Skip to main content

Table 2 Background characteristics and pregnancy outcomes in the Swedish Pregnancy Register 2011 to 2013 (N = 284,789)

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

Variable Total 2011 2012 2013 Test of differencea
  N = 284,789   n = 88,140   n = 96,043   n = 100,606   
  n % n % n % n %  
Maternal ageb, primiparous women (years)
 Mean (SD)c 28.83 (5.12)   28.78 (5.17)   28.82 (5.14)   28.87 (5.07)   0.053
 Min-max 13.49–56.30   13.52–52.64   13.78–56.30   13.49–52.89   
 Median (IQR)d 28.64 (7.07)   28.66 (7.08)   28.59 (7.05)   28.67 (7.04)   
Maternal ageb, multiparous women (years)
 Mean (SD)c 31.72 (4.90)   32.29 (4.89)   32.21 (4.90)   32.16 (4.89)   <0.001
 Min-max 15.00–57.00   17.07–53.25   16.41–54.47   15.67–57.34   
 Median (IQR)d 32.30 (6.88)   32.41 (6.91)   32.28 (6.84)   32.23 (6.89)   
Maternal ageb in age-groups (years)
  < 20 3976 1.4 1369 1.6 1319 1.4 1288 1.3  
 20–24 38,832 13.6 11,990 13.6 13,222 13.8 13,611 13.5  
 25–29 84,129 29.5 25,578 29.0 28,393 29.6 30,158 30.0  
 30–34 95,772 33.6 29,463 33.4 32,243 33.6 34,066 33.9  
 35–39 50,717 17.8 16,215 18.4 17,010 17.7 17,492 17.4  
 40–44 10,705 3.8 3323 3.8 3625 3.8 3757 3.7  
  > 44 583 0.2 167 0.2 213 0.2 203 0.2  
Body mass index (kg/m2)
 Mean (SD)c 24.79 (4.65)   24.75 (4.62)   24.82 (4.67)   24.81 (4.66)   0.002
 Min-max 13.03–71.63   13.82–62.06   13.63–67.22   13.03–71.63   
 Median (IQR)d 23.80 (5.00)   23.74 (5.41)   23.81 (5.45)   23.81 (5.52)   
  < 18.5 6838 2.5 2044 2.4 2328 2.5 2466 2.5  
 18.5–24.99 163,856 59.2 50,787 59.7 55,203 58.9 57,866 58.9  
 25–29.99 70,440 25.4 21,478 25.3 23,870 25.5 25,092 25.5  
 30–34.99 25,166 9.1 7526 8.8 8573 9.2 9067 9.2  
 35.39.99 7899 2.9 2374 2.8 2734 2.9 2791 2.8  
  ≥ 40 2759 1.0 836 1.0 969 1.0 954 1.0  
Educational level
 Elementary school 20,860 8.7 6662 9.4 6870 8.5 7328 8.4 <0.001
 High school 95,564 40.0 27,821 39.4 32,660 40.3 35,083 40.1  
 University 122,623 51.3 36,155 51.2 41,432 51.2 45,036 51.5  
Main occupation
 Employed 195,880 70.3 59,890 70.3 66,622 70.5 69,368 70.1 <0.001
 Student 31,021 11.1 9697 11.4 10,364 11.0 10,960 11.1  
 Parental leave 20,469 7.3 6082 7.1 6911 7.3 7475 7.5  
 Unemployed 15,163 5.4 4955 5.8 4996 5.3 5212 5.3  
 Sick leave 4421 1.6 1241 1.5 1557 1.6 1623 1.6  
 Other 11,686 4.2 3300 3.9 4013 4.2 4373 4.4  
Country of birth
 Sweden 221,398 79.4 70,376 81.8 74,187 78.9 76,835 77.8 <0.001
 Other Nordic countriese 2374 0.8 613 0.8 832 0.8 929 0.8  
 Europef 12,861 4.6 3486 4.0 4481 4.8 4900 5.0  
 Africa 10,782 3.9 2780 3.2 3658 3.9 4344 4.4  
 Asia 25,597 9.2 6886 8.0 8976 9.5 9735 9.9  
 Other 5902 2.1 1917 2.2 1940 2.1 2045 2.1  
Smoking 3 months prior to pregnancy 38,854 13.8 12,134 13.9 13,285 14.0 13,435 13.5 0.004
Smoking at first ANCg visit 15,874 5.6 5062 5.8 5475 5.7 5337 5.4 <0.001
Smoking at 32 weeks of gestation 11,990 4.2 3923 4.5 4133 4.3 3934 3.9 <0.001
Use of snuff 3 months prior to pregnancy 9954 3.5 2530 2.9 3506 3.7 3918 3.9 <0.001
Use of snuff at first ANCg visit 2858 1.0 793 0.9 945 1.0 1120 1.1 <0.001
Use of snuff at 32 weeks of gestation 1721 0.6 548 0.6 561 0.6 612 0.6 0.572
Alcohol screening (AUDIT)h 245,544 88.1 74,712 86.7 81,408 86.7 89,424 90.6 <0.001
AUDIT-scorej
 Mean (SD)c 2.19 (2.19)   2.28 (2.22)   2.20 (2.22)   2.09 (2.15)   
 Min-max 0–40   0–39   0–40   0–40   
 Median (IQR)d 2.00 (2)   2.00 (2)   2.00 (2)   2.00 (3)   
  ≤ 5p 229,854 94.0 69,110 93.6 76,327 93.8 84,417 94.4 <0.001
  ≥ 6p 14,751 6.0 4704 6.4 5044 6.2 5003 5.6  
Self-rated health prior to pregnancy 241,854 84.9 70,633 80.1 82,594 86.0 88,627 88.1  
 Very good 72,321 29.9 19,838 28.1 24,472 29.6 28,011 31.6 <0.001
 Good 141,251 58.4 41,299 58.5 48,441 58.6 51,511 58.1  
 Neither good nor poor 20,425 8.4 6793 9.6 6962 8.4 6670 7.5  
 Poor 6325 2.6 2174 3.1 2197 2.7 1954 2.2  
 Very poor 1532 0.6 529 0.7 522 0.6 481 0.5  
Counselling due to fear of childbirth 21,595 7.6 6518 7.5 7186 7.5 7891 7.9 0.001
Treatment of psychiatric disorder 17,724 6.3 5122 5.9 6061 6.4 6541 6.5 <0.001
Gestational age (days)
 Mean (SD)c 278.0 (13.8)   278.0 (13.9)   277.8 (13.9)   278.1 (13.7)   <0.001
 Min-max 154–301   155–301   154–301   154–301   
 Median (IQR)d 280.00 (13.00)   280.00 (13.00)   280.00 (13.00)   280.00 (13.00)   
Mode of delivery 283,660 99.6 87,915 99.7 95,594 99.5 100,151 99.5  
 Vaginal 217,898 76.8 67,277 76.5 73,333 76.7 77,288 77.2 <0.001
 Instrumental 19,177 6.8 6208 7.1 6616 6.9 6353 6.3  
 Caesarean section 46,585 16.4 14,430 16.4 15,645 16.4 16,510 16.5  
Caesarean section (CS)
 Elective CSj 20,272 43.6 6321 43.9 6718 43.0 7233 43.9 0.193
 Emergency CSj 26,214 56.4 8085 56.1 8897 57.0 9232 56.1  
Birth weight (grams)k
 Mean (SD)c 3542 (556)   3540 (557)   3543 (556)   3543 (556)   0.352
 Min-max 300–6640   300–6050   305–6270   300–6640   
 Median (IQR)d 3550 (670)   3550 (675)   3550 (674)   3550 (670)   
  1. aTest of difference between years using One-Way Anova test on numeric variables, and Pearsons’s Chi-Square test for categorical variables
  2. bMaternal age at delivery
  3. cSD = Standard Deviation
  4. dIQR = Interquartile Range
  5. eOther Nordic countries includes Norway, Finland, Iceland and Denmark
  6. fThe Nordic countries are excluded
  7. gAntenatal care
  8. hAssessment of use of alcohol prior to pregnancy with screening instrument Alcohol Use Disorder Identification Test (AUDIT)
  9. i AUDIT score ranging from 0 to 40
  10. jCaesarean section
  11. kSingletons exclusively included in analysis