Models for the prediction of successful induction of labor based on pre-induction sonographic measurement of cervical length

Objective.?To examine the effect of pre-induction cervical length, parity, gestational age at induction, maternal age and body mass index (BMI) on the possibility of successful delivery in women undergoing induction of labor.

Methods.?In 822 singleton pregnancies, induction of labor was carried out at 35 to 42^?+?6 weeks of gestation. The cervical length was measured by transvaginal sonography before induction. The effect of cervical length, parity, gestational age, maternal age and BMI on the interval between induction and vaginal delivery within 24?hours was investigated using Cox's proportional hazard model. The likelihood of vaginal delivery within 24?hours and risk for cesarean section overall and for failure to progress was investigated using logistic regression analysis.

Results.?Successful vaginal delivery within 24?hours of induction occurred in 530 (64.5%) of the 822 women. Cesarean sections were performed in 161 (19.6%) cases, 70 for fetal distress and 91 for failure to progress. Cox's proportional hazard model indicated that significant prediction of the induction-to-delivery interval was provided by the pre-induction cervical length (HR?=?0.89, 95 % CI 0.88–0.90, p?<?0.0001), parity (HR?=?2.39, 95% CI 1.98–2.88, p?<?0.0001), gestational age (HR?=?1.13, 95% CI 1.07–1.2, p?= <?0.0001) and birth weight percentile (HR?=?0.995, 95% CI 0.99?– 0.995, p?=?0.001), but not by maternal age or BMI. Logistic regression analysis indicated that significant prediction of the likelihood of vaginal delivery within 24?hours was provided by pre-induction cervical length (OR?=?0.86, 95% CI 0.84–0.88, p?<?0.0001), parity (OR?=?3.59, 95% CI 2.47–5.22, p?<?0.0001) and gestational age (OR =?1.19, 95% CI 1.07–1.32, p?= <?0.0001) but not by BMI or maternal age. The risk of cesarean section overall was significantly associated with all the variables under consideration, i.e., pre-induction cervical length (OR?=?1.09, 95% CI 1.06–1.11, p?<?0.0001), parity (OR?=?0.25, 95% CI 0.17–0.38, p?<?0.0001), BMI (OR?=?1.85, 95% CI 1.24–2.74, p?=?0.0024), gestational age (OR?=?0.88, 95% CI 0.78–0.98, p?=?0.0215) and maternal age (OR?=?1.04, 95% CI 1.01–1.07, p?=?0.0192). The risk of cesarean section for failure to progress was also significantly associated with pre-induction cervical length (OR?=?1.11, 95% CI 1.07–1.14, p?<?0.0001), parity (OR?=?0.26, 95% CI 0.15–0.43, p?<?0.0001), gestational age (OR?=?0.83, 95% CI 0.73–0.96, p?=?0.0097) and BMI (OR?=?2.07, 95% CI 1.27–3.37, p?=?0.0036).

Conclusion.?In women undergoing induction of labor, pre-induction cervical length, parity, gestational age at induction, maternal age and BMI have a significant effect on the interval between induction and delivery within 24?hours, likelihood of vaginal delivery within 24?hours and the risk of cesarean section.     

Transvaginal ultrasound and digital examination in predicting successful labor induction.

OBJECTIVE: To compare transvaginal ultrasound and digital cervical examination in predicting successful induction in post-term pregnancy. METHODS: Transvaginal ultrasound and digital vaginal examinations were performed on 122 women at 41 or more weeks' gestation, immediately before labor induction. Ultrasound assessments of cervical length, dilatation, and presence of funneling were compared with the components of the Bishop score. The primary outcome was the rate of vaginal delivery. Secondary outcomes assessed included the rates of active labor in 12 hours, vaginal delivery in 12 and 24 hours, mean duration of latent phase, and induction to vaginal delivery interval. Linear and multiple logistic regression models were generated to identify factors independently associated with successful induction. RESULTS: No ultrasound characteristic predicted primary or secondary outcomes. Bishop score (odds ratio [OR] 2.98, 95% confidence interval [CI] 1.71, 5.20), cervical position (OR 4.35, 95% CI 1.41, 12.50), and maternal age (OR 1.15, 95% CI 1.01, 1.30) independently predicted vaginal delivery. Maternal weight (OR 0.96, 95% CI 0.94, 0.98), cervical dilatation (OR 6.08, 95% CI 1.70, 21.68), and effacement (OR 2.34, 95% CI 1.16, 4.73) independently predicted active labor in 12 hours. Independent predictors of vaginal delivery in 12 hours were induction method (P <.001), cervical dilatation (OR 11.16, 95% CI 3.17, 39.29), gravidity (OR 2.06, 95% CI 1.13, 3.77), and maternal weight (OR 0.96, 95% CI 0.93, 0.99). Cervical effacement (OR 2.70, 95% CI 1.59, 4.57) and parity (OR 7.10, 95% CI 2.22, 22.72) independently predicted vaginal delivery in 24 hours. Maternal weight, cervical position, and cervical dilatation were independently associated with latent phase labor duration. Factors independently associated with length of induction to delivery interval were parity, cervical effacement, and maternal weight. CONCLUSION: Transvaginal ultrasound does not predict successful labor induction in post-term pregnancy as well as digital cervical examination.     

Factors affecting the likelihood of successful induction after intravaginal misoprostol application for cervical ripening and labor induction

OBJECTIVE: Our purpose was to determine whether maternal age, height and weight, parity, duration of pregnancy, cervical dilatation or Bishop score, and birth weight could be used to predict the likelihood of successful induction in women given intravaginal misoprostol. STUDY DESIGN: A computerized database was compiled of 1373 pregnancies in which intravaginal misoprostol was given for cervical ripening and labor induction. Most of these women were placed on investigational protocols in which the dose of misoprostol administered was 25 to 50 microg and the dosing intervals ranged from 3 to 6 hours. No more than 24 hours of administration was permitted. Induction was undertaken in women with unfavorable cervical examinations (Bishop scores of 4 or less) and without spontaneous labor or ruptured membranes. Univariate and stepwise multiple regression analyses were performed to identify those factors associated with successful induction, defined as vaginal delivery within 24 hours of induction. RESULTS: Six hundred fifty-seven (48%) had successful induction. Parity (odds ratio [OR] 2.5, 95% CI 2.0-2.9, P <.0001), initial cervical dilatation (OR 1.9, 95% CI 1.6-2.3, P <.0001), Bishop score (OR 1.6, 95% CI 1.3, 1.8, P <.0001), and gestational age at entry (OR 1.3, 95% CI 1.1-1.5, P =.002) were significant at the.05 level for predicting successful induction. A multivariate stepwise logistic regression was then performed to evaluate each of these as independent predictors. Parity (OR 2.4, 95% CI 2.0-3.0, P <.0001), initial cervical dilatation (OR 1.7, 95% CI 1.4-2.1, P <.0001), and estimated gestational age (OR 1.3, 95% CI 1.1-1.6, P =.003) are significant independent predictors for successful induction, but initial Bishop score is not significant (P =.19) after adjustment for other significant predicting factors. CONCLUSIONS: The clinical characteristics of parity, initial cervical dilatation, and gestational age at entry are predictors of the likelihood of success of cervical ripening and labor induction with intravaginal misoprostol administration.     

Pregnancy outcome in women aged 40 years or more

Objective: The study aimed to analyze the pregnancy outcome of women aged 40 years or more. Methods: A matched retrospective cohort study comparing women aged 40 years or more with a control group aged 20 to 30 years is described. Multivariate logistic regression models were fitted for the prediction of preterm birth and cesarean delivery. Results: Pregnancy-induced hypertension, preeclampsia and placenta previa were similar in both groups, but a higher rate of gestational diabetes was found in elderly patients (odds ratio [OR] 3.820, 95% confidence interval [CI] = 1.400–10.400; p < 0.0001). Preterm delivery was significantly more frequent in elderly women (OR 1.847, 95% CI = 1.123–3.037; p = 0.020). Gestational diabetes and pregnancy-induced hypertension were strongly associated with preterm delivery and advanced maternal age was not an independent risk factor for preterm delivery. The cesarean delivery rate was significantly higher in the study group (OR 3.234, 95% CI = 2.266–4.617; p < 0.0001). The variables most influencing the cesarean delivery rate were maternal age, analgesia, parity, premature rupture of the membranes and gestational hypertension. No significant differences were detected in neonatal birth weight and Apgar score. Conclusions: Patients aged 40 years or more have been demonstrated to carry a favorable pregnancy and neonatal outcome, similar to younger patients. The risk of cesarean delivery was higher in patients with advanced maternal age, in nulliparous and in women with a previous cesarean section. The risk of preterm delivery was not related to age but it was strongly associated with gestational diabetes and pregnancy-induced hypertension.     

Ultrasound and clinical predictors for Caesarean delivery after labour induction at term

OBJECTIVE: To assess the relationship of ultrasound assessment for amniotic fluid, fetal weight, cervical length, cervical funneling and clinical factors on the risk of Caesarean delivery after labour induction at term. METHODS: On hundred and fifty-two women scheduled for labour induction at term agreed to participate. Sonography was performed to obtain fetal biometry, amniotic fluid index and cervical length and to detect funneling at the internal cervical os. The sonographic findings were concealed. Study women received standard care during labour induction. RESULTS: On univariate analysis using Fisher's exact test, parity, cervical length and Bishop score were associated with Caesarean delivery. Following multivariable logistic regression analysis, only nulliparity (adjusted odds ratio (AOR) 5.2 (95% CI 2.2-12.2): P<0.001) and transvaginal ultrasound-determined cervical length of more than 20 mm (AOR 2.8 (95% CI 1.0-7.4): P=0.04) were independent predictors of Caesarean delivery in labour induction. Maternal age, maternal height, gestational age, indication for labour induction, amniotic fluid index, cervical funneling and ultrasound-estimated fetal weight did not predict Caesarean delivery. CONCLUSION: In women who had undergone labour induction at term with a singleton fetus, nulliparity and cervical length of more than 20 mm on transvaginal sonography were independent predictors of Caesarean delivery. This information is helpful for pre-induction counselling.     

Elective cervical ripening in women beyond the 290th day of pregnancy: a randomized trial comparing 2 dinoprostone preparations

OBJECTIVE: To determine the better performer among cervical ripening agents for the elective induction of labor. STUDY DESIGN: An open-label, randomized study was done in consecutive patients undergoing elective induction of labor at the 41st week and beyond. Inclusion criteria were: singleton pregnancy, gestational age ascertained through first-trimester ultrasound, Bishop score <4 and nulliparity. Exclusion criteria were: oligohydramnios, maternal/fetal disorder or pregnancy complication, previous uterine surgery, rupture of membranes and presence of uterine activity. Patients received either slow-release dinoprostone vaginal insert (VI) or 0.5-mg dinoprostone intracervical (IC) gel, twice, 6 hours apart. RESULTS: Women receiving VI showed increased risk of entering labor without further stimulation (OR = 6.48, 95% CI 2.06-21.67, p < 0.001) and delivering vaginally within 24 hours (OR = 2.71, 95% CI 1.19-6.21, p = 0.01) in comparison to those receiving IC gel. A stay in the hospital (> 4 days) was more prevalent in women treated with IC gel in comparison to those treated with VI (OR = 2.35, 95% CI 1.04-5.37). CONCLUSION: Preinduction cervical ripening with the dinoprostone slow-release vaginal insert is associated with a hight rate of women undergoing vaginal delivery within 24 hours, with a shorter stay. Considering its good performance, the dinoprostone slow-release vaginal insert is the first choice for elective induction of labor in postdate pregnancy.     

Impact of labor induction,gestational age,and maternal age on cesarean delivery rates

OBJECTIVE: To quantify the impact of labor induction and maternal age on cesarean delivery rates in nulliparous and multiparous women between 36 and 42 weeks' gestation. METHODS: We performed a retrospective cohort study on 14,409 women delivering at two teaching hospitals in metropolitan Boston during 1998 and 1999. Women who had contraindications to labor, including a prior cesarean delivery, were excluded. The risks for cesarean delivery by induction status, gestational age by completed week between 36 and 42 weeks, maternal age <35, 35-39, and >/=40 years, and stratified by parity, were calculated by logistic regression. RESULTS: In nulliparas, labor induction was associated with an increase in cesarean delivery from 13.7% to 24.7% (adjusted odds ratio [OR] 1.70; 95% confidence interval [CI] 1.48, 1.95]). In multiparas, induction was associated with an increase from 2.4% to 4.5% (OR 1.49; 95% CI 1.10, 2.00). Other variables that placed a nulliparous woman at increased risk for cesarean delivery included maternal age of at least 35 years and gestational ages over 40 weeks. For multiparas, only maternal age 40 years or older and gestational age of 41 weeks were associated with an increase in cesarean deliveries. CONCLUSION: Induction of labor, older maternal age, and gestational age over 40 weeks each independently increase the risk for cesarean delivery in both nulliparous and multiparous women. Although the relative risk from induction is similar in nulliparas and multiparas, the absolute magnitude of the increase is much greater in nulliparas (11% versus 2.1%).     

Risk factors for cesarean section and instrumental vaginal delivery after successful external cephalic version

Aim of this article is to examine if we could identify factors that predict cesarean section and instrumental vaginal delivery in women who had a successful external cephalic version. We used data from a previous randomized trial among 25 hospitals and their referring midwife practices in the Netherlands. With the data of this trial, we performed a cohort study among women attempting vaginal delivery after successful ECV. We evaluated whether maternal age, gestational age, parity, time interval between ECV and delivery, birth weight, neonatal gender, and induction of labor were predictive for a vaginal delivery on one hand or a CS or instrumental vaginal delivery on the other hand. Unadjusted and adjusted odds ratios were calculated with univariate and multivariate logistic regression analysis. Among 301 women who attempted vaginal delivery after a successful external cephalic version attempt, the cesarean section rate was 13% and the instrumental vaginal delivery rate 6%, resulting in a combined instrumental delivery rate of 19%. Nulliparity increased the risk of cesarean section (OR 2.7 (95% CI 1.2–6.1)) and instrumental delivery (OR 4.2 (95% CI 2.1–8.6)). Maternal age, gestational age at delivery, time interval between external cephalic version and delivery, birth weight and neonatal gender did not contribute to the prediction of failed spontaneous vaginal delivery. In our cohort of 301 women with a successful external cephalic version, nulliparity was the only one of seven factors that predicted the risk for cesarean section and instrumental vaginal delivery.     

The effect of gestational age on the outcome of second-trimester termination of pregnancies for foetal abnormalities

OBJECTIVE: To explore the effect of gestational age on the outcome of second-trimester termination of pregnancies for foetal abnormalities. METHOD: A retrospective study was conducted on 280 pregnancies terminated for foetal abnormalities in the second trimester using vaginal misoprostol. The gestational age at termination was divided into three groups: 13-16 weeks, 17-20 weeks and 21-23 weeks. The likelihood of (1) abortion within 24 h of commencement of misoprostol, (2) incomplete abortion and (3) experiencing significant side effects was compared among these three gestational groups after adjusting for maternal age, parity and body mass index (BMI). RESULTS: Compared to termination after 20 weeks, pregnancy termination for foetal abnormality before 17 weeks of gestation was associated with higher chance of incomplete abortion (OR 2.2, 95% CI 1.07-4.61, p = 0.032) and lower chance of experiencing significant side effects (OR 0.11, 95% CI 0.01-0.91, p = 0.041). CONCLUSION: Women undergoing pregnancy termination for foetal abnormalities in the early second trimester should be informed of possible higher chance of incomplete abortion.     

Induction of labor after one prior cesarean: predictors of vaginal delivery

OBJECTIVE: To estimate the characteristics most associated with vaginal birth in patients undergoing induction of labor after 1 prior cesarean delivery. METHODS: All patients who presented for induction of labor from 1996 to 2001 with a history of 1 prior cesarean delivery were identified. Relevant demographic and obstetric data were abstracted from the charts. Univariate analysis was used to identify predictive factors associated with vaginal birth after cesarean. Binary logistic regression was further used to identify which factors were independently associated with the outcome measure. RESULTS: Of the 429 women included in the study, 334 (77.9%) had a successful trial of labor. In the final binary logistic regression equation, prior vaginal delivery (odds ratio [OR] 3.75; 95% confidence interval [CI] 1.96, 7.18) remained independently associated with an increased chance of a vaginal delivery after a trial of labor. Conversely, prior cesarean delivery for dystocia (OR 0.46; 95% CI 0.27, 0.79), induction on or past the estimated date of delivery (OR 0.46; 95% CI 0.27, 0.78), need for cervical ripening (OR 0.35; 95% CI 0.20, 0.61), and maternal gestational or preexisting diabetes (OR 0.16; 95% CI 0.06, 0.40) were all factors associated with a decreased likelihood of achieving a successful trial of labor. CONCLUSION: Several factors are available which may assist in identifying patients with the best chance of vaginal delivery after an induction of labor in the presence of a prior low-transverse cesarean scar. LEVEL OF EVIDENCE: II-2     

A way to lend objectivity to Bishop score.

The aim of this study was to explore the possibility of utilising pre-induction cervical length assessment by trans-vaginal ultrasound to improve the predictive value of the Bishop score. The idea of this paper has evolved following our prospective study, which was designed to compare the pre-induction objective assessment of the cervix by ultrasound with the subjective one by Bishop Score. The Bishop scores of the 104 women included in the study were modified by replacing the digital assessment of the cervical length by ultrasound cervical length measurements. There was a significant statistical difference (p < 0.0001) between the median of the original and the modified Bishop scores. The original Bishop score showed insignificant association (p > 0.05) with the induction-delivery interval (IDI) and the mode of delivery while the modified score showed a significant association (r = 0.31, p < 0.05) with mode of delivery and a highly significant one (r = 0.55, p < 0.0001) with the IDI. The receiver operating characteristic curve showed that the optimised cut-off value for prediction of vaginal delivery was >5 for the original Bishop Score and >3 for the modified one. At those optimised cut-off values, the original Bishop Score predicted vaginal delivery with a sensitivity of 23% (95% CI; 14.6%, 33.2%) and specificity of 88.2% (95% CI; 63.5%, 98.5% while the modified Bishop score predicted vaginal delivery with a sensitivity of 62% [95%; CI 51 - 72.3] and specificity of 82% [95%; CI 56.6 - 96]). In conclusion, the modified Bishop score is better than the original one in predicting the IDI and the success of induction of labour. The sensitivity of the Bishop score in predicting the rate of vaginal delivery has been improved significantly following the modification.     

Obstetric outcome of twin pregnancies conceived by in vitro fertilization and ovulation induction compared with those conceived spontaneously

OBJECTIVE: To compare the obstetric characteristics of twin pregnancies conceived by in vitro fertilization (IVF) and ovulation induction with those conceived spontaneously. DESIGN: Case control study. SETTING: Tertiary Medical Center. PATIENTS: All twin deliveries that were achieved by IVF (n=558) and ovulation induction (n=478) from January 1988 through December 2002 were evaluated. Each group was compared with a control group that conceived spontaneously (n=3694) and was delivered during the same period. INTERVENTIONS: Ovulation induction, IVF-ET. MAIN OUTCOME MEASURES: Obstetrical complications. RESULTS: Multivariate analysis showed that patients who conceived with the assistance of IVF and ovulation induction had a significantly higher risk for gestational diabetes mellitus (odds ratio [OR]=2.41, 95% confidence interval [CI]=1.77-3.29 and OR=1.71, CI=1.2-2.42, respectively), cesarean section (OR=2.17, 95% CI=1.74-2.70 and OR=1.76, CI=1.43-2.16, respectively), and a lower gestational age at birth in the IVF group (OR=0.91, 95% CI=0.88-0.94), compared with their controls. CONCLUSIONS: After controlling for maternal age, and nulliparity we demonstrated that twin pregnancies conceived with the assistance of IVF and ovulation induction are at increased risk for gestational diabetes mellitus, and delivery by cesarean section. In addition, IVF conceived pregnancies have a lower gestational age at birth.     

Comparison between subjective and objective assessments of the cervix before induction of labour.

The aim of the study was to compare the pre-induction cervical assessment by Bishop's score with the transvaginal ultrasound cervical length as predictors of the induction-delivery interval (IDI) and the success of induction. This prospective study included 104 women with singleton pregnancies who were booked for induction of labour at term over a period of 3 years. Transvaginal ultrasound measurement of the cervical length and Bishop's Score were performed by different operators. Data were collected on parity, gestational age, methods of induction, Bishop's score, ultrasound cervical length measurements, IDI and mode of delivery. A total of 87 women (83.7%) delivered vaginally and 17 (16.3%) delivered by caesarean section. Linear regression models demonstrated that ultrasound cervical length was a better indicator of IDI than Bishop's score. The adjusted R2 for the regression including ultrasound cervical length was 0.87 compared with a value of 0.67 for the model including Bishop's score. Although logistic regression analysis confirmed that cervical effacement was the best component of Bishop's score to predict the mode of delivery, ultrasound cervical length assessment provided better prediction. Receiver operating characteristic curve showed that the optimised cut-off value for prediction of vaginal delivery was < or =3.4 cm for the cervical length and >5 for the Bishop's score. At those optimised cut-off values the cervical length predicted vaginal delivery with sensitivity of 62.1% (95% CI [51%, 72.3%]) and specificity of 100% (95% CI [80.5%, 100%]) while the Bishop's score predicted vaginal delivery with a sensitivity of 23% (95% CI [14.6%, 33.2%]) and specificity of 88.2% (95% CI [63.5%, 98.5%]). Further analysis showed that ultrasound cervical length has a higher sensitivity in prediction of vaginal delivery in multiparous than nulliparous women (85.1% compared with 35%) at a cut-off value of < or =3.4 cm. On the other hand, it has a higher sensitivity in nulliparous comparable with multiparous women (85.3% compared with 30%) in prediction of IDI at a cut-off value of >3.5 cm. In conclusion, transvaginal ultrasound cervical length assessment is better than Bishop's score in predicting the IDI and the success of induction of labour.     

Ethnic disparity in the success of vaginal birth after cesarean delivery.

OBJECTIVE: To estimate whether maternal race/ethnicity is independently associated with successful vaginal birth after cesarean delivery (VBAC). STUDY DESIGN: A retrospective cohort study from January 1, 1997 to July 30, 2002 of women with singleton pregnancies and a previous cesarean delivery. The odds ratio (OR) for successful VBAC as a function of ethnicity was corrected for age >35 years, parity, weight gain, diabetes mellitus, hospital site, prenatal care provider, gestational age, induction, labor augmentation, epidural analgesia, and birth weight >4000 g. RESULTS: Among 54 146 births, 8030 (14.8%) occurred in women with previous cesarean deliveries. The trials of labor rates were similar among Caucasian (46.6%), Hispanic (45.4%), and African American (46.0%) women. However, there was a significant difference among ethnic groups for VBAC success rates (79.3% vs. 79.3% vs. 70.0%, respectively). When compared to Caucasian women, the adjusted OR for VBAC success was 0.37 (95% confidence interval (CI) 0.27-0.50) for African American women and 0.63 (95% CI 0.51-0.79) for Hispanic women. CONCLUSION: African American and Hispanic women are significantly less likely than Caucasian women to achieve successful VBAC.     

Emergency cesarean delivery in induction of labor: an evaluation of risk factors

BACKGROUND: Induction of labor has been associated with an increased risk of emergency cesarean delivery. Knowledge of factors that influence the risk of cesarean delivery in women with induced labor is limited. METHODS: We performed a case-control study, nested within a population-based cohort of women with induced labor at term during 1991-1996 in Uppsala County, Sweden. Cases were women delivered with emergency cesarean delivery, and controls were women vaginally delivered (n = 193, respectively). Using logistic regression, analyses were performed. Odds ratio (OR) with 95% confidence intervals (CI) was used as a measure of relative risk. RESULTS: Women with a previous cesarean delivery had high risks of cesarean delivery (adjusted OR = 10.10, 95% CI = 3.30-30.92). The risk of cesarean delivery was also increased among nulliparous (adjusted OR = 4.92, 95% CI = 2.81-8.61), short (adjusted OR = 2.20, 95% CI = 1.06-4.59), and obese women (adjusted OR = 2.03, 95% CI = 1.07-3.84). A cervix dilatation less than 1.5 cm doubled the risk of cesarean delivery (adjusted OR = 2.26, 95% CI = 1.09-4.66). Mother's age, epidural analgesia, oxytocin augmentation, gestational age, and birthweight were not significantly associated with risks of cesarean delivery. CONCLUSIONS: Women with a previous cesarean delivery, nulliparous, short, and obese women with induced labor are at high risk of a cesarean delivery. When there is a need to deliver a woman with a previous cesarean section or a nulliparous woman with other risk factors for cesarean delivery, it may be prudent to consider an elective cesarean section.     

Vaginal delivery among women who underwent labor induction with vaginal dinoprostone (PGE2) insert: a retrospective study of 1656 women in China

Objective: This study aimed to qualify relevant factors for vaginal delivery among women who underwent labor induction with vaginal dinoprostone (PGE2) insert in a Chinese tertiary maternity hospital.

Material and methods: A retrospective study was conducted in Hubei Maternal and Child Health Hospital. A total of 1656 pregnancies that underwent labor induction with vaginal dinoprostone insert between January and August 2016 were finally included in this study. Data were analyzed using univariate and multivariable regression modeling.

Results: Of 1656 women with PGE2-induced labor at term, 396 (23.91%) gave birth by cesarean section, 1260 (76.09%) had a vaginal delivery among which 921 (55.61%) delivered vaginally within 24?h. Multivariable regression analysis showed that maternal age (p?p?p?=?.009, OR = 0.98, 95%CI 0.96–0.99), and birth weight (p?p?p?p?=?.004, OR = 0.96, 95%CI 0.94–0.99), and birth weight (p?Conclusions: Our findings suggested a vaginal delivery rate of 76.09% when dinoprostone vaginal insert was used for labor induction, which was markedly higher than the overall annual vaginal delivery rate of 65.1% in China during 2014. Maternal age, parity, baseline fetal heart rate, and birth weight were significant factors for vaginal delivery. This study enables us to better understand the efficiency of dinoprostone and the potential predictors of vaginal delivery in dinoprostone-induced labor, which may be helpful to guide the clinical use of dinoprostone and therefore provide better service clinically.     

Obstetric characteristics and perinatal outcome of pregnancies with uterine leiomyomas

OBJECTIVE: To determine the rate, obstetric characteristics and perinatal outcome of pregnancies with uterine leiomyomas. STUDY DESIGN: A population-based study comparing all singleton deliveries between the years 1988 and 1999 in women with and without uterine leiomyomas was performed. Patients lacking prenatal care were excluded from the analysis. Multivariable analysis, adjusting for possible confounders, such as maternal age, parity and gestational age, was performed to investigate associations between uterine leiomyomas and selected outcomes. RESULTS: There were 105,909 singleton deliveries with 690 (0.65%) complicated by uterine leiomyomas during the study period. Using a multivariable analysis, the following conditions were significantly associated with uterine leiomyomas: nulliparity (odds ratio [OR]=4.0, 95% confidence interval [CI] 3.3-4.7, P<.001), chronic hypertension (OR=1.9, 95% CI 1.6-2.4, P<.001), hydramnios (OR=1.5, 95% CI 1.2-2.0, P<.001), diabetes mellitus (OR=1.4, 95% CI 1.1-1.7, P=.001) and advanced maternal age (OR=1.2, 95% CI 1.1-1.2, P<.001). Higher rates of perinatal mortality (2.2% vs. 1.2%, OR=1.8, 95% CI 1.1-3.2, P<.001) were found in the uterine leiomyoma group as compared to the control group. While adjusting for maternal age, parity, gestational age and malpresentation, pregnancies with uterine leiomyomas had higher rates of cesarean deliveries (OR=6.7, 95% CI 5.5-8.1, P<.001), placental abruption (OR=2.6, 95% CI 1.6-4.2, P<.001) and preterm deliveries (<36 weeks' gestation, OR=1.4, 95% CI 1.1-1.7, P=.009) as compared to pregnancies without uterine leiomyomas. Conversely, no significant differences were noted regarding perinatal mortality (OR=1.4, 95% CI 0.7-2.8, P=.351) after controlling for maternal age, parity and gestational age using a multivariable analysis. CONCLUSION: Uterine leiomyomas increase the risk of adverse pregnancy outcomes, thus emphasizing the importance of appropriate intrapartum management of these high-risk pregnancies.     

A META-ANALYSIS OF CONTROLLED-RELEASE PROSTAGLANDIN FOR CERVICAL RIPENING AND LABOUR INDUCTION

OBJECTIVES: to examine the effectiveness and safety of controlled-release prostaglandin for cervical ripening. DATA SOURCES: we conducted a computerized search of Medline using the keywords "Cervidil"; or "Propess"; or "prostaglandin/dinoprostone" and "pessary"; or "prostaglandin/dinoprostone" and "controlled" and "release"; or "prostaglandin/dinoprostone" and "vaginal" and "insert"; identifying studies in the English literature published between January 1980 and December 1999. STUDY SELECTION: we included all randomized trials that compared controlled-release vaginal prostaglandin with a retrieval string with any other method of cervical ripening or with a placebo. Nine studies were identified.TABULATION, INTERACTION, AND RESULTS: the two coauthors independently abstracted the data and evaluated the studies for methodologic quality, blinded to each other's results. Homogeneity of results was evaluated, and if present, the summary odds ratio and 95 percent confidence intervals were determined. Compared with placebo, controlled-release prostaglandin resulted in cervical change (summary odds ratio [OR] = 3.99, 95% confidence interval [CI] = 2.71-5.86), a higher rate of vaginal delivery in 12 hours (OR = 29.01, 95% CI = 7.08-118.87), less need for oxytocin (OR = 0.14, 95% CI = 0.06-0.32), but a higher incidence of excessive uterine activity (P<0.0001) and hyperstimulation (P = 0.004). When compared with Prepidil, there was a higher rate of excessive uterine activity with controlled-release prostaglandin (P = 0.03), but less need for oxytocin (OR = 0.09, 95% CI = 0.01-0.53). When compared with Prepidil/immediate oxytocin, there was a lower rate of active labour in 12 hours with controlled-release prostaglandin (OR = 0.27, 95% CI = 0.10-0.72). There was a lower rate of vaginal delivery in 12 hours and higher incidence of oxytocin use with controlled-release prostaglandin as compared with misoprostol (OR = 0.53, 95% CI = 0.34-0.83 and OR = 1.58, 95% CI = 1.08-2.32 respectively). The induction to delivery interval was shorter with controlled-release prostaglandin than with placebo or Prepidil, but longer than with Prepidil/immediate oxytocin, or misoprostol. Although no differences were seen with maternal morbidity (such as Caesarean delivery) or neonatal outcomes, the sample size was not adequate to evaluate these outcomes. CONCLUSION: controlled-release prostaglandin appears to be an effective cervical ripening agent as compared with Prepidil, but may result in an increased incidence of excessive uterine activity. Controlled-release prostaglandin may not be as effective as misoprostol or Prepidil/immediate oxytocin. Further randomized trials with larger sample sizes are needed to evaluate maternal morbidity and neonatal outcomes.     

Cesarean delivery and peripartum hysterectomy

OBJECTIVE: To estimate the national incidence of peripartum hysterectomy and quantify the risk associated with cesarean deliveries and other factors. METHODS: A population-based, matched case-control study using the United Kingdom Obstetric Surveillance System, including 318 women in the United Kingdom who underwent peripartum hysterectomy between February 2005 and February 2006 and 614 matched control women. RESULTS: The incidence of peripartum hysterectomy was 4.1 cases per 10,000 births (95% confidence interval [CI] 3.6-4.5). Maternal mortality was 0.6% (95% CI 0-1.5%). Previous cesarean delivery (odds ratio [OR] 3.52, 95% CI 2.35-5.26), maternal age over 35 years (OR 2.42, 95% CI 1.66-3.58), parity of three or greater (OR 2.30, 95% CI 1.26-4.18), previous manual placental removal (OR 12.5, 95% CI 1.17-133.0), previous myomectomy (OR 14.0, 95% CI 1.31-149.3), and twin pregnancy (OR 6.30, 95% CI 1.73-23.0) were all risk factors for peripartum hysterectomy. The risk associated with previous cesarean delivery was higher with increasing numbers of previous cesarean deliveries (OR 2.14 with one previous delivery [95% CI 1.37-3.33], 18.6 with two or more [95% CI 7.67-45.4]). Women undergoing a first cesarean delivery in the current pregnancy were also at increased risk (OR 7.13, 95% CI 3.71-13.7). CONCLUSION: Peripartum hysterectomy is strongly associated with previous cesarean delivery, and the risk rises with increasing number of previous cesarean deliveries, maternal age over 35 years, and parity greater than 3. LEVEL OF EVIDENCE: II.     

Associations of hypertensive disorders of pregnancy and outcomes of labor induction with prostaglandin vaginal inserts

Objective: To evaluate the association between hypertensive (HTNsive) disorders of pregnancy and outcomes of labor induction, in two cohorts of women induced with either misoprostol vaginal insert (MVI) or dinoprostone vaginal insert (DVI). Study Design: This investigation was a post-hoc analysis of data from three Phase II and III, multi-center, double blind, randomized controlled trials of women induced with identical efficacy endpoints. A competing risk framework investigated the association between HTNsive disorders of pregnancy and the time-to-event endpoints of onset of active labor and vaginal delivery. We analyzed the overall incidence of the competing risk, cesarean delivery, by logistic regression to identify potential differences between the proportion of patients with cesarean and vaginal deliveries for each cohort. Results: 401 women with HTNsive disorders during pregnancy underwent induction of labor in these studies (175 with DVI and 226 with MVI). Significant differences were noted in the cumulative incidence of vaginal delivery 24 hours following insertion between the non-HTNsive and HTNsive groups for both treatments, (57.1% vs. 47.4% (p=0.023) among MVI patients and 39.9% vs. 27.2% (p=0.017) among DVI patients). However, upon adjusting for potential confounders, the estimated relative rates of vaginal delivery among HTNsive vs. non-HTNsive patients was 0.947 (95% CI (0.637, 1.371), p=0.631) and 0.904 (95% CI (0.735, 1.113) p=0.341) within the MVI and DVI sub-groups respectively. Conclusion: After adjustment for confounders, such as BMI, baseline modified Bishop score and gestational age, time-to-event outcomes for induction of labor using MVI or DVI in HTNsive women are not significantly different from non-HTNsive women