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Table 4 Background characteristics and pregnancy outcomes in relation to prenatal screening or diagnostic procedures in the Swedish Pregnancy Register 2011 to 2013 (N = 284,789)

From: Prenatal diagnosis in Sweden 2011 to 2013—a register-based study

Variable CUBa CVSb ACc All othersd Test of differencee
  n = 92,207 n = 2983 n = 7318 n = 186,092  
  n % n % n % n %  
Maternal agef, primiparous women (years)
 Mean (SD)g 31.34 (5.17)   33.79 (5.74)   33.65 (6.11)   27.09 (4.58)   <0.001
 Min-max 15.09–56.30   17.29–49.03   16.74–49.83   13–54   
 Median (IQR)h 31.34 (7.32)   34.41 (8.38)   34.92 (9.15)   27.51 (6.41)   
Maternal agef, multiparous women (years)
 Mean (SD)g 34.45 (4.45)   36.87 (4.65)   37.13 (4.66)   30.29 (4.52)   <0.001
 Min-max 16.41–55.34   19.10–51.76   16.41–48.68   15–57   
 Median (IQR)h 34.97 (5.72)   37.58 (5.66)   37.82 (5.45)   30.87 (6.07)   
Maternal agef in age-groups (years)
  < 20 388 0.4 8 0.3 23 0.3 3566 1.9  
 20–24 5863 6.4 99 3.3 313 4.3 32,702 17.6  
 25–29 17,617 19.1 300 10.1 733 10.0 65,926 35.4  
 30–34 31,792 34.5 649 21.8 1314 18.0 62,944 33.8  
 35–39 30,179 32.7 1262 42.3 3148 43.0 17,676 9.5  
 40–44 6093 6.6 628 21.1 1675 22.9 2991 1.6  
  > 44 270 0.3 36 1.2 109 1.5 211 0.1  
Body mass index (kg/m2)
 Mean (SD)g 24.40 (4.34)   24.10 (4.10)   24.94 (4.52)   24.99 (4.80)   <0.001
 Min-max 13.82–56.65   15.24–51.31   15.24–50.69   13.03–71.63   
 Median (IQR)h 23.45 (5.0)   23.18 (5.0)   24.01 (5.0)   23.95 (6.0)   
  < 18.5 1965 2.2 52 1.8 121 1.7 4766 2.6  
 18.5–24.99 56,723 63.2 1918 66.3 4140 58.2 103,359 57.2  
 25–29.99 21,639 24.1 663 22.9 1926 27.1 47,160 26.1  
 30–34.99 6863 7.6 195 6.7 652 9.2 17,741 9.8  
 35.39.99 1992 2.2 48 1.7 203 2.9 5744 3.2  
  ≥ 40 629 0.7 18 0.6 68 1.0 2071 1.1  
Educational level
 Elementary school 3242 4.1 69 2.7 334 5.3 17,353 11.2 <0.001
 High school 24,324 31.1 608 23.7 2078 33.1 69,523 44.8  
 University 50,763 64.8 1887 73.6 3869 61.6 68,302 44.0  
Main occupation
 Employed 72,519 80.3 2439 83.7 5582 77.8 118,371 65.0 <0.001
 Student 6467 7.2 146 5.0 524 7.3 24,121 13.3  
 Parental leave 5059 5.6 149 5.1 459 6.4 15,002 8.2  
 Unemployed 3320 3.7 78 2.7 294 4.1 11,601 6.4  
 Sick leave 1306 1.4 36 1.2 119 1.7 3009 1.7  
 Other 1610 1.8 66 2.3 194 2.7 9897 5.4  
Country of birth
 Sweden 76,276 84.5 2482 85.4 5876 81.8 139,881 76.7 <0.001
 Other Nordic countriesi 904 1.0 31 1.1 74 1.0 1406 0.8  
 Europej 3971 4.4 102 3.5 332 4.6 8617 4.7  
 Africa 1243 1.4 37 1.3 127 1.8 9438 5.2  
 Asia 6132 6.8 196 6.7 590 8.2 18,955 10.4  
 Other 1727 1.9 57 2.0 180 2.5 4007 2.2  
Smoking 3 months prior to pregnancy 9583 10.5 229 7.7 751 10.3 28,659 15.6 <0.001
Smoking at first ANCk visit 3445 3.8 76 2.6 347 4.8 12,144 6.6 <0.001
Smoking at 32 weeks of gestation 2527 2.8 48 1.6 289 4.0 9238 5.0 <0.001
Use of snuff 3 month prior to pregnancy 2493 2.7 64 2.2 213 2.9 7268 3.9 <0.001
Use of snuff at first ANC visit 646 0.7 22 0.7 85 1.2 2134 1.2 <0.001
Use of snuff at 32 weeks of gestation 385 0.4 13 0.4 41 0.6 1303 0.7 <0.001
Alcohol screening (AUDIT)l 81,686 90.3 2568 88.4 6313 86.3 158,335 87.0 <0.001
AUDIT-scorem
 Mean (SD) 2.34 (1.96   2.26 (1.74)   2.12 (1.90   2.11 (2.32)   
 Min-max 0–38   0–18   0–29   0–40   
 Median (IQR)h 2.00 (2)   2.00 (2)   2.00 (2)   2.00 (3)   
  ≤ 5p 76,786 94.5 2462 96.3 6012 95.7 82,067 94.6 <0.001
  ≥ 6p 4485 5.5 95 3.7 270 4.3 4703 5.4  
Self-rated health prior to pregnancy
 Very good 25,990 33.0 834 32.5 1887 30.5 44,643 28.3 <0.001
 Good 44,563 56.6 1433 55.9 3489 56.5 93,611 59.4  
 Neither good nor poor 5877 7.5 217 8.5 583 9.4 14,047 8.9  
 Poor 1817 2.3 64 2.5 187 3.0 4334 2.7  
 Very poor 440 0.6 15 0.6 34 0.6 1056 0.7  
Counselling due to fear of childbirth 8900 9.7 324 10.9 745 10.2 12,023 6.5 <0.001
Treatment of psychiatric disorder 6002 6.5 185 6.3 533 7.3 11,275 6.1 <0.001
Gestational age (days)
 Mean (SD)g 278.0 (13.7)   276.6 (15.0)   276.5 (15.4)   278.0 (13.8)   0.326
 Min-max 154–301   158–300   157–301   154–301   
 Median (IQR)h 280.0 (13.0)   279.0 (13.0)   279 (15.0)   280 (13.00)   
Mode of delivery
 Vaginal 6885 73.9 2079 70.2 5133 70.3 145,486 78.5 <0.001
 Instrumental 6376 6.9 163 5.5 392 5.4 12,468 6.7  
 Caesarean section 17,574 19.1 721 24.3 1772 24.3 27,405 14.8  
Caesarean section (CS) n
 Elective CSn 8650 49.3 297 58.7 916 51.7 10,700 39.1 <0.001
 Emergency CSn 8893 50.7 422 41.3 855 48.3 16,639 60.9  
Birth weight (grams)o
 Mean (SD)g 3549 (552)   3531 (585)   3510 (620)   3539 (557)   0.001
 Min-max 310–6270   400–5710   370–5776   300–6640   
 Median (IQR)h 3560 (665)   3555 (686)   3548 (706)   3545 (680)   
  1. aCUB = Combined Ultrasound and Biochemical test
  2. bCVS = Chorionic Villus Sampling
  3. cAC = Amniocentesis
  4. dAll others = Pregnant women who did not undergo any of the prenatal diagnostic procedures CUB, CVS or AC
  5. eTest of difference between the two groups; pregnant women who underwent CUB and “all others” using t-test for continuous variables and Pearson’s Chi-Square test for categorical variables
  6. fMaternal age at delivery
  7. gSD = Standard Deviation
  8. hIQR = Interquartile Range
  9. i Other Nordic countries includes Norway, Finland, Iceland and Denmark
  10. j The Nordic countries excluded
  11. kAntenatal care
  12. l Assessment of use of alcohol prior to pregnancy with screening instrument Alcohol Use Disorder Identification Test (AUDIT)
  13. mAUDIT score range from 0 to 40
  14. nCaesarean section
  15. oSingletons exclusively included in analysis