Sex chromosome markers: characterization using fluorescence in situ hybridization and review of the literature.

Fluorescence in situ hybridization (FISH) using biotin labeled X- and Y-chromosome DNA probes was utilized in the analysis of 23 sex chromosome-derived markers. Specimens were obtained through prenatal diagnosis, because of a presumptive diagnosis of Ullrich-Turner syndrome, mental retardation, and minor anomalies or ambiguous genitalia; three were spontaneous abortuses. Twelve markers were derived from the X chromosome and eleven from the Y chromosome; this demonstrates successfully the value and necessity of FISH utilizing DNA probes in the identification of sex chromosome markers. Both fresh and older slides, some of which had been previously G-banded, were used in these determinations. We have also reviewed the literature on sex chromosome markers identified using FISH.

Maternal thyroid function does not alter maternal serum alpha-fetoprotein interpretation.

OBJECTIVE: Endocrine alterations of metabolism such as diabetes and obesity are known to affect maternal serum alpha-fetoprotein interpretation. Thyroid function has been questioned, e.g., because of binding globulins, but not adequately studied as to its impact upon maternal serum alpha-fetoprotein. The purpose of this study was to assess the possible effects of T4 and thyroid-stimulating hormone (TSH) on alpha-fetoprotein production, and to determine if thyroid function (hypothyroidism) alters maternal serum alpha-fetoprotein. METHODS: We evaluated maternal serum alpha-fetoprotein, T4, and TSH records of 25,551 patients, between 14 and 20 weeks' gestation, on whom both studies had been ordered by the patient's primary obstetrician to rule out maternal thyroid disease in pregnancy. Statistical analyses were performed by chi 2 and regression analysis. RESULTS: Patients were stratified according to thyroid function tests into two groups: hypothyroidism (T4 < 6.5 micrograms/dL and/or TSH > 5.0 micrograms/mL), and normal or hyperthyroidism (T4 > or = 6.5 micrograms/dL and/or TSH > or = 5.0 microU/mL). Maternal serum alpha-fetoprotein values were compared among groups for each gestational age. No significant variation or correlation of maternal serum alpha-fetoprotein and thyroid function was observed. CONCLUSIONS: Although other endocrine abnormalities are known to impact maternal serum alpha-fetoprotein values either through decreased production, decreased placental permeability, or plasma volume distribution alterations, maternal thyroid status does not interfere with proper interpretation of maternal serum alpha-fetoprotein.

Hyperemesis gravidarum. Effects on fetal outcome.

OBJECTIVE: To study perinatal outcomes in pregnancies complicated by hyperemesis gravidarum (HG) as compared to controls. STUDY DESIGN: Between 1984 and 1991, 138 patients were diagnosed with HG according to Fairweather's criteria. Subjects were stratified into groups of mild and severe HG according to the presence of at least one of the following criteria: ketonuria, increased blood urea nitrogen and hematocrit, and/or abnormal electrolytes. All patients without HG on whom records were available and who delivered during the study period were included as controls. Multiple gestations and stillbirths were excluded from the analysis. Student's t test and X2 were used for statistical analysis. RESULTS: Demographic data were not significantly different between the groups. Forty patients were diagnosed as having mild HG and 98 patients as having severe; 12,335 patients were defined as controls. Mean fetal birth weights were 3,110, 3,093, and 3,160 g in the mild, severe and control groups, respectively. The incidence of congenital anomalies was 2.5%, 2.0% and 1.6%, respectively. The incidence of prematurity was 17.5%, 11.2% and 10.7% in mild and severe HG and controls, respectively. None of the outcome variables for mild or severe HG were significantly different as compared to the controls. Differences in other neonatal outcomes, including frequency of five-minute Apgar score < 7 and neonatal intensive care unit admissions, were not significantly different between the three groups. CONCLUSION: In contrast to previous reports, this study demonstrated that fetuses of gravidas admitted for HG are not at increased risk of growth retardation, congenital anomalies or prematurity. No beneficial effect on pregnancy outcome was detected.

Modified stylet technique for tenting of amniotic membranes.

A modified amniocentesis technique can reduce the failure rate in cases of tenting of the membranes. Failure to aspirate amniotic fluid (AF) because of amniotic membrane tenting may persist after advancement and rotation of the needle. In such cases, the membranes may be pierced by using a stylet that is longer than the length of the needle. With the needle in the middle of a suitable AF pocket, the stylet of the needle is replaced with a longer stylet. Under real-time ultrasonographic guidance, the tip of the stylet is then rapidly advanced 5-10 mm beyond the tip of the needle. During genetic amniocentesis, we have used the longer stylet technique to pierce tented membranes without complications in 21 of 22 cases.

Role of ultrasonography in pregnancies with marker chromosome aneuploidy.

The objective of this report was to evaluate the effect of ultrasonographic (US) findings on pregnancy management in patients with marker chromosome (MC) aneuploidy ascertained through prenatal diagnosis. From 1989 through June 1993, 15,522 prenatal diagnostic procedures were performed for accepted indications. Charts of patients with MC on amniocentesis or chorionic villus sampling (CVS) karyotype were evaluated with respect to US anomalies, pregnancy complications, and outcome. Nineteen cases of MC were identified. The prevalence of MC in our study was 0.12% (1:816 procedures). No significant difference between CVS and amniocentesis was found: 5/19 (26%) were CVS specimens, which is comparable to our CVS (3,259/15,522) case distribution. Three cases with incomplete records were excluded from the analysis. Four inherited MC cases were identified: 1 case had anencephaly. Of the 12 de novo MC cases 4 (33%) had abnormal US findings, and an additional 4 were found to have cytogenetic evidence for partial trisomy. Seven of these 8 abnormal de novo MC cases were terminated. MC aneuploidy is more common in pregnancies sampled for usual genetic indications than previously reported in pediatric series. High-resolution US may identify a major malformation not etiologically related to a MC inherited from a normal phenotypic parent. The association of the novo MC with US anomalies confers a poor prognosis, suggesting the expression of genetic imbalance from the accessory chromatin (partial trisomy). However, when US appears normal on initial and follow-up examinations, the chances for a normal-phenotypic newborn are high.

First-trimester septic abortion due to Salmonella enteritidis Oranienburg.

BACKGROUND: Septic abortion caused by transplacental salmonella infection is extremely rare; there are no reported cases of serotype oranienburg as an etiology. CASE: We describe a patient with non-typhoidal Salmonella enteritidis serotype oranienburg as a cause of first-trimester pregnancy loss. The rapid progression of this patient's septicemia and adverse outcome is described. The epidemiology and natural history of salmonella infections are also discussed. CONCLUSION: Non-typhoidal salmonella is still a cause of morbidity in Western countries. This infection can result in rapid-onset fetal demise and septic abortion.

Fluorescent in situ hybridization and second-trimester sonographic anomalies: uses and limitations.

The critical need for rapid and reliable karyotype analysis can be no greater than in the setting of sonographic fetal anomalies. Fluorescent in situ hybridization (FISH) directly applied to interphase chromosomes can decrease the time required to identify the common aneuploidies. Our retrospective study reviewed 50 consecutive patients with sonographic fetal anomalies who underwent FISH. Within this high risk group, nonmosaic chromosomal aneuploidies were present in 16% of the fetuses (8 of 50), and 2 additional fetuses had cytogenetic abnormalities: 1 case, 46,XY,-12,+der(12)t(12;13)(p13; q14.1), and 1 case a 10% mosaic for trisomy 21. Of the 10 cytogenetically abnormal fetuses, FISH was able to identify correctly all 8 of the nonmosaic aneuploidies within 2 days of receipt of the specimen in the laboratory. Clinical decisions can be made on the basis of concordant FISH and ultrasound abnormalities, shortening the decision-making process for most of the aneuploid cases. However, our experience demonstrates some of the limitations of current FISH protocols and the continued necessity for formal karyotype analysis.

Gastroschisis: can antenatal ultrasound predict infant outcomes?

OBJECTIVE: To test previously proposed but unproven antenatal ultrasound prognostic criteria in fetal gastroschisis. METHODS: Thirty consecutive gastroschisis-affected pregnancies and their outcomes were reviewed retrospectively. Data were tabulated by review of antenatal ultrasound videotapes, with blinded comparison to indicators of short- and long-term infant outcomes obtained from the medical records. Criteria of previous reports were applied to these data, focusing on their ability to prognosticate effectively. RESULTS: Applying a criterion of 10 mm bowel dilatation proved minimally useful in prognosticating infant outcomes. However, a stricter 17-mm criterion for clinically important bowel dilatation provided prognostic information, with remarkable improvement in specificity (75 versus 37%) and positive predictive value (55 versus 37%) for infant morbidity, with comparatively little loss of sensitivity (71 versus 85%). CONCLUSIONS: Bowel dilated more than 17 mm on antenatal ultrasound appears to be associated with increased short- and long-term infant morbidity. Whether this finding warrants obstetric intervention in the preterm gastroschisis-affected pregnancy with substantial bowel dilatation remains to be determined.

Risk of anomalies as a function of level of elevated maternal serum alpha-fetoprotein.

OBJECTIVE: Most neural tube defects risks are not actual but mathematical extrapolations. We sought to evaluate this risk and to compare actual performance. STUDY DESIGN: This was a retrospective study of a referral population with elevated maternal serum alpha-fetoprotein results between 1987 and 1992. Ultrasonography results, delivery records, and autopsy results were compared with entry levels of maternal serum alpha-fetoprotein, and the percentage of fetal anomalies detected in this study was evaluated. RESULTS: A total of 773 patients with elevated maternal serum alpha-fetoprotein levels were evaluated. There was a progressive increase in the incidence of anomalies as a direct function of the level of the maternal serum AFP, varying from 3.4% at a level of 2.5 to 40.3% at a level > 7.0. CONCLUSION: Data from this study support the correlation of maternal serum AFP levels with the risk of neural tube defect and ventral wall defects.

Fluorescent in situ hybridization utilization for high-risk prenatal diagnosis: a trade-off among speed, expense, and inherent limitations of chromosome-specific probes.

OBJECTIVE: The development of fluorescent in situ hybridization chromosome-specific probes has allowed the use of new fetal tissue collection techniques, such as fetal cells in maternal blood and coelocentesis--both of which, with current techniques, cannot generate complete karyotypes. We evaluated chromosome-specific probes for additional potential limitations in the setting of a high-risk prenatal diagnosis center. STUDY DESIGN: The last 24 months of fetal karyotypes from our prenatal cytogenetics laboratory were analyzed for those abnormalities that should be detectable by chromosome-specific probes and those that would likely be missed. RESULTS: In 6006 karyotypes 207 (3.4%) abnormalities were found, of which 104 were common trisomies, 12 triploidies, and 19 monosomies that would have been detected with current probe combinations (13, 18, 21, X, and Y) (135/207, 65.2%). Seventy-two abnormalities (35%) represented other trisomies (16/207, 7.7% for 9, 12, 15, 16) and rearrangements (inversions, translocation markers were 56/207, 27.1%), which would have been missed. CONCLUSIONS: Use of current fluorescent in situ hybridization chromosome-specific probes protocols would have detected only 65% of chromosome abnormalities in our high-risk population. Incomplete ascertainment must be weighed against the cost and speed of fluorescent in situ hybridization chromosome-specific probes when comparing it with traditional karyotyping. Although this new technique may prove useful in low-risk screening programs (fetal cells in maternal blood), its current use in high-risk populations should be questioned until its sensitivity is expanded to identify more subtle and less common chromosomal abnormalities.

In utero surgical treatment of fetal obstructive uropathy: a new comprehensive approach to identify appropriate candidates for vesicoamniotic shunt therapy.

OBJECTIVES: We present a new approach to prenatal evaluation and prediction of renal function and long-term outcomes for fetuses considered candidates for in utero surgery. STUDY DESIGN: A review of 34 cases of obstructive uropathies was made, with analysis of our approach to prenatal evaluation, the predictive value of urinary electrolytes and protein analysis in identifying renal dysplasia, and the outcomes of cases with and without in utero surgical intervention. RESULTS: Ten of 11 pregnancies that were terminated had dysplasia; one female had cloacal dysgenesis. In three of eight unshunted cases megacystis resolved after vesicocentesis. Eight of 15 shunted fetuses survived. Of those predicted to have good postnatal outcome, six of six demonstrated good postnatal renal function. Of those predicted to have poor outcomes, two of two had poor postnatal renal function and dysplasia. Seven of 15 shunted fetuses died, four of four predicted to have dysplasia were confirmed, and three died of nonrenal causes. CONCLUSIONS: Our prenatal approach successfully differentiated fetuses with underlying renal dysplasia from those without irreversible damage who subsequently benefited from in utero vesicoamniotic shunt placement.

Platelet activating factor-acetylhydrolase activity following chorionic villus sampling and amniocentesis.

OBJECTIVE: Platelet activating factor (PAF) is essential for embryonic development and is a potent vasodilator. It increases vascular permeability and stimulates prostaglandin E2 (PGE2) production. Platelet activating factor-acetylhydrolase (PAF-AH), the enzyme that degrades PAF, is synthesized by decidual macrophages. The aim of this study was to test the hypothesis that chorionic villus sampling (CVS) and/or amniocentesis might cause an increase in maternal PAF-AH activity. METHODS: Maternal plasma PAF-AH activity was evaluated before and after genetic amniocentesis (N = 13) and transcervical CVS (N = 29). A control group (N = 9) was evaluated to study the effects of venipuncture. RESULTS: Chorionic villus sampling caused a significant elevation in PAF-AH activity (P < .0005). No changes were noted in PAF-AH activity in the amniocentesis or the control group. CONCLUSIONS: Chorionic villus sampling causes subclinical release of PAF-AH, possibly from the decidual macrophages. Increased PAF-AH activity might result in decreased PAF levels, which might lead to vasoconstriction in the placental circulation due to lack of the vasodilator effects of PAF and possibly PGE2. This mechanism might explain the increased risk for fetal limb reduction noted with CVS performed at very early gestational ages.

Sonographic screening for trisomy 21: fetal humerus:foot length ratio, a useful new marker.

We have analyzed morphometric measurements from midgestational fetal necropsies and shown that arm and foot lengths are linear relationships versus gestational age (GA). Using foot length as the GA determinant, we found that the ratio of arm:foot length was also a linear relationship and was decreased in trisomy 21 fetuses when compared to age-matched normals. Based on these laboratory findings, we prospectively evaluated the use of the humerus:foot length ratio as a sonographic screening tool for identification of fetuses at risk for trisomy 21. Humerus length, foot length and the humerus:foot length ratio were found to be linear relationships vs. gestational age in both the normal and trisomy 21 populations. However, the regressions for the humerus:foot length ratio were significantly different between normals and Down's fetuses (p < 0.001). We found that a humerus:foot length ratio < or = 0.85 correctly identified 47% of our trisomy 21 fetuses (spec = 0.92, PPV = 0.25, NPV = 0.97). When compared to women > or = 35 years old in our high risk population, a humerus:foot length ratio < or = 0.85 carried an odds ratio of 52.7 (99% CL = 9.72-285.23) for trisomy 21.

Epidemic syphilis: maternal factors associated with congenital infection.

OBJECTIVE: Little is known about which cases of maternal syphilis will affect the newborn. Because of the current epidemic of syphilis in pregnancy in our city, we sought to identify risk factors during pregnancy associated with congenital infection. STUDY DESIGN: We reviewed 253 cases of maternal syphilis prospectively identified over a 1-year period. On the basis of neonatal diagnosis, these data were divided into two groups, those without evidence of presumptive congenital syphilis and those with evidence of presumptive congenital syphilis. Presumptive congenital syphilis was defined according to the Centers for Disease Control and Prevention surveillance case definition. Cases with bloody spinal taps and cases of suspected congenital syphilis that did not meet these criteria were excluded. Venereal Disease Research Laboratory titers are given as the inverse of the geometric mean. RESULTS: Venereal Disease Research Laboratory titer at time of diagnosis and unknown duration of disease were risk factors for congenital syphilis. There was a significantly decreased rate of congenital syphilis with single-dose therapy if disease length was < 1 year (p < 0.005). Unknown duration of disease was associated with 67.9% and 48.6% rates of congenital syphilis with one- and three-dose therapy respectively. There was a 28% incidence of preterm birth. CONCLUSION: Our study suggests an alarming rate of failure of current therapy to prevent congenital syphilis. Venereal Disease Research Laboratory titer at time of diagnosis and unknown duration of disease are risk factors for congenital syphilis. The high rate of presumptive congenital syphilis in the unknown duration group indicates that identification before or earlier in pregnancy will be necessary to prevent devastating consequences for the neonate.

Technical aspects of transcervical chorionic villus sampling.

Following the 1990 FDA approval of the Trophocan catheter for use in transcervical chorionic villus sampling (CVS), an increasing number of US physicians have begun offering the procedure. To obtain privileges to perform CVS, some states such as California have enacted legislation requiring the performance of a certain number of CVS procedures in pregnancies in which the patient has already chosen first-trimester abortion. This practice is not universally feasible for legal, logistic, or financial reasons. We describe our approach to training in a busy reproductive genetics service. The physician initially trains by performing amniocentesis to optimize skills in ultrasound-directed needle guidance and placement. During this initial period, he or she also assists in performing transabdominal CVS procedures. The initial transcervical CVS cases should be performed in those situations requiring minimal catheter manipulation, or in those individuals undergoing CVS in the setting of spontaneous abortion. Cases of increasing difficulty should only be performed as skill and familiarity increase. For a physician already skilled and experienced in ultrasound-guided invasive procedures, sequential periods of observation at a busy center allows him or her to become familiar with the common pitfalls in performing transcervical CVS, and thus avoid them. Using this approach, we have performed over 5,000 CVS procedures and trained 6 reproductive genetics fellows in transcervical CVS.

Maternal neurosurgical shunts and pregnancy outcome.

OBJECTIVE: To assess pregnancy outcome in women with ventriculoperitoneal or lumboperitoneal shunts. METHODS: Charts were reviewed retrospectively for mothers with ventriculoperitoneal or lumboperitoneal shunts delivered at Hutzel Hospital from 1976-1992. Patients were identified by cross-referencing medical records from Children's Hospital Neurosurgical Division and medical records at Hutzel Hospital during this period. RESULTS: Eight patients with 25 pregnancies were identified from 1976-1992. Indications for shunt placement were pseudotumor cerebri (four with lumboperitoneal shunts) and congenital hydrocephalus (four with ventriculoperitoneal shunts). Pregnancy outcomes were two elective abortions, five spontaneous abortions, two preterm vaginal deliveries, one mid-forceps rotation, two primary low transverse cesareans, two repeat low transverse cesareans, and 11 spontaneous vaginal deliveries. No patient received prophylactic antibiotics during labor and vaginal delivery because of the shunt. There were no shunt-related complications. CONCLUSIONS: This series doubles the number of previously reported pregnancy outcomes in women with neurosurgical shunts. Contrary to the literature suggesting cesarean delivery and prophylactic antibiotics for all patients, our experience suggests that vaginal delivery can be considered and that prophylactic antibiotics are not an absolute necessity in uncomplicated vaginal deliveries.

Prenatal diagnosis of congenital diaphragmatic hernia not amenable to prenatal or neonatal repair: Brachmann-de Lange syndrome.

Brachmann-de Lange syndrome (BDLS) is a variable multiple congenital anomaly syndrome that occasionally includes congenital diaphragmatic hernia (CDH). CDH per se is commonly diagnosed antenatally and has been corrected with increasing success in utero and by neonatal repair with extracorporeal membrane oxygenation (ECMO). In utero repair requires normal karyotype as well as the absence of other lethal anomalies. Postnatal repair in combination with ECMO has resulted in improved neonatal outcome and has been recommended in all cases not having in utero repair. We describe a fetus diagnosed with a diaphragmatic hernia at 18 weeks of gestation in a woman whose only other pregnancy has been a 16 week abortus diagnosed with Fryns syndrome (FS). FS is a lethal, variable congenital anomaly syndrome that includes CDH, which is thought to contribute to the lethality of the syndrome. In utero repair was considered, but rejected because of the position of the liver and suspected FS. The patient elected to carry the pregnancy to term. Postnatal repair with ECMO was considered; however, the infant died at several hours of age because of severe pulmonary hypoplasia, being considered ineligible for ECMO. The diagnosis of BDLS was made at autopsy and suggests that the first case may, in fact, have been BDLS. In spite of recent success in the repair of CDH both in et ex utero, CDH in association with BDLS is likely lethal, and women with fetuses diagnosed antenatally with CDH and BDLS should be counseled as such.

Meroanencephaly: pathology and prenatal diagnosis.

Meroanencephaly is a rare form of anencephaly characterized by malformed cranial bones and a median cranial defect, through which protrudes abnormal tissue, called the area cerebrovasculosa. Area cerebrovasculosa denotes abnormal spongy, vascular tissue admixed with glial tissue ranging from a thin membrane to a large pseudoencephalic mass simulating cerebral tissue, that is composed of connective tissue, hemorrhagic vascular channels, glial nodules, and disorganized choroid plexuses. There are three types of anencephaly: (1) meroanencephaly, where there is rudimentary brain tissue and partial formation of the cranium; (2) holoanencephaly, the most common type, in which the brain is completely absent, and (3) craniorachischisis, the most severe, where area cerebrovasculosa and area medullovasculosa fill both cranial defects and the spinal column. In meroanencephaly, there is a median defect present, through which protrudes the area cerebrovasculosa. We present 3 cases of meroanencephaly diagnosed prenatally, along with histopathologic analysis. One case showed ectopic glial tissue in the lung and adrenal medullary hyperplasia. Two cases were diagnosed in the early second trimester by ultrasound scanning. Meroanencephaly may be mistaken for encephalocele both at the bedside exam and sonographically, and should be included in the differential for protruding anterior cranial masses.

Maternal serum alpha-fetoprotein screening: the need to use race/ethnic specific medians in Asians.

OBJECTIVES: We questioned whether race-specific databases for maternal serum alpha-fetoprotein (MSAFP) screening should be added to those already available for African-American and white patients. STUDY DESIGN: We analyzed 138,272 MSAFP samples. The geographic origin of the samples was New York metropolitan area. Patients were classified as white, African-American, Hispanic or Asian. The usual adjustments were made and groups compared. Statistical analysis included ANOVA and multiple comparison test. RESULTS: MSAFP values are highest (p < 0.05) for Asians, followed by African-Americans, Hispanics, and whites, although the difference between Hispanic and white was not significant. CONCLUSIONS: Four separate databases are definable if specimen quantity is sufficient. Race/ethnic specific databases are more likely to yield the most accurate detection of abnormal MSAFP values, and therefore, fetal anomalies.