Table 1.
Socio-demographic and pregnancy characteristics of mothers with asthma, atopic dermatitis, allergic rhinoconjunctivitis, and no atopic disease among 1,974,226 births
| Mothers with asthma | Mothers with atopic dermatitis | Mothers with allergic rhinoconjunctivitis | Mothers with no atopic disease | |
|---|---|---|---|---|
| No.a | 35,771 | 66,535 | 8,505 | 1,876,211 |
| Maternal age at birth (years, mean) | 27.2 | 27.2 | 28.0 | 27.1 |
| Educationb | ||||
| <11 years | 25 % | 19 % | 14 % | 24 % |
| 11–14 years | 42 % | 43 % | 38 % | 45 % |
| >14 years | 32 % | 37 % | 47 % | 29 % |
| Single mother at birthb | ||||
| Yes | 13 % | 11 % | 8 % | 9 % |
| No | 87 % | 89 % | 92 % | 90 % |
| Parityc | ||||
| 0 | 46 % | 47 % | 47 % | 41 % |
| 1 | 32 % | 34 % | 35 % | 35 % |
| ≥2 | 22 % | 19 % | 19 % | 24 % |
| Season of birth | ||||
| Winter | 23.7 % | 23.5 % | 22.7 % | 23.9 % |
| Spring | 26.4 % | 26.9 % | 24.3 % | 27.2 % |
| Summer | 25.8 % | 25.3 % | 26.5 % | 25.2 % |
| Autumn | 24.2 % | 24.3 % | 26.5 % | 23.7 % |
| Pregnancy length (days, mean) | 280.1 | 281.0 | 281.3 | 280.7 |
| Gestational age of offspring | ||||
| 23–31 weeks | 1.2 % | 0.8 % | 0.6 % | 1.0 % |
| 32–36 weeks | 5.8 % | 4.6 % | 4.3 % | 4.9 % |
| 37–41 weeks | 78.5 % | 80.9 % | 81.4 % | 80.4 % |
| 42–43 weeks | 14.5 % | 13.7 % | 13.7 % | 13.7 % |
| Pregnancy complications | 13.3 % | 10.2 % | 12.3 % | 9.3 % |
| Chorioamnionitis | 0.4 % | 0.3 % | 0.4 % | 0.3 % |
| Placental abruption | 0.7 % | 0.6 % | 0.4 % | 0.6 % |
| Placenta previa | 0.2 % | 0.2 % | 0.2 % | 0.2 % |
| Prolonged rupture of membranes | 2.2 % | 0.7 % | 2.6 % | 1.2 % |
| Unspecified bleeding | 3.6 % | 3.1 % | 3.9 % | 2.5 % |
| Pre-eclampsia | 4.5 % | 3.7 % | 3.5 % | 2.9 % |
| Caesarean section | 13.8 % | 11.4 % | 10.9 % | 8.7 % |
| Birthweight (gram, mean) | 3,473 | 3,523 | 3,556 | 3,504 |
| Small for gestational aged | 3.2 % | 2.5 % | 2.3 % | 2.8 % |
| Apgar 1 min <7e | 5.3 % | 4.4 % | 4.4 % | 4.5 % |
| Apgar 5 min <7e | 1.3 % | 1.1 % | 0.8 % | 1.2 % |
| Stillbirth | 0.5 % | 0.4 % | 0.2 % | 0.6 % |
| Neonatal deathf | 0.3 % | 0.3 % | 0.2 % | 0.5 % |
a
Mothers with a record of more than one disease is registered in each category.
b
Percentages do not add up to 100% because of missing values.
c
Parity included previous live births and stillbirths.
d
Small for gestational age was defined as birthweight less than 2 standard deviations from the sex- and gestational age-specific mean.
e
Analyzed in a sub-cohort of 1,330,649 births, because of missing data before 1978.
f
Death before 28 days of age after live birth.