How to perform transabdominal chorionic villus sampling: a practical guideline.

The spread of both first trimester screening for chromosomal abnormalities and the possibility to check for single gene disorders at DNA-analysis has increased the request for chorionic villus sampling (CVS) in the first trimester. In order to perform placental biopsy, two routes are possible: the transcervical (TC) and the transabdominal (TA). In early days, the trancervical technique was the most diffused, but since its introduction into clinical practice, the TA technique has become the approach of choice in detriment of the TC technique. In our institution, we have a 30-year experience in TA-CVS with more than 26 000 procedures performed. Considering the expertise and the volume of procedures undertaken at our unit, we suggest a practical guideline for novel operators in TA-CVS.

A Case of Enlarged Intracranial Translucency in a Fetus with Blake's Pouch Cyst.

The intracranial translucency (IT) is a recently introduced marker of open spina bifida (OSB). In this study, we describe a case of a fetus affected by Blake's pouch cyst which showed alterations of BS/BSOB ratio at the first trimester screening.

Absence of fetal nasal bone and aneuploidies at first-trimester nuchal translucency screening in unselected pregnancies.

OBJECTIVES: The absence of nasal bone (NB) has been noted in trisomy 21 fetuses at first-trimester ultrasound, in high-risk pregnancies. In this study, the nasal bone was evaluated in relation to fetal karyotype, in unselected pregnancies. METHODS: From September 2001 to September 2002, the fetal facial profile was examined at the 11 to 14 weeks' scan for screening by nuchal translucency (NT). Risks for trisomy 21 were calculated using the Fetal Medicine Foundation's software, and the presence or absence of NB was noted. Prenatal karyotype and pregnancy outcomes were recorded. RESULTS: NT screening was performed in 5532 fetuses from 5425 pregnancies (85 twins, 8 triplets, 2 quadruplets). The visualization of fetal profile was obtained in 5525 fetuses (99.8%), and in 5491 fetuses (99.4%) the NB was present and in 34 cases (0.6%) it was absent. Fetal karyotype and pregnancy outcome were available in 3503 pregnancies, and 40 chromosomal abnormalities were diagnosed (27 trisomies 21, 5 trisomies 18, 2 trisomies 13, 3 Turner syndromes, 1 partial trisomy 9 and 2 others). The NB was absent in 19 (70%) trisomies 21, 4 trisomies 18 (80%), 2 Turner syndromes (66%), in the partial trisomy 9, in 7 normal karyotype fetuses (0.2%), and in a case with spontaneous first-trimester abortion before prenatal diagnosis. A significant difference was found between NT thickness, expressed as a multiple of the median, in trisomy 21 fetuses with present and absent nasal bone. CONCLUSIONS: The absence of NB at 11 to 14 weeks is more frequent in fetuses with trisomy 21 and other aneuploidies than in normal karyotype fetuses.

Neural tube defects in the offspring of thalassemia carriers.

OBJECTIVES: The risk of neural tube defects (NTDs) is negatively correlated with maternal folate levels in early pregnancy. Thalassemia carriers often have reduced red cell folate contents. The aim of this study was to verify whether thalassemia carriers are at increased risk of having offspring with a NTD. METHODS: We retrospectively evaluated the prevalence of thalassemia carriers among 75 women who had prenatal diagnoses of NTDs made at our center. RESULTS: The prevalence of beta-thalassemia carriers among the affected pregnancies was significantly higher than in the general population (22.5 versus 14%, p < 0.05, chi(2) test). CONCLUSION: Although inconclusive, these data indicate that folate supplementation is mandatory among women with thalassemia who are planning a pregnancy.