James P. Crane

A randomized trial of prenatal ultrasonographic screening: Impact on the detection, management, and outcome of anomalous fetuses

OBJECTIVE The objective of this randomized clinical trial was to test the hypothesis that ultrasonographic screening would significantly alter perinatal outcome as a result of the antenatal detection of fetal congenital malformations. STUDY DESIGN Pregnant women without a specific indication for ultrasonography were randomly assigned to have either two screening sonograms (15 to 22 weeks and 31 to 35 weeks) or conventional obstetric care with ultrasonography used only as determined by the clinical judgment of the patients physician. The frequency of birth defect detection in the screened and control populations was compared, as was the impact of discovery on pregnancy outcome. RESULTS Major congenital malformations occurred in 2.3% of the 15,281 fetuses and infants in this study. Antenatal ultrasonography detected 35% of the anomalous fetuses in the screened group versus only 11% in the control population (relative detection rate 3.1; 95% confidence interval 2.0 to 5.1). Ultrasonography screening did not, however, significantly influence the management or outcome of pregnancies complicated by congenital malformations. Specifically, only 9 abortions were performed for anomalies among 7685 fetuses in the screened group whereas 4 pregnancies were terminated for fetal anomalies detected among 7596 control subjects. Ultrasonography screening also had no significant impact on survival rates among infants with potentially treatable, life-threatening anomalies despite the opportunity to take precautionary measures such as delivery in a tertiary center. CONCLUSIONS Ultrasonography screening in a low-risk pregnant population had no significant impact on the frequency of abortion for fetal anomalies. Survival rates for anomalous fetuses were also unaffected by screening.

Congenital hydronephrosis: Correlation of fetal ultrasonographic findings with infant outcome

Although congenital hydronephrosis is a common fetal disorder, ultrasonographic criteria for prenatal diagnosis remain poorly defined. In this study prenatal ultrasonographic findings were correlated with postnatal outcome in 63 fetuses with suspected hydronephrosis. Prenatal ultrasonographic measurements included length, anteroposterior diameter, and transverse diameter of the kidney and renal pelvis, as well as dorsal renal parenchymal thickness. In 45 of the 63 fetuses, hydronephrosis was confirmed postnatally. These infants were divided into two groups on the basis of renal status: (1) abnormal renal function and/or surgery required (n = 31) and (2) normal renal function with no surgery required (n = 14). The anteroposterior diameter of the renal pelvis was the simplest and most sensitive technique for prenatal diagnosis of congenital hydronephrosis, allowing identification of 100% of cases. Postnatal follow-up studies are warranted if an anteroposterior pelvic diameter is greater than or equal to 4 mm before 33 weeks or greater than or equal to 7 mm after 33 weeks.

Revisiting the Fetal Loss Rate After Second-Trimester Genetic Amniocentesis : A Single Center's 16-Year Experience

OBJECTIVE: To estimate an institution’s specific fetal loss rate after a second-trimester genetic amniocentesis. METHODS: This is a retrospective cohort study using our prenatal diagnosis database for all pregnant women presenting for care between 1990 and 2006. We compared the fetal loss rate in women who underwent amniocentesis between 15 and 22 weeks of gestation with those women who did not have any invasive procedure and had a live fetus documented on ultrasound examination between 15 and 22 weeks. Only singleton gestations were included. Logistic regression analysis was used to adjust for potential confounders between the groups. RESULTS: Among 58,436 women meeting the inclusion criteria, complete outcome data were available for 51,557 (88%), 11,746 (91%) in the amniocentesis group and 39,811 (87%) in the group that did not have amniocentesis. The fetal loss (miscarriages and intrauterine fetal death) rate in the amniocentesis group was 0.4% compared with 0.26% in those without amniocentesis (relative risk 1.6, 95% confidence interval [CI] 1.1–2.2). Fetal loss less than 24 weeks (including induction for ruptured membranes and oligohydramnios) occurred in 0.97% of the amniocentesis group and 0.84% of the group with no procedure (P=.33). The fetal loss rate less than 24 weeks attributable to amniocentesis was 0.13% (95% CI –0.07 to 0.20%) or 1 in 769. The only subgroup that had a significantly higher amniocentesis attributable fetal loss rate was women with a normal serum screen (0.17%, P=.03). CONCLUSION: The institutional fetal loss rate attributable to amniocentesis is 0.13%, or 1 in 769 at Washington University School of Medicine. The total fetal loss rate was not significantly different from that observed in patients who had no procedure. LEVEL OF EVIDENCE: II

A randomized trial of prenatal ultrasonographic screening: Impact on maternal management and outcome

OBJECTIVES This randomized clinical trial of 15,530 women was designed to test the hypothesis that screening ultrasonography in low-risk pregnancies would improve perinatal outcome. A secondary hypothesis addressed in this article was that screening ultrasonography would have a favorable impact on maternal management or outcome. STUDY DESIGN Pregnant women without a specific indication for ultrasonographic examination in early pregnancy were randomly assigned to have either two screening sonograms or conventional obstetric care. Pregnancy interventions and maternal outcomes were compared in the two groups. RESULTS No significant differences were found in maternal outcomes. Use of ultrasonography was markedly higher in the screened group. The rates of induced abortion, amniocentesis, tests of fetal well-being, external version, induction, and cesarean section and the distribution of total hospital days were similar in the two groups. Use of tocolytics and the rate of postdate pregnancy were both slightly lower in the screened group. CONCLUSION Screening ultrasonography resulted in no clinically significant benefit.

Leiomyomas at routine second-trimester ultrasound examination and adverse obstetric outcomes.

OBJECTIVE: To estimate the risk of adverse pregnancy outcomes associated with the presence of leiomyomas. METHODS: This was a retrospective cohort study of all consecutive singleton pregnancies from 1990 to 2007 undergoing routine second-trimester fetal anatomic ultrasound survey. The presence or absence of leiomyomas was noted at second-trimester ultrasound examination. Primary and secondary obstetric outcomes were obtained as the individual progressed to delivery. Women with at least one leiomyoma at the time of second-trimester anatomic survey were compared with women without leiomyomas. Primary outcomes were intrauterine fetal death, breech presentation, placenta previa, cesarean delivery, placental abruption, preeclampsia, intrauterine fetal growth restriction, preterm premature rupture of membranes, and preterm birth. Univariable and multivariable analyses were performed. RESULTS: Of 72,373 women who underwent routine second-trimester anatomic survey, 64,047 women had complete obstetric follow-up data. The incidence of leiomyomas was 3.2% (n=2,058). Breech presentation (5.3% compared with 3.1%, adjusted odds ratio [OR] 1.5, 95% confidence interval [CI]1.3–1.9), placenta previa (1.4% compared with 0.5%, adjusted OR 2.2, 95% CI 1.5–3.2), cesarean delivery (33.1% compared with 24.2%, adjusted OR 1.2, 95% CI 1.1–1.4), placental abruption (1.4% compared with 0.7%, adjusted OR 2.1, 95% CI 1.4–3.0), preterm premature rupture of membranes (3.3% compared with 2.4%, adjusted OR 1.3, 95% CI 1.0–1.7), preterm birth less than 37 weeks (15.1% compared with 10.5%, adjusted OR 1.5, 95% CI 1.3–1.8), and less than 34 weeks (3.9% compared with 2.8%, adjusted OR 1.4, 95% CI 1.0–1.8), and intrauterine fetal death in women with a fetus with growth restriction (3.9% compared with 1.5%, adjusted OR 2.5, 95% CI 1.2–5.0) were significantly associated with the presence of leiomyomas. CONCLUSION: Women with leiomyomas are at low risk for obstetric complications compared with women without leiomyomas. LEVEL OF EVIDENCE: II

Familial congenital diaphragmatic hernia: Prenatal diagnostic approach and analysis of twelve families

Congenital diaphragmatic hernia is generally recognized as a sporadic malformation with little or no risk of recurrence. A family with three affected individuals in two generations is presented. In addition, new prenatal diagnostic techniques including ultrasonography and amniography are discussed.

Association between pregnancy complications and small-for–gestational-age birth weight defined by customized fetal growth standard versus a population-based standard

Objective. To derive coefficients for developing a customized growth chart for a Mid-Western US population, and to estimate the association between pregnancy outcomes and smallness for gestational age (SGA) defined by the customized growth chart compared with a population-based growth chart for the USA. Method. A retrospective cohort study of an ultrasound database using 54,433 pregnancies meeting inclusion criteria was conducted. Coefficients for customized centiles were derived using 42,277 pregnancies and compared with those obtained from other populations. Two adverse outcome indicators were defined (greater than 7 day stay in the neonatal unit and stillbirth [SB]), and the risk for each outcome was calculated for the groups of pregnancies defined as SGA by the population standard and SGA by the customized standard using 12,456 pregnancies for the validation sample. Results. The growth potential expressed as weight at 40 weeks in this population was 3524 g (standard error: 402 g). In the validation population, 4055 cases of SGA were identified using both population and customized standards. The cases additionally identified as SGA by the customized method had a significantly increased risk of each of the adverse outcome categories. The sensitivity and specificity of those identified as SGA by customized method only for detecting pregnancies at risk for SB was 32.7% (95% confidence interval [CI] 27.0–38.8%) and 95.1% (95% CI: 94.7–95.0%) versus 0.8% (95% CI 0.1–2.7%) and 98.0% (95% CI 97.8–98.2%)for those identified by only the population-based method, respectively. Conclusion. SGA defined by customized growth potential is able to identify substantially more pregnancies at a risk for adverse outcome than the currently used national standard for fetal growth.

Evaluating the Rate and Risk Factors for Fetal Loss After Chorionic Villus Sampling

OBJECTIVE: To estimate the fetal loss rate in our center and evaluate the risk factors associated with such losses after chorionic villus sampling (CVS). METHODS: This is a retrospective cohort study including all women undergoing chorionic villus sampling and a control group that had no invasive procedure at a single center over a 16-year period. Fetal loss was defined as any loss before 24 weeks of gestation. Univariable and multiple logistic regression analyses were used to compare pregnancies resulting in fetal loss to those without a loss and to adjust for potential confounders between the groups. RESULTS: Of 5,243 women who had CVS who were compared with 4,917 women seen before 14 weeks who had no invasive procedure, there were 138 (2.7%) fetal losses before 24 weeks of gestation in the CVS group compared with 161 (3.3%) in the control group (relative risk 0.80, 95% confidence interval, 0.64–1.0). The difference in loss rate of –0.7% (95% confidence interval, –0.02 to 1.3) between the CVS group and those who had no procedure was not statistically significant at P<.05. The significant risk factors for fetal loss were African-American maternal race, at least two aspirations/needle insertions, heavy bleeding during CVS, maternal age younger than 25 years, and gestational age at performing CVS before 10 weeks. CONCLUSION: The estimated fetal loss rate after CVS was not significantly different from the group that had no procedure. Significant predictors of fetal loss after CVS were identified, but the accuracy of the final model for predicting fetal loss was only modest. LEVEL OF EVIDENCE: II

Effect of placenta previa on fetal growth

OBJECTIVE To estimate the association between placenta previa and abnormal fetal growth. STUDY DESIGN Retrospective cohort study of consecutive women undergoing ultrasound between 15 and 22 weeks. Groups were defined by the presence or absence of complete or partial placenta previa. The primary outcome was intrauterine growth restriction (IUGR), defined as a birthweight <10th percentile by the Alexander growth standard. Univariable, stratified, and multivariable analyses were used to estimate the effect of placenta previa on fetal growth restriction. RESULTS Of 59,149 women, 724 (1.2%) were diagnosed with a complete or partial previa. After adjusting for significant confounding factors (black race, gestational diabetes, preeclampsia, and single umbilical artery), the risk of intrauterine growth restriction remained similar (adjusted odds ratio, 1.1; 95% confidence interval, 0.9-1.5). The presence of bleeding did not impact the risk of growth restriction. CONCLUSION Placenta previa is not associated with fetal growth restriction. Serial growth ultrasounds are not indicated in patients with placenta previa.

Is genetic amniocentesis warranted when isolated choroid plexus cysts are found

Our aim was to evaluate the prevalence of trisomy 18 in the setting of isolated fetal choroid plexus cysts and then to consider the risk of trisomy 18 versus the risks of genetic amniocentesis. Fetuses with choroid plexus cysts were prospectively obtained from a total mid‐trimester population of 18 861 fetuses with known outcomes. If the fetuses had trisomy 18, they were part of the study group and part of the control group if they had normal karyotypes. Scans were retrospectively reviewed for the characterization of cysts according to size, laterality, and appearance (simple or complex echo patterns). Chi‐square analysis of contingency tables of results was performed. 208/18 861 (1·1 per cent) fetuses had choroid plexus cysts. 201/208 (96·6 per cent) were normal fetuses or newborns, while 7/208 (3·4 per cent) of the fetuses with choroid plexus cysts had trisomy 18. Overall, 16 fetuses had trisomy 18 and seven (44 per cent) of these had choroid plexus cysts. 0/16 fetuses had choroid plexus cysts as the only sonographic finding. Although laterality or complexity of the cysts did not correlate with the presence or absence of a cytogenetic abnormality, cysts ⩾10 mm were more often associated with trisomy 18 than with a normal karyotype (P<0·01). We conclude that the discovery of choroid plexus cysts in otherwise normal fetuses in the late second trimester does not by itself justify the risks of genetic amniocentesis.