Table 1.
Characteristics of the study population for hypertensive disorders of pregnancy (HDP) exposed and unexposed women.
| Characteristic | HDP exposed | 2:1 unexposed | |||
|---|---|---|---|---|---|
| N | % | N | % | P* | |
| Total births | 31,454 | 100.0 | 62,908 | 100.0 | – |
| Characteristics of mother: | |||||
| Age at child’s birth (mean, ±SD) | 27.6 | ±6.38 | 27.4 | ±6.36 | <0.001 |
| 12 - 21y | 6,012 | 19.1 | 12,716 | 20.2 | |
| 22 - 26y | 9,005 | 28.6 | 17,860 | 28.4 | |
| 27 - 33y | 10,123 | 32.2 | 20,288 | 32.3 | |
| 34 - 55y | 6,314 | 20.1 | 12,044 | 19.1 | 0.22 |
| Birth year of mother | |||||
| 1900-1949 | 5,027 | 16.0 | 10,030 | 15.9 | |
| 1950-1965 | 11,452 | 36.4 | 22,711 | 36.1 | |
| 1966-1975 | 14,975 | 47.6 | 30,167 | 48.0 | 0.45 |
| Race/ethnicity of mother | |||||
| White and non-Hispanic | 26,906 | 85.5 | 54,054 | 85.9 | |
| White and Hispanic | 2,644 | 8.4 | 5,217 | 8.3 | |
| Non-white | 1,904 | 6.1 | 3,637 | 5.8 | 0.07 |
| Pre-pregnancy body mass index† | |||||
| Underweight, <18.5 | 760 | 2.4 | 3,251 | 5.2 | |
| Normal, 18.5-24.9 | 12,568 | 39.9 | 35,960 | 57.1 | |
| Overweight, 25.0-29.9 | 8,333 | 26.5 | 13,494 | 21.5 | |
| Obese, ≥30.0 | 8,830 | 28.1 | 8,560 | 13.6 | |
| Unavailable | 963 | 3.1 | 1,643 | 2.6 | <0.001 |
| History of type I or II diabetes | |||||
| No | 29,453 | 93.6 | 60,331 | 95.9 | |
| Yes | 2,001 | 6.4 | 2,577 | 4.1 | <0.001 |
| History of hypertension | |||||
| No | 30,732 | 97.7 | 62,688 | 99.7 | |
| Yes | 722 | 2.3 | 220 | 0.3 | <0.001 |
| Maximum number of children | |||||
| 1 child | 3,290 | 10.5 | 5,512 | 8.8 | |
| 2 children | 7,671 | 24.4 | 13,929 | 22.1 | |
| 3 children | 7,597 | 24.2 | 14,706 | 23.4 | |
| 4 or more children | 12,896 | 41.0 | 28,761 | 45.7 | <0.001 |
| Highest level of education | |||||
| Less than high school graduate | 494 | 1.6 | 799 | 1.3 | |
| High school graduate | 2,541 | 8.1 | 5,035 | 8.0 | |
| More than high school graduate | 24,746 | 78.7 | 49,714 | 79.0 | |
| Not reported | 3,673 | 11.7 | 7,360 | 11.7 | 0.56 |
| County of residence | |||||
| Urban counties | 26,521 | 84.3 | 54,236 | 86.2 | |
| Mixed urban/rural | 1,245 | 4.0 | 2,415 | 3.8 | |
| Rural | 3,435 | 10.9 | 5,769 | 9.2 | |
| Outside of Utah | 253 | 0.8 | 488 | 0.8 | 0.28 |
| Vital status | |||||
| Alive at last follow up | 28,922 | 92.2 | 57,466 | 91.3 | |
| Died prior to study end/diagnosis | 2,462 | 7.8 | 5,442 | 8.7 | <0.001 |
| Years of follow up (mean, ±SD) | 23.2 | ±13.87 | 23.9 | ±13.54 | <0.001 |
| Characteristics of child: | |||||
| Female | 15,037 | 47.8 | 30,072 | 47.8 | |
| Male | 16,417 | 52.2 | 32,836 | 52.2 | 0.99‡ |
| Birth year of child | |||||
| 1939-1979 | 5,750 | 18.3 | 11,504 | 18.3 | |
| 1980-1999 | 18,310 | 58.2 | 36,623 | 58.2 | |
| 2000-2013 | 7,394 | 23.5 | 14,781 | 23.5 | 0.97‡ |
| Birth order of child | |||||
| 1st | 16,480 | 52.4 | 32,953 | 52.4 | |
| 2nd | 5,472 | 17.4 | 10,951 | 17.4 | |
| 3rd or higher | 9,502 | 30.2 | 19,004 | 30.2 | 0.99‡ |
| Birth weight | |||||
| Very low (<1500 gm) | 1,044 | 3.3 | 420 | 0.7 | |
| Low (1500 to <2500 gm) | 4,181 | 13.3 | 2,523 | 4.0 | |
| Normal (2500 to 4500 gm) | 25,311 | 80.5 | 58,216 | 92.5 | |
| High (>4500 gm) | 388 | 1.2 | 674 | 1.1 | |
| Not reported | 530 | 1.7 | 1,075 | 1.7 | <0.001 |
| Gestation (weeks) | |||||
| Very early preterm (<29 wk) | 1,244 | 4.0 | 744 | 1.2 | |
| Early preterm (29 to <33 wk) | 4,597 | 14.6 | 3,368 | 5.4 | |
| Preterm (33 to <37 wk) | 1,160 | 3.7 | 3,078 | 4.9 | |
| Term (37 to 41 wk) | 23,715 | 75.4 | 53,989 | 85.8 | |
| Post-term (>41 wk) | 738 | 2.3 | 1,729 | 2.7 | <0.001 |
*
Mantel-Haenszel chi-square test of association, categorical variables; paired t-test, continuous variables.
†
Weight in kilograms divided by height in meters squared.
‡
Matching variable of exposed to unexposed subjects in the study design.