The distribution and predictive value of Bishop scores in nulliparas between 37 and 42 weeks gestation

Abstract

Objective.?The natural distribution and predictive accuracy of Bishop scores was evaluated to predict cesarean delivery (CD) in nulliparas between 37 and 42 weeks gestation.

Study design.?Subjects underwent serial digital cervical examinations. The Bishop score was evaluated as a binary and continuous factor to predict CD at each gestational week beginning at 37 weeks. Bishop scores were categorized as ≤5 or >5, and CD rates were compared across Bishop score categories using chi-square or Fisher exact tests at each gestational week beginning at 37 weeks.

Results.?In all, 171 patients were prospectively followed. The overall CD rate was 27.5%. The prevalence of unfavorable Bishop scores, categorized as ≤5, decreased with increasing gestation age until 41 weeks. CD rates for the cohort with unfavorable Bishop scores was higher than those with favorable scores at each week. The likelihood ratio for CD was 1.35–2.00, depending on gestational age. The Bishop score that best predicted subsequent vaginal delivery following expectant management was >3 at 37 weeks and >5 at 39 weeks.

Conclusion.?A Bishop score ≤5 between 37 and 39 weeks gestation predicts a higher CD rate compared to patients with a Bishop score >5 implying an intrinsically higher CD risk despite expectant management.     

Nuchal cord encirclements and birth weight

OBJECTIVE: To determine if the presence of a single or multiple nuchal cord encirclement has a negative effect on fetal growth. STUDY DESIGN: Data were retrieved from consecutive deliveries at our institution between January 1991 and December 1996. Our computerized database included live-born single and multiple births with a birth weight of > or = 300 g. ANOVA and multiple linear regression were used for statistical analysis. RESULTS: Among the 13,256 deliveries, a single nuchal cord encirclement was observed in 3,250 (24.5%), and multiple encirclements were present in 504 (3.8%). There was no association between the diagnosis of growth restriction and the presence of a cord encirclement. The mean birth weight was no different in the presence of a single or multiple nuchal cord encirclement than with no encirclement (3,206 g or 3.135 g vs. 3,252 g; F = .08, P = .7). After controlling for substance abuse, medical or obstetric complications, race, infant sex, congenital anomalies and gestational age, there was no effect of a single or multiple cord encirclement on mean birth weight. CONCLUSION: Birth weight is unaffected by a single or multiple nuchal cord encirclement.     

Nuchal cord management and nurse-midwifery practice

Nuchal cord, or cord around the neck of an infant at birth, is a common finding that has implications for labor, management at birth, and subsequent neonatal status. A nuchal cord occurs in 20% to 30% of births. All obstetric providers need to learn management techniques to handle the birth of an infant with a nuchal cord. Management of a nuchal cord can vary from clamping the cord immediately after the birth of the head and before the shoulders to not clamping at all, depending on the provider's learned practices. Evidence for specific management techniques is lacking. Cutting the umbilical cord before birth is an intervention that has been associated with hypovolemia, anemia, shock, hypoxic-ischemic encephalopathy, and cerebral palsy. This article proposes use of the somersault maneuver followed by delayed cord clamping for management of nuchal cord at birth and presents a new rationale based on the available current evidence.     

Nuchal cord and neurodevelopmental performance at 1 year.

OBJECTIVE: To test the null hypothesis that the presence of a nuchal cord at delivery has no effect on neurodevelopmental performance at 1 year of age. METHODS: The offspring of 190 women with clinically normal antenatal courses were evaluated within 1 month of their first birthday by a blinded observer using the Bayley Scales of Infant Development. The cases were grouped based on the presence of a symptomatic nuchal cord during labor (abnormal fetal heart rate patterns or meconium), and significant differences were detected using analysis of variance. RESULTS: A symptomatic nuchal cord was present during labor and delivery in 24% of the 190 cases. At 1 year of age scores on both Bayley scales were slightly but significantly (P < .01) lower in the offspring delivered with a symptomatic nuchal cord. The mental index was 116 +/- 9 versus 120 +/- 7, and the psychomotor index was 101 +/- 11 versus 107 +/- 9. These differences were accentuated (P = .09) when the symptomatic cases complicated by extreme tightness, multiple loops, or antenatal detection were compared to symptomatic cases without these additional complications (overall index 110 +/- 8 versus 105 +/- 10). There were no between group differences in multiple potential confounding obstetric or demographic variables. CONCLUSIONS: These data do not support the null hypothesis and suggest that symptomatic nuchal cords, which are identified before labor as being extremely tight or having multiple loops, may be associated with a subclinical deficit in neurodevelopmental performance at 1 year of age.     

Complications of term pregnancies beyond 37 weeks of gestation

OBJECTIVE: To estimate when rates of pregnancy complications increase beyond 37 weeks of gestation. METHODS: We designed a retrospective, cohort study of all women delivered beyond 37 weeks of gestational age from 1992 to 2002 at a single community hospital. Rates of perinatal complications by gestational age were analyzed with both bivariate and multivariable analyses. Statistical significance was designated by P <.05. RESULTS: Among the 45673 women who delivered at 37 completed weeks and beyond, the rates of meconium and macrosomia increased beyond 38 weeks of gestation (P <.001), the rates of operative vaginal delivery, chorioamnionitis, and endomyometritis all increased beyond 40 weeks of gestation (P <.001), and rates of intrauterine fetal death and cesarean delivery increased beyond 41 weeks of gestation (P <.001). CONCLUSION: Risks to both mother and infant increase as pregnancy progresses beyond 40 weeks of gestation.     

Gestation of 42 weeks or longer. Management protocol

We have evaluated, in a prospective approach to the perinatal results of 98 patients with gestation of 42 weeks and more. The patients with an uncertain gestation age were excluded. The vigilance of the fetus was realized by electronic monitorization, sonographic examination and amnioscopy 55.1% of patients begin labor spontaneously 44.9% were interrupted. The principals causes of interruption were pelvic score of bishop > 7 points and condition that suggest fetal injury. In 31.6% of patients a cesarean section was made. Neonatal morbidity was a 19.4% and we don't have mortality.     

Nuchal translucency thickness and fetal cardiac flow velocity in normal fetuses at 11-13 weeks of gestation

OBJECTIVE: To investigate the relationship between nuchal translucency thickness and cardiac flow velocity in normal fetuses at 11-13 weeks of gestation. Subjects and METHODS: Eighteen normal pregnancies were prospectively studied with transvaginal sonography and pulsed and color Doppler ultrasound. Flow velocities at the fetal atrioventricular valves (mitral and tricuspid valve) and outflow tract levels (ascending aorta and pulmonary artery), and at the descending aorta were recorded. Nuchal translucency thickness was also measured. RESULTS: Mitral peak velocity during early diastolic filling correlated with gestational age. Mitral peak velocities during early diastolic filling and atrial contraction, tricuspid peak velocity during early diastolic filling, ascending aorta peak velocity, and pulmonary artery peak velocity correlated well with nuchal translucency thickness. There was an inverse correlation between umbilical artery pulsatility index and gestational age. CONCLUSIONS: These results suggest that the increase of nuchal translucency thickness in normal fetuses at 11-13 weeks of gestation may be the consequence of changes in fetal cardiac functions.     

Doppler flow characteristics in ductus venosus between 22-42 weeks in intrauterine growth restriction and normal pregnancies

OBJECTIVES: The ductus venosus plays an important role in the oxygenated blood supply from the placenta directly to the fetal heart. Uterine blood flow restriction and placental insufficiency can cause intrauterine grow restriction. Permanent hypoxia triggers compensatory mechanisms to protect vital organs. Increased placental resistance and constriction of the fetal peripheral vessels, as evidenced by blood redistribution and increased right ventricular afterload and end-diastolic pressure lead to increased pulsatility in precordial veins. Doppler flow analysis of the DV allows the indirect estimation of the fetal heart function. Because it is not always possible to achieve correct ultrasound beam insonation there have been attempts to use angle-independent indices. The aim of the study was: to compare the Doppler indices in DV in growth restricted and normal fetuses. MATERIAL AND METHODS: 208 women were analyzed: 89 women between 22-42 weeks of pregnancy complicated by IUGR and 119 with normal pregnancy as a control group. Ultrasound examination using pulse and color Doppler was performed and PVIV, PIV, PLI and S/D ratio were estimated. RESULTS: The authors found that for the normal group PVIV, PIV, PLI and S/A decreased with advancing gestation. However in comparison in IUGR group these parameters were substantially higher. CONCLUSIONS: The improvement of maternal and fetal Doppler techniques allows us to distinguish the subgroups of IUGR fetuses with the uteroplacental insufficiency that will have an increased perinatal morbidity and mortality. Alterations in the venous blood velocity waveforms have a more precise relationship with the risk of adverse perinatal outcome than changes in the arterial blood flow usually recognized relatively early in placental function disorders.     

The efficacy of starting postterm antenatal testing at 41 weeks as compared with 42 weeks of gestational age

Postterm antenatal fetal surveillance has traditionally begun at 42 completed weeks of gestation. However, recent data have shown that a significant percentage of cases of perinatal asphyxia occurs between 40 and 42 weeks of gestation. We compared the perinatal outcome of fetuses with antenatal surveillance beginning at 41 weeks to those starting at 42 weeks of gestation. The study groups consisted of 908 patients who began antenatal testing at 41 weeks and 352 who began testing at 42 weeks. Antenatal testing consisted of twice-weekly amniotic fluid assessments and nonstress tests (including evaluation for late and variable decelerations). Between 41 and 42 weeks, the group whose testing started at 41 weeks had an overall incidence of intrapartum fetal distress of 2.7%, no stillbirths, and no infants with major neonatal morbidity. Patients without antenatal testing who delivered between 41 to 42 weeks did not have a significantly increased incidence of fetal distress (3.3%; p = 0.07). However, this group had a significantly increased incidence of adverse outcomes (p less than 0.05), including three stillbirths and seven cases of major neonatal morbidity. Beyond 42 weeks, the group whose testing started at 41 weeks had a 2.3% overall incidence of fetal distress. This was significantly less (p less than 0.01) than the group whose testing started at 42 weeks (5.6%). Neither of the groups had any stillbirths or infants with major neonatal morbidity. These findings suggest that starting antenatal testing at 41 weeks of gestation may result in decreased postterm perinatal mortality and morbidity as well as a decreased incidence of intrapartum fetal distress.     

Doppler flow characteristic in inferior vena cava between 22-42 weeks in intrau-terine growth restriction and normal pregnancies

Uterine blood flow restriction and placental insufficiency can cause intrauterine grow restriction. Permanent hypoxia triggers compensatory mechanisms to pro-tect vital organs. Increased placental resistance and constriction of the fetal pe-ripheral vessels, as evidenced by blood redistribution and increased right ven-tricular afterload and end-diastolic pressure lead to increased pulsality in pre-cordial veins. Doppler flow analysis of the IVC allows the indirect estimation of the fetal heart function. OBJECTIVE: The aim of the study was to compare the Doppler indices in IVC in growth restricted and normal fetuses. RESULTS: The authors found that for the normal group PVIV, PIV and S/D de-creased with advancing gestation. However in comparision in IUGR group these parameters were substantially higher. CONCLUSIONS: The improvement of maternal and fetal Doppler techniques allows us to distinguish the subgroups of IUGR fetuses with the uteroplacental insufficiency that will have an increased perinatal morbidity and mortality. Alterations in the venous blood velocity waveforms have a more precise relationship with the risk of adverse perinatal outcome than changes in the arterial blood flow usually recognized relatively early in placental function disorders.     

Nuchal cord detected by ultrasound at term is associated with mode of delivery and perinatal outcome

OBJECTIVES: To evaluate the clinical relevance of nuchal cord in normal, vertex, singleton pregnancies at term, and its effect on mode of delivery and perinatal outcome. STUDY DESIGN: Prospective study with 352 normal, singleton pregnancies, with fetuses in the vertex presentation, examined with real-time ultrasound at 37-39 weeks. Health care workers at labour and delivery blinded to previous detection of nuchal cord. RESULTS: Fetuses of nulliparous women with a nuchal cord were more likely to be delivered with operative vaginal or caesarean delivery (n = 153, p < 0.0001). This was not the case with higher parity (n = 199, p = 0.07). There was no difference between nuchal cord (n = 144) and control groups (n = 208) in amniotic fluid quantity at 37-39 weeks (p = 0.554) or intrapartum CTG (p = 0.9). On the other hand, nuchal cord group had lower Apgar scores at 1 and 5 min (p = 0.001 and 0.027 respectively); this difference remained significant when adjusted for birth weight (p = 0.001 and 0.016), but disappeared when adjusted for mode of delivery (p = 0.048 and 0.319). CONCLUSIONS: Nuchal cord in normal pregnancies at term is associated with increased rate of operative vaginal and caesarean delivery in nulliparae. The presence of a nuchal cord results in slightly lower Apgar scores at 1 and 5 min, mainly as a consequence of higher operative delivery rates.