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Abstract

Introduction

The aim of prenatal diagnosis is to detect fetal structural and genetic abnormalities. Some changes can be registered on chromosome level (chromosome mutations) or at the level of DNA (genetic or genomic mutations), which in turn can produce somatic malformations. When amniocentesis for fetal karyotyping was first performed it was limited to gestations at or beyond 16 weeks because it was associated with higher failure rate in obtaining amniotic fluid at earlier gestation. A major disadvantage of second trimester amniocentesis is late diagnosis beyond 17 weeks' gestation, when surgical termination of pregnancy becomes risky. Earlier options include chorionic villus sampling (CVS) and early amniocentesis. Early amniocentesis (9 to 14 weeks' gestation) was introduced in the late 1980s. It is technically the same as a ‘late’ procedure, except that less amniotic fluid is removed which reported to result in laboratory failure varied between 0% and 20%, however such observation decreased with advanced genetic technologies and experience of the practetioners.

Objectives

To study the feasibility and reproducibility of early amniocentesis (define as below 15 weeks) by studying the failure rate of the Amniocytes culture and the need to repeat the procedure. The aim is to fine an alternative way of invasive testing in case of difficult CVS and need for early diagnosis. Material and methods. It is a retrospective study. Diamniotic twins case were collected in the period from of September 2003 to October 2014, these cases were seen in the Feto-Maternal Unit which I specialized unit in the Obstetrics and Gynecology department started on 2003 and serving high risk pregnancies, including fetal anomalies, maternal diseases and prenatal intervention.. etc After obtaining permission for the Medical Research Center. The ultrasound data was collected form the ultrasound software (Astraia. Astraia Software GmbH Occamstr.20, 80802 Munich Germany). Data were collected and kept in password protected Excel sheet (© 2010 Microsoft Corporation) and the analysis carried using online statistics tools (http://www.numberempire.com/statisticscalculator.php, http://www.evanmiller.org/ab-testing/), P value below 0.05 was considered for statistical significance.

Results

Total of 1263 amniocentesis was done during the study period, of them 50 cases was done before 15 weeks (encompass), 9 case excluded due to incomplete data. The mean gestational age at the procedure was 14 weeks and 2 day (SD of 4 days), median was 14 weeks and 3 days (Range of 2 weeks and 5 days). There were 11 cases (26.8%) under 14 weeks (between 12 weeks+1 day and 13 weeks+6 days. The indications of the prenatal testing was high nuchal translucency or cystic hygroma in 32%, fetal anomaly in 27%, previous baby with genetic disease (mainly trisomy 21, Thalasimia, sickle cell disease, …etc) in 19%, Maternal age (more than 40 years) in 17 %, and family history of genetic diseases in 5% (Mucolipidosis, Hematological diseases) Placenta was anterior in 22 cases (53.6%) and posterior in 19 (46.4%) with no statistical deference (p value 0.51), however the approach was Transamniotic in 33 cases (80.5%) and Transplacental in 8 cases (19.6%). Among all the case only one case (2.4%) of Amniocytes culture failure was reported with need to repeat the test after 15 weeks, she had a family history of thalassemia and the procedure was Transplacental with bloody stained fluid; processed in the genetic lab and the results were inconclusive. The rest was reproducible with 13 cases showed abnormal karyotype and managed accordingly. There were no reported cases of miscarriages after the procedure (excluding 10 cases “those who had an elective termination due to positive genetic diseases after ethical committee approval)

Conclusion

Early amniocentesis is a feasible and reproducible procedure with very minimal failure rate and in an experienced hand and with advanced genetic technology can substitute difficult CVS after proper counseling.

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/content/papers/10.5339/qfarc.2016.HBPP2381
2016-03-21
2019-12-07
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