Combined First-Trimester Screening of Trisomy 21 in Women with Different Age in Southwest Iran


Mehran Dorostghoal 1 , * , Mojgan Barati 2 , Mojgan Harfsheno ORCID 1

1 Department of Biology, Faculty of Science, Shahid Chamran University of Ahvaz, Ahvaz, Iran

2 Fertility, Infertility and Perinatology Research Center, Ahvaz Jundishapur University of Medical Science, Ahvaz, Iran

How to Cite: Dorostghoal M, Barati M, Harfsheno M. Combined First-Trimester Screening of Trisomy 21 in Women with Different Age in Southwest Iran, Gene Cell Tissue.2021 In Press(In Press): e113112. doi: 10.5812/gct.113112.


Gene, Cell and Tissue: In Press (In Press); e113112
Published Online: June 05, 2021
Article Type: Research Article
Received: January 19, 2021
Revised: January 30, 2021
Accepted: February 06, 2021


Background: There is evidence that incidence of trisomy 21 has a direct linear relationship with maternal age and older women at higher risk for fetal Down syndrome (DS).

Objectives: Present study was done to evaluate the performance and effectiveness of combined first-trimester screening (FTS) for DS in women with different ages in Southwest Iran.

Methods: In this cross sectional study, first-trimester combined screening was conducted on 7192 pregnant women within 11-13 weeks of gestational age referred to Narges Medical Genetics and Prenatal Diagnosis Laboratory, Ahvaz, Iran. Amniocentesis and cytogenetic analysis were performed in all patients with a risk estimate of 1 in 100 and above.

Results: The FTS detection rate of DS was 83.3% with a false-positive rates of 2.1% and 13.5% in young and older women over 35 years, respectively. Significant correlation (r=0.137, p<0.001) was observed between the high risk of DS (1:100) and maternal age. The high risk of DS was found to be higher in women over 35 years of age than under 35 years (6.67% vs. 1.95%). Total DS prevalence was 2.64 per 1000 cases. Prevalence of DS in women under 35 years and over 35 years was 1.95 and 6.67 per 1000 pregnancy, respectively.

Conclusions: It is concluded that FTS is an effective screening method for DS in women under 35 years of age and older, and although advanced maternal age led to higher prevalence of DS, clinicians should recommend FTS as a first-line screening regardless of maternal age.


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