Virginia Borobio

Cytogenetic study of spontaneous abortions using semi‐direct analysis of chorionic villi samples detects the broadest spectrum of chromosome abnormalities

Conventional tissue culturing and karyotyping of spontaneous abortions has limitations such as culture failure, external contamination and selective growth of maternal cells. Molecular cytogenetic techniques such as FISH, QF‐PCR, and CGH allow diagnosis on uncultured cells but are also limited as to the spectrum of cytogenetic abnormalities detected. We describe the cytogenetic findings in a series of 116 first trimester arrested pregnancies, obtained through chorionic villi sampling (CVS) and semi‐direct analysis that avoids some of the long‐culture pitfalls such as maternal contamination, and compare our results with those that would have been obtained theoretically using molecular cytogenetic techniques. Samples were obtained by transcervical CVS from women with a diagnosis of missed abortion, most of them referred for cytogenetic prenatal diagnosis. Cytogenetic analysis was performed using semi‐direct technique. A karyotype was obtained in 103 cases. Eighty‐two abnormal karyotypes were found (80%), including 12 triploidies, 10 monosomies, 61 trisomies, and 9 structural abnormalities; a double abnormality being present in 10 cases. Between 10% and 50% of our abnormal results would have been missed using the most common molecular cytogenetic techniques. Semi‐direct analysis of CVS may still be considered as a comprehensive, reasonably rapid, cost‐effective and reliable method for detecting the broadest spectrum of chromosome abnormalities in missed abortions.

First‐trimester detection of structural abnormalities and the role of aneuploidy markers

To determine the sensitivity of first‐trimester ultrasound for diagnosing different structural anomalies in chromosomally normal pregnancies, and to establish the role of aneuploidy markers in the detection of abnormalities.

The effect of maternal age on chromosomal anomaly rate and spectrum in recurrent miscarriage

STUDY QUESTION Is there any effect of maternal age on chromosomal anomaly rate and spectrum in recurrent miscarriage? SUMMARY ANSWER There was no significant difference in the chromosome abnormality rate between sporadic and recurrent miscarriage but the chromosome abnormality rate increased significantly with maternal age. WHAT IS KNOWN ALREADY About 50-70% of non-recurrent miscarriages occur because of a chromosomal anomaly, but no agreement about the effect of either maternal age or the number of previous miscarriages on the chromosomal anomaly rate has been reached. STUDY DESIGN, SIZE, DURATION A retrospective cohort of 353 miscarriages successfully karyotyped in the same center between 2002 and 2011, grouped according to the number of miscarriages and maternal age. PARTICIPANTS/MATERIALS, SETTING, METHODS Among the 353 women, 153 were below 35 years (73 with sporadic, 48 with two and 32 with recurrent miscarriage) and 200 were 35 years or more (81 with sporadic, 55 with two and 64 with recurrent miscarriage). The chromosomal anomaly rate and the anomaly spectrum were compared between sporadic and recurrent miscarriage, within the two maternal age groups, using the chi-square test and the Bonferroni correction for all the P-values. Risk of chromosomal anomaly was estimated for maternal age, number of miscarriages and previous live births by multivariate binary logistic regression analysis. MAIN RESULTS AND THE ROLE OF CHANCE Sporadic and recurrent miscarriage did not show significantly different chromosomal anomaly rates (68 versus 60%) and maternal age was the only statistically significant predictor of the chromosomal anomaly risk we identified. Some trends were observed in the chromosomal anomaly spectrum when sporadic was compared with recurrent miscarriage: recurrent miscarriage exhibited a decrease in viable trisomies (37 versus 11%) and an increase in non-viable trisomies (38 versus 57%) in women >35 years, together with an increase in unbalanced structural anomalies (4.9 versus 29%) in younger women. LIMITATION, REASONS FOR CAUTION The mixed origin of our study population, and the limited number of recurrent miscarriages, particularly in the younger group, limits statistical power to detect differences. WIDER IMPLICATIONS OF THE FINDINGS The most commonly observed chromosomal anomaly type in recurrent miscarriage depends on maternal age: non-viable autosomal trisomies in older women and unbalanced structural anomalies in younger women. When a chromosomal anomaly is identified as the cause of miscarriage, additional maternal evaluation may be avoided. STUDY FUNDING/COMPETING INTERESTS No competing interests declared.

Combining fetal nuchal fold thickness with second-trimester biochemistry to screen for trisomy 21

To assess second‐trimester screening for trisomy 21 by combining ultrasound nuchal fold (NF) measurement with maternal serum biochemistry.

First‐trimester detection of major cardiac defects with the use of ductus venosus blood flow

To assess the best method of combining fetal nuchal translucency (NT) and ductus venosus (DV) blood flow measurements in the detection of major cardiac defects in chromosomally normal fetuses during the first‐trimester scan.

Translucencia nucal y ductus venoso: valores de referencia en el primer trimestre de la gestación

Resumen Objetivo Establecer los intervalos de referencia en nuestra poblacion de la translucencia nucal (TN) y del indice de pulsatilidad para venas (PIV) del ductus venoso (DV). Metodos Durante 4 anos, se estudiaron gestaciones consecutivas con ecografia realizada entre las 11,1-14,0 semanas procedentes de la poblacion general. Se construyeron intervalos de referencia siguiendo la metodologia descrita por las National Committee for Clinical and Laboratory Standards. De acuerdo con la conclusion del test de particion, se estimaron intervalos de referencia especificos para la edad gestacional mediante modelos de regresion lineal, para la TN. La desviacion de los modelos estimados respecto a la linealidad se evaluo mediante polinomios fraccionales de grado 1 o 2. Resultados Se incluyeron un total de 2.612 gestaciones. No se observaron diferencias significativas en los intervalos calculados para PIV del DV para los grupos de edad gestacional. Se observo una diferencia significativa de los valores de TN entre los grupos de edad (p Conclusion Se observo un incremento de la TN con la edad gestacional, mientras que el PIV del DV se mantuvo constante.

Transcervical chorionic villus sampling: a practical guide.

Abstract First trimester screening for fetal aneuploidies has made the implementation of diagnostic techniques essential. Chorionic villus sampling (CVS) is the method of choice for obtaining chorionic villi for molecular and cytogenetic analysis in the first trimester. Two techniques have been developed, a transcervical and a transabdominal. The selection criteria have been based historically on factors, such as placental location, parity, maternal weight and preference of the operator. In our institution, we developed an elevated level of expertise in the field of transcervical approach, resulting in good quality of samples and comparable fetal loss rate to other approaches. Despite three decades of transcervical CVS performance, little consensus in terms of its technique and clinical guidelines exists. Considering the expertise and the volume of procedures performed at our center, we suggest a practical clinical guideline for transcervical CVS.

How to perform an amniocentesis

Amniocentesis is a technique for withdrawing amniotic fluid from the uterine cavity using a needle, via a transabdominal approach and under continuous ultrasound guidance, in order to obtain a sample of fetal exfoliated cells, transudates, urine or secretions. It can be performed from 16 weeks of pregnancy onwards, with various chromosomal, biochemical, molecular and microbial studies being performed on the amniotic fluid sample. The most common reasons for the procedure are to enable prenatal diagnosis of chromosomal abnormalities, single gene disorders, fetal infection and intra-amniotic inflammation, as well as to assess fetal lung maturity and blood or platelet type. The procedure has a risk of fetal loss of approximately 0.5% (range, 0.06–1%)1 when performed in the second trimester, after the amniotic membrane has fused with the chorion; there is also a risk of amniotic fluid leakage (approximately 0.3% of cases) and other rare complications, such as placental hemorrhage, intra-amniotic infection, abdominal wall hematoma and fetal lesion. There is an important lack of good-quality evidence to support most recommendations for the procedure, and a recent review suggested that operators should use those methods and technique modifications with which they are most familiar when performing an amniocentesis2. The aim of this summary article and the full version, included as supplementary material online, is to describe the amniocentesis technique, presenting a practical guideline for its performance. We also describe the use of a Vacutainer® (BD Vacutainer Systems, Plymouth, UK) aspiration system in order to produce a continuous vacuum for amniotic fluid aspiration as an alternative to using manually operated syringes.

Nuchal translucency thickness in the prediction of unbalanced translocations

The aim of this study was to assess the role of nuchal translucency (NT) in the prediction of unbalanced translocation in offspring of couples in which one of the parents is a balanced translocation carrier.

Overview of Chromosome Abnormalities in First Trimester Miscarriages: A Series of 1,011 Consecutive Chorionic Villi Sample Karyotypes

In order to contribute to the knowledge of type and frequency of chromosome abnormalities in early pregnancy losses, we analyzed the cytogenetic results from a large series of first trimester miscarriages, using a diagnostic approach with a high success rate and no maternal contamination. A total of 1,119 consecutive chorionic villi samples were obtained before evacuation, and karyotypes were prepared after short-term culture (STC). In 603 samples, a long-term culture (LTC) was also performed. The overall and individual frequencies of the different types of chromosome abnormalities were established, including placental mosaicisms, and their relationship with maternal age and gestational weeks was assessed. An abnormal karyotype was detected in 70.3% of the samples. Single autosomal trisomy was the most frequent abnormality (64.6% of the abnormal cases), followed by triploidy (13.1%) and monosomy X (10.4%). Chromosome rearrangements were found in 5.2%, combined abnormalities in 8.9%, and placental mosaicism in 3.5% of the cases with STC and LTC performed. Individual trisomies behaved differently with respect to maternal age and intrauterine survival. Due to the combination of STC and LTC, our study offers reliable information on the incidence and type of chromosome abnormalities and placental mosaicism in miscarriages and contributes to define the cytogenetic implication in their etiology.