Harish M. Sehdev

Predictive factors for neonatal morbidity in neonates with an umbilical arterial cord pH less than 7.00

OBJECTIVE Fewer than 50% of neonates with an umbilical arterial pH < 7.00 have neonatal complications. Our objective was to identify clinical predictive factors for adverse outcomes in this group of neonates. STUDY DESIGN In this case-control study both cases and controls had an umbilical arterial cord pH < 7.00. Cases were defined as those neonates who had seizures, grade 3 to 4 intraventricular hemorrhage, gastrointestinal dysfunction, respiratory distress syndrome requiring intubation, sepsis, or death. Controls had an umbilical arterial cord pH < 7.00 and no complications. A multivariable prediction model was created, with variables having an association with adverse outcome by bivariate analyses, attempting to predict which neonates in this umbilical arterial pH range are at greatest risk for adverse outcomes. RESULTS We identified 73 of 10,705 neonates born between July 1992 and October 1996 with an umbilical arterial cord pH < 7.00. Thirty-five neonates met our case definition, and the remaining 38 composed the control group. Cases had significantly lower arterial pH values and 1- and 5-minute Apgar scores, greater arterial base deficit values, and a higher incidence of abruptio placentae and maternal cocaine use. More cases were delivered before 34 weeks. There were three neonatal deaths, two cases of grade 3 or 4 intraventricular hemorrhage, five cases of gastrointestinal dysfunction, and four cases of neonatal seizures. In our predictive model for adverse neonatal outcome, an arterial base deficit > or = 16 mmol/L and a 5-minute Apgar score < 7 had a sensitivity and a specificity of 79% and 80.8%, respectively. CONCLUSION Neonatal morbidity in neonates with an umbilical arterial cord pH < 7.00 can be predicted by a high arterial base deficit value and low 5-minute Apgar score.

Transvaginal ultrasonography of the cervix to predict preterm birth in women with uterine anomalies

Objective: Women with uterine anomalies have higher rates of preterm birth, but the reason for this has not been elucidated. Transvaginal ultrasound examination has been shown to be an accurate test for the prediction of preterm birth but has not been studied specifically in this population. Methods: Pregnant women with uterine anomalies were followed prospectively with transvaginal ultrasound examination of the cervix, performed between 14 and 23 6/7 weeks of gestation. A short cervical length was defined as less than 25 mm of cervical length. The primary outcome was spontaneous preterm birth, defined as birth at less than 35 weeks. Results: Of the 64 pregnancies available for analysis, there were 28 with a bicornuate uterus, 13 with a septate uterus, 11 with a uterine didelphys, and 12 with a unicornuate uterus. The overall incidence of spontaneous preterm birth at less than 35 weeks was 11%. Of the 10 (16%) women with a short cervical length, 5 (50%) had spontaneous preterm birth. Of the 54 women without a short cervical length, only 2 (4%) had a spontaneous preterm birth. The sensitivity, specificity, and positive and negative predictive values of a short cervical length for spontaneous preterm birth were 71%, 91%, 50%, and 96%, respectively (relative risk 13.5, 95% confidence interval 3.49–54.74). Of the 7 women with both short cervical length and preterm birth, all uterine subtypes were represented except septate uterus. Conclusion: A short cervical length on transvaginal ultrasonography in women with uterine anomalies has a 13-fold risk for preterm birth. Unicornuate uterus had the highest rate of cervical shortening and preterm delivery. Level of Evidence: II-2

False-positive 1-hour glucose challenge test and adverse perinatal outcomes.

OBJECTIVE: To determine whether a false-positive 1-hour glucose challenge test (GCT) is associated with perinatal complications. METHODS: We performed a retrospective cohort study of 1825 eligible pregnant women among a cohort of 1998 patients. Patients were screened for gestational diabetes mellitus (GDM) with the 1-hour 50-g GCT at 24–28 gestational weeks. A false-positive GCT was defined as a result greater than or equal to 135 mg/dL followed by a normal 3-hour glucose tolerance test (GTT). We compared the negative GCT and false-positive GCT cohorts for a composite perinatal outcome variable that included fetal macrosomia, antenatal death, shoulder dystocia, chorioamnionitis, preeclampsia, intensive care nursery admission, and postpartum endometritis. Secondary outcomes included cesarean delivery and each component variable of the composite. Unadjusted, stratified, and multiple logistic regression analyses were used to investigate the association between a false-positive GCT and the development of perinatal complications. RESULTS: We identified 164 patients with a false-positive GCT and 50 patients with GDM. The false-positive GCT cohort on average was older, of higher parity, had a higher body mass index, and more frequently had chronic hypertension, sickle cell trait, and elevated midtrimester human chorionic gonadotropin levels. The false-positive GCT cohort more frequently had adverse perinatal outcomes, including the composite perinatal outcome (odds ratio [OR] 5.96, 95% confidence interval [CI] 1.47, 24.16), macrosomia greater than 4500 g (OR 3.66, 95% CI 1.30, 10.32), antenatal death (OR 4.61, 95% CI 0.77, 27.48), shoulder dystocia (OR 2.85, 95% CI 1.25, 6.51), endometritis (OR 2.18, 95% CI 1.03, 4.63), and cesarean delivery (OR 1.76, 95% CI 0.99, 3.14). CONCLUSION: A false-positive GCT is an independent risk factor for adverse perinatal outcomes. LEVEL OF EVIDENCE: II-2

The association between fetal nasal bone hypoplasia and aneuploidy

OBJECTIVE: To determine the association between fetal nasal bone hypoplasia and aneuploidy in women undergoing prenatal diagnosis. METHODS: A prospective cohort study involving women undergoing chorionic villus sampling and amniocentesis for an increased risk of aneuploidy. Fetal biometric and nasal bone measurements were obtained at the time of prenatal diagnosis and compared with karyotypes. Nasal bone hypoplasia was defined as nasal bone less than 2.5th percentile for the gestational age. RESULTS: A total of 632 fetuses were evaluated. Twenty-nine (4.6%) had an aneuploidy (18 trisomy 21, 5 trisomy 18, 1 Turners syndrome, one Marker chromosome 1, 2 sex chromosome anomalies, and 2 triploidy). Nasal bone measurements were documented in 29 aneuploid fetuses. The nasal bone was either absent or hypoplastic in 12 of 29 (41%) fetuses with aneuploidy and in 8 of 18 (44%) with trisomy 21. By using receiver operating characteristics curves, the optimal threshold of nasal bone hypoplasia associated with fetal aneuploidy was a biparietal diameter/nasal bone ratio of 11 or greater. The sensitivity, specificity, and positive and negative predictive values for the detection of fetal aneuploidy were 50%, 93%, 24%, and 98%, respectively. CONCLUSION: Absent or hypoplastic nasal bone is a marker for fetal aneuploidy in a high-risk population. However, this marker needs to be evaluated by larger prospective studies in low-risk populations before adoption for clinical use. LEVEL OF EVIDENCE: II-2

A cost-effectiveness analysis of prenatal screening strategies for Down syndrome.

Objective: To evaluate which Down syndrome screening strategy is the most cost-effective. Methods: Using decision-analysis modeling, we compared the cost-effectiveness of 9 screening strategies for Down syndrome: 1) no screening, 2) first-trimester nuchal translucency (NT) only, 3) first-trimester combined NT and serum screen, 4) first-trimester serum only, 5) quadruple screen, 6) integrated screening, 7) sequential screening, 8) integrated serum only, or 9) maternal age. Costs included cost of tests and resources used for raising a child with Down syndrome. One-way and multiway sensitivity analyses were performed for all model variables. The main outcome measures were cost per Down syndrome case detected, rate of delivering a liveborn neonate with Down syndrome, and rate of diagnostic procedure–related pregnancy loss for each strategy. Results: Sequential screening detected more Down syndrome cases compared with the other strategies, but it had a higher procedure-related loss rate. Integrated serum screening was the most cost-effective strategy. Sensitivity analyses revealed the model to be robust over a wide range of values for the variables. The addition of the cost of genetic sonogram to the second-trimester strategies resulted in first-trimester combined screening becoming the most cost-effective strategy. Conclusion: Within our baseline assumptions, integrated serum screening was the most cost-effective screening strategy for Down syndrome. If the cost of nuchal translucency is less than

The association between maternal cocaine use and placenta previa

57 or when genetic sonogram is included in the second-trimester strategies, first-trimester combined screening became the most cost-effective strategy. Level of Evidence: III

EVIDENCE FOR MAGNESIUM SULFATE AS A TOCOLYTIC AGENT

OBJECTIVE Our aim was to determine whether maternal cocaine exposure is a risk factor for placenta previa. STUDY DESIGN In this case-control study, cases of placenta previa confirmed at delivery (ascertained by International Classification of Diseases, ninth revision, Clinical Modification, code-based search, N = 40) were compared with a random sample of patients without placenta previa (N = 80) in a ratio of two controls per case. Data on antecedent maternal cocaine use, as well as other potential risk factors for placenta previa, were obtained from a review of the prenatal chart and the hospital record. Categorization of cocaine use was based on either patient self-report or urine toxicologic testing, or both. Multiple logistic regression was performed to assess the association between cocaine and placenta previa while we controlled for other variables. RESULTS After the effects of other variables were adjusted for, maternal cocaine use was an independent risk factor for placenta previa (adjusted odds ratio = 4.39, 95% confidence interval 1.17 to 16.4). Other significant risk factors included a history of cesarean section and prior elective abortion. CONCLUSION These results suggest that cocaine use, as well as prior cesarean section, prior elective abortion, and parity, are associated with placenta previa.

Neonatal outcome after exposure to indomethacin in utero: a retrospective case cohort study

The objective of our study is to quantitatively examine the available evidence regarding the efficacy and side effects of magnesium sulfate for acute tocolysis (from randomized trials) compared with placebo and beta-agonist agents. Randomized trials comparing magnesium sulfate with placebo or beta-agonists for tocolysis were identified with a MEDLINE-based search and was supplemented by a search of obstetrical textbooks and bibliographies. Trials underwent quality evaluation and data abstraction by two independent, blinded investigators. Outcomes evaluated included delivery delay of various durations as well as the frequency of major and minor side effects. Summary odds ratios and 95 percent confidence intervals for dichotomous outcomes were calculated using a random effects model. Interstudy heterogeneity for these outcomes was assessed with a Q statistic. We identified 12 randomized controlled trials of magnesium sulfate for acute tocolysis. Four studies were excluded because of either lack of comparison of magnesium sulfate to either placebo or beta-agonists or lack of reporting clinical outcomes of interest. The eight remaining randomized trials comparing magnesium sulfate with placebo or beta-agonists were included in this analysis. There was no significant difference between MgSO4 and placebo for any of the measured outcomes for delay in delivery. Comparing magnesium sulfate to ritodrine or beta-agonists did not demonstrate any differences between the agents in achieving clinically significant tocolysis. There was a significant difference between MgSO4 and beta-agonists in the frequency of medication discontinuation because of side effects, but not in the frequency of major adverse drug events. There are few data comparing magnesium sulfate with a placebo for acute tocolysis. Magnesium sulfate seems to be comparable to ritodrine and beta-agonists, although the available data are not sufficient for a rational choice between these agents.

Does Light Pressure Effleurage Reduce Pain and Anxiety Associated With Genetic Amniocentesis? A Randomized Clinical Trial

OBJECTIVE This study was undertaken to determine the clinical outcome for neonates who were exposed to indomethacin during gestation. STUDY DESIGN We identified 124 infants with in utero exposure to indomethacin and matched them to 124 infants whose mothers did not receive indomethacin. The two groups were matched for gestational age at birth, sex, and exposure to antenatal betamethasone. Sixty-two of the indomethacin-exposed infants were born within 48 hours of last exposure. These infants were also compared with their matched controls. RESULTS There were no significant differences between the indomethacin-exposed infants and control infants in birth weight, Apgar scores, frequency of cesarean section deliveries, and multiple gestation. The incidence of respiratory distress syndrome, need for surfactant treatment, patent ductus arteriosus, necrotizing enterocolitis, and intraventricular hemorrhage was similar between the indomethacin-exposed group and the control group. Indomethacin-exposed infants who were born within 48 hours of last exposure had similar incidence of respiratory distress syndrome but greater need for surfactant treatment (P=.02) compared with controls. All other complication rates were similar. CONCLUSION Indomethacin exposure in our study was not associated with increased neonatal complications for infants delivered within or beyond 48 hours of last exposure.

Osteomyelitis of the pubic symphysis in pregnancy.

OBJECTIVE To determine if light pressure effleurage (leg rubbing) during genetic amniocentesis reduces procedure-related pain and anxiety. METHODS Two hundred women with singleton gestations undergoing genetic amniocentesis between 15-22 weeks recorded their level of anticipated pain and anxiety on a 10-cm linear visual analog scale prior to the amniocentesis. Subjects were then randomized to receive effleurage or no effleurage by the assisting nurse during the procedure. Subjects were blinded to the effleurage nature of the study. Following the amniocentesis, subjects repeated the pain and anxiety scoring. RESULTS The two groups were similar with respect to subject and procedure characteristics, as well as anticipated pain or anxiety prior to amniocentesis. Postamniocentesis pain and anxiety scoring were similar in the two groups. The mean effleurage acceptance score was 8.3 +/- 1.8 (out of 10), and 90.2% of subjects reported that they would want effleurage with future amniocenteses. CONCLUSIONS Although well accepted by women, light pressure effleurage during genetic amniocentesis does not reduce procedure-related pain or anxiety.