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Table 1 Demographic characteristics of women requesting cell-free DNA (cfDNA) screening for common trisomies and sex chromosome aneuploidies

From: Performance of cell-free DNA sequencing-based non-invasive prenatal testing: experience on 36,456 singleton and multiple pregnancies

Characteristics

n (%) unless otherwise stated

Low risk NIPT results

35,955 (98.6)

Singleton pregnancies (%)

35,650 (97.8)

Twin pregnancies (%)

800 (2.2)

Triplet pregnancies,(%)

6 (0.02)

ART Pregnancies(%)

1807 (5)

 Twin pregnancies (%)

403 (22.3)

 Egg donation (%)

16 (0.9)

Maternal age (yrs) mean (range)*

35.4 (18–48)

 < 35(%)

19,693 (54)

 ≥ 35(%)

16,763 (46)

Gestational age (wks + days) mean (range)

12 + 2 (9 + 1–32 + 6)

Samples drawn in first trimester (< 13 + 6 wks)

27,780 (76.2%)

Fetal fraction mean ± SD

9.55 ± 3.72

Fetal fraction first trimester mean ± SD

9.53 ± 3.69

  1. ART artificial reproductive technology
  2. *We excluded pregnancies with egg donation