Nitric oxide donors induce ripening of the human uterine cervix: a randomised controlled trial

A randomized double blinded clinical trial to explore the clinical outcomes of vaginal isonicotinic acid hydrazide (INH) administration six hours prior to T380A intrauterine device insertion in persons delivered only by cesarean delivery

OBJECTIVE

To compare insertion pain and ease of insertion in participants with a prior caesarean delivery having copper intrauterine device (IUD) after pretreatment with isonicotinic acid hydrazide (INH) 900 mg vaginally or placebo.

STUDY DESIGN

From September 2020 to September 2021, we conducted a randomized, double-blind, placebo-controlled experiment at Aswan University Hospital in Egypt with participants who were delivered solely by caesarean delivery and desired copper T380A IUD insertion. The participants were randomly assigned to either vaginal INH or placebo six hours before IUD insertion in a 1:1 ratio. The primary objective of the research was the individuals' self-reported pain during cervical tenaculum placement, sound insertion, IUD insertion, and 5 minutes after the placement, as measured by a 10-cm visual analogue scale (VAS). Our secondary outcomes were ease of insertion, satisfaction, the need for analgesics, and adverse effects. IUD insertion ease was graded from 0 to 10 on a 10-cm VAS scale, with 0 suggesting very easy insertion and 10 denoting extremely difficult insertion.

RESULTS

When compared to the placebo group, the INH group experienced considerably less pain during IUD insertion (2.9±0.85vs.5.11±0.82;p<0.01), lower median ease of insertion score (3(1-4)vs.5(3-6);p<0.01), and better satisfaction (8.17±0.69vs.5.57±0.75). The two groups had comparable side effects.

CONCLUSIONS

Vaginal INH administered before IUD insertion reduce the amount of discomfort participants feel throughout the process in individuals who had previously only been delivered via CD. It also has the potential to make insertion easier.

IMPLICATIONS

In participants who were delivered solely by CD before, vaginal INH given prior to IUD placement reduces the amount of discomfort participants experience throughout the procedure. Furthermore, it could increase the ease of insertion.

Evaluating the efficacy of outpatient use of isosorbide mononitrate on cervical ripening in pregnant women with unfavourable cervix

The aim of the present study was to evaluate the efficacy of outpatient administration of nitric oxide donor isosorbide mononitrate for cervical ripening. A randomised clinical trial was performed on term pregnant women with Bishop Score < 6. In the case group, Isosorbide-5-mononitrate capsule and in the control group, placebo was inserted in the posterior vaginal fornix for two consecutive days. The main outcomes were increases in Bishop Score after 48 hours of intervention, number of vaginal deliveries and interval from intervention to delivery.There was a significant increase of the mean Bishop score in the isosorbide group [3.57 ± 1.12 VS 1.54 ± 1.42 respectively (p = .001)]. The other outcome variables did not show a significant difference between the two groups except for headache which was significantly more in the case group. No cases of tachysystole were observed in the two groups. Additionally, haemoglobin levels after delivery did not show a significant difference between the two groups.Impact statement:What is already known on this subject? Cervical ripening in women with an unfavourable cervix and having an indication for induction of labour is an important issue in modern obstetrics. Different methods have been used for cervical ripening and induction of labour including mechanical (i.e. laminaria tents, Dilapan-S, foley catheter), medical (i.e. PGs) and supportive methods. There is no consensus on the best option for cervical ripeningWhat will the results of this study add to the current knowledge of this subject? Outpatient administration of nitric oxide could affect cervical ripening without a significant improvement in the duration of different stages of labour, intervention to delivery interval and number of vaginal deliveries.What are the implications of these findings for clinical practice and/or further research? Due to the contradictory results of various studies, more studies should be performed with greater sample size to evaluate nitric oxide donor isosorbide mononitrate effect on labour duration and reducing caesarean deliveries. Additional data is needed to assess the real impact of NO donors on different stages of labour and its implications.

Effect of topical glyceryl trinitrate cream on pain perception during intrauterine device insertion in multiparous women: A randomized double-blinded placebo-controlled study

OBJECTIVE

Intrauterine contraceptive device (IUD) insertion-related pain presents a push beyond the decline of women to use IUD for family planning. We aimed to investigate the analgesic effect of glyceryl trinitrate cream (GTN) in reducing pain during IUD insertion.

MATERIALS AND METHODS

We conducted a randomized double-blinded placebo-controlled study (NCT02708251, clinicaltrials.gov) in a tertiary University hospital. Reproductive-aged women requesting Copper IUD for contraception were considered. Eligible women for IUD insertion were randomized (1:1) to glyceryl trinitrate cream (GTN arm) or Placebo. Three minutes before IUD insertion, 1 ml of GTN cream or placebo was applied to the cervical lip at the planned tenaculum site, followed by 1 ml placed in the cervical canal up to the level of the internal os using a Q-tip applicator. Our outcomes were the participant's self-rated pain perception utilizing a 10-cm Visual Analogue Scale (VAS) during cervical tenaculum placement, uterine sound and IUD insertion, then 15 min post-procedure.

RESULTS

100 women were enrolled and randomized to GTN arm (n = 50) or placebo (n = 50). Women in the GTN arm reported lower VAS scores during tenaculum placement, sound and IUD insertion (median: 2 vs. 4, p < 0.0001; 2.5 vs. 4.5, p < 0.001;3 vs. 5.5, p < 0.0001, respectively). Higher ease of insertion score was also determined among GTN arm (mean ± SD: 6.9 ± 1.15 vs. 4.7 ± 1.38, p < 0.0001). Additionally, women in the GTN arm were more satisfied by the end of the insertion (92% vs. 74%, p = 0.003).

CONCLUSION

Application of cervical GTN cream before IUD insertion seems to reduce the induced pain with subsequent easy insertion.

Nitric oxide donors for cervical ripening and induction of labour

BACKGROUND

Sometimes it is necessary to bring on labour artificially because of safety concerns for the mother or baby. This review is one of a series of reviews of methods of labour induction using a standardised protocol.

OBJECTIVES

To determine the effects of NO donors (isosorbide mononitrate (ISMN), isosorbide dinitrate (ISDN), nitroglycerin and sodium nitroprusside) for third trimester cervical ripening or induction of labour, in comparison with placebo or no treatment or other treatments from a predefined hierarchy.

SEARCH METHODS

We searched Cochrane Pregnancy and Childbirth's Trials Register (15 August 2016) and the reference lists of trial reports.

SELECTION CRITERIA

Clinical trials comparing NO donors for cervical ripening or labour induction with other methods listed above it on a predefined list of methods of labour induction. Interventions include NO donors (isosorbide mononitrate, isosorbide dinitrate, nitroglycerin and sodium nitroprusside) compared with other methods listed above it on a predefined list of methods of labour induction.

DATA COLLECTION AND ANALYSIS

This review is part of a series of reviews focusing on methods of induction of labour, based on a generic protocol. Three review authors independently assessed trials for inclusion, assessed risk of bias and extracted data. In this update, the quality of the evidence for the main comparison was assessed using the GRADE approach.

MAIN RESULTS

We included 23 trials (including a total of 4777 women). Included studies compared NO donors with placebo, vaginal prostaglandin E2 (PGE2), intracervical PGE2, vaginal misoprostol and intracervical Foley catheter. The majority of the included studies were assessed as being at low risk of bias. Nitric oxide versus placebo There was no evidence of a difference for any of the primary outcomes analysed: vaginal delivery not achieved in 24 hours (risk ratio (RR) 0.97, 95% confidence interval (CI) 0.83 to 1.15; one trial, 238 women; low-quality evidence), uterine hyperstimulation with fetal heart rate (FHR) changes (RR 0.09, 95% CI 0.01 to 1.62; two trials, 300 women; low-quality evidence), caesarean section (RR 0.99, 95% CI 0.88 to 1.11; nine trials, 2624 women; moderate-quality evidence) or serious neonatal morbidity/perinatal death (average RR 1.61, 95% CI 0.08 to 33.26; two trials, 1712 women; low-quality evidence). There were no instances of serious maternal morbidity or death (one study reported this outcome).There was a reduction in an unfavourable cervix at 12 to 24 hours in women treated with NO donors (average RR 0.78, 95% CI 0.67 to 0.90; four trials, 762 women), and this difference was observed in both subgroups of standard release and slow release formulation. Women who received NO donors were less likely to experience uterine hyperstimulation without FHR rate changes (RR 0.05, 95% CI 0.00 to 0.80; one trial, 200 women), and more likely to experience side effects, including nausea, headache and vomiting. Nitric oxide donors versus vaginal prostaglandins There was no evidence of any difference between groups for uterine hyperstimulation with FHR changes or caesarean section (RR 0.97, 95% CI 0.78 to 1.21; three trials, 571 women). Serious neonatal morbidity and serious maternal morbidity were not reported. There were fewer women in the NO donor group who did not achieve a vaginal delivery within 24 hours (RR 0.63, 95% CI 0.47 to 0.86; one trial, 400 primiparae women). Nitric oxide donors versus intracervical prostaglandins One study reported a reduction in the number of women who had not achieved a vaginal delivery within 24 hours with NO donors (RR 0.63, 95% CI 0.47 to 0.86; one trial, 400 women). This result should be interpreted with caution as the information was extracted from an abstract only and a full report of the study is awaited. No differences were observed between groups for uterine hyperstimulation with FHR changes (RR 0.33, 95% CI 0.01 to 7.74; one trial, 42 women) or serious neonatal morbidity/perinatal death (RR 0.33, 95% CI 0.01 to 7.74; one trial, 42 women). Fewer women in the NO donor group underwent a caesarean section in comparison to women who received intracervical prostaglandins (RR 0.63, 95% CI 0.44 to 0.90; two trials, 442 women). No study reported on the outcome serious maternal morbidity or death. Nitric oxide donors versus vaginal misoprostol There was a reduction in the rate of uterine hyperstimulation with FHR changes with NO donors (RR 0.07, 95% CI 0.01 to 0.37; three trials, 281 women). There were no differences in caesarean section rates (RR 1.00, 95% CI 0.82 to 1.21; 761 women; six trials) and no cases of serious neonatal morbidity/perinatal death were reported. One study found that women in the NO donor group were more likely to not deliver within 24 hours (RR 5.33, 95% CI 1.62 to 17.55; one trial, 150 women). Serious maternal morbidity or death was not reported.In terms of secondary outcomes, there was an increase in cervix unchanged/unfavourable with NO (RR 3.43, 95% CI 2.07 to 5.66; two trials, 151 women) and an increase in the need for oxytocin augmentation with NO induction (RR 2.67, 95% CI 1.31 to 5.45; 7 trials; 767 women), although there was evidence of significant heterogeneity which could not be fully explained. Uterine hyperstimulation without FHR was lower in the NO group, as was meconium-stained liquor, Apgar score less than seven at five minutes and analgesia requirements. Nitric oxide donors versus intracervical catheter There was no evidence on any difference between the effects of NO and the use of a Foley catheter for induction of labour for caesarean section (RR 1.00, 95% CI 0.39 to 2.59; one trial, 80 women). No other primary outcomes were reported. One study of 75 participants did not contribute any data to the review.For all comparisons, women who received NO donors were more likely to experience side effects such as headache, nausea or vomiting.

AUTHORS' CONCLUSIONS

Available data suggests that NO donors can be a useful tool in the process of induction of labour causing the cervix to be more favourable in comparison to placebo. However, additional data are needed to assess the true impact of NO donors on all important labour process and delivery outcomes.

Effect of dystocia on some hormonal and biochemical parameters in the one-humped camel (Camelus dromedarius)

The present study compared some of the hormonal and biochemical constituents of serum from eutocic and dystocic one-humped camels (Camelus dromedarius). Sera were harvested from eutocic (n = 9) and dystocic (n = 20) camels within the first 15 minutes after delivery. Although there were no differences in the concentrations of estradiol-17β (E2) and prostaglandin F2α (PGF2α) between the eutocic and the dystocic animals, the level of progesterone (P4) and cortisol was significantly higher (P < 0.01) in animals that experienced dystocia than those that had a normal birth. There were no differences between the concentrations of alkaline phosphatase, aspartate aminotransferase, calcium, cholesterol, creatine kinase, creatinine, or magnesium (Mg) in eutocic and dystocic animals. The nitric oxide concentration was significantly higher (P < 0.01) in the serum from animals with dystocia than those that had normal births. By contrast, the serum concentrations of glucose, phosphorus (P), and triglycerides were significantly lower (P < 0.01) in eutocic camels compared with dystocic camels. As the delayed decline of P4 is reported to be the major hormonal difference between eutocic and dystocic camels, we propose that the insensitivity of corpus luteum to luteolytic action may be a cause of dystocia. Moreover, stress and hormonal changes may affect the metabolic traits in dystocia camels.

Positive correlation between patency and mRNA levels for cyclooxygenase-2 and prostaglandin E synthase in the uterine cervix of bitches with pyometra

Factors involved in patency of uterine cervices in the bitch with pyometra remain to be clarified. This study examined relationship between patency and mRNA levels for inducible nitric oxide synthase (iNOS), cyclooxygenase (COX)-1, COX-2 and prostaglandin E synthase (PGES) in the uterine cervix of bitches with pyometra. Cervical patency was measured by inserting the stainless steel rods with different diameter into cervical canals. Levels of mRNA expression were determined by semi-quantitative reverse transcription-polymerase chain reaction. The cervical patency was positively correlated with mRNA levels for COX-2 and PGES, but not those for iNOS and COX-1. The results suggest that gene expression of COX-2 and PGES may be involved in the regulation of patency in the uterine cervix of bitches with pyometra.

Role of NO-cGMP pathway in ovine cervical relaxation induced by Erythroxylum caatingae Plowman

Erythroxylum caatingae Plowman has a myorelaxing effect on smooth muscle tissue. We investigated the effect of the crude ethanolic extract of E. caatingae Plowman (Ec-EtOH) on the contractility of the ovine cervix. In an isometric system, circular strips were subjected to 90mM potassium (K(+)) or 30μM carbamylcholine (CCh)-induced contraction. We then exposed the tissue to cumulative concentrations of Ec-EtOH (1-729 μg/ml). In other bath solutions, the tissues were exposed to l-NG-nitroarginine methyl ester (l-NAME; 100μM), l-NAME (100μM)+l-arginine (300μM), 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one, ODQ; 5μM), 4-aminopyridine (4-AP; 3mM), tetraethylammonium (TEA; 0.3mM), glybenclamide (1μM), atosiban (10μM) or verapamil (3μM), followed by the addition of Ec-EtOH (1-729 μg/ml). We also evaluated the effect of cervical Ec-EtOH infusion (2mg) on cervical contractility in vivo. Ec-EtOH decreased cervical contractility induced by K(+) or CCh, and 729 μg/ml Ec-EtOH decreased 85.4±5.1% the amplitude of basal contractility in vitro, with an EC50 of 17.9±3.7 μg/ml. This effect of Ec-EtOH was prevented by l-NAME or ODQ. l-arginine impaired the blunting effect of l-NAME on cervical relaxation caused by Ec-EtOH. However, the potassium channel blockers 4-AP, TEA, and glybenclamide did not modify this myorelaxation triggered by Ec-EtOH. Ec-EtOH also decreased acetylcholine-induced contractions in tissue preincubated with verapamil. In addition, Ec-EtOH decreased ovine cervical contractions in vivo. Thus, Ec-EtOH had a relaxant effect on ovine cervical contractions. This may involve the nitric oxide signal, mediated by cGMP cellular transduction, and be related to intracellular calcium sequestration.

Interventions for pain with intrauterine device insertion

BACKGROUND

Fear of pain during insertion of intrauterine contraception (IUC) is a barrier to use of this method. IUC includes copper-containing intrauterine devices and levonorgestrel-releasing intrauterine systems. Interventions for pain control during IUC insertion include non-steroidal anti-inflammatory drugs (NSAIDs), local cervical anesthetics, and cervical ripening agents such as misoprostol.

OBJECTIVES

To review randomized controlled trials (RCTs) of interventions for reducing IUC insertion-related pain

SEARCH METHODS

We searched for trials in CENTRAL, MEDLINE, EMBASE, POPLINE, ClinicalTrials.gov, and ICTRP. The most recent search was 22 June 2015. We examined reference lists of pertinent articles. For the initial review, we wrote to investigators to find other published or unpublished trials.

SELECTION CRITERIA

We included RCTs that evaluated an intervention for preventing IUC insertion-related pain. The comparison could have been a placebo, no intervention, or another active intervention. The primary outcomes were self-reported pain at tenaculum placement, during IUC insertion, and after IUC insertion (up to six hours).

DATA COLLECTION AND ANALYSIS

Two authors extracted data from eligible trials. For dichotomous variables, we calculated the Mantel-Haenszel odds ratio (OR) with 95% confidence interval (CI). For continuous variables, we computed the mean difference (MD) with 95% CI. In meta-analysis of trials with different measurement scales, we used the standardized mean difference (SMD).

MAIN RESULTS

We included 33 trials with 5710 participants total; 29 were published from 2010 to 2015. Studies examined lidocaine, misoprostol, NSAIDs, and other interventions. Here we synthesize results from trials with sufficient outcome data and moderate- or high-quality evidence.For lidocaine, meta-analysis showed topical 2% gel had no effect on pain at tenaculum placement (two trials) or on pain during IUC insertion (three trials). Other formulations were effective compared with placebo in individual trials. Mean score for IUC-insertion pain was lower with lidocaine and prilocaine cream (MD -1.96, 95% CI -3.00 to -0.92). Among nulliparous women, topical 4% formulation showed lower scores for IUC-insertion pain assessed within 10 minutes (MD -15.90, 95% CI -22.77 to -9.03) and at 30 minutes later (MD -11.10, 95% CI -19.05 to -3.15). Among parous women, IUC-insertion pain was lower with 10% spray (median 1.00 versus 3.00). Compared with no intervention, pain at tenaculum placement was lower with 1% paracervical block (median 12 versus 28).For misoprostol, meta-analysis showed a higher mean score for IUC insertion compared with placebo (SMD 0.27, 95% CI 0.07 to 0.46; four studies). In meta-analysis, cramping was more likely with misoprostol (OR 2.64, 95% CI 1.46 to 4.76; four studies). A trial with nulliparous women found a higher score for IUC-insertion pain with misoprostol (median 46 versus 34). Pain before leaving the clinic was higher for misoprostol in two trials with nulliparous women (MD 7.60, 95% CI 6.48 to 8.72; medians 35.5 versus 20.5). In one trial with nulliparous women, moderate or severe pain at IUC insertion was less likely with misoprostol (OR 0.30, 95% CI 0.16 to 0.55). In the same trial, the misoprostol group was more likely to rate the experience favorably. Within two trials of misoprostol plus diclofenac, shivering, headache, or abdominal pain were more likely with misoprostol. Participants had no vaginal delivery. One trial showed the misoprostol group less likely to choose or recommend the treatment.Among multiparous women, mean score for IUC-insertion pain was lower for tramadol 50 mg versus naproxen 550 mg (MD -0.63, 95% CI -0.94 to -0.32) and for naproxen versus placebo (MD -1.94, 95% CI -2.35 to -1.53). The naproxen group was less likely than the placebo group to report the insertion experience as unpleasant and not want the medication in the future. An older trial showed repeated doses of naproxen 300 mg led to lower pain scores at one hour (MD -1.04, 95% CI -1.67 to -0.41) and two hours (MD -0.98, 95% CI -1.64 to -0.32) after insertion. Most women were nulliparous and also had lidocaine paracervical block.

AUTHORS' CONCLUSIONS

Nearly all trials used modern IUC. Most effectiveness evidence was of moderate quality, having come from single trials. Lidocaine 2% gel, misoprostol, and most NSAIDs did not help reduce pain. Some lidocaine formulations, tramadol, and naproxen had some effect on reducing IUC insertion-related pain in specific groups. The ineffective interventions do not need further research.

Nitric oxide donors for cervical ripening in first-trimester surgical abortion

BACKGROUND

Cervical priming before first-trimester surgical abortion is recommended in certain groups of women. Nitric oxide (NO) donors induce cervical ripening without uterine contractions, but the efficacy and side effects are of concern.

OBJECTIVES

To evaluate NO donors for cervical ripening before first-trimester surgical abortion, in terms of efficacy, side effects, and reduction of complications.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, and POPLINE. We also searched reference lists of retrieved papers. We contacted experts in the field for information on both published and unpublished trials.

SELECTION CRITERIA

Randomised controlled trials comparing NO donors alone or in combination with other methods for cervical ripening in first-trimester surgical abortion.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected and extracted the data onto a data extraction form. We processed the data using Review Manager (RevMan 5) software.

MAIN RESULTS

We included 9 studies involving 766 participants. There were no serious complications (infection requiring antibiotic treatment, blood transfusion, complications requiring unintended operation, cervical injury, uterine perforation, death or serious morbidity) in the included trials.NO donors were more effective in cervical ripening when compared with placebo or no treatment. Baseline cervical dilatation before the procedure was higher in NO donors group (mean difference (MD) 0.30, 95% confidence interval (CI) 0.01 to 0.58) The cumulative force required to dilate the cervix to 8 mm (MD -4.29, 95% CI -9.92 to 1.35), headache (risk ratio (RR) 1.73, 95% CI 0.86 to 3.46), abdominal pain (RR 0.87, 95% CI 0.50 to 1.50), or patient satisfaction (RR 0.95, 95% CI 0.84 to 1.07) were not different. More nausea and vomiting occurred in the women who received a NO donor (RR 2.62, 95% CI 1.07 to 6.45).NO donors were inferior to prostaglandins for cervical ripening. The cumulative force required to dilate the cervix to 8 mm to 9 mm was higher (MD 13.12, 95% CI 9.72 to 16.52), and baseline cervical dilatation was less (MD -0.73, 95% CI -1.01 to -0.45) in the NO donor group. However, the probability of dilation greater than 8 mm at three hours was higher in the NO donor group (RR 6.67, 95% CI 2.21 to 20.09). Side effects including headache (RR 5.13, 95% CI 3.29 to 8.00), palpitation (RR 3.43, 95% CI 1.64 to 7.15), dizziness (RR 3.29, 95% CI 1.46 to 7.41), and intraoperative blood loss (MD 33.59 ml, 95% CI 24.50 to 42.67) were also higher. However, abdominal pain (RR 0.33, 95% CI 0.25 to 0.44) and vaginal bleeding (RR 0.14, 95% CI 0.07 to 0.27) were less in the NO donor group. No difference for nausea/vomiting in both groups(RR 1.17, 95% CI 0.94 to 1.46). Patient satisfaction was not different.One trial compared a NO donor with a NO donor plus prostaglandin. The cumulative force required to dilate the cervix to 8 mm was higher (MD 14.50, 95% CI 0.50 to 28.50) in the NO donor group. There was no difference in headache (RR 0.88, 95% CI 0.38 to 2.00), abdominal pain (RR 0.14, 95% CI 0.02 to 1.07), or intraoperative blood loss (MD -50, 95% CI -164.19 to 64.19).

AUTHORS' CONCLUSIONS

NO donors are superior to placebo or no treatment, but inferior to prostaglandins for first-trimester cervical ripening, and associated with more side effects.

Outpatient cervical ripening by nitric oxide donors for prolonged pregnancy: a randomized controlled trial

OBJECTIVE

To assess whether outpatient cervical ripening at 41 0/7 weeks of gestation with the nitric oxide donor isosorbide mononitrate reduces cesarean delivery rates in nulliparous women with an unfavorable cervix.

METHODS

We recruited nulliparous pregnant women with a Bishop score less than 6 in a randomized, multicenter, double-blind, placebo-controlled trial. Women received 40 mg vaginal isosorbide mononitrate or a placebo at 41 0/7, 41 2/7, and 41 4/7 weeks of gestation. They returned home between visits. At 41 5/7 weeks of gestation, for women who had not yet given birth, labor was induced with oxytocin or prostaglandins, depending on cervical status. We needed 685 women per group to detect a 25% reduction in the cesarean delivery rate, the primary outcome measure, from 25% in the placebo group to 18.75% in the isosorbide mononitrate group (1-β=0.8, α=0.05, two-sided).

RESULTS

The NOCETER (NO donors for reduction of CEsareans at TERm) trial was a negative study. The cesarean delivery rate was 27.3% (185/678) in the isosorbide mononitrate group and 27.2% (186/684) in the placebo group (relative risk 1.00, 95% confidence interval [CI] 0.84-1.19). None of the maternal secondary efficacy outcomes differed between groups. Side effects were more common among women receiving isosorbide mononitrate than in the placebo group (78.8% [534/678] compared with 27.9% [191/684], relative risk 2.82, 95% CI 2.49-3.20). Composite perinatal morbidity did not differ between groups.

CONCLUSION

Outpatient cervical ripening with vaginal isosorbide mononitrate for prolonged pregnancy in nulliparous women does not reduce cesarean delivery rate.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov, www.clinicaltrials.gov, NCT00930618.

Nitric oxide donors for cervical ripening in first-trimester surgical abortion

BACKGROUND

Cervical priming before first-trimester surgical abortion is recommended in certain groups of women. Nitric oxide (NO) donors induce cervical ripening without uterine contractions, but the efficacy and side effects are of concern.

OBJECTIVES

To evaluate efficacy, side effects and complications of NO donors for cervical ripening before first-trimester surgical abortion.

SEARCH METHODS

We searched the Cochrane Controlled Trials Register, MEDLINE, EMBASE and POPLINE. We also searched reference lists of retrieved papers. We contacted experts in the field for information on both published and unpublished trials.

SELECTION CRITERIA

Randomised controlled trials comparing NO donors alone or in combination with other methods for cervical ripening in first-trimester surgical abortion.

DATA COLLECTION AND ANALYSIS

Two reviewers independently selected and extracted the data onto a data extraction form. We processed the data using Review Manager (RevMan5) software.

MAIN RESULTS

We included nine studies involving 766 participants. There were no serious complications (infection requiring antibiotic treatment, blood transfusion, complications requiring unintended operation, cervical injury, uterine perforation, death or serious morbidity) in the trials included.NO donors were more effective in cervical ripening comparing with placebo or no treatment. Baseline cervical dilatation before the procedure was higher in NO donors group (mean difference 0.30, 95% CI 0.01, 0.58) The cumulative force required to dilate the cervix to 8 mm (mean difference -4.29, 95% CI -9.92, 1.35), headache (RR 1.73, 95% CI 0.86, 3.46), abdominal pain (RR 0.87, 95% CI 0.50, 1.50) or patient satisfaction (RR 0.95, 95% CI 0.84, 1.07) were not different. More nausea and vomiting occurred in the women who received a NO donor (RR 2.62, 95% CI 1.07, 6.45).NO donors were inferior to prostaglandins for cervical ripening. The cumulative force required to dilate the cervix to 8-9 mm was higher (mean difference 13.12, 95% CI 9.72, 16.52) and baseline cervical dilatation was less (mean difference -0.73, 95% CI -1.01, -0.45) in the NO donor group. Side effects including headache (RR 5.13, 95% CI 3.29, 8.00), palpitation (RR 3.43, 95% CI 1.64, 7.15), dizziness (RR 3.29, 95% CI 1.46, 7.41) and intraoperative blood loss (mean difference 33.59 ml, 95% CI 24.50, 42.67) were also higher. However, abdominal pain (RR 0.33, 95% CI 0.25, 0.44) and vaginal bleeding (RR 0.14, 95% CI 0.07, 0.27) was less in the NO donor group. Patient satisfaction was not different.One trial compared a NO donor with a NO donor plus prostaglandin. The cumulative force required to dilate the cervix to 8 mm was higher (mean difference 14.50, 95% CI 0.50, 28.50) in the NO donor group. There was no difference in headache (RR 0.88, 95% CI 0.38, 2.00), abdominal pain (RR 0.14, 95% CI 0.02, 1.07) or intraoperative blood loss (mean difference -50, 95% CI -164.19, 64.19).

AUTHORS' CONCLUSIONS

NO donors are superior to placebo or no treatment, but inferior to prostaglandins for first-trimester cervical ripening, and associated with more side effects.

Nitric oxide donors for cervical ripening and induction of labour

BACKGROUND

Sometimes it is necessary to bring on labour artificially because of safety concerns for the mother or baby. This review is one of a series of reviews of methods of labour induction using a standardised protocol.Induction of labour occurs in approximately 20% of pregnancies in the UK. The ideal agent for induction of labour would induce cervical ripening without causing uterine contractions. Currently most commonly used cervical ripening or induction agents result in uterine activity or contractions, or both. Cervical ripening without uterine contractility could occur safely in an outpatient setting and it may be expected that this would result in greater maternal satisfaction and lower costs.

OBJECTIVES

To determine the effects of nitric oxide (NO) donors for third trimester cervical ripening or induction of labour, in comparison with placebo or no treatment or other treatments from a predefined hierarchy.

SEARCH STRATEGY

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (31 December 2010) and the reference lists of trial reports and reviews.

SELECTION CRITERIA

Clinical trials comparing NO donors for cervical ripening or labour induction to other methods listed above it on a predefined list of methods of labour induction. The trials include some form of random allocation to either group; and report one or more of the prestated outcomes. NO donors (isosorbide mononitrate, nitroglycerin and sodium nitroprusside) are compared to other methods listed above it on a predefined list of methods of labour induction.

DATA COLLECTION AND ANALYSIS

This review is part of a series of reviews focusing on methods of induction of labour. Three review authors independently assessed trials for inclusion, assessed risk of bias and extracted data.

MAIN RESULTS

We considered 19 trials; we included 10 (including a total of 1889 women) trials, excluded eight trials and one trial report is awaiting classification. Included studies compared NO donors to placebo, vaginal prostaglandin E2, intracervical PGE2 and vaginal misoprostol. All included studies were of a generally high standard with a low risk of bias.There are very limited data available to compare nitric oxide donors to any other induction agent. There is no evidence of any difference between any of the prespecified outcomes when comparing NO donors to other induction agents, with the exception of an increase in maternal side effects.

AUTHORS' CONCLUSIONS

NO donors do not appear currently to be a useful tool in the process of induction of labour. More studies are required to examine how NO donors may work alongside established induction of labour protocols, especially those based in outpatient settings.

Decreased type III collagen expression in human uterine cervix of prolapse uteri

The precise mechanism of prolapse uteri is not fully understood. There is evidence to suggest that abnormalities of collagen, the main component of extracellular matrix, or its repair mechanism, may predispose women to prolapse. To investigate the characteristic structure of human uterine cervix of patients with prolapse uteri, various types of collagen expression in the uterine cervix tissues of the prolapse uteri were compared to those of normal uterine cervix. After informed consent, 36 specimens of uterine cervical tissues were obtained at the time of surgery from 16 postmenopausal women with prolapse uteri (stage III-IV by the Pelvic Organ Prolapse Quantification examination) and 20 postmenopausal women without prolapse uteri (control group). Collagens were extracted from the uterine cervix tissues by salt precipitation methods. The relative levels of various collagens were evaluated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The uterine cervix was longer in the patients with prolapse uteri than those of postmenopausal controls without prolapse uteri. The ratios of type III to type I collagen in the uterine cervical tissues were significantly decreased in the prolapse uteri, as compared to those of the postmenopausal uterine cervix without prolapse. These results suggest that decreased type III collagen expression may play an important role in determing the physiology and structure of the uterine cervix tissues of prolapse uteri.

Oral misoprostol and vaginal isosorbide mononitrate for labor induction: a randomized controlled trial

OBJECTIVE

To estimate whether vaginal isosorbide mononitrate, added to oral misoprostol for cervical ripening and labor induction, shortens time to vaginal delivery.

METHODS

A prospective, randomized trial was conducted. Women scheduled for labor induction between 32 and 42 weeks and with unfavorable cervices (modified Bishop score 6 or lower) were randomized to receive oral misoprostol every 4 hours, up to four doses, with or without isosorbide mononitrate every 6 hours, up to two doses. A strict protocol was used, including timing of oxytocin use and amniotomy. Side effects were assessed 6 hours after study initiation. One hundred forty-two patients were required to detect a change in time to vaginal delivery of 4 hours (alpha=.05 and beta=.20). Data were analyzed by intent to treat. Student's t, chi square, Fisher's exact, and Mann-Whitney tests were used where appropriate with P< or =.05 deemed significant.

RESULTS

One hundred fifty-six women were randomized; three were excluded after randomization. Seventy-eight women received misoprostol, and 78 received misoprostol with isosorbide mononitrate. Demographic characteristics were similar between groups. The time to vaginal delivery was not reduced when isosorbide mononitrate was added to misoprostol. Cesarean delivery rates and contraction and fetal heart rate abnormalities were similar between groups. Side effects were also similar between groups, except that women given isosorbide mononitrate experienced headaches more often. Neonatal outcomes were similar between groups.

CONCLUSION

The addition of vaginal isosorbide mononitrate to oral misoprostol for cervical ripening and labor induction did not reduce time to vaginal delivery and was associated with a greater incidence of headache.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov, www.clinicaltrials.gov, NCT00374621.

LEVEL OF EVIDENCE

I.

Effect of isosorbide mononitrate for cervical ripening before surgical termination of pregnancy in the first trimester

OBJECTIVE

To evaluate the efficacy of isosorbide mononitrate (IMN) for cervical ripening prior to first trimester surgical termination of pregnancy.

METHODS

A prospective, double-blind, randomized, placebo-controlled trial. Women scheduled for surgical termination of a nonviable fetus before 12 weeks of gestation from October 2008 to June 2009 were enrolled and randomly assigned to receive either 20 mg vaginally of IMN (n=24) or a placebo (n=24) 4 hours before suction evacuation. Cervical dilation before evacuation was assessed with 10-mm Hegar dilators followed by smaller sizes that were measured until the instrument passed freely through the internal os. Cervical dilation, adverse effects, termination complications, and patient satisfaction were the main outcomes.

RESULTS

Mean cervical dilation was not significantly different between the IMN and placebo groups (6.29+/-0.99 mm vs 5.71+/-1.04 mm; P=0.05). Mean operative time did not differ between the groups (16+/-0.07 min vs 18+/-0.06 min; P=0.55), nor did patient satisfaction measured by visual analogue scale (7.04+/-1.68 vs 6.54+/-1.22; P=0.24).

CONCLUSION

IMN was comparable to placebo in terms of efficacy and patient satisfaction for cervical priming prior to first-trimester termination of pregnancy.

Nitric oxide platelet production in spontaneous miscarriage in the first trimester

OBJECTIVE

To investigate the role played by platelet nitric oxide (NO) metabolism in patients with spontaneous miscarriage (SM) and recurrent spontaneous miscarriage (RSM) compared with healthy pregnant women.

DESIGN

Retrospective case-control study.

SETTING

Patients and controls in an academic research environment.

INTERVENTION(S)

None.

PATIENT(S)

Thirty singleton pregnant women who experienced SM, nine singleton pregnant women who presented with RSM, and 30 singleton healthy pregnant women matched for age, parity, and gestational age were enrolled.

MAIN OUTCOME MEASURE(S)

NO levels and peroxynitrite (ONOO(-)) production; moreover, inducible NO synthase (iNOS), endothelial NO synthase (eNOS), and nitrotyrosine expression (N-Tyr) were observed in the same samples.

RESULT(S)

A significant increase was shown in platelet NO and ONOO(-) levels and in iNOS and N-Tyr both in SM and in RSM pregnant women compared with controls.

CONCLUSION(S)

The data herein reported imply that a modified NO pathway might play a key role in the physiological changes of advancing gestation but may also contribute to the pathophysiology of spontaneous miscarriage. Thus, any factors balancing NO metabolism might be useful in the treatment of miscarriage, thus reducing the substantial morbidity and associated mortality.

A combination of misoprostol and estradiol for preoperative cervical ripening in postmenopausal women: a randomised controlled trial

OBJECTIVE

To compare the impact of 1000 microg of self-administered vaginal misoprostol versus self-administered vaginal placebo on preoperative cervical ripening after 2 weeks of pretreatment with estradiol vaginal tablets in postmenopausal women prior to day-care operative hysteroscopy.

DESIGN

Randomised, double-blind, placebo-controlled sequential trial.

SETTING

Norwegian university teaching hospital.

POPULATION

Sixty-seven postmenopausal women referred for day-care operative hysteroscopy.

METHODS

The women were randomised to receive either 1000 microg of self-administered vaginal misoprostol or self-administered vaginal placebo on the evening before day-care operative hysteroscopy. All women had administered a 25-microg vaginal estradiol tablet daily for 14 days prior to the operation.

MAIN OUTCOME MEASURES

PRIMARY OUTCOME

preoperative cervical dilatation at hysteroscopy.

SECONDARY OUTCOMES

difference in dilatation at recruitment and before hysteroscopy, number of women who achieved a preoperative cervical dilatation of 5 mm or more, acceptability, complications and adverse effects.

RESULTS

The mean cervical dilatation was 5.7 mm (SD, 1.6 mm) in the misoprostol group and 4.7 mm (SD, 1.5 mm) in the placebo group, the mean difference in cervical dilatation being 1.0 mm (95% CI, 0.2-1.7 mm). Self-administered vaginal misoprostol of 1000 microg at home on the evening before day-care hysteroscopy is safe and highly acceptable, although a small proportion of women experienced lower abdominal pain.

CONCLUSIONS

One thousand micrograms of self-administered vaginal misoprostol, 12 hours prior to day-care hysteroscopy, after 14 days of pretreatment with vaginal estradiol, has a significant cervical ripening effect compared with placebo in postmenopausal women.

Nitric oxide donors for cervical ripening in first-trimester surgical abortion

BACKGROUND

Cervical priming before first-trimester surgical abortion is recommended in certain groups of women. Nitric oxide (NO) donors induce cervical ripening without uterine contractions, but the efficacy and side effects are of concern.

OBJECTIVES

To evaluate efficacy, side effects and complications of NO donors for cervical ripening before first-trimester surgical abortion.

SEARCH STRATEGY

We searched the Cochrane Controlled Trials Register, MEDLINE, EMBASE and Popline. We also searched reference lists of retrieved papers. We contacted experts in the field for information on both published and unpublished trials.

SELECTION CRITERIA

Randomised controlled trials comparing NO donors alone or in combination with other methods for cervical ripening in first-trimester surgical abortion.

DATA COLLECTION AND ANALYSIS

Two reviewers independently selected and extracted the data onto a data extraction form. We processed the data using Review Manager (RevMan5) software.

MAIN RESULTS

We included eight studies involving 718 participants. There were no serious complications (infection requiring antibiotic treatment, blood transfusion, complications requiring unintended operation, cervical injury, uterine perforation, death or serious morbidity) in the trials included.NO donors were ineffective in cervical ripening comparing with placebo or no treatment. The cumulative force required to dilate the cervix to 8 mm (mean difference -4.29, 95% CI -9.92, 1.35), baseline cervical dilatation before the procedure (mean difference 0.21, 95% CI -0.12, 0.53), headache (RR 1.73, 95% CI 0.86, 3.46), abdominal pain (RR 0.87, 95% CI 0.51, 1.50) or patient satisfaction (RR 0.95, 95% CI 0.84, 1.07) were not different. More nausea and vomiting occurred in the women who received a NO donor (RR 2.62, 95% CI 1.07, 6.75).NO donors were inferior to prostaglandins for cervical ripening. The cumulative force required to dilate the cervix to 8-9 mm was higher (mean difference 13.12, 95% CI 9.72, 16.52) and baseline cervical dilatation was less (mean difference -0.73, 95% CI -1.01, -0. 45) in the NO donor group. Side effects including headache (RR 5.13, 95% CI 3.29, 8.00), palpitation (RR 3.43, 95% CI 1.64, 7.15), dizziness (RR 3.29, 95% CI 1.46, 7.41) and intraoperative blood loss (mean difference 33.59 ml, 95% CI 24.50, 42.67) were also higher. However, abdominal pain (RR 0.33, 95% CI 0.25, 0.44) and vaginal bleeding (RR 0.14, 95% CI 0.07, 0.27) was less in the NO donor group. Patient satisfaction was not different.One trial compared a NO donor with a NO donor plus prostaglandin. The cumulative force required to dilate the cervix to 8 mm was higher (mean difference 14.50, 95% CI 0.50, 28.50) in the NO donor group. There was no difference in headache (RR 0.88, 95% CI 0.38, 2.00), abdominal pain (RR 0.14, 95% CI 0.02, 1.07) or intraoperative blood loss (mean difference -50, 95% CI -164.19, 64.19).

AUTHORS' CONCLUSIONS

NO donors are inferior to prostaglandins for first-trimester cervical ripening, and associated with more side effects. NO donors are comparable to placebo and no treatment for cervical ripening.

Inflammatory pathways in female reproductive health and disease

Inflammation involves alterations to vascular and immune cell function. It is well recognised that many physiological reproductive events such as ovulation, menstruation, implantation and onset of labour display hallmark signs of inflammation. These are orchestrated by specific molecular pathways involving a host of growth factors, cytokines, chemokines and lipid mediators. Resumption of normal reproductive function involves prompt and proper resolution of these inflammatory pathways. Recent literature confirms that resolution of inflammatory pathways involves specific biochemical events that are activated to re-establish homeostasis in the affected tissue. Moreover, initiation and maintenance of inflammatory pathways are the key components of many pathologies of the reproductive tract and elsewhere in the body. The onset of reproductive disorders or disease may be the result of exacerbated activation and maintenance of inflammatory pathways or their dysregulated resolution. This review will address the role of inflammatory events in normal reproductive function and its pathologies.

Clinical use of nitric oxide donors and L-arginine in obstetrics

Nitric oxide (NO) is a free radical that plays a fundamental role in human physiology, being involved in the homeostasis of different functions. In obstetrics this molecule is determinant in the physiology of labor and cervical ripening; it possibly plays a fundamental role in the etiology of preeclampsia and intrauterine growth restriction, and it could also be utilized in view of its ability to induce smooth muscle relaxation. Several clinical trials have ascertained the ability of the topical application of NO donors to promote cervical ripening, and also labor induction. There is much less evidence on the use of NO donors in the vascular complications of pregnancy, either as prophylactics or therapeutic agents. Due to the capacity of NO to promote relaxation of smooth muscle, NO donors have been employed as tocolytics with performance similar to other agents. Moreover, although anecdotal, the experience of sudden uterine relaxation using NO donors in obstetric emergencies remains of great clinical value.

Inflammatory pathways in the mechanism of parturition

Increasing evidence suggests that parturition is an inflammatory process. In this brief overview, inflammatory events occurring in association with parturition, and the mechanism by which they may contribute to labour and delivery will be discussed. Mention will be made of how this information may be of use in regulating the timing and the onset of parturition.

Outpatient vaginal administration of the nitric oxide donor isosorbide mononitrate for cervical ripening and labor induction postterm: a randomized controlled study

OBJECTIVE

Our aim was to examine the efficacy, safety, and acceptability of isosorbide mononitrate for cervical ripening and labor induction in women in an outpatient setting.

STUDY DESIGN

Two hundred pregnant women of at least 42 weeks' gestation with an unripe cervix were randomly selected to receive vaginally either 40 mg isosorbide mononitrate or placebo tablets.

RESULTS

Twenty-two women treated with isosorbide mononitrate went into labor within 24 hours compared to 8 women in the placebo group (P < .05). In women who did not go into labor, cervical status was similar in the 2 groups the next day. Headache was a common side effect. No maternal or fetal side effects of clinical importance were registered.

CONCLUSION

Outpatient cervical ripening and labor induction with isosorbide mononitrate seems to be an effective, safe, and well tolerated procedure. The definitive clinical efficacy and safety needs to be evaluated in larger series of patients.

Cervical ripening: biochemical, molecular, and clinical considerations

The physiologic and pathologic changes of the uterine cervix during pregnancy leading to cervical ripening are not well understood though are related to the chief pathology and a commonly performed intervention in obstetrics: Preterm birth and labor induction. Normal cervical ripening is thought to be controlled by a variety of hormonal changes occurring during pregnancy leading to softening and dilation. Abnormal premature ripening, usually resulting in preterm labor, is thought to be associated with infection and inflammatory events. Despite many studies of the cervix, we still rely upon relatively crude methods for clinical evaluation of the cervix. In the past several years, we have developed and evaluated a method to measure cervical collagen noninvasively using an instrument called Collascope. Studies in animals and humans conducted in a variety of settings indicate that cervical function can be successfully monitored using the Collascope during pregnancy. We suggest that this technique might be useful to better define management in cases of spontaneous preterm and induced term cervical ripening.

IMOP: randomised placebo controlled trial of outpatient cervical ripening with isosorbide mononitrate (IMN) prior to induction of labour - clinical trial with analyses of efficacy, cost effectiveness and acceptability

Background

There is increasing interest in carrying out pre-induction cervical ripening on an outpatient basis. However, there are concerns about the use of prostaglandins, the agents commonly used in hospital settings for this indication, because prostaglandins induce uterine contractions that may lead to fetal hypoxia. Indeed, in a recent study we demonstrated abnormalities in 9% of fetal heart rate tracings performed following prostaglandin induced cervical ripening at term. In contrast, we confirmed in the same study that isosorbide mononitrate (IMN) (administered on an inpatient basis) was both effective in inducing cervical ripening at term, and was associated with no associated fetal heart rate abnormalities.

Methods/design

The aim of this study is to determine whether IMN self administered by women on an outpatient basis improves the process of induction of labour. Specifically, we hypothesise that the use of outpatient IMN will result in a shorter inpatient stay before delivery, decreased costs to the health service and greater maternal satisfaction with ripening and induction of labour, compared with placebo treatment.

In the study described here (the "IMOP" study), women scheduled for induction of labour at term, and who require pre-induction cervical ripening will be randomised to self-administer at home either IMN 40 mg, or a placebo, each vaginally, at 48 hours, 32 hours and 16 hours before scheduled hospital admission.

After admission to hospital, treatment will revert to the usual induction of labour protocol. We will compare the primary outcomes of the elapsed time interval from hospital admission to vaginal delivery, the costs to the health service of induction of labour, and women's experience of induction of labour in the two groups.

Discussion

This trial will provide evidence on the efficacy of outpatient IMN for pre-induction cervical ripening at term. We will study a formulation of IMN which is cheap and widely available. If the treatment is effective, acceptable to women, and cost effective, it could be implemented into obstetric practice worldwide.

Trial registration

The trial has been registered on the International Standard Randomised Controlled Trial Number Register (ISRCTN) and given the registration number ISRTN39772441.

Induction of labour at the start of the new millennium

Around 20% of all deliveries are preceded by labour induction, a proportion that has not varied dramatically over recent years. Fetal death was the only indication for labour induction centuries ago, while this is now a very rare indication, with prolonged pregnancy and maternal hypertensive disorders being the major indications for the last 50–60 years. Techniques for inducing labour have also changed from dietary delicacies and verbal threats giving way to physical stimulation mainly achieved by cervical stretching and amniotomy and more recently to sophisticated pharmacological manipulation using oxytocin and prostaglandins, based on our expanding knowledge of the physiological processes involved in spontaneous parturition. Relaxin, antiprogestins, nitric oxide as well as complementary medicines have also been explored in recent years. Successful induction is, however, still not guaranteed and there has been increasing emphasis during the past decade on exploring strategies for identifying the probability of success. Measurement of fetal fibronectin in cervical mucus, maternal serum nitrite/nitrate concentrations, ultrasound delineation of cervical form and electrical impedance measurements across the cervix are all being investigated. Safety, success, and patient satisfaction continue to be the major objectives with economic evaluations now becoming a significant factor in the search for the ideal induction method.

Isosorbide mononitrate induces increased cervical expression of cyclooxygenase-2, but not of cyclooxygenase-1, at term

OBJECTIVE

Prostaglandin and nitric oxide (NO) are both known to be involved in cervical ripening at term. The aim of the study was to investigate if NO has an effect on cervical expression of cyclooxygenase-1 (COX-1) and cyclooxygenase-2 (COX-2), the two main isoenzymes involved in prostaglandin synthesis, and to localize these enzymes within the cervix.

STUDY DESIGN

Women with an unripe cervix scheduled for elective caesarean section at term were randomly selected to receive vaginally either the NO donor isosorbide mononitrate (IMN) or placebo 4h before surgery. At the operating theatre, cervical tissue specimens were obtained for immunoblotting and immunohistochemistry.

RESULTS

Increased expression of COX-2 was found in specimens exposed to IMN compared to specimens obtained from women in the placebo group. There was no difference in the expression of COX-1. Immunohistochemistry revealed similar localization of the two enzymes in treated and untreated women.

CONCLUSIONS

Vaginal administration of IMN induces increased cervical expression of COX-2, but not of COX-1. This pathway may be of importance in the process of cervical ripening at term.

Intravaginal glyceryl trinitrate and dinoprostone for cervical ripening and induction of labor

OBJECTIVE

This study was undertaken to evaluate the efficacy and safety of intravaginal administration of glyceryl trinitrate plus dinoprostone versus dinoprostone, for cervical ripening and induction of labor.

STUDY DESIGN

A prospective, double-blind, placebo-controlled, randomized clinical trial was conducted among 196 singleton low-risk nullipara women with term pregnancies and unfavorable cervices who were randomly assigned to receive intravaginal glyceryl trinitrate plus dinoprostone or placebo plus dinoprostone. The main outcome variables were time from application to active phase of labor and to delivery. Secondary outcomes were change in Bishop score, fetal and maternal morbidity, and incidence of cesarean deliveries.

RESULTS

The interval from application of the initial dose to the beginning of active phase of labor was 868 +/- 582 and 1136 +/- 692 minutes (P = .004) and from initial dose to delivery was 1339 +/- 826 and 1620 +/- 975 minutes (P = .03) for the glyceryl trinitrate and placebo groups, respectively. There were no significant differences in Bishop score change, cesarean section rate, and in the incidence of hypersystole and hyperstimulation. The incidence of tachysystole was significantly lower in the glyceryl trinitrate group (4% vs 15%, P < or = .02). No maternal and neonatal adverse effects were noted.

CONCLUSION

The association of glyceryl trinitrate with dinoprostone is more effective than dinoprostone alone for labor induction in low-risk patients at term with unfavorable cervices.

Effects of progesterone on iNOS, COX-2, and collagen expression in the cervix

This study examines the relationship between inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) in the control of cervical ripening and parturition under normal (normal term pregnancy) and abnormal (preterm labor and prolongation of pregnancy) conditions by (a) measuring changes in the collagen both visually and quantitatively, (b) localizing and characterizing iNOS and COX-2 under normal conditions, and (c) characterizing the changes in iNOS and COX-2 under abnormal conditions. Cervices are obtained from estrus and timed pregnant Sprague-Dawley rats (n=4-10 per group). Preterm labor is induced with Onapristone (3 mg/rat; progesterone antagonist) and the prolongation of pregnancy with progesterone (2.5 mg, twice daily). Collagen changes are measured and visualized with the picrosirius polarization method. RT-PCR is used to characterize the mRNA expression (p<0.05), and immunohistochemistry is used to localize the protein expression for iNOS and COX-2. The organization and birefringence of the collagen during pregnancy decreased and is supported by changes in the luminosity (p<0.001). The iNOS and COX-2 enzymes were localized in cervical smooth muscle, vascular smooth muscle, and epithelium. Under normal conditions, iNOS mRNA levels decreased as COX-2 mRNA levels increased demonstrating an inverse correlation (Spearman r = -0.497; p=0.00295). Onapristone stimulated preterm labor, increasing the iNOS and COX-2 mRNA (p<0.05). The increase demonstrated a positive correlation (Spearman r = 0.456; p=0.03). Progesterone prolonged pregnancy, decreasing the iNOS and COX-2 mRNA (p=0.036). In conclusion, there may be an interaction between the nitric oxide and prostaglandin pathways in cervical ripening and parturition.

High iNOS mRNA and protein levels during early third trimester suggest a role for NO in prelabor cervical ripening in the bovine

Nitric oxide (NO) plays a key role in the processes leading to cervical softening prior to labor. Inducible nitric oxide synthase (iNOS) contributes most to the increased production of NO during labor, as demonstrated in the rat cervix, or at term pregnancy in women. Changes in expression of iNOS during late gestation have not yet been studied longitudinally in any species, because repeatedly taking biopsies could not be performed. iNOS mRNA (n = 6) and protein expression (n = 3) in serial cervical biopsies of pregnant pluriparous cows taken around days 225, 250, and 275 of pregnancy and within 1.5 hr after calving (d225, d250, d275 and parturition biopsies, respectively) were measured using quantitative RT-PCR and Western blotting. iNOS mRNA expression decreased from the d225 biopsy onwards, differences being significant between the d250 and d275 (P < 0.05) and between the d275 and parturition biopsies (P < 0.05). iNOS protein expression decreased from d225 to d250 onwards. Immunohistochemical analysis of biopsies showed, besides positive staining in endothelium and epithelium, which remained unchanged at different time points, that iNOS expressing cells in the connective tissue cells of early biopsies were predominantly spindle shaped (mostly smooth muscle cells and some fibroblasts). In the parturition biopsies, iNOS reactivity was mainly found in mononuclear leucocytes. These results lead us to suggest that iNOS from spindle shaped cells is involved in prepartum cervical ripening, while iNOS in mononuclear inflammatory cells may be important for local tissue repair mechanisms during postpartum cervical involution.

Intracervical application of the nitric oxide donor isosorbide dinitrate for induction of cervical ripening: a randomised controlled trial to determine clinical efficacy and safety prior to first trimester surgical evacuation of retained products of conception

OBJECTIVE

To determine the therapeutic efficacy and safety of a nitric oxide (NO) isosorbide dinitrate donor to induce cervical ripening of women with missed abortions before surgical evacuation of the uterus.

DESIGN

A prospective, randomised, double-blind controlled trial.

SETTING

Tertiary referral maternity teaching hospital. Population Sixty women with missed abortions and no cervical dilation.

METHODS

Women requesting surgical evacuation of the uterus were randomly selected to receive endocervical 80 mg/1.5 mL isosorbide dinitrate gel solution (n= 30) or 400 mug/1.5 mL misoprostol gel solution (n= 30) every 3 hours to a maximum of four doses or until reaching cervical ripening. Vital signs and symptoms were recorded at baseline and then every 3 hours until finishing therapy. Adverse events, such as headache, abdominal pain, pelvic pain, backache, nausea and vomiting, were evaluated.

MAIN OUTCOME MEASURES

Probability of reaching cervical ripening >8 mm Hegar dilator; evaluated at 3, 6, 9 and 12 hours after application of isosorbide dinitrate or misoprostol.

RESULTS

The probabilities of induction of cervical ripening by isosorbide dinitrate and misoprostol after four repeated doses at 3-hour intervals were significantly different (P<0.001). Efficacy of therapy after 12 hours was 97% for the isosorbide dinitrate group and 70% for the misoprostol group. Systolic and diastolic blood pressures were lower after administration of isosorbide dinitrate than prostaglandin analogues. The difference in the mean systolic and diastolic blood pressure between treatment groups was greatest at 3 hours, with a difference of 7.7 mmHg (P<0.001) and 5.9 mmHg (P<0.003), respectively. The most frequent side effect associated with isosorbide dinitrate administration was headache, which occurred in 18 out of 30 patients, compared with only 5 out of 30 women in the misoprostol group [relative risk (RR) 2.41, 95% confidence interval (CI) 1.45-4.03, P<0.001). Women treated with misoprostol reported mainly pelvic pain (RR 3.24, 95% CI 1.99-5.27, P<0.001).

CONCLUSIONS

Intracervical administration of 80 mg isosorbide dinitrate in women with missed abortions appears to be effective for cervical ripening prior to surgical evacuation of the uterus. Differences in the incidence of non-serious adverse events are not likely to be clinically significant.

Misoprostol induces cervical nitric oxide release in pregnant, but not in nonpregnant, women

OBJECTIVE

The cells of the human uterine cervix synthesize nitric oxide, which may be a factor in cervical ripening. We studied the effect of misoprostol on cervical nitric oxide release in nonpregnant and pregnant women.

STUDY DESIGN

Seventy-two nonpregnant (n=15) and pregnant (n=57; 26 in early pregnancy, 31 in late pregnancy) women were treated with either vaginal misoprostol (n=54) or vaginal placebo (n=18). The dose of misoprostol was 400 mug in nonpregnant and early pregnancy group, and 25 mug in late pregnancy group. Serial cervical fluid samples, collected before and up to 3 hours after misoprostol/placebo, were assessed for the concentration of nitric oxide metabolites by means of the Griess reaction.

RESULTS

Placebo had no effect on cervical fluid nitric oxide metabolite level. In 1 to 3 hours, misoprostol induced 4.3- to 5.2-fold elevations in cervical fluid Nox concentrations in early pregnancy (P < .01), and 4.4- to 18.2-fold elevations in late pregnancy (P < .01), but these responses did not differ significantly from each other. Misoprostol had no effect on cervical fluid nitric oxide metabolites in nonpregnant women. There was a trend towards a relationship between cervical nitric oxide stimulation after misoprostol and cervical ripening.

CONCLUSION

Vaginal misoprostol stimulates cervical nitric oxide release in pregnancy. This suggests a joint action of nitric oxide and prostaglandins in cervical ripening.

Randomized controlled trial of vaginal misoprostol versus vaginal misoprostol and isosorbide dinitrate for termination of pregnancy at 13-29 weeks

When compared to the use of 12 hourly 200 microg vaginal misoprostol on its own, the addition of a single dose of 5 mg did not significantly increase the abortion or delivery rate in pregnancy termination at 13-29 weeks gestation. All patients were given intravenous syntocinon at 30 mU/min from the first dose of misoprostol onwards.

Evaluation of glyceryl trinitrate, misoprostol, and prostaglandin E2 gel for preinduction cervical ripening in term pregnancy

AIM

To compare the efficacy of glyceryl trinitrate (GTN), dinoprostone and misoprostol for preinduction cervical ripening in primigravida at term.

METHODS

Sixty-five term primigravida, each with an unfavorable cervix (Bishop score </=5), were randomized to receive GTN (0.5 mg perivaginally, n = 21), dinoprostone gel (0.5 mg intracervically, n = 21) and misoprostol (50 microg perivaginally, n = 23) for a maximum of two doses, 6 h apart. Statistical analysis included paired t-tests to compare pre- and post-treatment Bishop scores, one-way analysis of variance (anova) tests to compare quantitative variables and chi-squared tests to compare the proportion of subjects achieving favorable Bishop scores.

RESULTS

Baseline Bishop scores were similar in the GTN (3.4 +/- 0.9), dinoprostone (3.4 +/- 1.0) and misoprostol groups (3.2 +/- 1.2). The final outcome was favorable (Bishop score >6) in a greater proportion of subjects in the misoprostol (n = 18, 81.8%) and dinoprostone (n = 14, 66.7%) groups compared with the GTN group (n = 11, 55%). In subjects with a severely unfavorable cervix (Bishop score </=3), treatment with misoprostol led to a favorable response in 61.6% of patients compared with 45.6% in the misoprostol group and 33.3% in the GTN group. A significant improvement was noted in the Bishop score of all three groups (P < 0.001) but the increase in Bishop score was greater in misoprostol (3.5 +/- 2.1) and dinoprostone groups (2.8 +/- 1.5), compared with the GTN group (2.0 +/- 1.0, ANOVA F = 4.8, P = 0.01). Hyperstimulation and tachysystole were observed only in the misoprostol (9% and 4.3%) and dinoprostone groups (4.7% and 16.2%). The most common adverse effect in the GTN group was headache, which was observed in 47.6% of this group's subjects.

CONCLUSION

The findings of the present study suggest that GTN is safer, but less efficacious, compared with prostaglandins for preinduction cervical ripening at term.

Intracervical sodium nitroprusside versus vaginal misoprostol in first trimester surgical termination of pregnancy: a randomized double-blinded controlled trial

BACKGROUND

Results from small-scale randomized studies on the effectiveness of different preparations of nitric oxide donors in cervical priming before first trimester termination of pregnancies are not consistent. We compared sodium nitroprusside gel to misoprostol, the standard agent for cervical priming in this randomized double-blinded controlled trial.

METHODS

Two hundred pregnant patients between 8 to 12 weeks admitted for surgical termination of pregnancy were recruited. They were randomized into either 400 microg vaginal misoprostol and intracervical placebo gel, or 10 mg intracervical sodium nitroprusside gel and placebo tablets 3 h before the procedure. The baseline cervical dilatation and cumulative force required to dilate the cervix from 4 to 9 mm were measured with a tonometer. Blood pressure was measured and side effects were assessed.

RESULTS

The cumulative force to dilate the cervix from 4 to 9 mm was significantly higher in the sodium nitroprusside group, and the difference remained when a sub-group analysis was performed according to parity. Baseline cervical dilatation, duration of operation and operative blood loss were all in favour of misoprostol. Transient drop in blood pressure was observed after sodium nitroprusside treatment.

CONCLUSIONS

Intracervical sodium nitroprusside is not as effective as misoprostol in cervical priming.

Second trimester abortion using isosorbide mononitrate in addition to gemeprost compared with gemeprost alone: a double-blind randomized, placebo-controlled multicenter trial

OBJECTIVE

We aimed to determine whether second-trimester abortion using isosorbide mononitrate (IMN) in addition to gemeprost is more effective and reduces side effects compared with gemeprost alone.

STUDY DESIGN

Eighty women who were age 13 to 23 weeks' gestation were randomly assigned to receive per vaginam either IMN 40 mg (group 1, 40 women) or placebo (group 2, 40 women) in addition to gemeprost 1 mg up to 3 times daily 3 hours apart for 2 days. Analysis of variance, a chi 2 test, and a multivariate analysis were performed.

RESULTS

Of the 72 women analyzed, 68% (group 1) and 38% (group 2) underwent abortion within day 1 (P < .05). However, group 1 was associated with more headache (18% of women) 3 hours after induction compared to group 2 (0% of women, P = .038).

CONCLUSION

IMN in addition to gemeprost is effective for second-trimester abortion, but is associated with more headache compared with gemeprost alone.

Changes in the cervical competence in preterm labour

Cervical competence is a key function in normal and abnormal labour. Remodelling of the cervical structure, by reorientation and changes in the integrity of collagen fibres by an alteration in the content of water, proteoglycans and hyaluronic acid, takes place before parturition. Such morphological changes have been associated with the activation of several biochemical pathways, sharing those of an apyretic, proinflammatory reaction, including the inducible isoform of the nitric oxide synthase (NOS). Nitric oxide (NO) is believed to be the final mediator in the mechanisms that allow ripening of the cervix. A reduction of NO activity in the uterus, together with its activation in the cervix, is hypothesised to be a facilitating factor in human parturition. The local application of NO donors in both animals and humans induces ultrastructural changes similar to those occurring during physiological cervical maturation. NO donors have proven to be clinically effective in facilitating first trimester dilation and curettage. Preliminary data also suggest that in women presenting with threatening preterm labour, there is increased activity of NO in the cervix, which is associated with shortening. A complex interaction between cytokines, prostaglandins (PGs) and NO is the key biochemical pathway accounting for the preterm ripening of the cervix.

Factors involved in the inflammatory events of cervical ripening in humans

BACKGROUND

Cervical ripening is an inflammatory reaction. The glucocorticoid receptor (GR) mediates glucocorticoid anti-inflammatory reactions, whereas nuclear factor (NF)kappaB is a key pro-inflammatory transcription factor. Prostaglandins as well as platelet activating factor (PAF) are inflammatory mediators. Inducible nitric oxide synthase (iNOS) regulates the level of nitric oxide (NO) in response to various inflammatory stimuli. We hypothesize that a changed biological response to glucocorticoids could be a mechanism regulating the inflammatory events resulting in cervical ripening.

METHODS

We monitored GR and NFkappaB, prostaglandin synthases cyclooxygenase (COX)-1 and -2, iNOS, as well as the PAF-receptor (PAF-R) in the uterine cervix from term pregnant women (with unripe cervices) before the onset of labor (TP), immediately after parturition (PP), as compared to non-pregnant (NP), using immunohistochemistry and RT-PCR.

RESULTS

The GR protein was detected by immunohistochemistry in the nuclei of stroma and squamous epithelium (SQ). Stromal GR staining was increased in TP as compared to the NP group and decreased again after parturition. GR staining in SQ was decreased after parturition as compared to term. NFkappaB was present in SQ and glandular epithelium (GE), stroma and vascular endothelium. Increased nuclear NFkappaB staining was observed postpartum as compared to term pregnancy in stroma and GE. Stromal immunostaining for COX-1 as well as COX-2 was increased in the TP and PP groups as compared to the NP, and GE displayed an intensely increased COX-2 immunostaining at term and postpartum. Stromal PAF-R immunostaining was highest at term, while it was greatly increased in GE postpartum. No difference in the immunostaining for iNOS was found between the groups. RT-PCR showed a predominance of GRalpha to GRbeta mRNA in cervical tissue. The COX-2 mRNA level was increased in the PP group as compared to the TP group.

CONCLUSIONS

There is a decrease in GR levels in human cervix at parturition. Concomitantly there is an increase of factors such as NFkappaB, PAF-R, COX-1 and COX-2, suggesting that they may participate in the sequence of events leading to the final cervical ripening.