Table 1.
Infant and Maternal Characteristics by Gestational Age at Birth, Sweden, 1973–1979
| Gestational Age, % |
||||||
| 23–27 Weeks (n = 174) | 28–32 Weeks (n = 3,167) | 33–34 Weeks (n = 5,685) | 35–36 Weeks (n = 19,194) | 37–42 Weeks (n = 589,573) | ≥43 Weeks (n = 18,759) | |
| Infant's gender | ||||||
| Female | 44.8 | 43.7 | 44.4 | 44.8 | 48.8 | 49.9 |
| Male | 55.2 | 56.3 | 55.6 | 55.2 | 51.2 | 50.1 |
| Maternal marital status in 1990 | ||||||
| Married/cohabiting | 74.3 | 70.4 | 70.3 | 72.0 | 76.4 | 72.9 |
| Never married | 13.5 | 13.0 | 12.9 | 11.7 | 9.4 | 11.5 |
| Divorced | 12.3 | 15.8 | 15.7 | 14.8 | 13.0 | 14.6 |
| Widowed | 0.0 | 0.8 | 1.1 | 1.5 | 1.2 | 1.0 |
| Maternal education in 1990 | ||||||
| Compulsory high school or less (≤9 years) | 29.2 | 31.2 | 32.0 | 30.8 | 26.9 | 29.4 |
| Practical high school or some theoretical high school (10–11 years) | 47.4 | 46.7 | 47.1 | 46.5 | 47.2 | 47.4 |
| Theoretical high school and/or college (≥12 years) | 23.4 | 22.1 | 20.9 | 22.7 | 25.9 | 23.1 |
| Family income in 1990 | ||||||
| Lowest quartile | 29.9 | 28.4 | 27.6 | 26.1 | 23.0 | 24.1 |
| Second quartile | 21.8 | 25.3 | 24.8 | 25.8 | 25.7 | 25.3 |
| Third quartile | 25.3 | 24.7 | 24.7 | 25.0 | 25.7 | 25.8 |
| Highest quartile | 23.0 | 21.6 | 22.9 | 23.1 | 25.6 | 24.8 |
| Maternal prescription of antihypertensive medicationsa from July 1, 2005, through December 31, 2009 | 29.3 | 30.8 | 32.4 | 31.2 | 29.1 | 28.9 |
a
Defined as 1 or more prescriptions per year of any antihypertensive medication (Anatomical Therapeutic Chemical (Classification) code(s) C02, C03, C07, C08, and/or C09).