ISSN:1040-872X    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

Embryo biopsy for preimplantation genetic diagnosis can be performed on the oocyte/zygote, cleavage stage embryo, or blastocyst, but the majority of centres perform cleavage stage biopsy. Single-cell diagnosis is undertaken by the polymerase chain reaction or fluorescent in-situ hybridization. Technical difficulties have arisen with preimplantation genetic diagnosis, such as allele dropout and chromosomal mosaicism. However, it is hoped that these difficulties can be overcome in the future with the advent of new techniques.

ISSN:1040-872X    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

Fluorescence in-situ hybridization has become essential in prenatal diagnosis for identifying chromosome aberrations as well as in preimplantation genetic diagnosis and the analysis of fetal cells in maternal blood. Comparative genome hybridization, multicolor fluorescence in-situ hybridization and telomere probes provide technical approaches for the characterization of fetal chromosome anomalies not possible by conventional karyotyping.

ISSN:1040-872X    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

Advances in technology and skills have resulted in the improved detection of fetal ultrasound abnormalities by ultrasound. In addition, the development of new diagnostic methods has resulted in major advances in our ability to detect microscopic and submicroscopic chromosome abnormalities as well as single gene disorders. This often enables us to provide the family with accurate information regarding the aetiology, prognosis, the risk of recurrence and the prenatal diagnosis options available in future pregnancies. Genetic counselling is important because this information should be communicated to the family in simple language, with care and sensitivity, so that the family can make decisions that are fully informed.

ISSN:1040-872X    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

Invasive prenatal diagnosis continues to be the gold standard for pregnancies at increased risk of chromosomal aneuploidy or other genetic disease. Chorionic villus sampling is the procedure of choice for the first trimester. Early amniocentesis has been shown to carry increased risks of pregnancy loss, amniotic fluid leakage and talipes equinovarus. Mid-trimester amniocentesis continues to be the most common form of invasive prenatal diagnosis, with post-procedural loss rates of between 0.5 and 1%. This present review summarizes information on technique risks, looks at new technology applied to invasive prenatal diagnosis testing, and reports on new diagnoses that could be made either by amniocentesis or chorionic villus sampling.

ISSN:1040-872X    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

Prenatal diagnosis in multiple gestations poses unique problems. The use of screening modalities is limited, diagnostic procedures are more complicated, and the management of discordant results may be required. This article reviews work, both past and present, regarding these issues.

ISSN:1040-872X    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

Current ultrasound equipment allows the antenatal identification of many central nervous system anomalies from early gestation. In selected cases, special techniques (transvaginal sonography, three-dimensional ultrasound, colour Doppler) may enhance the diagnostic potential. Diagnostic accuracy, however, remains heavily dependent upon the expertise of the sonologist. Fetal ultrasound is effective in identifying neural tube defects, although alpha-fetoprotein screening seems to yield a greater sensitivity. The sensitivity in the diagnosis of central nervous system malformations other than neural tube defects remains unclear because of the ascertainment biases of the few large prospective studies that have been carried out so far. Magnetic resonance imaging may play a major role in the evaluation of cases with suboptimal ultrasound visualization, or when specific anomalies are suspected, such as intracranial haemorrhage or migrational disorders.

ISSN:1040-872X    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

Screening for fetal cardiovascular malformations is widely performed. Its accuracy is not yet satisfactory, but better training of ultrasonographers and extension from the four-chamber view to the study of the outflow tract are probably clues to an improvement. The main impact of prenatal diagnosis is still the termination of pregnancy for severe malformations and for those associated with chromosomal or extracardiac anomalies. There is now evidence that prenatal diagnosis improves perinatal morbidity or mortality for some malformations. New information about the molecular genetic basis of congenital heart disease will help in management and counselling.

ISSN:1040-872X    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

Recent epidemiological and experimental studies show that abnormal fetal growth can lead to serious complications, including stillbirth, perinatal morbidity and disorders extending well beyond the neonatal period. It is now clear that the intrauterine milieu is as important as genetic endowment in shaping the future health of the conceptus. Maternal characteristics such as weight, height, parity and ethnic group need to be adjusted for, and pathological factors such as smoking excluded, to establish appropriate standards and improve the distinction between what is normal and abnormal. Currently, the aetiology of growth restriction is not well understood and preventative measures are ineffective. Elective delivery remains the principal management option, which emphasizes the need for better screening techniques for the timely detection of intrauterine growth failure.

ISSN:1040-872X    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

Recent publications have produced some new estimates of the incidence of pregnancy-related venous thromboembolic disease, and have found increasing evidence of an association between inherited thrombophilias and pregnancy complications and fetal loss. The balance of benefit and risk of thromboprophylaxis remains to be evaluated, and studies are needed to provide a sound basis for clinical practice.

ISSN:1040-872X    

出版商:OVID    

年代:2000

数据来源: OVID