Reliability of the Bishop score before labour induction at term

OBJECTIVE: To review the incidence, indications, risk factors, and complications associated with emergency peripartum hysterectomy. STUDY DESIGN: We analyzed retrospectively 38 cases of emergency peripartum hysterectomy operations performed between January 1996 and June 2001 at Zekai Tahir Burak Women's Health Research and Education Hospital. The indications, risk factors and the associated complications were noted. Standard tests were used to calculate odds ratios (ORs) and their 95% confidence intervals (CI). RESULTS: Thirty-eight cases of postpartum hysterectomy were performed. All of these cases were referred to our center from rural areas. The rate of peripartum hysterectomy was 1/3736 deliveries. The main indications for hysterectomy were placenta accreata, uterine rupture and uterine atony. There were four maternal deaths. CONCLUSION: Peripartum hysterectomy is a necessary life saving operation. Timely operation minimizes the morbidity and mortality.     

Chemoreflex activity increases prostaglandin endoperoxide synthase mRNA expression in the late-gestation fetal sheep brain

Fetal sheep defend blood pressure, blood volume, and blood gases using baro- and chemoreflexes that influence autonomic and neuroendocrine responses. The local generation of prostanoids within the fetal brain is also an important component in activating hormone responses to these stimuli, but the relationship between the reflexes and prostanoid biosynthesis is unclear. The present study was performed to test the hypothesis that the abundances of prostaglandin biosynthetic enzymes in the fetal brain are dependent upon the activity of the baro- and chemoreflex pathways. We subjected chronically catheterized fetal sheep in late gestation to a 10-minute period of brachiocephalic occlusion (BCO), a stimulus that provokes brisk cardiovascular and neuroendocrine responses. We compared the central nervous system abundance of prostaglandin endoperoxide synthases 1 and 2 (PGHS-1 and PGHS-2) after BCO to (1) fetal sheep that had been subjected to BCO after chronic sinoaortic denervation plus bilateral vagotomy and (2) fetal sheep in which the N-methyl d-aspartate (NMDA) receptor antagonist, ketamine, had been administered prior to BCO. Abundances of messenger RNA (mRNA) for PGHS-1 and of mRNA and protein for PGHS-2 in fetal hippocampus were reduced significantly by either prior denervation or ketamine administration. Prostaglandin endoperoxide synthases 1 and 2 mRNA in pituitary were decreased and increased, respectively, by ketamine pretreatment. The results of this study are consistent with the conclusion that the expression of PGHS-1 and -2 in fetal hippocampus and pituitary are influenced by the baro- and/or chemoreflex pathways within the fetal brain in late gestation.     

Prostaglandin dehydrogenase in the placenta before and after the onset of labour.

Inactivation of prostaglandins in the placenta was studied using an assay for 15-hydroxy-prostaglandin dehydrogenase (PGDH). Forty-four patients with normal single pregnancies between 38 and 42 weeks gestation were studied. Placentae were obtained before the onset of labour in 9, after spontaneous labour in 18, and after oxytocin-induced labour in 17 cases, PGDH-activity ranged from 54 to 495 nanomoles PGF2alpha/g placenta/minute, with a mean +/- SEM of 207 +/- 18 nanomoles/g/minute. The results indicate that the PGDH content of the human placenta does not change markedly with the onset or during the process of labour. The length of either spontaneous or oxytocin-induced labour was not influenced by the PGDH content of the placenta.     

Prostaglandin E production by the fetal membranes in unexplained preterm labour and preterm labour associated with chorioamnionitis

The production of prostaglandin E (PGE) by amnion, choriodecidua and placenta was measured in 45 women delivered after spontaneous preterm labour, in 10 women delivered electively preterm, in 30 women at elective caesarean section at term, and in 28 women after spontaneous labour at term. In the preterm labour group 24 women had normal placental histology, and gestational age was 34 (31-36) weeks (median and range); 18 women had evidence of chorioamnionitis and gestational age was significantly shorter, 30 (24-36) weeks; three other patients had placental abruption. In the absence of inflammatory infiltration of these tissues the highest PGE output (fmol/mg dry weight/2 h) was found after labour at term and the lowest after uncomplicated preterm labour: 2640 (360-15,580) (median and range) compared with 1414 (164-11,045) in amnion, 677 (100-3245) compared with 308 (39-1086) in choriodecidua, and 1200 (520-3022) compared with 578 (150-1859) in placenta, respectively. Tissues showing chorioamnionitis produced much higher outputs of PGE from amnion (12,278, 1799-82,617) and from choriodecidua (1018, 216-11,768), but not from placenta (616, 89-4131). Chorioamnionitis seems to cause very early preterm labour by increasing PG production in the amnion and choriodecidua.     

Prostaglandin E2 for induction of labor in patients with premature rupture of membranes at term.

OBJECTIVE: A prospective study comparing three management schemes for patients at term with premature rupture of membranes was performed. STUDY DESIGN: One hundred forty patients were randomized to one of three study groups: prostaglandin E2, placebo, or oxytocin. Patients randomized to prostaglandin E2 and placebo received vaginal suppositories containing 3 mg prostaglandin E2 or glycerin only, respectively; suppositories were administered in a double-blind fashion, on one or two occasions, 6 hours apart. Oxytocin was given only if labor was not established after 12 hours or to augment inadequate labor. In patients randomized to oxytocin labor was induced with intravenous oxytocin. The time interval to delivery, delivery outcome, and complications were analyzed. RESULTS: Patients receiving prostaglandin E2 were more likely to be in labor after one suppository and to be delivered without the addition of oxytocin when compared with placebo. The time interval to delivery was shorter with prostaglandin E2 and oxytocin induction versus placebo ("expectant management"). The incidence of maternal infection was lowest in patients with labor induced by prostaglandin E2. Although the overall cesarean section rate was low, there was a trend toward a lower rate with prostaglandin E2 induction. No adverse effects were observed with prostaglandin E2. CONCLUSION: Prostaglandin E2 can be used successfully to induce labor after premature rupture of membranes at term with greater ease of administration when compared with oxytocin.     

Evaluation of the expression and enzyme activity of matrix metalloproteinase-7 in fetal membranes during premature rupture of membranes at term in humans

Amnion, chorion, and decidua were separated from fetal membranes at term from women with no labor (cesarean delivery [CS], n = 10), labor (normal delivery, n = 10), and labor during premature rupture of membranes (PROM; n = 8) for evaluation of matrix metalloproteinase (MMP)-7. The expression of pro-MMP-7 was immunohistochemically demonstrated in amnion, chorion, and decidua. Interestingly, however, Western blotting revealed that pro-MMP-7 and MMP-7 expression was the lowest in amnion from PROM, whereas it was the highest in chorion and decidua from PROM. Importantly, the enzymatic activity of MMP-7 determined with an MMP-7-specific substrate was higher in amnion from PROM than that from CS. Moreover, the tissue inhibitor of metalloproteinase (TIMP)-1 level was lower in amnion from PROM than that from CS. Thus, MMP-7 is expressed in fetal membranes (amnion, chorion, and decidua), and its activity is increased in amnion of PROM at term, accompanied with the reduced level of TIMP-1, which may suggest the possible involvement of MMP-7 in PROM.     

Prostaglandin endoperoxide H synthase type 1 and type 2 messenger ribonucleic acid in human fetal tissues throughout gestation and in the newborn infant

OBJECTIVE: We determined the relative abundance of prostaglandin endoperoxide H synthase type 1 and type 2 messenger ribonucleic acid levels in the human fetus and newborn infant. STUDY DESIGN: We used ribonuclease protection assays and normalized values to messenger ribonucleic acid of cyclophilin. Tissues were obtained from all 3 trimesters and in the first 9 days of the newborn period. RESULTS: Prostaglandin endoperoxide H synthase type 1 and type 2 messenger ribonucleic acid is present in every fetal tissue examined (lung, kidney, intestine, heart, brain, and stomach). Kidney and lung demonstrated no changes in the expression of prostaglandin endoperoxide H synthase type 1 messenger ribonucleic acid with gestational age, whereas postnatal levels in lung were one third those in the first trimester (P <.05). A large increase (5-fold to 30-fold; P <.05) occurred throughout gestation for the expression of prostaglandin endoperoxide H synthase type 2 messenger ribonucleic acid in intestine, lung, and kidney, which extended into the newborn period for lung and kidney. CONCLUSIONS: These data imply that the expression of prostaglandin endoperoxide H synthase type 2 messenger ribonucleic acid may be responsible for prostaglandin-related effects and is coordinated in several human fetal tissues in late gestation.     

Misoprostol compared with prostaglandin E2 for labour induction in women at term with intact membranes and unfavourable cervix: a systematic review

BACKGROUND: Misoprostol is a commonly used prostaglandin to induce labour. A potential risk of induction, however, is caesarean delivery, especially in women with an unfavourable cervix. OBJECTIVES: To evaluate the use of misoprostol, compared with prostaglandin E2 (PgE2), for labour induction in women at term with an unfavourable cervix and intact membranes. SEARCH STRATEGY: PubMed, Medline, EMBASE and the Cochrane Library were searched for articles published in any language from January 1987 to December 2005, using the keywords 'misoprostol', 'labour/labor' and 'induction'. SELECTION CRITERIA: We identified randomised trials of women at term (> or =37 weeks of gestation) with intact membranes and unfavourable cervix, undergoing labour induction with misoprostol, orally, vaginally, sublingually or buccally, compared with PgE2 vaginally or intracervically. DATA COLLECTION AND ANALYSIS: Caesarean delivery was the primary outcome, with tachysystole and hyperstimulation as secondary outcomes. The primary analysis compared any misoprostol with any PgE2 for all women, with a subgroup analysis for nulliparous women. Secondary analyses compared different routes and doses of misoprostol (oral or vaginal and 25 microgram or >25 microgram) and PgE2 (intracervical or vaginal). Relative risks (RR) and 95% confidence intervals (CI) were calculated using random effects models.Main results Fourteen of 611 articles identified met the criteria for systematic review, with three providing information for nulliparous women. There was no difference in the risk of caesarean delivery between misoprostol and PgE2 groups (RR = 0.99, 95% CI = 0.83-1.17). Any misoprostol was associated with higher risks of tachysystole and hyperstimulation compared with any PgE2 (RR = 1.86, 95% CI = 1.01-3.43 and RR = 3.71, 95% CI = 2.00-6.88, respectively). There was a higher rate of vaginal delivery within 24 hours among all vaginal deliveries with any misoprostol compared with any PgE2 (RR = 1.14, 95% CI = 1.00-1.31), and among all deliveries, a lower rate of oxytocin use (RR = 0.71, 95% CI = 0.60-0.85) but a trend towards increased meconium staining was observed (RR = 1.22, 95% CI = 0.96-1.55). The use of misoprostol at starting dosages >25 microgram had similar findings to the primary analysis. Studies of lower misoprostol dosing (starting dose of 25 microgram) did not show any differences in the outcomes of interest, but the sample size of this secondary analysis was small (304 women, 155 receiving misoprostol). AUTHOR'S CONCLUSIONS: Although misoprostol in women at term with an unfavourable cervix and intact membranes was more effective than PgE2 in achieving vaginal delivery within 24 hours, misoprostol does not reduce the rate of caesarean delivery either in all women or in the subgroup of nulliparous women, and it increases the rates of tachysystole and hyperstimulation. Further studies of misoprostol using a starting dose of 25 microgram may be warranted.     

Increased concentration of pro-matrix metalloproteinase 9 in term fetal membranes overlying the cervix before labor: implications for membrane remodeling and rupture

OBJECTIVES: Regional structural alterations that develop before labor are important in the mechanisms of both physiologic and pathologic membrane rupture, because they are also detected in preterm prelabor rupture of the fetal membranes, the most common cause of preterm birth (as great as 60%). Matrix metalloproteinases are located in the fetal membranes and are the main mediators of extracellular matrix degradation. The objective of this study was to examine whether gelatinases (matrix metalloproteinases 2 and 9) could be involved in the development of these regional structural changes seen at term before labor. STUDY DESIGN: Fetal membranes from patients undergoing elective cesarean delivery were regionally sampled from over the cervix (cervical membranes) and midway between this area and the placental edge (midzone). Fetal membranes obtained after spontaneous labor and delivery at term were also regionally sampled. Matrix metalloproteinase 2 and 9 activities were assessed by gelatin zymography, whereas total matrix metalloproteinase 9 protein was determined by enzyme-linked immunosorbent assay. RESULTS: Zymography only detected activity corresponding to the pro-matrix metalloproteinase 2 (72 kd) and 9 (92 kd) forms in prelabor fetal membranes. Although the levels of pro-matrix metalloproteinase 2 showed no regional differences, the pro-matrix metalloproteinase 9 level was higher in the cervical area than in the midzone (2.5 +/- 0.98 vs 0.76 +/- 0.28 optical density units/20 microg protein; P <.01). The concentration of pro-matrix metalloproteinase 9 protein in the cervical area was also significantly higher than that in the midzone (6.69 +/- 4.8 vs 1.58 +/- 1.14 ng/mg protein; P <.01). After delivery both pro-matrix metalloproteinase 2 and 9 activities were elevated, whereas pro-matrix metalloproteinase 9 protein activity showed no regional difference between the rupture site and midzone (23.47 +/- 4.5 vs 25. 3 +/- 6.2 ng/mg protein). Active bands of matrix metalloproteinases 2 (66 kd) and 9 (83 kd) were also detected after delivery. CONCLUSION: This study suggests that a specific regional induction of pro-matrix metalloproteinase 9 occurs in the cervical area before labor and may play a role in "programming" this area for subsequent rupture after activation during labor.     

Prostaglandin E2 induction of labor for isolated oligohydramnios in women with unfavorable cervix at term

OBJECTIVE: To evaluate the maternal and neonatal outcomes of pregnancies complicated with isolated oligohydramnios at term, managed by induction of labor. METHODS: We conducted a retrospective case-control study. 138 women with uncomplicated oligohydramnios at term [amniotic fluid index (AFI) < or =5 cm] and a low Bishop score (< or =6) underwent induction of labor with prostaglandin E2. These women were compared to 67 women who underwent induction of labor at 42 weeks' gestation and 276 women at low-risk pregnancy and spontaneous onset of labor, matched for parity and race. RESULTS: Cesarean section (CS) rate was similar in the study and the post-date group (17.4 and 17.9%, respectively), but significantly higher than the spontaneous labor group (5.8%, OR 3.42, 95% CI 1.75-6.68). No differences were found with other outcomes. CONCLUSION: Pregnancies with isolated oligohydramnios at term apparently are not at higher risk of perinatal complications, but induction of labor is associated with increased rate of CS.     

Mode of delivery in pregnancies with premature rupture of membranes at or before term following induction of labor with vaginal prostaglandin E2

Our aim was to evaluate the mode of delivery in pregnancies complicated with premature rupture of the membranes (PROM) at or before term following induction of labor with vaginal application of prostaglandin E2 (PGE2), and to identify possible predictors leading to cesarean section (CS). The study sample consisted of 220 women with term-PROM who did not enter spontaneous labor after 24 hours of expectant management and 42 with preterm (P)-PROM, who underwent labor induction with vaginal PGE2. Findings were compared with 115 women admitted for elective induction of labor, and 510 women with normal spontaneous-onset labor. There were no between-group differences in gravidity, parity, nulliparity rate, or number of PGE2 tablets used. Women with P-PROM were admitted at 34.6 +/- 2.4 weeks gestation, and delivered at 36.1 +/- 1.6 weeks (mean interval, 5.0 +/- 7.9 days; range, 0.5 to 40 days). The rate of CS was different only between the term-PROM (18.6%) and spontaneous onset of labor (9%) groups (odds ratio, 2.08; 95% confidence interval, 1.4 to 3.4). The rate of low 5-minute Apgar score (< 7) was similar in all groups, but the incidence of nonreassuring fetal heart rate pattern leading to CS was significantly lower in the PROM groups. A logistic regression model and forward likelihood analysis in the PROM groups yielded parity, higher number of PGE2 tablets used, and higher birth weight as independent and significant variables associated with increased risk of CS. Using our management protocol, 36.4% and 20.4% of women with term-PROM and P-PROM, respectively, required labor induction with PGE2, which was successful in more than 80% of cases, with no apparent serious maternal or fetal complications.     

Prediction of time to spontaneous onset of labour with lactate concentration in vaginal fluid in women with suspected preterm prelabour rupture of the membranes

Objective  To assess whether lactate determination in vaginal fluid is associated with and can predict onset of labour for women with suspected preterm prelabour rupture of membranes (PPROMs).
Design  Prospective observational study.
Setting  Labour ward at South General Hospital, Stockholm, Sweden.
Population/participants  Women with suspected PPROMs at 20–36 completed weeks of gestation ( n = 81).
Methods  All women underwent a speculum examination and a test for determining lactate concentration in vaginal fluid. We used logistic regression to estimate the association between lactate concentration in vaginal fluid and time to onset of labour.
Main outcome measure  Time from examination to spontaneous onset of labour (cervix ≥4 cm).
Results  The median time between examination and onset of labour was 13.6 hours for those with a high (≥4.5 mmol/l) lactate concentration and 1152 hours (i.e. 48 days) for those with a low (<4.5 mmol/l) lactate concentration. For a lactate threshold of 4.5 mmol/l, the likelihood ratio for positive test (LR+) was 12.6, and LR− was 0.14 for the outcome of spontaneous onset of labour within 48 hours.
Conclusions  A high lactate concentration in vaginal fluid is strongly associated with whether a woman with suspected PPROM will commence onset of labour within 48 hours. If confirmed, use of lactate ('LAC test') as a predictive test for onset of preterm labour may be an attractive tool in bedside obstetrics.     

Changes in the expression of the type-2 but not the type-1 cyclo-oxygenase enzyme in chorion-decidua with the onset of labour

Objective To determine the relative expression of cyclo-oxygenase (COX)-1 and COX-2 in the chorion-decidual part of human fetal membranes following delivery at term and to identify any changes in expression associated with labour.
Methods Fetal membranes were collected from 12 term pregnancies before labour following elective caesarean section and from 12 spontaneous vaginal deliveries. Expression of COX-1 and COX-2 mRNA was measured using a previously validated quantitative RT-PCR assay.
Results COX-2 expression exceeded that of COX-1 by approximately eight-fold. COX1 expression did not change but COX-2 expression was found to increase four-fold with labour.
Conclusions Chorion-decidua has the capacity to contribute to the increase in prostaglandin synthesis within the uterus associated with labour. As in the amnion, it is COX-2 and not COX-1 which is upregulated with labour. COX-2 selective anti-prostaglandins should therefore be as effective as nonselective drugs in inhibition of fetal membrane prostaglandin synthesis.