IMPORTANT COPYRIGHT NOTICE: This electronic article is provided to you by courtesy of Ferring Pharmaceuticals. The document is provided for personal usage only. Further reproduction and/or distribution of the document is strictly prohibited. Title: Evaluation of a controlled release vaginal prostaglandin E2 pessary with a retrieval system for the induction of labour Authors: Westgate J and Williams JA Journal: J Obstet Gynaecol 1994 J Obstet Gynaecol Downloaded from informahealthcare.com by ReprintsDesk on 06/22/14 For personal use only. Westgate and Williams: Controlled release prostaglandin EZ 141 Women with a singleton, cephalic, pregnancy mean initial Bishop’s score was 4.2 (primigravi- of at least 38 weeks duration who were thought to dae 4.2, multigravidae 4.1). require induction of labour for medical or obst- etric reasons were recruited for the study if their Ease of removal and patient acceptability modified Bishop’s score was 6 or less. Patients The pessary was removed with little or no with more than three previous full term pregnan- difficulty for either staff or patient in 97 per cent cies, a previous caesarean section, ruptured mem- of cases (Table). All patients who experienced branes, evidence of fetal compromise or asthma slight discomfort during removal likened the sen- were excluded. sation to removal of a tampon. Removal was very At entry, all patients were examined by a single difficult in one case who became very distressed research midwife who allocated a Bishop’s score. at the onset of labour and developed vaginismus. Uterine activity and fetal heart rate were moni- The retrieval system allowed the pessary to be tored by a cardiotocogram at baseline and then removed but a full vaginal examination could not again 1 hour after insertion of the pessary, during be performed until after epidural analgesia was which time the patients remained in bed. The established. No uterine hyperstimulation occurred cardiotocogram was repeated at the onset of tight- and the patient did not have a precipitate labour. enings or contractions. The pessary was removed All 11 1 patients provided information about their by the research midwife after 12 hours, or earlier experience of the pessary in siru. Ninety-eight if there was concern about fetal or maternal con- patients (88 per cent) were unaware of its pres- dition or uterine contraction frequency; or if the ence, 10 (9 per cent) were aware but felt no membranes ruptured or labour ensued. Labour discomfort, two (2 per cent) were aware with mild was defined as the onset of regular painful con- discomfort and one (I per cent) had marked dis- tractions which lasted at least 45 seconds at a comfort with the pessary in frequency of three to four contractions in 10 situ. The pessary fell out in 11 patients. Eight of minutes. In all cases a cervical assessment was these occurred in the first 51 patients when the made at the time of removal. Ease of removal was pessary was left lying longitudinally in the vagina assessed by staff and patients on a 4-point scale. following insertion. In the next 60 patients the Patients also rated their experience of the pessary in situ on a 4-point scale. Treatment was con- insertion technique was modified to leave the sidered effective if labour began during the 12 pessary lying transversely in the posterior fornix. hour observation period or if the Bishop’s scorc After that only three pessaries were lost, all from patients in early labour; one loss with spontaneous For personal use only. increased by three or more points. Patients who rupture of the membranes, one with a heavy did not go into labour or who were unsuitable for mucous show and one with a amniotomy following the 12 hours observation contraction. were managed at the discretion of their attending obstetrician. Efficacy Following removal all pessaries were placed in Treatment success, defined as the onset of labour a plastic bag labelled with the study number, date within 12 hours or an increase in Bishop’s score and time of removal and placed immediately into of at least 3, occurred in 78 (70 per cent) of all a freezer. The pessaries were analysed by high I11 patients (primigravidae 73 per cent; multi- performance liquid chromatography by Con- gravidae, 67 per cent). If the patients in whom the trolled Therapeutics (Scotland) Ltd. (East Kil- pessary was lost (n = 1 1 ) or in whom the pessary J Obstet Gynaecol Downloaded from informahealthcare.com by ReprintsDesk on 06/22/14 bride, Scotland). The amount of prostaglandin E2 was removed early due to an adverse event released was calculated by subtraction of the (iz = 8) are excluded, treatment success occurred residual prostaglandin from the batch potency. in 70 of 92 patients (76 per cent) of cases (primi- Statistical analysis was by Student’s t test, Mann-Whitney U test, analysis of variance or x2 Table. Ease of pessary removal in 100 patients analysis. Odds ratios and their 95 per cent confidence intervals are given where appropriate. As assessed by Midwife Patient RESULTS One hundred and eleven patients (63 primigravi- No difficulty 78 88 dae, 48 multigravidae) were recruited. The mean Slight difficulty 19 9 Moderate difficulty 2 2 gestational age at induction was 40.7 weeks Very difficult 1 1 (primigravidae 40.9, multigravidae 40.4) and the 148 Journal of Obstetrics and Gynaecology (1994) Vol. 14/No. 3 gravidae 80 per cent; multigravidae, 71 per cent). in good condition at delivery although one was In this group, although the median pre-treatment postmature and treated for hypoglycaemia neona- Bishop’s scores were the same, patients with a tally. The two other cases had decelerations ac- treatment success tended to have had higher initial companying mild, infrequent contractions (one in scores compared with those with a treatment fail- 5 to 10 minutes) which resolved when the pessary ure (difference, P<O.O5). The success rate in was removed. Both went into spontaneous labour multigravidae was lower than that of primigravi- the following day, one with an uneventful labour, dae. No differences in gestational age or pre-treat- normal delivery and good neonatal outcomes. The ment Bishop’s scores were found, but when other had continued decelerations and meconium individual components of the Bishop’s score were stained amniotic fluid throughout labour with two examined there were more multigravidae induced normal fetal blood samples before a normal deliv- with a very high presenting part (station 3 cm ery and outcome. above the ischial spines or higher; 71 per cent Propess-RS was removed from two multigravi- versus 35 per cent, P<O.OOl; odds ratio 4.53, dae (2 per cent) because of hyperstimulated uter- 2.01-1 0.17). ine activity (>5 contractions in 10 minutes). A 3 mg prostaglandin E2 pessary (Prostin, Up- Both episodes occurred within I hour of insertion john Ltd) was administered vaginally to 27 pa- and resolved within 30 minutes of removal. Nei- tients (24 per cent) who did not go into labour ther case had fetal heart rate changes and both within 12 hours and who were not considered delivered normally after uneventful labours. In six suitable for artificial rupture of the membranes. cases the pessary was left in situ at the onset of Of these, 10 were treatment successes (with a labour. In all these cases the onset of contractions Bishop’s score increase of at least 3); nine re- had been slow and gradual and, despite the proto- ceived one 3 mg pessary before labour ensued, the col, staff did not remove the pessary once regular other received three 3 mg pessaries before being painful contractions were established because sent home to return 2 days later in spontaneous they were unable to detect any change in the labour. These patients had good outcomes with cervix on vaginal examination. One of the six had nine normal deliveries and one caesarean section a contraction frequency of 5 in 10 minutes in the for failure to progress. Of the 17 patients who did second stage of labour. All six had normal out- not have a satisfactory cervical change with comes. Propess-RS, five patients had one 3 mg pessary. nine had two doses and three had three doses. For personal use only. Eight (47 per cent) were sent home after failing to Residual prostaglandin EP respond to extra prostaglandin El, two were read- One hundred and three pessaries were recovered mitted in spontaneous labour, five were readmit- for analysis of residual prostaglandin content. The ted for further induction attempts and one was amount released from each pessary is shown in delivered by elective caesarean section. The over- the Figure. all caesarean section rate in this group was 35 per The mean rate of prostaglandin E2 release was cent. 0.33 2 0.15 mg/hour (s.d.; range 0.12 to 0.78; 95 per cent confidence interval 0.30-0.36 mghour). No difference wa5 found in release rates between Adverse events with Propess in situ primigravidae and multigravidae or between treat- The pessary was removed early from six patients ment successes and treatment failures. Less than J Obstet Gynaecol Downloaded from informahealthcare.com by ReprintsDesk on 06/22/14 because of an abnormal cardiotocogram and from two mg of prostaglandin E2 was released in the 12 two patients because of uterine hyperstimulation. hours in 13 (22 per cent) of the 60 patients who All six cases of cardiotocographic abnormality had the pessary in for that time, nevertheless were associated with uterine activity but none was treatment success occurred in seven cases (54 per hyperstimulated. In two cases the record showed cent).