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Biomedical subjects

J P Crane

Publications and source records attributed to J P Crane.

At least 19 recordsLinked to original sources
PubMed1996

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 18861 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. 208/18861 (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 > or = 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.

Adult↗
PubMed1996

The clinical significance of ultransonographically detected subchorionic hemorrhages.

OBJECTIVES: The null hypothesis is that there is no difference in outcome when pregnancies with ultrasonographically documented subchorionic hemorrhages are compared with those without these hemorrhages. STUDY DESIGN: We performed a case-control study, utilizing our computerized ultrasonographic database. Cases were matched with two or three controls in two separate control groups. Matching criteria were maternal age, gestational age at scan, and invasive procedures (chorionic villus sampling or amniocentesis). General exclusion criteria were absence of fetal heart motion and fetal anomalies. Presence of subchorionic hemorrhage was an exclusion criterion for both control groups; however, in addition, presence of vaginal bleeding was a further criterion for one of the two. Statistical analysis was performed with chi2 analysis and Yates' correction. Odd ratios and 95% confidence intervals were calculated. RESULTS: There was no difference in maternal characteristics between the cases and controls. The incidence of subchorionic hemorrhage was 1.3%. There was an increased risk of miscarriage (odds ratio 2.8, 95% confidence interval 1.7 to 7.4), stillbirth (4.5, 1.5 to 13.2), abruptio placentae (11.2, 2.7 to 46.4), and preterm labor (2.6, 1.5 to 4.6) when cases were compared with controls without subchorionic hemorrhage or bleeding. These risks were also increased in comparison with the control group with bleeding, except with respect to miscarriage. In this case the risks were similar in both cases and controls but increased with respect to the controls without bleeding. The mean birth weight was lower in the cases than in both control groups. CONCLUSION: The presence of an ultransonographically detected subchorionic hemorrhage increases the risk of miscarriage, stillbirth, abruptio placentae, and preterm labor. The presence of bleeding alone appears to increase the risk of miscarriage. It is unclear whether the subchorionic hemorrhage is causative or whether it is simply a sign of an underlying process that produces these negative effects.

Abortion, Spontaneous↗
PubMed1994

Optimal nuchal skin-fold thresholds based on gestational age for prenatal detection of Down syndrome.

OBJECTIVE: We attempted to determine optimal nuchal skin-fold thresholds throughout the second trimester of pregnancy for the detection of Down syndrome. STUDY DESIGN: Thresholds of 5, 6, and 7 mm were prospectively tested in 8138 consecutive midtrimester pregnancies. The pregnancies were divided into early (14 to 18 weeks) and late (19 to 24 weeks) second-trimester time frames. The pregnancies were also subdivided by maternal age, and the same thresholds were tested for efficacy in the women < 35 years old versus those > or = 35 years old. RESULTS: There were a total of 32 fetuses with trisomy 21 in the study population. From 14 to 18 weeks' gestation, a nuchal fold thickness of > or = 5 mm was the optimal threshold. Measurements of this magnitude were found in 2.9% of pregnancies and produced a sensitivity of 42% (11/26) for the detection of Down syndrome. When adjusted for the incidence of Down syndrome in the general population, the 5 mm threshold had a positive predictive value of 1 in 48. In the 19 to 24 week gestational time frame, > or = 6 mm appeared to be the optimal threshold, yielding a positive screen rate of 3.7% with a sensitivity of 83% (5/6). The adjusted positive predictive value was 1 in 38. The sensitivity of nuchal skin-fold thickness for Down syndrome detection was similar in women < 35 and > or = 35 years old. Positive predictive value was better in the women > or = 35 years old because of the higher prevalence of affected fetuses in this group. CONCLUSIONS: Whereas definitive diagnostic testing should still be offered to all women with risk factors for a fetus with trisomy 21, differential nuchal skin-fold thresholds based on gestational age are effective for the detection of Down syndrome in pregnancies at low risk.

Adult↗
PubMed1994

A randomized trial of prenatal ultrasonographic screening: impact on the detection, management, and outcome of anomalous fetuses. The RADIUS Study Group.

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 patient's 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.

Abortion, Induced↗
PubMed1993

Effect of prenatal ultrasound screening on perinatal outcome. RADIUS Study Group.

BACKGROUND: Many clinicians advocate routine ultrasound screening during pregnancy to detect congenital anomalies, multiple-gestation pregnancies, fetal growth disorders, placental abnormalities, and errors in the estimation of gestational age. However, it is not known whether the detection of these conditions through screening leads to interventions that improve perinatal outcome. METHODS: We conducted a randomized trial involving 15,151 pregnant women at low risk for perinatal problems to determine whether ultrasound screening decreased the frequency of adverse perinatal outcomes. The women randomly assigned to the ultrasound-screening group underwent one sonographic examination at 15 to 22 weeks of gestation and another at 31 to 35 weeks. The women in the control group underwent ultrasonography only for medical indications, as identified by their physicians. Adverse perinatal outcome was defined as fetal death, neonatal death, or neonatal morbidity such as intraventricular hemorrhage. RESULTS: The mean numbers of sonograms obtained per woman in the ultrasound-screening and control groups were 2.2 and 0.6, respectively. The rate of adverse perinatal outcome was 5.0 percent among the infants of the women in the ultrasound-screening group and 4.9 percent among the infants of the women in the control group (relative risk, 1.0; 95 percent confidence interval, 0.9 to 1.2; P = 0.85). The rates of preterm delivery and the distribution of birth weights were nearly identical in the two groups. The ultrasonographic detection of congenital anomalies had no effect on perinatal outcome. There were no significant differences between the groups in perinatal outcome in the subgroups of women with post-date pregnancies, multiple-gestation pregnancies, or infants who were small for gestational age. CONCLUSIONS: Screening ultrasonography did not improve perinatal outcome as compared with the selective use of ultrasonography on the basis of clinician judgment.

Adolescent↗
PubMed1993

A randomized trial of prenatal ultrasonographic screening: impact on maternal management and outcome. RADIUS (Routine Antenatal Diagnostic Imaging with Ultrasound) Study Group.

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.

Female↗
PubMed1992

Sonographically detected hyperechoic fetal bowel: significance and implications for pregnancy management.

OBJECTIVE: The clinical significance of sonographically detected hyperechoic fetal bowel has not been fully established. This report describes the natural history, pregnancy outcome, and associated features of 30 cases of prenatally diagnosed hyperechoic fetal bowel. METHODS: Fetal bowel of similar or greater echogenicity than surrounding bone was considered hyperechoic. Fetuses so diagnosed were compared with matched controls and with our general obstetric population to determine the relative frequencies of cystic fibrosis, perinatal death, fetal growth retardation, and fetal trisomies. RESULTS: The incidence of hyperechoic fetal bowel during the study period was 0.2% (30 of 12,776 fetuses). Four of the 30 fetuses (13.3%) with hyperechoic bowel were found to have cystic fibrosis, as compared with one in 2200 (0.05%) in the general population. Hyperechoic fetal bowel was also associated with increased risks for perinatal death (16.7%, versus 3.8% in matched controls and 1.9% in the general obstetric population) and fetal growth retardation (23.3% versus 1.9% and 5%, respectively). One fetus with hyperechoic bowel had trisomy 18, an incidence of cytogenetic abnormalities of 3.3%. This was not significantly greater than observed in our general obstetric population (1.2%) (P > .25). CONCLUSIONS: The sonographic finding of hyperechoic fetal bowel is associated with an increased risk for cystic fibrosis, perinatal death, and growth retardation. The risk of fetal trisomy in cases of isolated hyperechoic bowel appears small. When detected, hyperechoic bowel should prompt a complete and careful fetal anatomical survey, consideration of parental carrier testing for cystic fibrosis, and serial sonographic assessment of fetal growth, with cytogenetic testing reserved for cases demonstrating other structural malformations.

Cystic Fibrosis↗
PubMed1992

Fetal pyelectasis and Down syndrome: is genetic amniocentesis warranted?

An association between pyelectasis and Down syndrome has recently been reported. The purpose of this investigation was twofold: 1) to test the hypothesis that pyelectasis is more common in fetuses with Down syndrome, and 2) to determine whether genetic amniocentesis should be offered when dilated renal pelves are identified during fetal ultrasound examination. The study population of 5944 fetuses was separated into two groups by infant outcome: 1) phenotypically and/or chromosomally normal, and 2) chromosomally abnormal. Each group was examined for the presence of pyelectasis, defined as an anteroposterior renal pelvic diameter of 4 mm or greater before 33 weeks or 7 mm or greater after 33 weeks. Pyelectasis was observed in 17.4% (four of 23) of Down syndrome fetuses versus only 2% (120 of 5876) of normal controls, a statistically significant difference (P less than .001). The predictive value of pyelectasis for Down syndrome (one in 90) compares favorably with other accepted indications for genetic amniocentesis, such as advanced maternal age and low maternal serum alpha-fetoprotein (MSAFP). When fetuses with concomitant sonographic abnormalities were excluded, the predictive value of isolated pyelectasis fell to one in 340. We conclude that although renal pyelectasis is more common in Down syndrome fetuses, genetic amniocentesis should be reserved for those cases presenting other risk factors such as advanced maternal age, low MSAFP, or other sonographic abnormalities.

Amniocentesis↗
PubMed1991

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.

False Positive Reactions↗
PubMed1991

Sonographic recognition of major malformations and aberrant fetal growth in trisomic fetuses.

Structural malformations and growth retardation are commonly observed in chromosomally abnormal newborns. This study assesses the sensitivity of ultrasound for detecting aberrant fetal growth patterns and chromosome-related major malformations. The study population consisted of 74 trisomic fetuses (trisomy 13, 9; trisomy 18, 22; trisomy 21, 43). Overall, 63% (38 of 60) of trisomic fetuses had at least one major malformation on postnatal examination. One or more major anomalies were identified by prenatal sonography in 68% (26 of 38) of these malformed fetuses and 43% (26 of 60) of the entire trisomic population. Midtrimester onset growth retardation was evident in 43% of fetuses with trisomy 13 and 59% of fetuses with trisomy 18. These findings suggest that a systematic fetal anatomic survey can be a powerful screening tool for the prenatal detection of chromosome abnormalities.

Chromosome Aberrations↗
PubMed1991

Sonographically measured nuchal skinfold thickness as a screening tool for Down syndrome: results of a prospective clinical trial.

Second-trimester sonographic measurement of nuchal skinfold thickness has been proposed as a potential screening tool for Down syndrome detection. The feasibility of this technique was tested in a prospective study of 3338 consecutive pregnancies at 14-21 weeks' gestation. A nuchal skinfold thickness of 6 mm or greater was identified in 47 fetuses (1.4%), 12 of whom proved subsequently by either amniocentesis or postnatal follow-up to have Down syndrome. The sensitivity of nuchal skinfold thickness for Down syndrome detection was 75% (12 of 16 cases). When adjusted for the incidence of Down syndrome in the general population (one in 710 births), the positive predictive value of nuchal skinfold thickness for Down syndrome detection was one in 13. The observed sensitivity, false-positive rate, and predictive value suggest that amniocentesis should be offered when a nuchal skinfold thickness of 6 mm or greater is observed between 14-21 weeks' gestation.

Adolescent↗
PubMed1990

Exclusion of chromosomal mosaicism in amniotic fluid cultures: efficacy of in situ versus flask techniques.

Accurate diagnosis of mosaicism in amniotic fluid cell cultures represents a major problem. If insufficient cells are analysed, true fetal mosaicism may go undetected. False-positive diagnosis is also possible since a second cell line may arise in vitro and not reflect the true fetal genetic constitution. These difficulties apply to both flask and in situ culture techniques, to varying degrees. The relative accuracy of flask versus in situ culture techniques in excluding mosaicism was determined by statistical analysis of experimental data from ten pairs of mixed male-female amniotic fluid specimens. The data support the idea that the majority of in situ colonies are independent of one another. The following conclusions are drawn: (1) analysis of a single metaphase from a number of different colonies enhances the confidence for excluding mosaicism; (2) analysis of more than one cell per colony offers little advantage; (3) exclusion of a given level of mosaicism requires analysis of fewer metaphases using the in situ method; (4) the confidence for excluding mosaicism is high with both in situ and flask techniques, using the provided guidelines; and (5) it is shown that the two-stage approach used by many laboratories is currently the most efficient way to exclude mosaicism.

Amniotic Fluid↗
PubMed1990

Correlation between phenotypic expression of de novo marker chromosomes and genomic organization using replicational banding.

It has been suggested that actively expressed genes are primarily located in early replicating bands. This hypothesis is supported by cytogenetic and pregnancy outcome data from four consecutive cases of prenatally detected de novo marker chromosomes. Two fetuses with major anomalies had large early replicating bands, while the marker in a third phenotypically normal fetus was late replicating. In the fourth case, a ring marker chromosome had only a small early replicating region. Pregnancy termination was elected. While no structural malformations were apparent, potential intellectual function in this case remains unresolved. An understanding of the relationship between genomic organization and chromosome banding is critical in counseling for prenatally detected de novo marker chromosomes. Replicational banding is particularly helpful in recognizing genes that may be actively expressed and result in developmental abnormality.

Adult↗
PubMed1989

Direct preparations from chorionic villi--relationship between villous morphology and mitotic index.

It has been postulated that chorionic villi with abundant sprouts have a higher mitotic index and are therefore preferable for obtaining direct chromosome preparations from chorionic villus samples. This theory was tested by correlating villous morphology with mitotic index. Surprisingly, no statistically significant relationship was found. Choice of culture medium, however, was found to be important, with serum-free RPMI yielding a higher mitotic index than 40 per cent FCS in MEM. We conclude that villous morphology, as assessed in this study, is not a major factor in determining the success of direct chromosome preparations.

Cells, Cultured↗
PubMed1989

Prenatal fetal adrenal suppression following in utero diagnosis of congenital adrenal hyperplasia.

Congenital adrenal hyperplasia due to 21-hydroxylase deficiency can result in marked virilization of the external genitalia of affected female subjects. Theoretically, suppression of the fetal pituitary-adrenal axis with glucocorticoid during gestational weeks 9 to 17 should prevent the development of ambiguous genitalia in the female fetus. Prenatal diagnosis of congenital adrenal hyperplasia can be made on elevated amniotic fluid 17-hydroxyprogesterone and adrenal androgen concentrations, and HLA typing of cultured amniotic fluid cells. However, these tests cannot be completed before 16 to 17 weeks of gestation, and maternal therapy would have to be instituted before the exact genetic status of the fetus is known. Chorionic villus sampling during the first trimester provides an alternative to second trimester diagnosis in patients who are at risk for bearing offspring with congenital adrenal hyperplasia. We report the use of dexamethasone suppression at 8 weeks of gestation in a 34-year-old woman whose son had congenital adrenal hyperplasia due to severe salt-losing 21-hydroxylase deficiency and whose biopsy revealed a 46XX chromosomal pattern. Cultured cells from the biopsy confirmed the fetus to be of identical HLA haplotype to the previous affected sibling. At 41 weeks the patient delivered a female neonate with minimal prominence of the clitoris, mildly rugated labia, a single perineal opening and minimal posterior labial fusion. Postnatal tapering of maternal steroids was performed with no long-term sequelae.

Adrenal Hyperplasia, Congenital↗
PubMed1989

Differential diagnosis of first trimester ventral wall defect.

Documentation of early fetal developmental events has become possible with the use of high-resolution sonography. We report two cases of first trimester physiologic bowel herniation and contrast them with a first trimester diagnosis of omphalocele. The normal development of the fetal abdominal wall and the mechanisms proposed for pathogenesis of omphalocele are reviewed. The sonographic differentiation between physiologic herniation and pathologic ventral wall defects may be very subtle, making definitive first trimester diagnosis difficult.

Abdominal Muscles↗