The impact of occiput posterior fetal head position on the risk of anal sphincter injury in forceps-assisted vaginal deliveries

OBJECTIVE: A forceps-assisted vaginal delivery is a well-recognized risk factor for anal sphincter injury. Some studies have shown that occiput posterior (OP) fetal head position is also associated with an increased risk for third- or fourth-degree lacerations. The objective of this study was to assess whether OP position confers an incrementally increased risk for anal sphincter injury above that present with forceps deliveries. STUDY DESIGN: This was a retrospective cohort study of 588 singleton, cephalic, forceps-assisted vaginal deliveries performed at our institution between January 1996 and October 2003. Maternal demographics, labor and delivery characteristics, and neonatal factors were examined. Statistical analysis consisted of univariate statistics, Student t test, chi2, and logistic regression. RESULTS: The prevalence of occiput anterior (OA) and OP positions was 88.4% and 11.6%, respectively. The groups were similar in age, marital status, body mass index, use of epidural, frequency of inductions, episiotomies, and shoulder dystocias. The OA group had a higher frequency of rotational forceps (16.2% vs 5.9%, P = .03), greater birth weights (3304 +/- 526 g vs 3092 +/- 777 g, P = .004), and a larger percentage of white women (48.8% vs 34.3%, P = .04). Overall, 35% of forceps deliveries resulted in a third- or fourth-degree laceration. Anal sphincter injury occurred significantly more often in the OP group compared with the OA group (51.5% vs 32.9%, P = .003), giving an odds ratio of 2.2 (CI: 1.3-3.6). In a logistic regression model that controlled for occiput posterior position, maternal body mass index, race, length of second stage, episiotomy, birth weight, and rotational forceps, OP head position was 3.1 (CI: 1.6-6.2) times more likely to be associated with anal sphincter injury than OA head position. CONCLUSION: Forceps-assisted vaginal deliveries have been associated with a greater risk for anal sphincter injury. Within this population of forceps deliveries, an OP position further increases the risk of third- or fourth-degree lacerations when compared with an OA position.     

The usefulness of the intrapartum fetal pulse oximetry in anticipating the neonatal outcome

OBJECTIVE: The aim of the study was to evaluate the usefulness of the intrapartum fetal pulse oximetry in anticipating the neonatal outcome. MATERIALS AND METHODS: The saturation of the fetal blood (SpO2) was measured during labor with non-invasive pulse oximeter designed for fetal application. The average, minimum and maximum SpO2 were evaluated separately for the first and the second stage of labor. The average SpO2 of the fetus was compared to neonatal condition assessed by umbilical vein pH, pO2 and pCO2 and according to Apgar score. RESULTS: Twenty patients have been monitored with fetal pulse oximetry. All those patients had normal vaginal delivery. During the first stage of labor, the average fetal SpO2 was 51.94 +/- 8.03%, the minimum SpO2 was 38.35 +/- 9.15%, and the maximum SpO2 was 63.35 +/- 7.75%; in the second stage of labor average fetal SpO2 was 43.82 +/- 7.16%, minimum SpO2 was 34.35 +/- 7.79% and the maximum SpO2 was 50.94 +/- 8.37%. A significant decrease in fetal average and maximum SpO2 occurred from stage I to stage II of labor (average SpO2: 51.94 +/- 8.03% vs. 43.82 +/- 7.16%, p = 0.0002; maximum SpO2: 63.35 +/- 7.75% vs. 50.94 +/- 8.37%, p < 0.00001). The significant correlation between the average SpO2 during the first stage of labor and umbilical vein pH (R = 0.60, p = 0.02) and pO2 (R = 0.54, p = 0.04) was found. No relationship between fetal SpO2 in the first and second stage of labor and Apgar score was observed. CONCLUSIONS: 1. The second stage of labor results in significant decrease in fetal SpO2. 2. The fetal SpO2 > 30% in the first and second stage of labor is related to good neonatal outcome. 3. The fetal SpO2 assessment in first stage of labor seems to be important in newborn's acidosis and hypoxemia predicting.     

Immediate maternal and neonatal effects of forceps and vacuum-assisted deliveries

OBJECTIVE: To estimate the differences in immediate maternal and neonatal effects of forceps and vacuum-assisted deliveries. METHODS: We conducted a medical record review of all forceps and vacuum-assisted deliveries that occurred from January 1, 1998, to August 30, 1999, at Winthrop-University Hospital. Maternal demographics and delivery characteristics were recorded. Maternal outcomes, such as use of episiotomy and presence of lacerations, were studied. Neonatal outcomes evaluated were Apgar scores, neonatal intensive care unit admissions, cephalohematomas, instrument marks and bruising, and caput and molding. RESULTS: Of 508 operative vaginal deliveries, 200 were forceps and 308 were vacuum assisted. Forceps were used more often than vacuum for prolonged second stage of labor (P =.001). There was a higher rate of epidural (P =.02) and pudendal (P <.001) anesthesia, episiotomies (P =.01), maternal third- and fourth-degree perineal (P <.001) and vaginal lacerations (P =.004) with the use of forceps, whereas periurethral lacerations were more common in vacuum-assisted (P =.026) deliveries. More instrument marks and bruising (P <.001) were found in the neonates delivered by forceps, whereas there was a greater incidence of cephalohematomas (P =.03) and caput and molding (P <.001) in the neonates delivered with vacuum. Multivariable logistic regression analysis showed that forceps use was associated with an increase in major perineal and vaginal tears (odds ratio [OR] 1.85; 95% confidence interval [CI] 1.27, 2.69; P =.001), an increase in instrument marks and bruising (OR 4.63; 95% CI 2.90, 7.41; P <.001) and a decrease in cephalohematomas (OR 0.49; 95% CI 0.29, 0.83; P =.007) compared with the vacuum. CONCLUSIONS: Maternal injuries are more common with the use of forceps. Neonates delivered with forceps have more facial injuries, whereas neonates delivered with vacuum have more cephalohematomas. LEVEL OF EVIDENCE: II-3     

Vacuum assisted delivery in Ecuador for prolonged second stage of labor: maternal-neonatal outcome.

BACKGROUND: In South America, and particularly Ecuador, cesarean section rates have risen markedly over the past five years. The associated increases in maternal morbidity and healthcare costs indicate the need for alternative strategies. Operative vaginal delivery is minimally utilized in Ecuador, as neither vacuum nor forceps have been available. OBJECTIVE: As vacuum delivery was recently introduced to our clinical service, we sought to examine our initial experiences (i.e., maternal and neonatal outcome) with operative vaginal delivery for prolonged second stage of labor. METHODS: Following an initial educational program at the Enrique C. Sotomayor Obstetrics and Gynecology Hospital, Guayaquil, Ecuador, vacuum extraction cups (Mityvac, Cooper Surgical) were offered to laboring women with term singleton gestations and cephalic presentations no higher than +3 station. Maternal and neonatal data were analyzed. RESULTS: During the study period, 100 vacuum applications were performed on laboring women complicated with prolonged second stage of labor. Mean maternal age was 23.8 +/- 6.4 years (range 14-41 years) with 57% of patients nulliparous. Left anterior and right posterior fetal positions were the most frequent (85% and 11%, respectively). Maternal complications included need for blood transfusion (1%), shoulder dystocia (1%) and perineal tears (first degree 6%, second degree 5%). Vaginal delivery was successful in 97% of cases. Among neonates, the average weight was 3149 +/- 410 g, with 10% neonates small for gestational age and 5% large for gestational age. Only 1% of infants presented an Apgar score <7 at 5 min. There were no scalp lacerations, cephalohematomas, or subgaleal bleeds. CONCLUSIONS: In this initial observational study, vacuum extraction for prolonged second stage was safe and effective. We propose that the introduction of operative vaginal delivery to developing countries will mitigate rising cesarean section rates.     

Uterine contractility in women whose fetus is delivered in the occipitoposterior position

OBJECTIVE: Most fetuses in the occipitoposterior position rotate spontaneously after striking the pelvic floor. The increased prevalence of prolonged labor, operative delivery, and oxytocin augmentation in women with an occipitoposterior fetal position seems consistent with decreased uterine contractility. We sought to test the hypothesis that women with a persistent occipitoposterior fetal position have inadequate intrauterine pressure. STUDY DESIGN: Intrauterine pressure was measured prospectively electronically in 94 women whose labor pain was controlled by patient-requested epidural analgesia. Eleven women (12%) were delivered as a persistent occipitoposterior fetal position. In a nested case-control study, these women were compared with 22 women who were delivered as an occipitoanterior fetal position who were matched for age, parity, gestational age, cervical examination at study enrollment, and body mass index. The intrauterine pressure measurements were initiated during the first stage of labor and continued throughout the entire labor process. Women were encouraged in the second stage of labor, after a period of recording baseline contractility, to push using a standardized Valsalva maneuver once the vertex reached the +2 station. The area under the intrauterine pressure curve (integral) was used to estimate uterine contractility and expulsive performances. RESULTS: Five women (45%) in the occipitoposterior group required operative delivery. The average duration of the second stage of labor in the occipitoposterior group was 91.4 +/- 23.2 minutes compared with 51.7 +/- 6.6 minutes in the occipitoanterior fetal position (P =.04). Ninety percent of women in the occipitoposterior group required oxytocin, compared with 59% of the women in the occipitoanterior group (P =.11). There were no differences in uterine contractility between occipitoposterior and occipitoanterior groups during either the first stage of labor (integral mean +/- SEM: occipitoposterior [1685.3 +/- 194.6 mm Hg. s] vs occipitoanterior fetal position [1700.8 +/- 128.9 mm Hg. s, P =.98]) or second stages of labor (occipitoposterior [1952.6 +/- 186.5 mm Hg. s] vs occipitoanterior fetal position [1740.8 +/- 104.3 mm Hg. s, P =.46]). Further, there were no significant differences in pushing performances between the occipitoposterior and occipitoanterior groups (Valsalva maneuver: occipitoposterior 2864.9 +/- 328.8 mm Hg. s] vs occipitoanterior [2898.6 +/- 222.2 mm Hg. s, P =.90]). CONCLUSION: Women who were delivered as a persistent occipitoposterior fetal position do not have lower intrauterine pressure levels immediately before or during the second stage of labor.     

Maternal and neonatal effects of outlet forceps delivery compared with spontaneous vaginal delivery in term pregnancies

Previous retrospective studies have suggested that the prophylactic use of outlet forceps has a beneficial impact on the neonate because it shortens the second stage of labor and decreases the incidence of neonatal hypoxia. The purpose of this study was to compare the immediate maternal and neonatal effects of outlet forceps delivery (N = 165) with spontaneous vaginal delivery (N = 168) in term parturients. Subjects were randomized to the study or control group immediately before delivery. There were 88 nulliparas and 77 multiparas in the forceps delivery group and 90 and 78, respectively, who delivered spontaneously, a nonsignificant difference. There were no significant differences in gestational age, parity, infant birth weight, length of the first and second stages of labor, use of conduction (continuous epidural) anesthesia, decrease in hematocrit values, Apgar scores, or umbilical arterial pH values between the forceps and spontaneous delivery groups. Seventeen infants in the forceps group and 16 in the control group had cephalhematoma, facial bruising, subconjunctival hemorrhage, or scalp abrasion (not significant). No neonate had fractures, nerve palsies, or intracranial hemorrhage (determined by cranial ultrasound). In the nulliparous population, significant differences were found in the use of episiotomy (93 versus 78%) and the incidence of deep perineal lacerations (24 versus 10%) with forceps compared with spontaneous delivery, respectively (P less than .05). No significant differences between the groups were found in multiparas. We conclude that the use of outlet forceps in patients with uncomplicated labor has no immediate effect on the neonate. Furthermore, outlet forceps delivery does not significantly shorten the second stage of labor and is associated with an increased incidence of maternal perineal trauma.     

脐血乳酸水平及胎心监护图形预测胎儿窘迫的价值

目的　探讨新生儿脐动脉血乳酸水平及胎心监护图形预测胎儿窘迫的价值。方法　测定 73例胎心监护图形为不良图形 (胎心基线异常、重度变异减速、轻度变异减速、心动过速 )的新生儿(病例组 )和 118例产前无胎儿窘迫征象 ,出生后 1分钟Apgar评分≥ 9分的新生儿 (对照组 )出生后脐动脉血乳酸水平。结果　病例组中产钳助产率明显高于对照组 (P <0 0 1) ,顺产率低于对照组 (P<0 0 1)。病例组中 ,胎心重度变异减速多发于第二产程 ;胎心基线异常的新生儿Apgar评分≤ 7分的发生率高于重度变异减速、轻度变异减速、心动过速的新生儿 (P <0 0 5 )。病例组中 ,胎心基线异常者脐动脉血乳酸水平为 (4 5 5± 0 2 3 )mmol/L ;重度变异减速者为 (3 84± 0 40 )mmol/L ,出现以上两种图形的新生儿脐动脉血乳酸水平均明显高于对照组 (P <0 0 1)。轻度变异减速者脐动脉血乳酸水平为 (2 63± 0 3 2 )mmol/L ;心动过速者脐动脉血乳酸水平为 (2 5 5± 0 46)mmol/L。并且轻度变异减速与心动过速者脐动脉血乳酸水平与对照组比较 ,差异无显著性 (P >0 0 5 )。结论　测定新生儿脐动脉血乳酸水平是一种有效、准确的诊断胎儿窘迫的方法。胎心基线异常、重度变异减速与胎儿窘迫的发生密切相关 ;轻度变异减速、心动过速与胎     

Clinical and sonographic fetal weight estimates in active labor with ruptured membranes

OBJECTIVE: To determine and compare the accuracy of clinical and sonographic estimates of fetal weight (EFW) in active labor with ruptured membranes. STUDY DESIGN: Clinical and sonographic EFWs were obtained on 107 term patients in active labor, with cervical dilatation of 4 cm or more and ruptured membranes. Accuracy of birth weight was determined by calculating percentage error, absolute percentage error and ratio of estimates within 10% of actual birth weight for all stages of labor. Statistical analysis was by paired t test, Wilcoxon sign test, chi 2 test and Mann-Whitney U test; P < .05 was considered significant. RESULTS: Absolute percentage errors were lower by the sonographic method at all stages. Except for the second stage of labor, the rates of birth weight +/- 10% were higher with the sonographic method than with the clinical method (83.17% vs. 60.75% and 84.9% vs. 63.44%, respectively). Estimations performed in the first stage were more accurate than in the second stage with both methods (absolute error of 7.82 +/- 5.5 vs. 12.38 +/- 4.9 for clinical and 5.44 +/- 5.99 vs. 9.08 +/- 3.19 for sonographic). CONCLUSION: During active labor with ruptured membranes, sonographic EFWs are more accurate than clinical estimations. The accuracy of both methods is reduced during the second stage of labor.     

Pregnancy outcome in women with preterm labor symptoms without cervical change

OBJECTIVE: This study was undertaken to determine pregnancy outcome in women who have preterm labor symptoms without cervical change according to fetal fibronectin status. STUDY DESIGN: Patients who were examined at the obstetric emergency department with symptoms of preterm labor but without cervical change underwent fetal fibronectin collection. Pregnancy outcome and fetal fibronectin results were analyzed after delivery. RESULTS: Of the 235 patients sampled, 20% (n = 48) had positive fetal fibronectin results. The mean +/- SD gestational age at delivery was lower in women with positive fetal fibronectin results (34.2 +/- 4.1 vs 37.7 +/- 2.3 weeks; P <.001); these women were more likely to deliver preterm as a result of preterm labor than women with other obstetric indications (46% vs 19%; P <.001). Infants born to these women demonstrated lower birth weight (2317 +/- 895 g vs 2877 +/- 557 g; P =.003), were more likely to be admitted to the neonatal intensive care unit (42% vs 14%; P <.001), and were more likely to die in the neonatal period (11% vs 0%; P <.001). CONCLUSION: Patients with symptoms of preterm labor but without cervical change who have negative fetal fibronectin results are less likely to deliver preterm. Therefore in women with symptoms but without cervical change fetal fibronectin should be considered for risk assessment.     

Neonatal acidosis and method of delivery

Seven hundred and four women who had a forceps termination (177 elective, 293 indicated low, and 234 indicated midforceps) of labor over 24 months were compared with 303 spontaneous and 111 cesarean deliveries over the same time period. There was no significant difference between indicated low or midforceps either for fetal distress or arrest of descent with regard to fetal acidosis (pH less than 7.20), one- or five-minute Apgar scores less than 7, fetal trauma, or neurologic deficit at discharge. Fourteen percent of indicated forceps for arrest of descent had neonatal acidosis, versus 8% of cesarean sections for cephalopelvic disproportion (P = NS), and 23% of indicated forceps for fetal distress had acidosis, versus 33% of cesarean sections (P = not significant). There was no significant difference either in the incidence of acidosis or in low Apgar scores in neonates delivered by elective low forceps compared with those born by spontaneous vaginal delivery. The only significant differences in midforceps versus low forceps were between maternal pre- and postdelivery hematocrits (P less than .0001) and vaginal lacerations (P less than .0001). The authors' data support the continued usage of indicated low and selected midforceps operations.     

Neonatal acidemia with trial of labor among parturients with prior cesarean delivery: a case-control study

OBJECTIVE: To determine the risk factors for neonatal acidemia with trial of labor among parturients with a prior cesarean delivery. METHODS: From a prospectively collected database on all parturients attempting a trial of labor, newborns with umbilical arterial pH < 7.15 were selected as cases and the controls (1:4) were the next four patients who delivered nonacidotic (pH > or = 7.15) neonates. Exclusion criteria were no prior cesarean delivery, anomalous fetus, and nonavailability of umbilical arterial blood gas analysis. Student's t-test, chi2, and Fisher's exact tests were utilized and odds ratio (OR) and 95% confidence intervals (CI) were calculated. P < 0.05 was considered significant. RESULTS: The frequency of neonatal acidemia among patients undergoing trial of labor was 12% (28/234). The cases and controls (n = 112) were similar (P > 0.05) with regards to maternal age, frequency of more than one prior cesarean delivery (11% vs. 8%), gestational age, cervical exam on admission (3.0 +/- 1.5 vs. 3.4 +/- 1.7 cm), usage of oxytocin, and duration of first or second stage of labor. The mean birthweight was significantly higher among acidotic (3,758 +/- 670 g) than nonacidotic (3,470 +/- 545 g; P = 0.018) newborns. Compared to the controls, the cases had a significantly higher frequency of unsuccessful trial of labor (19% vs. 50%; OR: 4.09; 95% CI: 1.70, 9.82) and separation of the uterine scar (0.8% vs. 14%; OR: 18.50; 95% CI: 1.98, 173.05). CONCLUSIONS: Acidotic newborns with trial of labor tend to be heavier. Parturients have a failed attempt at vaginal birth after cesarean, and have separation of the uterine scar during labor.     

Fetal blood saturation during the 1st and 2nd stage of labor and its relation to the neonatal outcome

OBJECTIVE: The aim of this study was to evaluate fetal blood oxygenation (SpO(2)) by means of continuous pulse oximetry during labor and its relation to the neonatal outcome. MATERIALS AND METHODS: Fetal SpO(2) was measured continuously during labor with a noninvasive pulse oximetry for fetal application. The average, minimum and maximum SpO(2) levels were evaluated separately for the 1st and 2nd stage of labor. The average SpO(2) of the fetus was compared to the neonatal outcome assessed by the levels of pH, pO(2) and pCO(2) in the fetus' umbilical blood and to the Apgar score. RESULTS: Twenty-eight patients were monitored by fetal pulse oximetry. All the patients had normal, vaginal delivery. During the 1st stage of labor, the average fetal SpO(2) was 51.78 +/- 8.00%, the minimum SpO(2) level was 37.61 +/- 9.86%, and the maximum level of SpO(2) was 63.82 +/- 7.37%; in the 2nd stage of labor, the average SpO(2) level was 44.91 +/- 8.28%, the minimum level was 35.00 +/- 9.22%, and the maximum SpO(2) was 52.30 +/- 9.36%. A significant decrease in the fetal average and maximum SpO(2) levels was observed between the 1st and the 2nd stages of labor (the average SpO(2) was 51.78 +/- 8.00% vs. 44.91 +/- 8.28%, p = 0.00029; the maximum SpO(2) was 63.82 +/- 7.37% vs. 52.30 +/- 9.36%, p < 0.00001). A significant correlation between the average SpO(2) level during the 1st and 2nd stage of labor and the Apgar score at the first minute of outcome was observed (R = 0.43, p = 0.031). No relationship between the fetal SpO(2) during the 1st and the 2nd stage of labor and the pH, pCO(2), and pO(2) in the fetal umbilical blood were observed. CONCLUSIONS: During the 2nd stage of labor, a significant decrease in the fetus' SpO(2) can be observed. The fetus' SpO(2) level >30% in the 1st and 2nd stage of labor was related to the good neonatal outcome. The assessment of the fetal SpO(2) during the 1st stage of labor seems to be important in predicting neonatal outcome.     

Maternal and neonatal outcomes in patients with a prolonged second stage of labor

OBJECTIVE: To determine risk factors for a prolonged second stage of labor and evaluate the maternal and neonatal outcomes of such pregnancies. METHODS: We reviewed all 7818 patients who delivered at the University of Illinois at Chicago from 1996 to 1999. Excluding nonvertex and multiple gestations, 6791 reached the second stage. Group 1 (n = 6259) consisted of patients with a second stage of 120 minutes or less; group 2, greater than 120 minutes (n = 532 [7.8%]); group 2A, 121-240 minutes (n = 384 [5.7%]); and group 2B, greater than 240 minutes (n = 148 [2.2%]). We compared pregnancy outcomes for these groups with respect to maternal and neonatal morbidity factors using chi(2), Student t, and Wilcoxon rank-sum tests (significance, P <.05). RESULTS: Vaginal delivery rates were 98.7% (group 1), 84.0% (group 2), 90.2% (group 2A), and 65.5% (group 2B). Group 2 had higher rates of perineal trauma, episiotomy usage, chorioamnionitis, postpartum hemorrhage, and operative vaginal delivery than group 1 (P <.001, all comparisons). Group 2B had higher rates of episiotomy usage, operative vaginal deliveries, and perineal trauma than group 2A (P <.001, all comparisons). The neonatal morbidity rates were similar for the three groups. Diabetes, preeclampsia (P <.023), macrosomia, nulliparity, chorioamnionitis, oxytocin usage, and labor induction were each independently associated with an increased risk of a prolonged second stage (all but preeclampsia, P <.001). CONCLUSION: A prolonged second stage is associated with a high rate of vaginal delivery, but a high rate of maternal, though not neonatal, morbidity was observed. Certain antenatal and intrapartum conditions are associated with a prolonged second stage of labor.     

Risk factors for arrest of descent during the second stage of labor.

OBJECTIVE: To define obstetrical risk factors for arrest of descent during the second stage of labor and to determine perinatal outcome. STUDY DESIGN: All singleton, vertex, term deliveries with an unscarred uterus, between the years 1988 and 1999 were included. Univariable and multivariable analysis were performed to investigate independent risk factors associated with arrest of descent during the second stage of labor and the perinatal outcome. RESULTS: The study included 93266 deliveries, of these 1545 (1.7%) were complicated with arrest of descent during the second stage of labor. Using a multivariable analysis, the following obstetric risk factors were found to be significantly associated with arrest of descent: nulliparity (OR=7.8, 95% CI=6.9-8.7; P<0.001), birth weight >4 kg (OR=2.3, 95% CI=1.9-2.8; P<0.001), epidural analgesia (OR=1.8, 95% CI=1.6-2.0; P<0.001), hydramnios (OR=1.6, 95% CI=1.3-2.0; P<0.001), hypertensive disorders (OR=1.5, 95% CI=1.3-1.8; P<0.001), gestational diabetes A1 and A2 (OR=1.5, 95% CI=1.2-1.8; P<0.001), male gender (OR=1.4, 95% CI=1.2-1.5; P<0.001), premature rupture of membranes (PROM, OR=1.3, 95% CI=1.04-1.6; P=0.021), and induction of labor (OR=1.2, 95% CI=1.02-1.4; P=0.030). Deliveries complicated by arrest of descent resulted in cesarean section in 20.6%, vacuum extraction in 74.0%, and forceps delivery in 5.4%. Newborns delivered after arrest of descent during the second stage of labor had significantly higher rates of low Apgar scores (<7) at 1 and 5 min, as compared to the controls (12.7 vs. 2.1%, P<0.001; and 0.9 vs. 0.2%, P<0.001, respectively). Nevertheless, no significant differences were noted between the groups regarding perinatal mortality (0.38 vs. 0.44%; P=0.759). CONCLUSIONS: Major risk factors for arrest of descent during the second stage of labor were nulliparity, fetal macrosomia, epidural analgesia, hydramnios, hypertensive disorders and gestational diabetes mellitus. These risk factors should be carefully evaluated during pregnancy in order to actively manage high-risk pregnancies.     

Epidural analgesia and the course of delivery in term primiparas

OBJECTIVES: Epidural analgesia provides the most effective pain control during labor. Of great concern is its influence on the course of delivery and perinatal complications. DESIGN: The aim of the study was to assess the effect of epidural analgesia on the course of delivery and perinatal outcome. MATERIALS AND METHODS: 609 deliveries among 1334 (323 women with epidural analgesia (53%) and 548 without epidural analgesia (47%)) met the following criteria: primipara, singleton, live pregnancy, > =37 weeks' gestation, cephalic presentation of a fetus, lack of contraindication for vaginal delivery. The incidence of instrumental deliveries and fetal distress, duration of the first, second and third stage of labor, perinatal outcome, perinatal complications and perinatal blood loss and were analyzed. RESULTS: The incidence of fetal distress during second stage of labor was significantly higher in the epidural group (12.69 vs. 6.99%, P=0.02). The incidence of fetal distress during first stage of labor did not differ in both groups (10.53% vs. 8.74%, NS). Cesarean sections rate was similar in epidural and non-epidural group (17.7 vs. 18.2%, NS). Among vaginal deliveries duration of the first and second stage of labor was longer in epidural group (6.5+/-2.4 vs. 5.4+/-2.5 godz., P=0,000003 and 47.3+/-34.8 vs. 29.1+/-25.8 min., P=0.000003) and this was independent of period of time between onset of first stage of labor and epidural analgesia. Oxitocin use was significantly more frequent in the epidural group (20.6 vs. 10.3%, P<0.004). There were no statistically significant differences in the rates of instrumental vaginal deliveries, 1 and 5-minute Apgar scores, length of third stage of labor and perinatal blood loss in patients with and without epidural analgesia. Perinatal outcome did not depend on previous use of epidural analgesia or mode of analgesia for the operation in cesarean section subgroup. CONCLUSION: Epidural labor analgesia is associated with slower progress of labor but has no adverse effect on perinatal outcome and perinatal complications.     

How long is too long: Does a prolonged second stage of labor in nulliparous women affect maternal and neonatal outcomes?

OBJECTIVE: The purpose of this study was to examine maternal and neonatal outcomes in relation to lengthening intervals of the second stage of labor. STUDY DESIGN: This is a retrospective cohort study of 15,759 nulliparous, term, cephalic, singleton births at the University of California, San Francisco, between 1976 and 2001. The second stage of labor was divided into 1-hour intervals. Maternal and neonatal outcomes were compared with the use of chi-squared and Student t tests, and a probability value of < or =.05 was used to indicate statistical significance. Potential confounders were controlled for with multivariate logistic regression. RESULTS: Increasing rates of cesarean delivery, operative vaginal delivery, and perineal trauma were associated with the second stage beyond the first hour. In multivariate analysis, the >4-hour interval group had higher rates of cesarean delivery (odds ratio, 5.65; P < .001), operative vaginal deliveries (odds ratio, 2.83; P < .001), 3rd- or 4th-degree perineal lacerations (odds ratio, 1.33; P = .009), and chorioamnionitis (odds ratio, 1.79; P < .001). There were no differences in neonatal acid-base status associated with length of second stage. However, there were fewer neonates with a 5-minute Apgar score of <7 (odds ratio, 0.45; P = .01). CONCLUSION: Although the length of the second stage of labor is not associated with poor neonatal outcome, a prolonged second stage is associated with increased maternal morbidity and operative delivery rates.     

Differences in perineal lacerations in black and white primiparas

OBJECTIVE: To test the null hypothesis that there are no differences in incidence of perineal and vaginal lacerations in primiparous black and white women. METHODS: We reviewed University of Michigan Hospital delivery records, from July 1996 to December 1998, of black and white women 18 years and older and at least 35 weeks' gestation who had their first vaginal delivery. Birth weight, episiotomy, gestational age, laceration, length of second stage, oxytocin use, epidural use, and operative vaginal delivery were analyzed by univariable and multivariable tests. RESULTS: We analyzed 176 black women (mean age +/- standard deviation 23.7 +/- 4.7 years; range 18-41 years) and 1633 white women (27.8 +/- 5.4 years; 18-49 years; P <.001). Black women were less likely to have second, third, or fourth degree lacerations (43% compared with 59%; P <.001). The mean length of second stage of labor was shorter in the black women (73 +/- 69 minutes; range 3-494 minutes compared with 106 +/- 78 minutes; range 2-642 minutes; P <.001). Infants of black women weighed less (3292 +/- 490 g; 1990-5190 g compared with 3429 +/- 470 g; 1860-4950 g; P <.001). Multivariable analysis showed that black women were twice as likely to deliver with intact perineums than white women (P <.001). CONCLUSION: Black primiparas were less likely to deliver with second-degree or greater lacerations and more likely to deliver with their perineums intact.     

Intrapartum risk factors for permanent brachial plexus injury

OBJECTIVE: The purpose of this study was to compare maternal, neonatal, and second stage of labor characteristics in shoulder dystocia deliveries that result in permanent brachial plexus injury with shoulder dystocia deliveries that result in no injury. STUDY DESIGN: Our cases were culled from a database of deliveries that resulted in permanent brachial plexus injuries and matched to control cases that were taken from a database of consecutive shoulder dystocia deliveries from one hospital. Deliveries that resulted in injury were excluded from the control cases; those cases with no recorded shoulder dystocia were excluded from the cases. Matching was for birth weight (+/-250 g), parity, and diabetic status. Rates of precipitous and prolonged second stage, operative delivery, neonatal depression, and average number of shoulder dystocia maneuvers used were compared between the two groups with chi(2) test, Fisher exact test, and the Student t test; a probability value of <.05 was considered significant. RESULTS: There were 80 matched patients, of which 26 patients were nulliparous and 11 patients were diabetic. Mothers of the uninjured group were younger than those of the injured group (23.7+/-6.2 years vs 27.4+/-5.1 years, P<.001). The injured group had a significantly higher rate of 5-minute Apgar scores of <7 (13.9% vs 3.8%, P=.04). Differences in maternal weight, body mass index, height, race, gestational age, average number of maneuvers, head-to-body delivery interval, operative delivery rate, prolonged second stage rate, precipitous second stage rate, and sex were not significant between groups. The rates of precipitous second stage for both groups (28.0% injured and 35.0% uninjured) were more than triple the rates of prolonged second stage (9.5% injured and 11.3% uninjured). CONCLUSION: No characteristic of second-stage of labor predicts permanent brachial plexus injury. Precipitous second stage is the most prevalent labor abnormality that is associated with shoulder dystocia.     

Outcomes with premature rupture of membranes at 32 or 33 weeks when management is based on evaluation of fetal lung maturity.

OBJECTIVE: To assess outcomes of patients with premature rupture of membranes (PROM) at 32 or 33 weeks gestation. METHODS: This historical cohort study included all immune competent patients managed at our institution from October 1, 1999 to March 31, 2003 with singleton gestations and PROM at 32 or 33 weeks, and without clinical chorioamnionitis at presentation or antenatal diagnosis of a fetal anomaly. If amniotic fluid studies revealed pulmonary maturity, patients were intentionally delivered. Otherwise, they were expectantly managed until intentional delivery at 34 weeks, or labor, chorioamnionitis, or non -reassuring testing led to delivery sooner. RESULTS: For the groups with mature (n = 29) and immature or unobtainable (n = 60) fluid, respectively, rates of neonatal ICU admission (83% vs. 77%; p = 0.51), respiratory distress (41% vs. 45%; p = 0.75), mechanical ventilation (10% vs. 17%; p = 0.53), and proven neonatal infection (4% vs. 2%; p = 0.60) were similar, as were rates of other neonatal and maternal complications. The mature group had shorter mean maternal hospital stays (3.6 +/- 0.6 vs. 6.4 +/- 2.9 d; p < 0.001) and latency periods (30.2 +/- 19.3 vs. 83.8 +/- 68.7 h; p < 0.001). CONCLUSION: Compared to those managed expectantly due to immature or unavailable fetal lung studies, intentional delivery of patients with PROM at 32 or 33 weeks with mature fetal lung studies did not increase neonatal morbidity in our small cohort.     

Forty weeks and beyond: pregnancy outcomes by week of gestation

OBJECTIVE: To assess pregnancy outcomes at 40, 41, and 42 weeks' gestation when labor induction is done routinely at 42 but not 41 weeks. METHODS: We reviewed all singleton pregnancies delivered at 40 or more weeks' gestation between 1988 and 1998 at Parkland Memorial Hospital, Dallas, Texas. We excluded women with hypertension, prior cesarean, diabetes, malformations, breech presentation, and placenta previa. Labor characteristics and neonatal outcomes of pregnancies at 41 and 42 weeks' gestation were compared with pregnancies that ended at 40 weeks. Women with certain dating criteria had induction of labor at 42 weeks. Gestational age was calculated from the last menstrual period (LMP), sonography when available, and clinical examination. If the fundal height between 18 and 30 weeks was within 2 cm of gestational age, the reported LMP was accepted as correct. Sonogram was used to calculate gestational age if a discrepancy was identified. Statistical analysis consisted of chi(2) and analysis of variance. RESULTS: We studied 56,317 pregnancies: 29,136 at 40 weeks, 16,386 at 41 weeks, and 10,795 at 42 weeks. Labor complications increased from 40 to 42 weeks, including oxytocin induction (2% versus 35%, P <.001), length of labor (5.5 +/- 4.9 versus 8.8 +/- 6. 5 hours, P <.001), prolonged second stage of labor (2% versus 4%, P <.001), forceps use (6% versus 9%, P <.001), and cesarean delivery (7% versus 14%, P <.001). Neonatal outcomes were similar in the three groups, including 5-minute Apgar score less than 4, admission to the neonatal intensive care unit (NICU), umbilical artery pH less than 7, seizures, and perinatal mortality. Sepsis was more frequent in the 42-week group than the other groups (0.1 versus 0.3%, P =. 001), as was admission to the NICU (0.4 versus 0.6%, P =.008). CONCLUSION: Routine labor induction at 41 weeks likely increases labor complications and operative delivery without significantly improving neonatal outcomes.