Chromosome aberrations Archives - Revista Brasileira de Ginecologia e Obstetrícia
Summary
Rev Bras Ginecol Obstet. 2007;29(12):647-653
DOI 10.1590/S0100-72032007001200008
Screening for major chromosomal abnormalities can be provided in the first trimester of pregnancy. Screening by a combination of fetal nuchal translucency and maternal serum free human chorionic gonadotropin and pregnancy-associated plasma protein-A can identify 90% of fetuses with trisomy 21 and other major chromosomal abnormalities for a false-positive rate of 5%. This is superior to the 30% detection rate achieved by maternal age and 65% by second-trimester maternal serum biochemistry. A further improvement in the effectiveness of first-trimester screening is likely to be achieved by a risk-orientated two-stage approach. In this approach, the patients are subdivided into a high-risk group, requiring invasive testing; a low-risk group, which can be reassured that an abnormality is unlikely, and an intermediate-risk group (risk of 1 in 101 to 1 in 1000), in which further assessment is performed by first-trimester ultrasound examination (for presence/absence of the nasal bone or presence/absence of tricuspid regurgitation or normal/abnormal Doppler velocity waveform in the ductus venosus), and chorionic villus sampling is performed if their adjusted risk becomes 1 in 100 or more. Those performing first-trimester scans should be appropriately trained and their results subjected to external quality assurance. This process was well established by the Fetal Medical Foundation several years ago and is widely accepted internationally.
Summary
Rev Bras Ginecol Obstet. 2007;29(12):647-653
DOI 10.1590/S0100-72032007001200008
Screening for major chromosomal abnormalities can be provided in the first trimester of pregnancy. Screening by a combination of fetal nuchal translucency and maternal serum free human chorionic gonadotropin and pregnancy-associated plasma protein-A can identify 90% of fetuses with trisomy 21 and other major chromosomal abnormalities for a false-positive rate of 5%. This is superior to the 30% detection rate achieved by maternal age and 65% by second-trimester maternal serum biochemistry. A further improvement in the effectiveness of first-trimester screening is likely to be achieved by a risk-orientated two-stage approach. In this approach, the patients are subdivided into a high-risk group, requiring invasive testing; a low-risk group, which can be reassured that an abnormality is unlikely, and an intermediate-risk group (risk of 1 in 101 to 1 in 1000), in which further assessment is performed by first-trimester ultrasound examination (for presence/absence of the nasal bone or presence/absence of tricuspid regurgitation or normal/abnormal Doppler velocity waveform in the ductus venosus), and chorionic villus sampling is performed if their adjusted risk becomes 1 in 100 or more. Those performing first-trimester scans should be appropriately trained and their results subjected to external quality assurance. This process was well established by the Fetal Medical Foundation several years ago and is widely accepted internationally.
Summary
Rev Bras Ginecol Obstet. 2007;29(7):358-365
DOI 10.1590/S0100-72032007000700006
PURPOSE: to evaluate fetal maternal complications after chorionic villus sampling (CVS) for prenatal diagnosis of genetic disorders in pregnant women of Salvador (BA), Brazil. METHODS: case-series study of 958 pregnancies with high risk for chromosomal abnormality submitted to CVS transabdominal between the ninth to the 24th week of gestation, using an ultrasound-guided 18G 3½ spinal needle, from 1990 to 2006. The variables for the analysis of immediate complications were uterine cramps, subchorionic hematoma, accidental amniotic cavity punction, pain in the punction area, amniotic fluid leakage, abdominal discomfort, fetal arrhythmias and vaginal bleeding, and of late complication, abdominal pain, vaginal bleeding, amniotic fluid leakage, infection and spontaneous miscarriage. Premature labor, obstetrical complications (abruption placenta and placenta previa) and newborn malformation were also studied. Qui-square, Student’s "t" or Mann-Whitney tests were used for the statistical analysis; the significance level was 5%. RESULTS: maternal mean age was 36.3±4.9 years old. Immediate complications ware found in 182 (19%) cases (uterine cramp in 14%, subchorionic hematoma in 1.8% and accidental amniotic cavity punction in 1.3%). Late complications were found in 32 (3.3%) cases (vaginal bleeding in 1.6%, abdominal pain in 1.4%, amniotic fluid leakage in 0.3% and spontaneous miscarriage in 1.6% cases). There was no case of abruption placentae, placenta previa or fetal malformation. CONCLUSIONS: CVS is a simple and safe procedure. CVS should be performed in high risk pregnant patients who need prenatal diagnosis of fetal chromosomal abnormalities.
Summary
Rev Bras Ginecol Obstet. 2007;29(7):358-365
DOI 10.1590/S0100-72032007000700006
PURPOSE: to evaluate fetal maternal complications after chorionic villus sampling (CVS) for prenatal diagnosis of genetic disorders in pregnant women of Salvador (BA), Brazil. METHODS: case-series study of 958 pregnancies with high risk for chromosomal abnormality submitted to CVS transabdominal between the ninth to the 24th week of gestation, using an ultrasound-guided 18G 3½ spinal needle, from 1990 to 2006. The variables for the analysis of immediate complications were uterine cramps, subchorionic hematoma, accidental amniotic cavity punction, pain in the punction area, amniotic fluid leakage, abdominal discomfort, fetal arrhythmias and vaginal bleeding, and of late complication, abdominal pain, vaginal bleeding, amniotic fluid leakage, infection and spontaneous miscarriage. Premature labor, obstetrical complications (abruption placenta and placenta previa) and newborn malformation were also studied. Qui-square, Student’s "t" or Mann-Whitney tests were used for the statistical analysis; the significance level was 5%. RESULTS: maternal mean age was 36.3±4.9 years old. Immediate complications ware found in 182 (19%) cases (uterine cramp in 14%, subchorionic hematoma in 1.8% and accidental amniotic cavity punction in 1.3%). Late complications were found in 32 (3.3%) cases (vaginal bleeding in 1.6%, abdominal pain in 1.4%, amniotic fluid leakage in 0.3% and spontaneous miscarriage in 1.6% cases). There was no case of abruption placentae, placenta previa or fetal malformation. CONCLUSIONS: CVS is a simple and safe procedure. CVS should be performed in high risk pregnant patients who need prenatal diagnosis of fetal chromosomal abnormalities.
