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296: Ultrasonographic cervical length versus Bishop score for preinduction cervical assessment in parous women: a randomized clinical trial
Poster Session II
Clinical Obstetrics, Diabetes, Labor, Medical-Surgical-Disease, Physiology/Endocrinology, Prematurity
difference by BMI category (p⫽0.5). Among nulliparas, there is increased risk of CD for OB vs. NW after controlling for age and race (aOR 2.0 [1.0-3.7], p⫽0.04). This risk is not seen for OW vs. NW (OR 1.3 [0.8-2.4], p⫽0.3). In nulliparas with CD, there was a difference in CD rate for failed IOL among groups (OB-27%, OW-32%, NW-6%, p⫽0.001). In multiparas, BMI category was not associated with CD (p⫽0.6). CONCLUSION: Our study demonstrates no difference in latent LT for women undergoing IOL, regardless of parity. However, there is an increased risk of CD and CD for failed IOL in OB nulliparas undergoing IOL. Further research is needed to understand labor curves in OB women to optimize labor and delivery management and minimize unnecessary CD.
296 Ultrasonographic cervical length versus Bishop score for preinduction cervical assessment in parous women: a randomized clinical trial Aeli Ryu1, Kyo Hoon Park1, Sung Youn Lee1, Eun Ha Jeong1, Kyung Joon Oh1, Ahra Kim1 1 Seoul National University College of Medicine, Seoul National University Bundang Hospital, Department of Obstetrics and Gynecology, Seongnam-si, Republic of Korea
OBJECTIVE: To compare the ultrasonographic cervical length with the Bishop score in determining the administration of prostaglandin for preinduction cervical ripening in parous women at term. STUDY DESIGN: This trial enrolled 154 parous women at term presenting for labor induction with a singleton, cephalic fetus and intact membranes. Patients were randomly assigned to receive prostaglandin for preinduction cervical ripening based on the Bishop score or the sonographically-measured cervical length. An unfavorable cervix to be treated with prostaglandin for preinduction cervical ripening was defined as either a Bishop score ⱕ4 or a cervical length ⱖ28 mm. The primary outcome measures were induction success (defined as an ability to achieve the active phase of labor) and the percentage of patients treated with prostaglandin for preinduction cervical ripening. RESULTS: Baseline demographic characteristics, including gestational age, cervical length, and Bishop score were similar between the two groups. While 74% of parous women in the Bishop score group (n⫽77) received prostaglandin, only 34% of those in the transvaginal ultrasound group (n⫽77) received prostaglandin (P ⬍0.0001). The rates of induction success and cesarean delivery, and the induction to delivery intervals were similar in the two groups. CONCLUSION: With the suggested cutoff values of a Bishop score ⱕ4 and a cervical length ⱖ28 mm for choosing candidates for pre-induction cervical ripening, the use of sonographic cervical length, compared with the Bishop score for assessing the cervix prior to the induction of labor, can reduce the need for prostaglandin administration by approximately 50% without adversely affecting the outcome of induction in parous women at term. (ClinicalTrials.gov number, NCT01317823)
297 Birthweight difference from previous pregnancies is an independent risk factor for shoulder dystocia Aharon Tevet1, Shunit Armon1, Rachel Michaelson Cohen1, Rivka Farkash1, Sorina Grisaro Granovsky1, Arnon Samueloff1 1 Shaare Zedek M.C. Hebrew University, Obstetrics & Gynecology, Jerusalem, Israel
OBJECTIVE: Objective: To determine whether a birthweight difference from previous pregnancies is associated with the occurrence of shoulder dystocia (SD) in the index pregnancy. STUDY DESIGN: A case control retrospective study. All cases of SD between May 2005 and July 2011 were identified and stratified according to birthweight (100 gram intervals). Cases of Primiparity, Diabetes mellitus, intrauterine fetal death, preterm deliveries and multifetal gestation were excluded. Each Shoulder Dystocia case was matched with 4 cases of uncomplicated vaginal delivery according to birthweight and use of instrumental delivery.Birthweight difference was
S134
www.AJOG.org
defined as the difference between the birthweight in the index pregnancy and the maximal birthweight in previous pregnancies. Cases of SD were compared to controls for birthweight difference (as defined), birthweight, parity, maternal age, epidural anesthesia and use of instrumental delivery. Statistical analysis: descriptive, t test, chi-square, Pearson coefficient, Fisher’s Exact test as appropriate and logistic regression model. RESULTS: During the study period 73,871 births were attended. 133 cases of SD that met the entry criteria were identified, included in the study and matched to 514 controls similar in fetal birthweight (100 gram intervals) and use of instrumental delivery. The study and control groups did not differ in fetal birthweight, parity, maternal age, epidural anesthesia and use of instrumental delivery. The mean birthweight difference from previous deliveries in the SD group was 415 grams and 148 grams in the control group (p⬍0.0001). An Increase in birthweight of more than 500 grams from the maximal PREVIOUS birthweight was positively associated with the risk of shoulder dystocia (OR 3.42 CI 2.28-5.15). This association is independent of birthweight and other characteristics analyzed. CONCLUSION: A large fetal birthweight difference from previous pregnancies is positively associated with and may be a risk factor for shoulder dystocia.
298 Cesarean for first stage arrest: modern practice does not follow contemporary labor patterns Amanda Trudell1, Anthony Odibo1, Methodius Tuuli1, Kimberly Roehl1, George Macones1, Alison Cahill1 1 Washington University in St. Louis, Obstetrics and Gynecology, St. Louis, MO
OBJECTIVE: The rise in the cesarean delivery (CD) rate has become a public health concern. Recent evidence suggests a significant proportion of primary CDs are performed for arrest of dilation. We sought to investigate labor patterns preceding CD for arrest in the first stage of labor. STUDY DESIGN: We performed a retrospective cohort study of consecutive births via CD over a four year period. We analyzed the labor patterns of women who underwent CD for arrest in the first stage of labor. Mean cervical dilation at arrest and mean duration of time spent at the arrested dilation with 95% CI were calculated. Duration of arrest was defined as time of no appreciable change (⬍ 1cm) prior to delivery. A stratified analysis was performed based on parity. RESULTS: Of 549 women who underwent CD for arrest in the first stage, 320 (58%) were delivered prior to 6 cm of cervical dilation (active first stage). The average duration of arrest at 6 cm was 5.0 hours (95% CI 4.8-7.1). In the stratified analysis, a majority of both nulliparous and multiparous women underwent CD at or before 6 cm (55% and 63%). The duration of arrest in primiparous and multiparous women at 6 cm was 5.0 hours (95% CI 4.7-6.4) and 4.2 hours (95% CI 3.4-10.1), respectively. The shortest duration of arrest prior to 6 cm in primiparous and multiparous women occurred at 2 cm and 3 cm (4.3 hours [95% CI 0.1-27.0] and 2.0 hours [95% CI 1.3-7.0]), respectively. CONCLUSION: According to contemporary labor patterns, active labor does not begin until after 6 cm dilation and women may take up to 10 hours to advance 1 cm of dilation before reaching 6 cm. We report a large proportion of laboring women undergo CD for arrest of dilation prior to active labor, and the median time at the dilation of arrest is much shorter than what most women require to advance in the latent phase. The potential to reduce the unyielding rise in the CD rate exists if obstetricians adopt contemporary labor curves and have the patience to utilize these new standards.
American Journal of Obstetrics & Gynecology Supplement to JANUARY 2013
Clinical Obstetrics, Diabetes, Labor, Medical-Surgical-Disease, Physiology/Endocrinology, Prematurity
difference by BMI category (p⫽0.5). Among nulliparas, there is increased risk of CD for OB vs. NW after controlling for age and race (aOR 2.0 [1.0-3.7], p⫽0.04). This risk is not seen for OW vs. NW (OR 1.3 [0.8-2.4], p⫽0.3). In nulliparas with CD, there was a difference in CD rate for failed IOL among groups (OB-27%, OW-32%, NW-6%, p⫽0.001). In multiparas, BMI category was not associated with CD (p⫽0.6). CONCLUSION: Our study demonstrates no difference in latent LT for women undergoing IOL, regardless of parity. However, there is an increased risk of CD and CD for failed IOL in OB nulliparas undergoing IOL. Further research is needed to understand labor curves in OB women to optimize labor and delivery management and minimize unnecessary CD.
296 Ultrasonographic cervical length versus Bishop score for preinduction cervical assessment in parous women: a randomized clinical trial Aeli Ryu1, Kyo Hoon Park1, Sung Youn Lee1, Eun Ha Jeong1, Kyung Joon Oh1, Ahra Kim1 1 Seoul National University College of Medicine, Seoul National University Bundang Hospital, Department of Obstetrics and Gynecology, Seongnam-si, Republic of Korea
OBJECTIVE: To compare the ultrasonographic cervical length with the Bishop score in determining the administration of prostaglandin for preinduction cervical ripening in parous women at term. STUDY DESIGN: This trial enrolled 154 parous women at term presenting for labor induction with a singleton, cephalic fetus and intact membranes. Patients were randomly assigned to receive prostaglandin for preinduction cervical ripening based on the Bishop score or the sonographically-measured cervical length. An unfavorable cervix to be treated with prostaglandin for preinduction cervical ripening was defined as either a Bishop score ⱕ4 or a cervical length ⱖ28 mm. The primary outcome measures were induction success (defined as an ability to achieve the active phase of labor) and the percentage of patients treated with prostaglandin for preinduction cervical ripening. RESULTS: Baseline demographic characteristics, including gestational age, cervical length, and Bishop score were similar between the two groups. While 74% of parous women in the Bishop score group (n⫽77) received prostaglandin, only 34% of those in the transvaginal ultrasound group (n⫽77) received prostaglandin (P ⬍0.0001). The rates of induction success and cesarean delivery, and the induction to delivery intervals were similar in the two groups. CONCLUSION: With the suggested cutoff values of a Bishop score ⱕ4 and a cervical length ⱖ28 mm for choosing candidates for pre-induction cervical ripening, the use of sonographic cervical length, compared with the Bishop score for assessing the cervix prior to the induction of labor, can reduce the need for prostaglandin administration by approximately 50% without adversely affecting the outcome of induction in parous women at term. (ClinicalTrials.gov number, NCT01317823)
297 Birthweight difference from previous pregnancies is an independent risk factor for shoulder dystocia Aharon Tevet1, Shunit Armon1, Rachel Michaelson Cohen1, Rivka Farkash1, Sorina Grisaro Granovsky1, Arnon Samueloff1 1 Shaare Zedek M.C. Hebrew University, Obstetrics & Gynecology, Jerusalem, Israel
OBJECTIVE: Objective: To determine whether a birthweight difference from previous pregnancies is associated with the occurrence of shoulder dystocia (SD) in the index pregnancy. STUDY DESIGN: A case control retrospective study. All cases of SD between May 2005 and July 2011 were identified and stratified according to birthweight (100 gram intervals). Cases of Primiparity, Diabetes mellitus, intrauterine fetal death, preterm deliveries and multifetal gestation were excluded. Each Shoulder Dystocia case was matched with 4 cases of uncomplicated vaginal delivery according to birthweight and use of instrumental delivery.Birthweight difference was
S134
www.AJOG.org
defined as the difference between the birthweight in the index pregnancy and the maximal birthweight in previous pregnancies. Cases of SD were compared to controls for birthweight difference (as defined), birthweight, parity, maternal age, epidural anesthesia and use of instrumental delivery. Statistical analysis: descriptive, t test, chi-square, Pearson coefficient, Fisher’s Exact test as appropriate and logistic regression model. RESULTS: During the study period 73,871 births were attended. 133 cases of SD that met the entry criteria were identified, included in the study and matched to 514 controls similar in fetal birthweight (100 gram intervals) and use of instrumental delivery. The study and control groups did not differ in fetal birthweight, parity, maternal age, epidural anesthesia and use of instrumental delivery. The mean birthweight difference from previous deliveries in the SD group was 415 grams and 148 grams in the control group (p⬍0.0001). An Increase in birthweight of more than 500 grams from the maximal PREVIOUS birthweight was positively associated with the risk of shoulder dystocia (OR 3.42 CI 2.28-5.15). This association is independent of birthweight and other characteristics analyzed. CONCLUSION: A large fetal birthweight difference from previous pregnancies is positively associated with and may be a risk factor for shoulder dystocia.
298 Cesarean for first stage arrest: modern practice does not follow contemporary labor patterns Amanda Trudell1, Anthony Odibo1, Methodius Tuuli1, Kimberly Roehl1, George Macones1, Alison Cahill1 1 Washington University in St. Louis, Obstetrics and Gynecology, St. Louis, MO
OBJECTIVE: The rise in the cesarean delivery (CD) rate has become a public health concern. Recent evidence suggests a significant proportion of primary CDs are performed for arrest of dilation. We sought to investigate labor patterns preceding CD for arrest in the first stage of labor. STUDY DESIGN: We performed a retrospective cohort study of consecutive births via CD over a four year period. We analyzed the labor patterns of women who underwent CD for arrest in the first stage of labor. Mean cervical dilation at arrest and mean duration of time spent at the arrested dilation with 95% CI were calculated. Duration of arrest was defined as time of no appreciable change (⬍ 1cm) prior to delivery. A stratified analysis was performed based on parity. RESULTS: Of 549 women who underwent CD for arrest in the first stage, 320 (58%) were delivered prior to 6 cm of cervical dilation (active first stage). The average duration of arrest at 6 cm was 5.0 hours (95% CI 4.8-7.1). In the stratified analysis, a majority of both nulliparous and multiparous women underwent CD at or before 6 cm (55% and 63%). The duration of arrest in primiparous and multiparous women at 6 cm was 5.0 hours (95% CI 4.7-6.4) and 4.2 hours (95% CI 3.4-10.1), respectively. The shortest duration of arrest prior to 6 cm in primiparous and multiparous women occurred at 2 cm and 3 cm (4.3 hours [95% CI 0.1-27.0] and 2.0 hours [95% CI 1.3-7.0]), respectively. CONCLUSION: According to contemporary labor patterns, active labor does not begin until after 6 cm dilation and women may take up to 10 hours to advance 1 cm of dilation before reaching 6 cm. We report a large proportion of laboring women undergo CD for arrest of dilation prior to active labor, and the median time at the dilation of arrest is much shorter than what most women require to advance in the latent phase. The potential to reduce the unyielding rise in the CD rate exists if obstetricians adopt contemporary labor curves and have the patience to utilize these new standards.
American Journal of Obstetrics & Gynecology Supplement to JANUARY 2013