Maternal race/ethnicity impacts the success rates of external cephalic version (ECV) in the United States.

OBJECTIVES: Racial and ethnic disparities in obstetrics are prevalent in the United States (US). We aimed to assess whether the success rate of external cephalic version (ECV) is affected by maternal race/ethnicity. METHODS: We conducted a retrospective analysis based on the CDC Natality Live Birth database for 2016-2018. We compared the success rates of ECV across US pregnant women of different racial/ethnic groups (non-Hispanic Whites, non-Hispanic Blacks, non-Hispanic Asians, and Hispanics) using the Pearson chi-square test and used multivariate logistic regression to control for confounding variables. Statistical signiciance was determined as p<0.05 and results were displayed as adjusted odds ratios (aOR) with 95% confidence intervals (95% CI). RESULTS: Of the 11,150,527 births, 26,255 women underwent an ECV and met inclusion criteria. The overall ECV success rate was 52.75% (13,850 women). Non-Hispanic Blacks had the highest ECV success rate (64.52%), followed by Hispanics (59.21%) and non-Hispanic Asians (55.51%). These rates were significantly higher than those of non-Hispanic Whites (49.27%, p<0.001). Non-Hispanic Blacks were associated with the highest success rate compared to non-Hispanic Whites (adjusted OR 1.95, 95% CI 1.77-2.15). CONCLUSIONS: The success rate of ECV varies among different maternal racial/ethnic groups. Non-Hispanic White women have the lowest ECV success rate, while non-Hispanic Black women have the highest ECV success rate.

Nucleated Red Blood Cells as a Marker of Acute and Chronic Fetal Hypoxia in a Rat Model.

OBJECTIVE: To examine the relationship between duration of fetal hypoxia, nucleated red blood cell (NRBC) count, and fetal growth. METHODS: Pregnant rats were exposed to a severe hypoxia (9.5%-10% O2) for varying time intervals (2, 6, 12, 24, 48, and 120 hours; n=4 for each time interval) immediately prior to delivery at term. Normoxic controls were exposed to room air (21% O2) and matched for all other study variables (n=4 rats for each time interval). Pups were delivered via hysterotomy while maintaining exposure gas concentrations. Blood gas analysis and NRBC counts were performed, and fetal body and liver weights were recorded. Student's t test and simple regression were used for statistical analysis. RESULTS: As the duration of hypoxia increased, fetal weight, liver weight, blood bicarbonate, and base excess levels decreased significantly; concomitantly, NRBC counts increased. This increase in NRBCs became statistically significant after 24 hours of exposure. After 48 hours of hypoxia there was a 2.5-fold rise in NRBC count, and after 120 hours of hypoxia there was a 4.5-fold rise in NRBC count over control levels. After 12 or more hours of hypoxia, fetal body weights were significantly reduced; 120 hours of hypoxia resulted in a 35% reduction in fetal body weight, a 34% reduction in fetal liver weight, and 356% increase in NRBC count. CONCLUSION: In a pregnant rat model, chronic maternal hypoxia (≥24 hours) results in a significant increase in fetal NRBC counts as well as reduced fetal body weight and organ growth.

Values of amniotic fluid index in cases of preterm premature rupture of membranes.

AIMS: To measure the amniotic fluid index (AFI) in cases of preterm premature rupture of membranes (PPROM). METHODS: A retrospective study of pregnancies complicated with PPROM was performed. Data collected included maternal age, parity, gestational age at PPROM and at birth, and AFI on admission. Gestational age matched AFIs were obtained from a low-risk control group in a 3:1 ratio. RESULTS: One hundred and two singleton pregnancies with PPROM formed the study population. The mean gestational age at PPROM was 29+/-5.3 weeks (range: 14-36.6 weeks). The mean AFI in the PPROM and the control groups was 5.8+/-3.6 cm (0-18.5 cm) and 13.7+/-3.2 cm (7.3-24.4 cm), respectively (P<0.001). The area under the ROC curve of AFI in the prediction of PPROM was 0.95 (P<0.001). An AFI of < or =10 cm had sensitivity, specificity, positive and negative predictive values of 89.2%, 88.5%, 72.2% and 96%, respectively, in supporting the diagnosis of PPROM. CONCLUSIONS: The presence of low AFI supports the diagnosis of PPROM. ROC curve analysis revealed that an AFI < or =10 cm is the optimal cut-off value in the suspicion of PPROM.

The risk of a major trisomy in fetuses with pyelectasis: the impact of an abnormal maternal serum screen or additional sonographic markers.

OBJECTIVE: This study was undertaken to evaluate the contribution of either an abnormal second-trimester maternal serum screen or the presence of additional sonographic markers of aneuploidy to the risk of a major trisomy (13, 18, and 21) in fetuses with pyelectasis. STUDY DESIGN: A retrospective review of a large amniocentesis database was performed. Specimens obtained after the sonographic detection of fetal pyelectasis were eligible for analysis. Age-matched women who underwent amniocentesis solely for maternal anxiety or advanced maternal age served as controls. RESULTS: 760,495 amniocentesis specimens were analyzed. Fetal pyelectasis was detected in 671 cases. Pyelectasis, with either a single or multiple additional sonographic markers, was associated with an 8-fold and 62-fold increase in the prevalence of major trisomies (odds ratio = 7.7, 95% CI = 1.2-32.6, P = 0.02) and (odds ratio = 61.9, 95% CI = 13.2-144.6, P < .001), respectively. Pyelectasis with an abnormal maternal serum screen, with or without additional sonographic markers, was associated with a 32-fold and a 205-fold increase in major trisomies (odds ratio = 32.2, 95% CI = 5.3-94.8, P < .001) and (odds ratio = 205.8, 95% CI = 37.9-427.6, P < .001), respectively. CONCLUSION: In fetuses with pyelectasis, the presence of additional sonographic markers or an abnormal maternal serum screen significantly increases the risk of trisomy 13, 18, and 21.

Combined analysis with amniotic fluid index and estimated fetal weight for prediction of severe macrosomia at birth.

OBJECTIVE: To evaluate combined analysis with amniotic fluid index (AFI) and estimated fetal weight (EFW) for prediction of severe macrosomia at birth. STUDY DESIGN: In this retrospective case-control study, 50 term severe macrosomic newborns (birthweight [BW] > or = 97th percentile) were included in the study group and 100 appropriate for gestational age newborns served as controls. All pregnancies underwent a third-trimester sonographic evaluation in which AFI and EFW were measured. The association between BW and AFI and EFW percentiles was examined. The statistical analysis included Student t test, simple regression and receiver-operating curve analyses, and 2x2 tables. RESULTS: The mean mid-third-trimester AFI percentile and EFW percentile in severe macrosomic infants were 72.4 +/- 22.5 and 83 +/- 12, respectively, which was significantly higher than in controls (P < .0001). Significant correlations were detected between BW and AFI and EFW percentiles (r = 0.44 and r = 0.72, respectively; P < .0001). Receiver-operating characteristic analysis identified AFI > or = 60th percentile and EFW > or = 71st percentile as best predictors of severe macrosomia. The combined analysis with AFI > or = 60th percentile and EFW > or = 71st percentile resulted in a positive predictive value of 85%. CONCLUSION: There is a significant correlation between mid-third-trimester AFI and BW. AFI > or = 60th percentile and EFW > or = 71st percentile during the mid third trimester are useful predictors of severe macrosomia at birth.

The impact of maternal age, body mass index and maternal weight gain on the glucose challenge test in pregnancy.

OBJECTIVE: The aim of this study was to determine whether maternal age, prepregnancy and mid-trimester body mass index (BMI), or excessive mid-pregnancy weight gain predict abnormal glucose challenge test (GCT) results. METHODS: A retrospective chart review of 75 consecutive singleton pregnancies was performed. Patients were screened at 24-28 weeks of gestation with a 50-g oral GCT. Prepregnancy BMI and pregnancy weight gain up to the time of GCT testing, as well as other demographic data, were recorded. Statistical analysis included regression analysis and Student's t-test, receiver-operator characteristic curve and multivariate logistic regression. RESULTS: Maternal age and prepregnancy and mid-trimester BMI were significantly higher in women with an abnormal GCT (p<0.05). A direct correlation was found between these parameters and GCT results (R(2)=0.08, R(2)=0.102 and R(2)=0.116, respectively; p<0.05). Mid-trimester maternal BMI of >or=30 kg/m(2) and maternal age >or=32 years are the optimal predictors of abnormal GCT results. CONCLUSIONS: Mid-trimester maternal BMI of >or=30 kg/m(2) and maternal age >or=32 years are useful predictors of abnormal GCT results. We suggest that these factors should also be considered when selective screening for gestational diabetes mellitus is practiced.

Fetal pyelectasis: does fetal gender modify the risk of major trisomies?

OBJECTIVE: Several studies have noted an increased prevalence of pyelectasis in male fetuses. It is speculated that pyelectasis represents a normal physiologic variant in males, whereas its presence in females indicates an increased risk of chromosomal abnormalities. Thus, we sought to investigate the association between fetal gender and the risk of major trisomies in fetuses with pyelectasis. METHODS: Retrospective analysis of a Genzyme Genetics amniocentesis database (1995 to 2004) was performed. Specimens obtained after an ultrasonographic finding of pyelectasis were eligible for analysis. The prevalence of major trisomies (trisomy 13, 18, or 21) in male and female fetuses with pyelectasis was compared using binomial distribution. RESULTS: A total of 760,495 amniocentesis specimens were analyzed. Fetal pyelectasis was reported in 671 cases. A male predominance, with a male-to-female ratio of 2.14:1 (457 compared with 214) was statistically significant (P < .001). A major trisomy was detected in 26 male fetuses (5.7%): 18 cases of trisomy 21, 2 cases of trisomy 18, and 6 cases of trisomy 13. Nine female fetuses had a major trisomy (4.2%): 6 cases of trisomy 21 and 3 cases of trisomy 13. There was no significant difference in the overall prevalence of trisomies between male and female fetuses (P = .14). CONCLUSION: We concur with previous studies documenting a higher prevalence of pyelectasis in male fetuses. In addition, our results indicate that the prevalence of major trisomies among fetuses with pyelectasis is unlikely to be dependent on fetal gender. Thus, counseling patients with regard to the genetic implications of fetal pyelectasis should be gender independent. LEVEL OF EVIDENCE: II-2.

Fetal "nonreassuring status" is associated with elevation of nucleated red blood cell counts and interleukin-6.

OBJECTIVE: Previous studies have established the association between fetal hypoxia and elevated nucleated red blood cells (NRBCs). Animal studies have demonstrated that a rise in plasma erythropoietin (EPO) is not detectable until 4 to 6 hours after the initiation of hypoxia. In contrast, interleukin-6 (IL-6) has the capacity to directly induce erythroid maturation. Therefore, we set forth to evaluate the role of EPO and IL-6 as potential mediators of elevated fetal NRBCs in response to acute hypoxia. STUDY DESIGN: Low-risk pregnancies with a normal fetal heart rate at admission to labor and delivery were eligible for participation. Deliveries for "nonreassuring fetal status" comprised the study group. All other deliveries served as controls. Umbilical cord blood was prospectively collected for blood gas analysis, NRBC counts, EPO, and IL-6. RESULTS: One hundred women participated in the study. Nonparametric univariate analysis demonstrated a significant association between elevated NRBC counts and Apgar scores, arterial cord blood pH, base excess, EPO, and IL-6 levels (all P values <.01). Stepwise regression analysis identified only pH, IL-6, and EPO as independent variables associated with elevated NRBC counts at birth (all P values <.0001 with R2 of 0.27, 0.42, and 0.46, respectively). A significant increase in NRBC counts was noted in study patients. IL-6 was significantly increased in study patients, whereas there was no difference in EPO between groups. CONCLUSION: The fact that NRBC counts were elevated in fetuses who were delivered for "nonreassuring fetal status" with EPO being normal and IL-6 being elevated implies that IL-6 may have a unique, short-term role in elevating fetal NRBC counts.

Nucleated red blood cells in uncomplicated prolonged pregnancy.

OBJECTIVE: Elevated counts of nucleated red blood cells (NRBCs), as well as prolongation of pregnancy, have been suggested as predictors of adverse perinatal outcome. However, the association between these 2 variables has received only minimal attention. We sought to evaluate fetal NRBCs in prolonged pregnancies. METHODS: Umbilical cord blood was prospectively collected at delivery from 75 prolonged (at or beyond 287 days) pregnancies. One hundred and fifty term deliveries (260-286 days) served as controls. All pregnancies were accurately dated with the use of first-trimester sonography. Fetal biophysical profile testing was initiated at 40 weeks of gestation. Patients were delivered if they were in spontaneous labor or the biophysical profile was nonreassuring or by 42 weeks of gestation. Nucleated red blood cell counts were expressed per 100 white blood cells (WBC). Umbilical artery pH studies, as well as other demographic and clinical variables, were obtained. RESULTS: Prolonged pregnancy was associated with a significantly increased incidence of induction of labor and a greater birth weight. There were no other differences between the study group and controls. The median NRBCs per 100 WBCs in prolonged pregnancy was not significantly elevated over the term values (median 3, range 0-35 versus median 3, range 0-34, respectively; P =.25). Neonatal outcome was also comparable between groups. The univariate regression analysis demonstrated a significant association between elevated NRBC counts and low arterial cord blood pH (P <.008, R = 0.175), elevated base excess (P =.02, R = 0.149), low platelet counts (P =.046, R = 0.134), and male gender (P =.028). Stepwise regression analysis revealed that low arterial cord blood pH and male gender were the only independent variables predicting elevated NRBC counts at birth. CONCLUSION: The findings of this study suggest that elevated NRBC counts are associated with specific pregnancy complications rather than uncomplicated prolonged pregnancies in general.

Are elevated fetal nucleated red blood cell counts an indirect reflection of enhanced erythropoietin activity?

OBJECTIVE: Animal and human studies demonstrated elevated erythropoietin (EPO) levels in response to intrauterine hypoxic events. Other studies documented an association between fetal hypoxia and elevated nucleated red blood cell (NRBC) counts and have speculated that it is the elevation of EPO that results in an increase in NRBC counts. Thus, the purpose of our study was to determine the correlation between EPO levels and NRBC counts in the human fetus. STUDY DESIGN: Data were collected prospectively between April and July of 2003. Term singleton pregnancies were eligible to participate in the study. Umbilical cord blood was collected immediately after birth for determination of fetal EPO levels and NRBC counts. RESULTS: Forty pregnancies formed the study population. The mean gestational age at delivery was 39.5 +/- 1.2 weeks (+/-SD) and the mean birth weight was 3500 +/- 372 g. The median EPO (mU/mL) was 34 (range 13-427). The median NRBC/100 white blood cells was 10 (range 0-150). A simple regression analysis indicated that NRBC counts are significantly and positively correlated with EPO (P=.0004, R(2)=0.287). CONCLUSION: Our results suggest a significant association between EPO and NRBC counts in term singleton fetuses. These results support the hypothesis that fetal NRBC and EPO are interrelated. However, the relatively low R(2) indicates that there are other (yet to be determined) hypoxia-derived mediators that result in an elevation of fetal NRBC counts.

Placental transfer of measles antibodies: effect of gestational age and maternal vaccination status.

Despite nationwide measles vaccination coverage in Israel of over 90%, repeated outbreaks of measles have spread from isolated communities with poor immunization uptake. Some severely affected individuals were children under 1 year of age, including premature infants. We evaluated the serological status of 195 newborn infants and their 161 mothers divided into four groups: vaccinated mothers (VMs) and premature infants, VM and full term infants, naturally immunized mothers (NIMs) and premature infants, NIM and full term infants. Maternal and cord blood measles antibody titers were determined by haemagglutination inhibition (HI) test and microneutralization test (mNT). Fewer than 40% of preterm infants of VM and less then 70% of preterm infants of NIM had protective titers at birth. The results of this study may aid in formulating new measles vaccination recommendations for preterm infants.

Fine-needle aspiration in the evaluation of nucleated red blood cells in the human placenta.

OBJECTIVE: The purpose of this study was to evaluate the correlation between placental and umbilical cord nucleated red blood cell counts. STUDY DESIGN: Eighty placentas and their matched umbilical cord blood samples were collected prospectively immediately after delivery. In vitro fine-needle aspiration biopsy specimens were used to obtain placental tissue samples. Nucleated red blood cells were counted by both manual microscopy and flow cytometry. Statistical analysis included Wilcoxon signed rank test and Spearman correlation. RESULTS: The median nucleated red blood cell counts/100 white blood cell counts for manual microscopy in umbilical cord blood; placental samples were 7.5 and 3.0, respectively (P <.0001). The median nucleated red blood cell counts for flow cytometric determination in umbilical cord blood and placental samples were 11.3 and 8.6, respectively (P <.0001). The Spearman correlation between manually counted umbilical cord blood samples and the placental tissue specimens was 0.66 (P <.0001). The Spearman correlation between flow cytometrically counted umbilical cord blood nucleated red blood cell and nucleated red blood cell counts that were obtained from the placenta was statistically significant (r = 0.74, P <.0001). The Spearman correlation between manual microscopy and flow cytometry for umbilical cord samples and their matched placental tissue specimens were 0.80 and 0.58, respectively, with all probability values at <.0001. CONCLUSION: Previous studies have reported an association between acute and chronic hypoxia and elevated nucleated red blood cells. Our results indicate that in vitro placental nucleated red blood cell counts correlate with umbilical cord nucleated red blood cell counts and suggest that antenatal evaluation of fetal nucleated red blood cells could be achieved by placental fine-needle aspiration biopsy.

The association of fetal heart rate patterns with nucleated red blood cell counts at birth.

OBJECTIVE: The purpose of this study was to evaluate the relationship between fetal heart rate patterns and fetal nucleated red blood cell counts. STUDY DESIGN: Data were collected prospectively from March through September 2000. Umbilical cord blood was used for nucleated red blood cell analysis. The fetal heart rate pattern was analyzed for reactivity; presence, duration, and type of decelerations; and time interval between the last acceleration and delivery. RESULTS: Two hundred seventy-nine singleton term pregnancies formed the study population, 67% of which were delivered vaginally. The median nucleated red blood cells per 100 white blood cells was 7 (range, 0-158). The univariate analysis indicated that nucleated red blood cells are correlated significantly with abnormal fetal heart rate patterns, time interval between the last acceleration and delivery, fetal growth restriction, the presence of meconium, and a 1-minute Apgar score of < or =7. However, the stepwise regression analysis identified the time interval between the last acceleration and delivery as the only variable that independently predicted elevated nucleated red blood cell count at birth (P <.0001, R (2) = 0.26). CONCLUSION: Earlier studies have demonstrated an association between adverse perinatal outcome and elevated nucleated red blood cell count. In view of the high false-positive rate that is associated with the prediction of adverse perinatal outcome by fetal heart rate abnormalities, our results support previous studies that indicate that the presence of fetal heart rate accelerations is a reliable predictor of the nonhypoxic fetus.

Male gender predisposes to prolongation of pregnancy.

OBJECTIVE: The purpose of this study was to evaluate the association between fetal gender and prolonged pregnancy. STUDY DESIGN: All deliveries in Sweden between 1987 and 1996 were evaluated for participation in this study. Inclusion criteria included (1) singleton pregnancy, (2) the absence of apparent congenital or chromosomal anomalies, (3) accurate dating established by early second trimester ultrasound examination, and (4) gestational age at delivery of > or =37 weeks (ie, > or =259 days). Initially, we calculated the mean gestational age at delivery and the percentage of prolonged pregnancies by fetal gender. Subsequently, the Mantel-Haenszel chi-square analysis was used to calculate the weekly odds ratios and their corresponding 95% confidence intervals for the delivery of a male fetus beyond 37 weeks of gestation. RESULTS: The study population comprised 656,423 deliveries; 333,192 were male deliveries, and 323,231 were female deliveries (male/female ratio, 1.03). The mean gestational age at delivery was significantly higher in male fetuses (280.6 +/- 8.9 days vs 279.8 +/- 8.6 days, respectively; P <.0001). The percentage of pregnancies that delivered beyond term was significantly higher for male relative to female fetuses (26.5% vs 22.5% [P <.000001] at > or =41 weeks of gestation and 7.6% vs 5.5% [P <.000001] at > or =42 weeks of gestation, respectively). The weekly odds ratios for a delivery of a male fetus beyond term were 1.14, 1.39, and 1.50 at 41, 42, and 43 weeks, respectively. CONCLUSION: Male gender significantly predisposes to the prolongation of pregnancy to the extent that, by 43 weeks of gestation, there are 3 male deliveries for every 2 female deliveries.

A randomised comparison of early versus late amniotomy following cervical ripening with a Foley catheter.

OBJECTIVES: Ripening of the cervix with a Foley catheter commonly results in cervical dilatation without contractions. We examined the outcome of labour in women who underwent induction of labour using a Foley catheter, followed by either 1. early amniotomy, or 2. augmentation of labour by oxytocin and late amniotomy. DESIGN: Prospective randomised clinical trial. SETTING: Labour and delivery ward of a university teaching hospital. PARTICIPANTS: Pregnant women > or =38 weeks of a singleton gestation, who had had no prior caesarean section. METHODS: All women underwent cervical ripening using a Foley catheter. Following removal of the catheter, women were randomly assigned to either early (n = 80) or late amniotomy (n = 88). MAIN OUTCOME MEASURES: Comparison of mode of delivery and duration of labour between the two groups. RESULTS: The rate of caesarean section was significantly higher in the early amniotomy group compared with the late amniotomy group (25% vs 7.9%; relative risk 1.74; 95% CI 1.3 - 2.34). The increase in caesarean section rate was due primarily to dystocia (15% vs 3.3%; relative risk 1.8; 95% CI 1.32 - 2.45). When excluding caesarean deliveries, no significant difference was found in duration of labour between the groups (8.3 hours (3.8) vs 7.7 hours (2.9)). CONCLUSIONS: In women who undergo cervical ripening with a Foley catheter, augmentation of labour by oxytocin followed by amniotomy during active labour results in a lower rate of caesarean delivery for dystocia.