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Biomedical subjects

B R Benacerraf

Publications and source records attributed to B R Benacerraf.

At least 37 records · Page 2Linked to original sources
PubMed1998

The second-trimester fetal iliac angle as a sign of Down's syndrome.

OBJECTIVE: To determine whether the iliac angle of second-trimester fetuses is a useful sonographic marker for the detection of fetuses with Down's syndrome. METHODS: We prospectively measured the iliac angle for all fetuses karyotyped over a 17-month period. A transverse view of the upper fetal pelvis was obtained at the time of amniocentesis and, by means of a protractor, the angle between the two iliac bones was measured. The angles of all those fetuses with Down's syndrome and the first 500 fetuses with normal karyotypes were compared, as was gestational age and maternal age. RESULTS: Nineteen fetuses with Down's syndrome and 1167 fetuses with normal karyotypes underwent genetic amniocentesis over the study period. The mean gestational age of the fetuses with Down's syndrome was 16.6 weeks (+/- 1.9 weeks), and for the controls, 16.1 weeks (+/- 1.4 weeks) (p = 0.3). The mean maternal ages were 34.7 years (+/- 4.8 years) and 35.4 years (+/- 4.1 years) for those pregnancies with Down's syndrome and with normal karyotypes, respectively (p = 0.5). The mean iliac angle was 80.1 degrees (+/- 19.7 degrees) for those fetuses with Down's syndrome, and 63.1 degrees (+/- 20.3 degrees) for those fetuses with normal karyotypes (p = 0.0004). The iliac angle was at least 90 degrees in 36.8% (seven of 19 fetuses) with Down's syndrome and in 12.8% (64 of 500 fetuses) with normal karyotypes (p = 0.003). CONCLUSION: Fetuses with Down's syndrome have a significantly larger iliac angle than fetuses with normal karyotypes. Use of an iliac angle cut-off point of 90 degrees would identify over one-third of second-trimester fetuses with Down's syndrome. However, because of the high false-positive rate (12.8%), the iliac angle is not useful in a high-risk population as a screening test when used in isolation.

Adult↗
PubMed1998

Significance of an echogenic intracardiac focus in fetuses at high and low risk for aneuploidy.

Our objective was to evaluate the significance of an echogenic intracardiac focus in a mixed population of fetuses at high and low risk for aneuploidy. Over a 1 year period, we prospectively identified all fetuses with an echogenic intracardiac focus seen during prenatal sonography. A detailed structural evaluation was performed on each fetus as permitted by gestational age. The location and number of foci were tabulated prospectively, as were associated abnormalities. Follow-up was obtained by review of the medical record. Of the 290 fetuses who had an echogenic intracardiac focus, 14 of them were aneuploid (4.8%). Of the 290 mothers, 125 women were aged 35 years or older and 165 women were younger than 35 years old. Among the 125 fetuses born to women 35 years or older, eight were aneuploid fetuses (6.4%), while among the 165 fetuses of younger mothers, six were aneuploid fetuses (3.6%) (rate ratio = 1.8; 95% confidence interval [extremes] = 0.6, 4.9). Only one of the 14 aneuploid fetuses had an echogenic intracardiac focus as the only sonographic finding, and this occurred in a woman aged 41 years. The majority of the echogenic intracardiac foci (87.6%) were located in the left ventricle, while 4.8% of the foci were right-sided and 7.6% were bilateral. Among the 14 aneuploid fetuses, 14% had bilateral echogenic intracardiac foci and 7% had right-sided foci. Among the euploid fetuses, 7.3% had bilateral echogenic intracardiac foci and 4.7% had right-sided foci. In conclusion, we have shown that the presence of an echogenic intracardiac focus does raise the risk that the fetus has a chromosomal abnormality, most commonly Down syndrome, although all but one aneuploid fetus in our study had other sonographic findings.

Adult↗
PubMed1997

The iliac angle as a sonographic marker for Down syndrome in second-trimester fetuses.

OBJECTIVE: To determine whether measurements of the iliac wing angle on sonograms of the second-trimester fetus can be used to detect fetuses at increased risk for Down syndrome. METHODS: All second-trimester Down syndrome fetuses karyotyped by amniocentesis over 5 years for whom adequate views of the iliac bones were available were reviewed retrospectively. The control group consisted of consecutive, normal second-trimester fetuses undergoing karyotyping during the same period. The angles between the iliac bones of the fetal pelves were measured on transverse sonograms, and the two groups were compared. A separate prospective evaluation of the ideal level for measurement of the iliac angle was made in two fetuses, one with and one without Down syndrome. RESULTS: We evaluated 38 Down syndrome and 46 control fetuses. The mean iliac-angle measurements differed significantly for the Down syndrome fetuses as compared with normal control fetuses: 78.8 degrees +/- standard deviation (SD) 18.5 and 66.9 degrees +/- SD 13.9, respectively. An iliac angle of at least 90 degrees was measured in 14 (36.8%) Down syndrome fetuses and in two (4.3%) control fetuses, also a significant difference. In a prospective pilot evaluation of two fetuses, we measured the largest iliac angle at the most cephalad level of the iliac bones, and the smallest angle was measured at the most caudad level. The iliac angle measurements for the fetus with Down syndrome ranged from 55 degrees to 100 degrees; for the normal fetus, the range was 52 degrees to 80 degrees. CONCLUSION: Although there is considerable overlap, the average iliac angle for fetuses with Down syndrome is significantly larger than that of normal fetuses. The angle measurement varies widely in any given fetus and is dependent on the level of the image. A prospective study is needed to evaluate the best level of angle measurement for the detection of fetuses with Down syndrome.

Adult↗
PubMed1997

The incorporation of maternal age into the sonographic scoring index for the detection at 14-20 weeks of fetuses with Down's syndrome.

Sonographic markers for Down's syndrome have been useful in the identification of affected fetuses. In this study, we evaluated the accuracy of an expanded scoring index that included recently described sonographic markers as well as maternal age to optimize identification of fetuses with Down's syndrome. Over a 27-month period, we performed 4075 genetic amniocenteses for advanced maternal age or an abnormal triple panel. Prior to each amniocentesis, a complete sonographic assessment of the fetus was performed including a structural survey and fetal biometry. Each patient was assigned a score based on the sonographic markers in a previously reported scoring system, modified by the addition of an echogenic intracardiac focus. The sonographic scoring system was then combined with the assignment of additional points based on maternal age. Karyotypic results were obtained subsequent to the scans, and Down's syndrome fetuses and a control group of normal fetuses were compared. Fifty-three fetuses with Down's syndrome were identified by karyotype and compared to a control group of 177 normal fetuses. A score of > or = 2 as a criterion for a positive test resulted in the identification of 75.4% of fetuses with Down's syndrome, with a 5.7% false-positive rate. A score of > or = 1 increased the sensitivity to 83.0%, with a false-positive rate of 17.5%. The age-adjusted modification resulted in the identification of 86.8% of fetuses with Down's syndrome, with a false-positive rate of 27.1%. It is for the individual patient and her practitioner to weigh the risks and benefits in selecting her options for prenatal diagnosis.

Adult↗
PubMed1997

First trimester isolated fetal nuchal lucency: significance and outcome.

In this study, we determined the outcome in cases of isolated nuchal lucency seen sonographically in the first trimester in fetuses without karyotypic abnormalities. We reviewed all cases of isolated localized fetal nuchal lucency (3 mm or greater) in 9 to 14 week fetuses over a 4 year period. Fetuses with additional sonographic abnormalities were excluded. The width of the nuchal lucency at initial sonogram as well as findings on subsequent scans were tabulated. Karyotypic, pathologic, and clinical follow-up data were obtained. Of 44 fetuses with an isolated, localized first trimester nuchal lucency, one was lost to follow-up and two were excluded owing to pregnancy termination without karyotype or pathologic analysis, thus resulting in 41 fetuses in our study group. Five fetuses (12%) had abnormal karyotypes. Twenty-seven of the remaining 36 fetuses had normal karyotypes, eight others showed no evidence of aneuploidy at birth, and one patient underwent spontaneous abortion prior to a karyotypic analysis. Among the 36 fetuses without evidence of aneuploidy, six had a poor outcome: two were spontaneous abortions, one was a therapeutic abortion of a fetus with hydrops and a pericardial effusion seen on fetopsy; one fetus died at birth of pulmonary hypoplasia associated with autosomal recessive polycystic kidney disease, and one fetus each had Noonan syndrome, and Joubert syndrome. In addition, three patients delivered their infants prematurely. Overall, 32 of 41 fetuses survived, and two (6%) were abnormal. Excluding premature infants, 27 were normally grown, term survivors. We conclude that other than having an increased risk for aneuploidy, fetuses with isolated nuchal lucency are also at risk for spontaneous miscarriage, premature delivery, and congenital anomalies unassociated with an abnormal karyotype.

Down Syndrome↗
PubMed1997

Unilateral lung hypoplasia: report of three cases.

We describe three cases of unilateral pulmonary agenesis as an etiological basis for a mediastinal shift in utero. This cause of mediastinal shift is easily overlooked in the differential diagnosis, which includes diaphragmatic hernia, adenomatoid cystic malformation, and sequestrations. The sonographic findings and obstetric outcome are presented.

Diagnosis, Differential↗
PubMed1996

Epidemiology of osteochondrodysplasias: changing trends due to advances in prenatal diagnosis.

The osteochondrodysplasias (skeletal dysplasias) are a heterogeneous group of disorders characterized by abnormalities in cartilage and bone growth and development. Some of these disorders are detectable during the second trimester by sonographic techniques. We ascertained cases of osteochondrodysplasias in elective pregnancy terminations, stillborn infants older than 20 gestational weeks, and liveborn infants diagnosed by the fifth day of life as part of an ongoing active malformation surveillance program. Forty-nine cases of osteochondrodysplasias were identified among approximately 126,000 deliveries at Brigham and Women's Hospital (BWH) during a 15-year period (Feb. 16, 1972-Feb. 15, 1975; Jan. 1, 1979-Dec. 31, 1990). When cases delivered to women who had planned to deliver at another hospital but were transferred for high-risk care (transfers) were excluded, the prevalence rate was 2.14 cases per 10,000 deliveries. During the early period (1972-1975) no cases were suspected prenatally, while during the 1988-1990 period, 80% of all cases and 57% of cases delivered to women who had always planned to deliver at BWH (non-transfers) were suspected by ultrasonography. Birth status changed through our period of surveillance. In the final 3-year period (1988-1990), 40% of all cases and 29% of non-transfers with osteochondrodysplasias were pregnancy terminations, compared to none during the 1972-1975 period. The increasing frequency of pregnancy terminations complicated the diagnosis of these conditions. Despite extensive evaluation, a definitive diagnosis was not possible in 8 of 49 cases (16%). Biochemical and molecular genetic methods of diagnosis will continue to become more important if the current trend of wide utilization of prenatal sonography and termination of affected pregnancies continues.

Abortion, Induced↗
PubMed1996

Fetal ultrasonography in maternal PKU.

Maternal phenylketonuria (PKU) is teratogenic and results in birth defects that include microcephaly, mental retardation, congenital heart disease, and intrauterine growth retardation. Treatment with a low phenylalanine diet can prevent or reduce the severity of the complications. Optimal benefit, however, requires frequent monitoring with fetal ultrasonography as a critical element. We have studied ultrasonography in 39 pregnancies enrolled in the Maternal PKU Collaborative Study and followed at our centre. First-trimester examinations in 24 pregnancies resulted in the discovery of non-viability in five. In each, this led to discontinuation of the difficult and expensive diet. Among the 33 pregnancies with second-trimester evaluation, congenital heart disease was identified in five. Two of these pregnancies were terminated. Microcephaly as determined by biparietal diameter (BPD) was identified in the second trimester in only one of nine fetuses who had microcephaly at birth. Among 20 pregnancies with third-trimester ultrasound, fetal microcephaly was identified by BPD in three of seven who had birth microcephaly. We conclude that fetal ultrasonography in maternal PKU is valuable during the first trimester in identifying non-viable pregnancies and determining gestational age and is also valuable during the second trimester in identifying congenital heart disease and perhaps other major anomalies, but not in identifying fetal microcephaly. Third-trimester ultrasound seems to be of limited usefulness.

Female↗
PubMed1996

Acute reversal of oligohydramnios-polyhydramnios sequence in monochorionic twins.

Two cases of monochorionic diamniotic twin gestation with severe oligohydramnios-polyhydramnios sequence ('stuck' twin) are described. In each of these cases there was a marked fluctuation in amniotic fluid volume and reversal of which twin was 'stuck'. The definitive identification of the twins was evident due to a discordant fetal malformations in each twin pair.

Adult↗
PubMed1996

Outcome of singleton pregnancies with severe oligohydramnios in the second and third trimesters.

We evaluated the significance of severe oligohydramnios, or anhydramnios, in the second and third trimesters, by determining the range of etiologies as well as the differences in fetal and neonatal outcome. All prenatal ultrasound results on pregnancies found to have severe oligohydramnios over a 7.5-year period at 13-42 weeks' gestation were retrospectively collected. Follow-up results were obtained from review of medical records, autopsies and pathology reports. A total of 250 singleton pregnancies met the criteria of having severe oligohydramnios. A bimodal distribution in gestational age at diagnosis was seen, with more cases diagnosed at 13-21 weeks and at 34-42 weeks. Fetal abnormalities were present in 50.7% of those diagnosed with severe oligohydramnios in the second trimester and in 22.1% of those in the third trimester. There were 10.2% and 85.3% survivors when severe oligohydramnios was diagnosed in the second and third trimesters, respectively. The rate of aneuploidy was at least 4.4% for the entire singleton population. A bimodal distribution of pregnancies presenting with severe oligohydramnios represents two different naturally occurring populations in terms of both etiology and prognosis.

Female↗
PubMed1996

The second-trimester fetus with Down syndrome: detection using sonographic features.

Down syndrome (trisomy 21) is the most common chromosomal abnormality among liveborn infants in the United States, with an incidence of 1/700 to 1/1000 births. Its incidence rises with maternal age, thus prompting the current practice of offering genetic amniocentesis to women 35 years of age or older. However, even if every pregnant woman of advanced maternal age (> or = 35 years) were to undergo karyotyping, only 20% of fetuses with Down syndrome would be detected. Until approximately 10 years ago, karyotyping of the fetuses of older women was practically the only antenatal method of identifying any fetus with trisomy 21. In 1984, Cuckle and associates first reported the use of a low level of serum alpha-fetoprotein as a screening tool for identifying affected fetuses in younger women. Combining the criteria based on both maternal age and serum alpha-fetoprotein resulted in identifying 40% of fetuses with Down syndrome, as well as 6.8% of unaffected fetuses. Still, at least 60% of fetuses with Down syndrome remained undetected with these screening techniques. It is logical to expect that sonographic imaging of the second-trimester fetus itself would result in the optimal detection of the anatomical features of Down syndrome (Figure 1). To this end, many researchers have attempted to identify sonographic findings that would serve to detect fetuses likely to have Down syndrome. This review summarizes the characteristic sonographic findings associated with an increased risk of a fetus having trisomy 21.

Dilatation, Pathologic↗
PubMed1996

Uterine arcuate artery Doppler and decidual microvascular pathology in pregnancies complicated by type I diabetes mellitus.

The objective was to correlate Doppler indices from the uterine arcuate arteries with an analysis of the decidual vascular histology in patients with type I diabetes. Pulsed wave Doppler was used to sample the uterine arcuate artery system beneath the placenta within 8 days of delivery in 47 patients with type I diabetes mellitus. A placental pathologist, without knowledge of either clinical outcome or Doppler information, classified the histological appearance of the decidual arteries as normal, type A (hyalinization, mural thickening), or type B (fibrinoid necrosis, atherosis, thrombosis). Patients were then grouped according to the histology of the decidual arteries. An analysis of variance (ANOVA) of the systolic/diastolic (S/D) ratios (log. S/D) showed significant variation (p < 0.025). A multiple range comparison test showed that patients with normal or only mildly abnormal (type A) vessels had similar values, whereas those with severe vasculopathy (type B) had significantly higher S/D ratios (p < 0.05). The study confirmed a relationship between arcuate artery Doppler indices and downstream decidual vascular pathology.

Arteries↗
PubMed1996

Choroid plexus cysts: not associated with Down syndrome.

We sought to determine whether there is an association between choroid plexus cysts identified in the second-trimester fetus and trisomy 21. Over a 7-year period, fetuses scanned between 14 and 22 weeks were prospectively evaluated for the presence of choroid plexus cysts. Follow-up on fetuses with choroid plexus cysts was obtained by review of the medical records. Over the same time period, the scans and reports of all fetuses with trisomy 21 detected in our laboratory by mid-trimester amniocentesis were reviewed. The prevalence of choroid plexus cysts in fetuses with and without trisomy 21 were compared by means of X2 analysis. A total of 473 fetuses with choroid plexus cysts were identified among 32,053 second-trimester fetuses. Sixteen fetuses were lost to follow-up, three had structural defects and normal karyotypes and 21 had abnormal karyotypes, two of which were trisomy 21. Other abnormal karyotypes included trisomy 18, unbalanced translocation and triploidy, previously reported elsewhere. The remaining 433 fetuses either had normal karyotypes or were normal newborns. The prevalence of choroid plexus cysts (excluding fetuses with trisomy 18) was 1.38% in our general population. During the study period, 143 fetuses with trisomy 21 were karyotyped in our laboratory, and two of these (1.40%) had choroid plexus cysts. Both had other sonographic abnormalities suggesting trisomy 21. The difference in prevalence of fetuses with choroid plexus cysts and trisomy 21 vs. those without trisomy 21 was not statistically significant (X2 = 0.98; relative risk (RR) = 1.02; 95% CI = 0.26, 4.03). We conclude that choroid plexus cysts occur with similar frequency in fetuses with trisomy 21 to that in fetuses from the general population. The finding of choroid plexus cysts should not be used to increase the patient's calculated risk of having a fetus with trisomy 21.

Adult↗
PubMed1996

Agenesis of the corpus callosum: prenatal detection usually is not possible before 22 weeks of gestation.

PURPOSE: To determine whether agenesis of the corpus callosum can be diagnosed prenatally with standard ultrasonographic (US) evaluation before 22 weeks of gestation. MATERIALS AND METHODS: Initial scans obtained on or before 22 weeks and follow-up scans obtained in the third trimester were selected from all cases of agenesis of the corpus callosum diagnosed prenatally at the authors' laboratory. Follow-up was attained by means of review of the medical records and included imaging, karyotype, and clinical outcome. RESULTS: Among 15 fetuses with callosal agenesis confirmed by means of third-trimester scans, 10 had completely normal US scans at 16-22 weeks and five had other US abnormalities. Isolated callosal agenesis was identified in six children with normal development (except one with polydactyly). Among the others, four were developmentally delayed, three died, and two others had abnormal karyotype. CONCLUSION: Standard second-trimester US before 22 weeks of gestation may not show isolated callosal agenesis. Fetuses with this abnormality can have normal second-trimester scans and develop abnormal US findings in the third trimester.

Agenesis of Corpus Callosum↗
PubMed1996

Subchorionic hemorrhage in first-trimester pregnancies: prediction of pregnancy outcome with sonography.

PURPOSE: To determine the effects of subchorionic hematoma size, gestational age, and maternal age on pregnancy outcome in patients with vaginal bleeding in the first trimester of pregnancy. MATERIALS AND METHODS: A retrospective review was performed with ultrasound images obtained in 516 patients with vaginal bleeding, a live fetus, and a subchorionic hematoma in the first trimester. Hematoma size was graded according to the percentage of the chorionic sac circumference elevated by the hematoma. Patients were also classified according to gestational age and maternal age. Logistic regression analysis was used to determine the effect of each variable on pregnancy outcome. RESULTS: The overall spontaneous abortion rate was 9.3% (48 of 516 patients). The rate nearly doubled when the separation was large (18.8%) compared with small and moderate hematomas (7.7% and 9.2%, respectively). A large separation was found to be associated with an almost three-fold increase in risk of spontaneous abortion. The spontaneous abortion rate was approximately twice as high for women aged 35 years or older versus younger women (13.8% and 7.3%, respectively) and for women with bleeding at 8 weeks gestation or less compared with those with bleeding at greater than 8 weeks gestation (13.7% vs 5.9%). CONCLUSION: For women with a subchorionic hematoma that is sonographically identified, fetal outcome is dependent on size of the hematoma, maternal age, and gestational age.

Abortion, Spontaneous↗