Comparative analysis of cesarean delivery rates over a 10-year period in a single Institution using 10-class classification.

OBJECTIVE: To evaluate the variables associated with changes in cesarean delivery (CD) rates in a University Hospital with standardized and unchanged protocols of care. METHODS: Retrospective analysis of consecutive deliveries between two triennia 10 years apart. The Robson classification of CD was used, and the analysis focused on factors affecting Robson's classes 1 and 2 combined (term singleton cephalic nulliparae) and class 5 (previous CD). RESULTS: A total of 8237 deliveries occurred in the 1st period, and 8420 in the 2nd. CD increased from 12.5 to 18% (p < 0.001). Robson's classes 1 and 2 combined contributed more than other classes to CD rates (32 vs 36%; p < 0.001). At multivariate analysis, BMI (Odds ratio [OR]: 1.08; 95% CI: 1.06-1.1) and maternal age (OR: 1.06; 95% CI: 1.05-1.08) were independently related to CD. In Robson class 5, the rate of CD increased from 34 to 46%, p < 0.001, mostly due to an increase in elective CD (39 vs 67.5%; p < 0.001). At multivariate analysis, BMI (OR: 1.06 95% CI: 1.02-1.1) and more than one previous CD (OR: 18.7; 95% CI: 9.6-36.4) were independently related to CD. CONCLUSIONS: BMI and maternal age are independent factors associated to the increasing rate of CD in nulliparae with spontaneous or induced labor at term. In women with previous CD, BMI and more than one previous CD are factors associated with the increasing rate of CD.

Variability in rate of cervical dilation in nulliparous women at term.

BACKGROUND: Cervical dilatation is commonly documented on a partogram indicating the expected rate of progress of labor. Although deviations from such a line can be used to indicate abnormal progress, what constitutes the "normal" rate of cervical dilation is still largely unknown. The objectives of this study were to assess the variability of the rate of cervical dilation in nulliparous women and to determine whether the rate of labor was independent of dilation on admission. METHODS: We analyzed a cohort of consecutive nulliparous women with spontaneous labor at term and singleton fetuses in cephalic presentation. Exclusion criteria were gestational age less than 37 weeks, induction of labor, or the presence of a uterine scar. Management of labor was standardized using set protocols of care. Active labor was diagnosed as regular contractions every 10 minutes or less, lasting more than 40 seconds, with cervical effacement more than 80 percent and dilation of 2 cm. Vaginal examinations were performed by a dedicated midwife every 2 hours. Amniotomy was performed for slow progress or arrest of dilation over 2 hours. Oxytocin was administered for arrest of cervical dilation for 2 hours with membranes ruptured. Data pertaining to cases ending in cesarean delivery were included up to the time of cesarean section. RESULTS: The study sample comprised 1,119 women at 39.7 ± 1.1 weeks with an average duration of labor of 4.1 ± 2.4 hours. The rate of oxytocin use was 27 percent and of epidural analgesia 5 percent. The rate of oxytocin use was inversely related to cervical dilation on admission. Cesarean delivery was performed in 6 percent of women. Duration of labor at each centimeter of cervical dilation on admission showed a broad distribution (e.g., at 4 cm: median = 5.5, range: 0.8-12.5 hr). The rate of labor progression (expressed as the slope of the dilation-vs-time curve) was approximately 1.5 cm/hr, and it was essentially independent of cervical dilation on admission (r = 0.034, p = 0.267). A deceleration phase seemed to be present toward the end of the active phase of labor (approximately 9 cm). CONCLUSION: In our setting, the rate of labor in nulliparous women at term was highly variable, and it did not appear to be affected by cervical dilation on admission.

Prediction of duration of active labor in nulliparous women at term.

We have assessed the independent predictors of duration of active labor in nulliparous women at term. Using a cohort of 1067 nulliparae in spontaneous labor at > 37.0 weeks with singleton fetuses in vertex presentation, multivariate analysis was used to identify independent predictors of duration of active labor. Duration of active labor was 4.1 +/- 2.4 hours. Stepwise linear regression selected 10 independent predictors of duration of active labor: gestational age at delivery ( P < 0.001), race ( P = 0.014), obstetric risk factors ( P = 0.022), amniotomy ( P < 0.001), fundal height ( P = 0.005), cervical dilation on admission ( P < 0.001), frequency of contractions ( P < 0.001), station of presenting part ( P < 0.001), oxytocin ( P < 0.001), and epidural use ( P < 0.001). A prediction formula incorporating the 10 predictors accounted for 51% of the total variance of the observed duration of active labor. Ten variables are independent predictors of duration of active labor; when incorporated in a prediction formula they account for > 50% of the variability of duration of labor in nulliparous women.

Fetal intra-abdominal calcifications from meconium peritonitis: sonographic predictors of postnatal surgery.

OBJECTIVE: To study the relationship between prenatal ultrasound features and postnatal course of meconium peritonitis. STUDY DESIGN: We reviewed our cohort of cases of meconium peritonitis (MP) (n = 13/37, 225 pregnancies or 0.3/1000) as well as those published in the English literature with prenatal ultrasonographic findings and postnatal follow-up (n = 56). The total number of cases (n = 69) was divided into 4 grades of progressive severity based on the number of pertinent sonographic findings: grade 0, isolated intra-abdominal calcifications (n = 18); grade 1, intra-abdominal calcifications and ascites (n = 17) or pseudocyst (n = 2) or bowel dilatation (n = 6); grade 2, two associated findings (n = 20); and grade 3, all sonographic features (n = 6). Presence of polyhydramnios was also recorded. Prenatal predictors of need for neonatal surgery and risk of neonatal death were identified using Chi-square and Fisher exact test, with P < 0.05 considered significant. RESULTS: Neonatal surgical intervention was required in 0% (0/18) of newborns with grade 0 MP; in 52% (13/25) of those with grade 1; in 80% (16/20) with grade 2; and in 100% (6/6) with grade 3 MP (P < 0.001, Chi-square for trend). Moreover, neonatal surgery was more frequent in the presence than absence of polyhydramnios [69% (18/26) vs 37% (16/43); P = 0.007]. Neonatal mortality was 6% (4/69; 3 after surgery and 1 for premature delivery) and it was confined to the subgroup with polyhydramnios (4/26, 15%). CONCLUSIONS: Prenatal sonographic features are related to postnatal outcome. Persistently isolated intra-abdominal calcifications have an excellent outcome. Delivery in a tertiary care center is recommended when calcifications are associated with other sonographic findings.

Induction of labor: comparison of a cohort with uterine scar from previous cesarean section vs. a cohort with intact uterus.

OBJECTIVE: To compare the risk of uterine rupture between a cohort of women with previous low-transverse cesarean section (CS) and a cohort with intact uterus. METHODS: All women with a singleton pregnancy and previous low-transverse CS requiring induction of labor from January 1, 1992 to December 30, 2001 (n = 310) were compared with a cohort of women with intact uterus undergoing induction of labor during the same study period (n = 5420). Protocols of induction using prostaglandin E2 gel and oxytocin infusion were consistent within groups, but differed between the previous CS and the intact uterus group. RESULTS: Uterine rupture occurred in 0.3% in the previous CS group vs. 0.03% in the intact uterus group (p = 0.37). Logistic regression analysis showed no significant difference in rate of uterine rupture between the previous CS vs. intact uterus group (p = 0.16) after controlling for maternal age, parity, gestational age at delivery, Bishop score on admission, use of prostaglandin and oxytocin, and birth weight. Our study had adequate power to detect a 0.38% difference in rate of uterine rupture between the two groups (alpha = 0.05, beta = 0.80). CONCLUSION: Induction of labor is not associated with significantly higher rates of uterine rupture among women with previous low-transverse CS compared with women with intact uterus provided a consistent protocol with strict intervention criteria is adopted.

Fetal arrhythmias: natural history and management.

The aim was to delineate the significance and natural history of fetal arrhythmias and provide information about their management. A cohort of 114 infants with fetal arrhythmias detected during prenatal ultrasound (US) screening were studied. All subjects underwent echocardiography and were treated as clinically indicated. Postnatal outcome was obtained in 100% of infants until 1 year of age. The incidence of fetal arrhythmias was 0.3%. Among the 87 fetuses with atrial extrasystoles, 2.3% developed supraventricular tachycardia (SVT) in utero. Of the 10 SVT cases, only five required antiarrhythmic therapy in utero with digoxin and propafenone, which successfully restored sinus rhythm in 100% of fetuses, both nonhydropic and hydropic. Sinus bradycardia was associated with structural anomalies in 5 of 6 patients and only 2 of 4 fetuses with atrioventricular block survived. It is concluded that prognosis is good for most fetal tachyarrhythmias, whereas it is less favorable for bradyarrhythmias.

Role of FISH on uncultured amniocytes for the diagnosis of aneuploidies in the presence of fetal anomalies.

OBJECTIVE: To assess the accuracy of fluorescent in situ hybridization (FISH) on amniocytes in fetuses affected by structural malformations suggestive of chromosomal anomalies. METHODS: FISH of uncultured amniotic fluid cells and conventional cytogenetic analysis were performed on 48 pregnancies with ultrasonographic (US) evidence of fetal anomalies. The AneuVysion assay (Vysis) with specific probes for chromosomes 13, 18, 21, X and Y, was used. Amniotic fluid samples were obtained between the 14th and 34th weeks of gestation. RESULTS: In cases with a single abnormal US finding (n = 15), 5 aneuploidies were detected (1 case of trisomy 13 and 4 of trisomy 21). In the group with two or more malformations (n = 33) there were 15 aneuploidies (9 cases of trisomy 18, 2 of trisomy 21, 2 monosomy X, 1 trisomy 13, and 1 triploidy). In this group, conventional cytogenetic analysis revealed two additional chromosomal anomalies not detectable by FISH (1 trisomy 16 mosaic, and a terminal deletion 4p). No sex aneuploidies were observed. CONCLUSIONS: The lack of false-positive diagnosis in the FISH analysis in our sample prompts us to consider interphase FISH as a useful tool in pregnancies at high risk for chromosomal aneuploidies. When FISH analysis is normal, the overall risk of chromosomal abnormalities is significantly reduced. However, the finding of two chromosomal anomalies undetectable by AneuVysion assay confirms the need for conventional chromosome analysis to complement FISH results. Moreover, the results collected here, in agreement with those already reported in the literature, indicate that FISH analysis on uncultured amniocytes can play an important role in counselling and decision-making, especially in cases at risk for aneuploidies, such as those with structural abnormalities at US.

Risks of induction of labour in women with a uterine scar from previous low transverse caesarean section.

OBJECTIVE: Recent studies have shown that among women with uterine scars from previous caesarean section of any type, induction of labour is associated with increased risk of uterine rupture compared with spontaneous labour. We have assessed the risk of uterine rupture in a cohort of women with a previous low transverse caesarean section in whom induction and management of labour were performed according to a strict protocol. DESIGN: Cohort study. SETTING: University Hospital. POPULATION: All women with a singleton pregnancy and a previous low transverse caesarean section requiring induction of labour from 1/1/1992 to 12/30/2001 (n = 310) were compared with a control cohort during the same study period constituted of women with a previous low transverse caesarean section in spontaneous labour (n = 1011). METHODS: Clinical characteristics and rate of uterine rupture of women with previous caesarean section undergoing induction of labour were compared with those of women with previous caesarean section in spontaneous labour. MAIN OUTCOME MEASURE: Incidence of uterine rupture. RESULTS: Uterine rupture occurred in 0.3% in the previous caesarean section--induction group versus 0.3% in the previous caesarean section--spontaneous labour group (P = 0.9). Logistic regression analysis showed no significant difference in the rate of uterine rupture between the induction and spontaneous labour group (P = 0.67) after controlling for maternal age, parity, duration of labour, gestational age at delivery and birthweight. CONCLUSION: Among women with a previous low transverse caesarean section, induction of labour is not associated with significantly higher rates of uterine rupture compared with spontaneous labour, provided a consistent protocol with strict criteria for intervention is adopted.

Factors affecting the decision regarding amniocentesis in women at genetic risk because of age 35 years or older.

OBJECTIVE: To evaluate the effects of anamnestic factors and sonographic findings on the patient's decision regarding amniocentesis in a cohort of women at genetic risk because of advanced age. METHODS: All women 35 years of age or older registered for prenatal care between January 1990 and December 1998 were asked about their attitude towards genetic amniocentesis during the course of individual genetic counseling and once again after ultrasound examination inclusive of markers of aneuploidies (nuchal fold thickness greater than 6 mm, renal pyelectasis, choroid plexus cysts, and hyperechogenic bowel). Their attitudes towards genetic amniocentesis before and after ultrasound examination were compared using chi-square, Fisher's exact test, Mann-Whitney U-test, and logistic regression analysis, with a two-tailed p < 0.05 or an odds ratio (OR) with 95% confidence interval (CI) not inclusive of the unity considered significant. RESULTS: Among the 1486 women in the cohort, 1368 (97%) expressed an opinion towards genetic testing at the time of counseling: 501 (37%) were in favor and 867 (63%) were against having the procedure. After ultrasonographic examination, 33% (446/1368) of women opted for amniocentesis, 36% (146/402) after abnormal findings and 31% (300/966) after normal ultrasound findings. Significantly more women with abnormal than normal ultrasound findings opted for diagnostic testing in both groups. Overall, only 8% (115/1368) of women changed their attitude towards diagnostic testing after ultrasonographic examination. Normal sonographic findings were three times more likely to change the attitude of women initially interested in amniocentesis than abnormal sonographic findings did in women a priori not interested in the procedure (20% versus 7%, p < 0.001, OR = 3.2, 95% CI 1.8; 5.8). CONCLUSIONS: In a cohort of women at genetic risk because of advanced age, the key determinant of the choice regarding genetic amniocentesis is the a priori opinion of the woman towards the procedure, which was expressed by 93% of women. Ultrasonography plays a secondary role in changing or confirming women's attitude towards invasive diagnostic testing. Normal sonographic findings affect women's decisions more powerfully than abnormal sonographic findings, suggesting that ultrasonography has an important reassuring function for the woman.