to a final concentration of 0.1 mg./ml. An initial dose of 5 ml. (0.5 mg.) was given in a small amount of water for the patient to drink. In the absence of any undesirable side-effects, a dose of 10 ml. (1.0 mg.) was administered half-an-hour later and repeated every 2 hours until the patients was delivered. In a few instances, the administration was discontinued prior to delivery, owing to the incidence of severe gastro-intestinal side-effects or lack of uterine response. In some women, if the standard dose of 1.0 mg. did not elicit an adequate uterine response, individual doses were increased to 15 ml. (1.5 mg.) and, exceptionally, to 20 ml. (2.0 mg.).
Curr Med Res Opin 1975.3:397-406. Downloaded from informahealthcare.com by CDL-UC Davis on 01/07/15. For personal use only.
The role of amniotomy in induction of labour with oral administrationof prostaglandin E,
Labour Standard supervision and management for women undergoing induction of labour was undertaken. This included monitoring the progress of labour by clinical methods as well as by cardiotocograph (Sonicaid FM2 model) in the majority of instances. Particular attention was paid to the detection of alterations of fetal heart sounds, uterine contractions and tonus. Analgesia was provided in most patients by parenteral injections of pethidine and prochlorperazine. Pre-mixed oxygen and nitrous oxide (‘Entonox’) was given towards the end of the first stage and during the second stage of labour.
Results Outcome Regular uterine activity was demonstrated within 30 minutes of taking the first dose of prostaglandin E2 in the majority of instances. The attempt at induction of labour was considered a failure if a cervical dilatation of 6 cm. or more was not established within 12 hours or if the severity of side-effects necessitated discontinuing the intake of the drug. Satisfactory uterine activity was established in 126 patients after administration of 1.0 mg. prostaglandin E2 repeated every 2 hours. In 41 women, the dose was increased to 1.5 mg. given every 2 hours, and in only 2 women a dose of 2.0 mg. every 2 hours had to be administered. Vaginal delivery was achieved in 153 women (90.5 %). The frequency of success was slightly higher in multigravidae than in primigravidae, in women with total cervical scores of 6 or more than in those with lower scores, and in those who had amniotomy performed at the beginning of induction than in those who had intact membranes at the beginning. The results are shown in Table 111. Table UL. Number and percentageof successful induction of labour Patient group
Prostaglandin Ea alone
Amniotomy and prostaglandin Ea
Total
Success
Failure
Success
Failure
Success
Primigravidae Cervical score 0 to 5 Cervicalscore6to 13
10(71%) 15(88%)
4(29 %) 2(12%)
lO(77 %) 37(95%)
3(23 %) 2(5%)
20(74 %) 52(93%)
7(26 %) 4(7%)
Total primigravidae
25(81%)
6(19 %)
47(90 %)
5(10 %)
7x87%)
ll(13 %)
Multigravidae CervicalscoreOto5 Cervicalscore6 to 13
15(79%) 20(100%)
4(21%)
9(90%) 37(1@3%)
1(10%)
24(83%) 57(100%)
5(17%)
Total multigravidae
35(90 %)
4(10 %)
46(98 %)
l(2 %)
81(94%)
5(6 %)
Failure
Although the differences were not statistically significant, the results indicated a general trend that primigravidae with low cervical scores had the lowest and multi-
Curr Med Res Opin 1975.3:397-406. Downloaded from informahealthcare.com by CDL-UC Davis on 01/07/15. For personal use only.
H. K. Basu and K. T. J. Rajan
gravidae with high cervical scores had the highest success rates. Of the women who delivered vaginally, 8 primigravidae and 2 multigravidae had forceps delivery for prophylactic reasons. In no patient could an operative delivery be attributed entirely to the administration of prostaglandin E2.One patient suffered from atonic postpartum haemorrhage. None of the parturients had a retained placenta. The mean blood loss amongst all the women delivered vaginally was 152 ml. Induction-delivery interval and total dosage Of the 153 women who had successful induction of labour, the mean inductiondelivery interval and the mean total dose of prostaglandin E2 required were dependent upon the cervical score, gravidity, and the timing of amniotomy as shown in Tables IV and V. The performance of amniotomy at the beginning of induction of labour led to a statistically significant shorter induction-delivery interval and lower total dose of prostaglandin E2 required (p
Curr Med Res Opin 1975.3:397-406. Downloaded from informahealthcare.com by CDL-UC Davis on 01/07/15. For personal use only.
The role of amniotomy in induction of labour with oral administration of prostaglandin E2
Vol. 3, No. 6, 1975
H.K. Basu,Ph. D.,F.R.C.S.(Ed.), M.R.C.O.G. and
K.T. J. Rajan, M.B., B.S., D.Obst.R.C.0.G West Hill Hospital Dartford, England
Cum. med. Res. Opin., (1975), 3, 397.
Received: 26th June 1975
Summary Prostagland~nE2 was administered orally in doses of 0.5 mg. to 2.0 mg. every 2 hours to 169 women for induction of labour. Induction was successful in 153 women (90%). In 99 of these women, low amniotomy was performed at the beginning. Performance of amniotomy at the beginning of induction did not alter the incidence of successful induction but did lead to a mean induction-delivery interval shorter than that in women who had amniotomy performed in the active phase of labour. Vomiting andlor diarrhoea occurred in 34 women (20 %). Uterine hypertonus of only transient nature occurred in 3 women. One woman suffered from atonic post-partum haemorrhage. No adverse effects on the fetus were apparent. The presence of fetopelvic disproportion was associated with a slow rate of cervicaldilatation andunsuccessful induction. Key words: Prostaglandins - labour, induced- amniotomy
Introduction Prostaglandin E2 and Fzcradministered intravenously have been proved to be an effectivemethod of inducing labour, particularly following a m n i ~ t o m y .It~ has . ~ been shown that prostaglandin E2 administered orally in 0.5 to 1.0 mg. doses stimulates effective uterine contractions at or near term without producing undesirable gastrointestinal or cardiovascular side-effectsand that the oxytocic effect of a single dose lasts for 2 to 3 hours.10 Karim and Sharma,” Barr and Naismith,’ and Yip et aI.13 induced labour successfully in a high proportion of cases by oral administration of prostaglandin E2without prior amniotomy. Membranes were ruptured artificially during the active phase of labour, corresponding to a cervical dilatation of 3 to 6 cm. Craft5 reported on the successful induction of labour by oral administration of prostaglandin E2 of 0.5 mg. to 3.0 mg. given every 2 hours following amniotomy. He compared the induction-delivery interval following oral administration of prostaglandin E2 and amniotomy performed in multigravid patients and that of a nonselected group in whom labour was induced by amniotomy alone. He found that the induction-delivery interval was shorter in the group who had prostaglandin orally along with amniotomy, than in the group who had amniotomy as the only method of inducing labour.6 Kelly et a1.12 observed that the success rate and mean inductiondelivery interval in women given prostaglandin E2orally following amniotomy was not different from that in women given oxytocin intravenously following amniotomy for induction of labour. 397
Curr Med Res Opin 1975.3:397-406. Downloaded from informahealthcare.com by CDL-UC Davis on 01/07/15. For personal use only.
The role of amniotomy in induction of labour with oral administration of prostaglandin E,
The present study was undertaken to compare the efficacy of performing amniotomy at the beginning of induction of labour with that of delaying amniotomy until the labour is established in pregnant women receiving prostaglandin E2 orally for induction of labour. Furthermore, as it has been previously suggested that a dose of prostaglandin E2 of up to 1.5 mg. given orally every 2 hours may be adequate for the purpose of induction of labour,2 it was decided to continue with this dose regime to assess its efficacy and the incidence of side-effects. This was done in preference to gradually increasing the dose on a titration basis as was done in the study reported by Craft.5
Patients and method Induction of labour was undertaken in 169 women for a variety of reasons, the major indications being as follows : prolonged pregnancy- 79 patients ;hypertensive complications - 54 patients; antepartum haemorrhage - 10 patients; uterine growth retardation- 16patients; blood group incompatibility-4 patients; and other reasons in 6 patients. Of the 169 women, 83 were primigravidae and 86 were multigravidae. The maturity at induction varied between 37 and 42 weeks (average 39.1 weeks). Patients were excluded from the study if they (a) were grand multiparae, (b) had Caesarian section or hysterotomy in a previous pregnancy, (c) had cardiac or respiratory diseases, (d) did not wish to participate in the study after an adequate explanation was given, or (e) had premature rupture of membranes, abdominal pain or irritableuterus. During the first half of the study period, doses of prostaglandin E2 were administered orally, as described below. Membranes were intact at the beginning of the induction procedure in all the cases. They either ruptured spontaneously or were ruptured artificially in the active phase of labour corresponding to a cervical dilatation of approximately 5 cm. A total of 70patients were thus treated. During the second half of the study period, 99 patients had low amniotomy performed at the beginning of induction of labour. Women started taking doses of prostaglandin E2 simultaneously as described below. The only element of selection as to whether the women had prior amniotomy or not was determined by the policy in force at the time the induction was carried out. Cervical assessment Prior to the administration of prostaglandin E2, a pelvic examination was performed by one of us. The condition of the cervix was recorded by the Bishop scoring method,3 as shown in Table I. Scores of 0 to 5 were considered as unfavourable, whilst scores of 6 to 13 were considered favourable for a successful outcome. The individual and the total score for all five parameters were recorded for each patient. The distribution of patients according to age, gravidity, body weight and cervical score is given in Table 11. 398
H. K. Basu and K. T. J. Rajan
Table I. Clinical assessment of cervix: Bishop scoring
Curr Med Res Opin 1975.3:397-406. Downloaded from informahealthcare.com by CDL-UC Davis on 01/07/15. For personal use only.
~
~
~~~~
Parameter
Score
Dilatation of 0s (cm.)
0 0
1to2 1
3 to4 2
5 to 6 3
Effacement of cervix (%)
0 to 30 0
40 to 50 1
60 to 70 2
80+ 3
Station
-3 0
-2 1
-1 t o o 2
3
Firm 0
Medium 1
Soft 2
Posterior
Middle 1
Anterior 2
Consistency Position
0
$ 1 to + 2
-
Total score: 0 to 5 = unfavourable; 6 to 13 = favourable Table 11. Details of patients studied Data
Prostaglandin E, alone
Amniotomy and prostaglandin E,
Total
No. of patients Age (years) : Range Average Weight (Ibs): Range Average
70 16 to 40 24 96 to 21 1 147
99 16to44 25 76 to 193 135
169 16 to 44 25 76 to 21 1 140
Cervical score 0 to 5 Cervical score 6 to 13
14 17
13 39
27 56
Total primigravidae
31
52
83
Cervical score 0 to 5 Cervical score 6 to 13
19 20
10 37
29 57
Total multigravidae
39
47
86
Primigravidae
Multigravidae
Prostaglandin E2 A solution of prostaglandin E2 (‘Prostin E2’) in either N:N dimethylacetamide (DMA) or ethanol was diluted in distilled water to a final concentration of 0.1 mg./ml. An initial dose of 5 ml. (0.5 mg.) was given in a small amount of water for the patient to drink. In the absence of any undesirable side-effects, a dose of 10 ml. (1.0 mg.) was administered half-an-hour later and repeated every 2 hours until the patients was delivered. In a few instances, the administration was discontinued prior to delivery, owing to the incidence of severe gastro-intestinal side-effects or lack of uterine response. In some women, if the standard dose of 1.0 mg. did not elicit an adequate uterine response, individual doses were increased to 15 ml. (1.5 mg.) and, exceptionally, to 20 ml. (2.0 mg.).
Curr Med Res Opin 1975.3:397-406. Downloaded from informahealthcare.com by CDL-UC Davis on 01/07/15. For personal use only.
The role of amniotomy in induction of labour with oral administrationof prostaglandin E,
Labour Standard supervision and management for women undergoing induction of labour was undertaken. This included monitoring the progress of labour by clinical methods as well as by cardiotocograph (Sonicaid FM2 model) in the majority of instances. Particular attention was paid to the detection of alterations of fetal heart sounds, uterine contractions and tonus. Analgesia was provided in most patients by parenteral injections of pethidine and prochlorperazine. Pre-mixed oxygen and nitrous oxide (‘Entonox’) was given towards the end of the first stage and during the second stage of labour.
Results Outcome Regular uterine activity was demonstrated within 30 minutes of taking the first dose of prostaglandin E2 in the majority of instances. The attempt at induction of labour was considered a failure if a cervical dilatation of 6 cm. or more was not established within 12 hours or if the severity of side-effects necessitated discontinuing the intake of the drug. Satisfactory uterine activity was established in 126 patients after administration of 1.0 mg. prostaglandin E2 repeated every 2 hours. In 41 women, the dose was increased to 1.5 mg. given every 2 hours, and in only 2 women a dose of 2.0 mg. every 2 hours had to be administered. Vaginal delivery was achieved in 153 women (90.5 %). The frequency of success was slightly higher in multigravidae than in primigravidae, in women with total cervical scores of 6 or more than in those with lower scores, and in those who had amniotomy performed at the beginning of induction than in those who had intact membranes at the beginning. The results are shown in Table 111. Table UL. Number and percentageof successful induction of labour Patient group
Prostaglandin Ea alone
Amniotomy and prostaglandin Ea
Total
Success
Failure
Success
Failure
Success
Primigravidae Cervical score 0 to 5 Cervicalscore6to 13
10(71%) 15(88%)
4(29 %) 2(12%)
lO(77 %) 37(95%)
3(23 %) 2(5%)
20(74 %) 52(93%)
7(26 %) 4(7%)
Total primigravidae
25(81%)
6(19 %)
47(90 %)
5(10 %)
7x87%)
ll(13 %)
Multigravidae CervicalscoreOto5 Cervicalscore6 to 13
15(79%) 20(100%)
4(21%)
9(90%) 37(1@3%)
1(10%)
24(83%) 57(100%)
5(17%)
Total multigravidae
35(90 %)
4(10 %)
46(98 %)
l(2 %)
81(94%)
5(6 %)
Failure
Although the differences were not statistically significant, the results indicated a general trend that primigravidae with low cervical scores had the lowest and multi-
Curr Med Res Opin 1975.3:397-406. Downloaded from informahealthcare.com by CDL-UC Davis on 01/07/15. For personal use only.
H. K. Basu and K. T. J. Rajan
gravidae with high cervical scores had the highest success rates. Of the women who delivered vaginally, 8 primigravidae and 2 multigravidae had forceps delivery for prophylactic reasons. In no patient could an operative delivery be attributed entirely to the administration of prostaglandin E2.One patient suffered from atonic postpartum haemorrhage. None of the parturients had a retained placenta. The mean blood loss amongst all the women delivered vaginally was 152 ml. Induction-delivery interval and total dosage Of the 153 women who had successful induction of labour, the mean inductiondelivery interval and the mean total dose of prostaglandin E2 required were dependent upon the cervical score, gravidity, and the timing of amniotomy as shown in Tables IV and V. The performance of amniotomy at the beginning of induction of labour led to a statistically significant shorter induction-delivery interval and lower total dose of prostaglandin E2 required (p
