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Table 1 Characteristics of the 77,344 women with live-born singletons according to maternal fever in 1st trimester

From: Fever in pregnancy and the risk of congenital malformations: a cohort study

  Total Fever in 1st trimester No fever in 1st trimester
  N % PPa N % N %
Total study population 77,344 100 3.7 8321 100 69,023 100
Parity
 0 36,017 46.6 4.1 3375 40.6 32,642 47.3
 1 28,843 37.3 3.4 3502 42.1 25,341 36.7
 2 10,159 13.1 3.4 1191 14.3 8968 13.0
  ≥ 3 2325 3.0 3.2 253 3.0 2072 3.0
Previous spontaneous abortion
 No 62,570 80.9 3.7 6646 79.9 55,924 81.0
 Yes 14,774 19.1 3.8 1675 20.1 13,099 19.0
Maternal age at conception
  ≤ 24 9656 12.5 3.7 1012 12.2 8644 12.5
 25–29 32,370 41.9 3.8 3477 41.8 28,893 41.9
 30–34 26,466 34.2 3.7 2940 35.3 23,526 34.1
  ≥ 35 8852 11.4 3.6 892 10.7 7960 11.5
In Vitro Fertilization
 No/Irrelevant 75,646 97.8 3.7 8178 98.3 67,468 97.8
 Yes 1698 2.2 4.7 143 1.7 1555 2.3
Maternal diabetes
 No 77,127 99.7 3.7 8285 99.6 68,842 99.7
 Yes 217 0.3 6.5 36 0.4 181 0.3
Medical treatment of maternal epilepsy
 No 77,120 99.7 3.7 8306 99.8 68,814 99.7
 Yes 224 0.3 9.4 15 0.2 209 0.3
Maternal rheumatoid arthritis
 No 77,243 99.9 3.7 8312 99.9 68,931 99.9
 Yes 101 0.1 8.9 9 0.1 92 0.1
Binge drinking in 1st trimester
 No 59,006 76.3 3.7 6218 74.7 52,788 76.5
 Yes 18,338 23.7 3.8 2103 25.3 16,235 23.5
Smoking during pregnancy
 No 57,719 74.6 3.7 6116 73.5 51,603 74.8
 Yes 19,625 25.4 3.8 2205 26.5 17,420 25.2
Socio-occupational status
 Higher grade professionals 18,443 23.9 3.7 2118 25.5 16,325 23.7
 Lower grade professionals 24,247 31.4 3.6 2716 32.6 21,531 31.2
 Skilled workers 21,635 28.0 3.9 2127 25.6 19,508 28.3
 Unskilled workers 10,697 13.8 3.6 1084 13.0 9613 13.9
 Students 1782 2.3 4.3 217 2.6 1565 2.3
 Unemployed >1 year 540 0.7 4.3 59 0.7 481 0.7
Child sex
 Male 39,546 51.1 4.0 4211 50.6 35,335 51.2
 Female 37,798 48.9 3.5 4110 49.4 33,688 48.8
Pre-conceptional intake of folic acid
 No 67,892 87.8 3.7 7283 87.5 60,609 87.8
 Yes 9353 12.1 3.8 1029 12.4 8324 12.1
 Total 77,245 99.9 3.7 8312 99.9 68,933 99.9
 Missing 99 0.1 3.0 9 0.1 90 0.1
Antipyretic use in 1st trimester
 No 65,205 84.3 3.8 6558 78.8 58,647 85.0
 Yes 11,982 15.5 3.5 1748 21.0 10,234 14.8
 Missing 157 0.2 4.5 15 0.2 142 0.2
Infections in 1st trimester
 No 64,164 83.0 3.7 6012 72.2 58,152 84.3
 Yes 12,145 15.7 3.8 2196 26.4 9949 14.4
 Missing 1035 1.3 3.2 113 1.4 922 1.3
  1. The Danish National Birth Cohort 1996–2002
  2. aPP: Prevalence Proportion of overall congenital malformations per 100 live births