Objective-To describe contemporary cesarean delivery practice in the U.S.Study Design-Consortium on Safe Labor collected detailed labor and delivery information from 228,668 electronic medical records from 19 hospitals across the U.S., 2002 -2008. Results-The overall cesarean delivery rate was 30.5%. 31.2% of nulliparas were delivered by cesarean section. Prelabor repeat cesarean delivery due to a previous uterine scar contributed 30.9% of all cesarean sections. 28.8% of women with a uterine scar had a trial of labor and the success rate Corresponding author: Dr. Jun Zhang, Epidemiology Branch, NICHD, National Institutes of Health, Building 6100, Room 7B03, Bethesda, MD 20892, Tel: 301-435-6921, zhangj@mail.nih.gov. Publisher's Disclaimer: This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. NIH Public Access Author ManuscriptAm J Obstet Gynecol. Author manuscript; available in PMC 2011 October 1. NIH-PA Author ManuscriptNIH-PA Author Manuscript NIH-PA Author Manuscript was 57.1%. 43.8% women attempting vaginal delivery had induction. Half of cesarean for dystocia in induced labor were performed before 6 cm of cervical dilation.Conclusion-To decrease cesarean delivery rate in the U.S., reducing primary cesarean delivery is the key. Increasing VBAC rate is urgently needed. Cesarean section for dystocia should be avoided before the active phase is established, particularly in nulliparas and in induced labor.

Thyroid diseases were associated with obstetrical, labor, and delivery complications. Although we lacked information on treatment during pregnancy, these nationwide data suggest either that there is a need for better thyroid disease management during pregnancy or that there may be an intrinsic aspect of thyroid disease that causes poor pregnancy outcomes.

Objective To assess neonatal and maternal outcomes when when the second stage of labor was prolonged according to American College of Obstetricians and Gynecologists guidelines. Methods Electronic medical record data from a retrospective cohort (2002–2008) from 12 U.S. clinical centers (19 hospitals), including 43,810 nulliparous and 59,605 multiparous singleton deliveries ≥ 36 weeks, vertex presentation, who reached 10 cm cervical dilation were analyzed. Prolonged second stage was defined as: nulliparous women with epidural > 3 hours, without > 2 hours; multiparous women with epidural > 2 hours, without > 1 hour. Maternal and neonatal outcomes were compared and adjusted odds ratios calculated controlling for maternal race, BMI, insurance, and region. Results Prolonged second stage occurred in 9.9% and 13.9% of nulliparous and 3.1% and 5.9% of multiparous women, with and without an epidural, respectively. Vaginal delivery rates with prolonged second stage compared to within guidelines were 79.9% versus 97.9% and 87.0% versus 99.4% for nulliparous women with and without epidural, respectively, and 88.7% versus 99.7% and 96.2% versus 99.9% for multiparous women with and without epidural, respectively (P<.001 for all comparisons). Prolonged second stage was associated with increased chorioamnionitis and third-degree or fourth-degree perineal lacerations. Neonatal morbidity with prolonged second stage included sepsis in nulliparous women [with epidural: 2.6% versus 1.2% (AOR 2.08; 95%CI 1.60–2.70); without epidural: 1.8% versus 1.1% (AOR 2.34; 95%CI 1.28–4.27)]; asphyxia in nulliparous women with epidural [0.3% versus 0.1%, AOR 2.39; 95% CI 1.22–4.66]; and perinatal mortality without epidural [0.18% versus 0.04% for nulliparous women (AOR 5.92; 95% CI 1.43–24.51)], and 0.21% versus 0.03% for multiparous women (AOR 6.34; 95%CI 1.32–30.34)]. However, among the offspring of women with epidurals whose second stage was prolonged (3,533 nulliparous and 1,348 multiparous women), there were no cases of hypoxic ischemic encephalopathy or perinatal death. Conclusions Benefits of increased vaginal delivery should be weighed against potential small increases in maternal and neonatal risks with prolonged second stage.

Objective Attention for recurrent preterm delivery has primarily focused on spontaneous subtypes with less known about indicated preterm delivery. Study Design In a retrospective cohort of consecutive pregnancies among 51,086 women in Utah (2002–2010), binary relative risk regression was performed to examine risk of preterm delivery < 37 weeks (PTD) in the second observed delivery by PTD in the first, adjusting for maternal age, race/ethnicity, prepregnancy body mass index, insurance, smoking, alcohol and/or drug use, and chronic disease. Analyses were also performed stratified by prior preterm delivery subtype: spontaneous, indicated, or no recorded indication. Results There were 3,836 (7.6%) women that delivered preterm in the first observed pregnancy, of which 1,160 (30.7%) repeated in the second. Rate of recurrent PTD was 31.6% for prior spontaneous, 23.0% for prior indicated delivery, and 27.4% for prior elective delivery. Prior spontaneous PTD was associated with RR 5.64 (95% CI 5.27–6.05) of subsequent spontaneous and RR 1.61 (95% CI 0.98–2.67) of subsequent indicated PTD. Prior indicated PTD was associated with RR 9.10 (95% CI 4.68–17.71) of subsequent indicated and RR 2.70 (2.00–3.65) of subsequent spontaneous PTD. Conclusions Prior indicated PTD was strongly associated with subsequent indicated PTD and with increased risk for subsequent spontaneous PTD. Spontaneous PTD had the highest rate of recurrence. Some common pathways for different etiologies of preterm delivery are likely, and indicated PTD merits additional attention for recurrence risk.

Objective To describe details of labor induction, including precursors and methods, and associated vaginal delivery rates. Study Design A retrospective cohort study of 208,695 electronic medical records from 19 hospitals across the United States, 2002–2008. Results Induction occurred in 42.9% of nulliparas and 31.8% of multiparas and elective or no recorded indication for induction at term occurred in 35.5% and 44.1%, respectively. Elective induction at term in multiparas was highly successful (vaginal delivery 97%) compared to nulliparas (76.2%). For all precursors, cesarean delivery was more common in nulliparas in the latent compared to active phase of labor. Regardless of method, vaginal delivery rates were higher with a ripe versus unripe cervix, particularly for multiparas (86.6 – 100%). Conclusions Induction of labor was a common obstetric intervention. Selecting appropriate candidates and waiting longer for labor to progress into the active phase would make an impact on decreasing the national cesarean delivery rate.

Objective To characterize potentially modifiable risk factors for third- or fourth-degree perineal lacerations and cervical lacerations in a contemporary U.S. obstetric practice. Methods The Consortium on Safe Labor collected electronic medical records from 19 hospitals within 12 institutions (228,668 deliveries from 2002 to 2008). Information on patient characteristics, prenatal complications, labor and delivery data, and maternal and neonatal outcomes were collected. Only women with successful vaginal deliveries of cephalic singletons at 34 weeks of gestation or later were included; we excluded data from sites lacking information about lacerations at delivery and deliveries complicated by shoulder dystocia; 87,267 and 71,170 women were analyzed for third- or fourth-degree and cervical lacerations, respectively. Multivariable logistic regressions were used to adjust for other factors. Results Third- or fourth-degree lacerations occurred in 2,516 women (2,223 nulliparous [5.8%], 293 [0.6%] multiparous) and cervical lacerations occurred in 536 women (324 nulliparous [1.1%], 212 multiparous [0.5%]). Risks for third or fourth-degree lacerations included nulliparity (7.2-fold risk), being Asian or Pacific Islander, increasing birth weight, operative vaginal delivery, episiotomy, and longer second stage of labor. Increasing body mass index was associated with fewer lacerations. Risk factors for cervical lacerations included young maternal age, vacuum vaginal delivery, and oxytocin use among multiparous women, and cerclage regardless of parity. Conclusion Our large cohort of women with severe obstetric lacerations reflects contemporary obstetric practices. Nulliparity and episiotomy use are important risk factors for third- or fourth-degree lacerations. Cerclage increases the risk for cervical lacerations. Many identified risk factors may not be modifiable.

OBJECTIVE To delineate adverse obstetric and neonatal outcomes as well as indications for cesarean delivery by maternal age in a contemporaneous large national cohort. METHODS This was a retrospective analysis of electronic medical records from 12 centers and 203,517 (30,673 women aged 35 years or older) women with singleton gestations stratified by maternal age. Logistic regression was performed to investigate maternal and neonatal outcomes for each maternal age strata (referent group, age 25.0–29.9 years), adjusting for race, parity, body mass index, insurance, pre-existing medical conditions, substance and tobacco use, and site. Documented indications for cesarean delivery were analyzed. RESULTS Neonates born to women aged 25.0–29.9 years had the lowest risk of birth weight less than 2,500 g (7.2%; P<.001), admission to neonatal intensive care unit (11.5%; P<.001), and perinatal mortality (0.7%; P<.001). Hypertensive disorders of pregnancy were higher in women aged 35 years or older (cumulative rate 8.5% compared with 7.8%; 25.0–29.9 years; P<.001). Previous uterine scar was the leading indication for cesarean delivery in women aged 25.0 years or older (36.9%; P<.001). For younger women, failure to progress or cephalopelvic disproportion (37.0% for those younger than age 20.0 years and 31.1% for those aged 20.0– 24.9-years; P<.001) and nonreassuring fetal heart tracing (28.7% for those younger than 20.0 years and 21.2% for those aged 20.0–24.9-years; P<.001) predominated as indications. Truly elective cesarean delivery rate was 20.2% for women aged 45.0 years or older (adjusted odds ratio 1.85 [99% confidence interval 1.03–3.32] compared with the referent age group of 25.0–29.9 years). CONCLUSIONS Maternal and obstetric complications differed by maternal age, as did rates of elective cesarean delivery. Women aged 25.0–29.9 years had the lowest rate of serious neonatal morbidity.

Objectives Previous studies have investigated the consequences of late preterm birth between 34 – 36 weeks gestation, but less is known about the “indicated” reasons and potential differences in neonatal outcomes from various delivery indications. . In singletons, we characterized precursors for late preterm birth and incidences of neonatal morbidities and perinatal mortality by gestational age and precursor. Methods Using retrospective observational data, we compared 15,136 gestations born late preterm to 170,593 deliveries between 37 0/7 and 41 6/7 weeks. We defined the following categories of precursors for late preterm delivery: “spontaneous labor”, “premature rupture of the membranes (preterm PROM)”, “indicated” delivery and “unknown.” Incidences of neonatal morbidities were calculated according to category of precursor stratified by gestational age at delivery. Neonatal morbidities and mortality associated with potentially avoidable deliveries (e.g. “soft” precursors or elective) were compared between late preterm births and neonates born at 37 – 40 weeks. Results Late preterm birth comprised 7.8% of all births and 65.7% of preterm births. Percentages of precursors were 29.8% spontaneous labor, 32.3% preterm PROM, 31.8% indicated and 6.1% unknown. Different precursors for delivery were associated with varying incidences of neonatal morbidity. One in 15 neonates delivered late preterm for “soft” or elective precursors, and neonatal morbidity and mortality were increased compared to delivery ≥ 37 weeks for these same indications Conclusion A significant number of late preterm births were potentially avoidable Elective deliveries should be postponed until 39 weeks' gestation. More prospective data is needed to guide which indications can be managed expectantly.