Table 1 Pregnancy characteristics of women with two screening tests
From: A new contingent screening strategy increased detection rate of trisomy 21 in the first trimester
Characteristic | Serum biochemical screening | Combined first-trimester screening | P |
|---|---|---|---|
Number | 35,308 | 35,026 | |
Age distribution | |||
Maternal age at expected date of delivery < 35 years(%) | 34,724(98.35%) | 34,467(98.40%) | 0.543 |
Maternal age at expected date of delivery ≥ 35 years(%) | 584(1.65%) | 559(1.60%) | 0.543 |
Maternal age (years) at expected date of delivery (IQR) | 30.00(28.06–32.13) | 30.02(27.52–31.62) | 0.215 |
Method of conception (%) | |||
Spontaneous | 33,118(93.80%) | 32,798(93.64%) | 0.387 |
Assisted | 2,190(6.20%) | 2,228(6.36%) | 0.387 |
Median maternal weight (IQR) | 53(49–58) | 53(49–58) | 0.896 |
Median gestational age (days) at blood sample (IQR) | 88(85–92) | 88(85–92) | 0.605 |
Insulin-dependent diabetes (%) | 24(0.07%) | 24 (0.07%) | 0.978 |
Smoker (%) | 362(1.03%) | 356(1.02%) | 0.907 |
Incidence of Down syndrome(‰) | 47(1.33‰,1/751) | 47(1.34‰,1/745) | 0.969 |