Table 3.
Hypertensive Disorders in First Pregnancy and Cardiovascular Disease by Gestation Length
| Hypertensive Disorder in Pregnancy & Gestational Length at Delivery Status | |||||||
|---|---|---|---|---|---|---|---|
| Term (≥37 weeks) | Preterm (<37 weeks) | ||||||
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|
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| Normotensive Pregnancy 50,404 (83.5%) | Gestational Hypertension 1,643 (2.7%) | Preeclampsia 3,216 (5.3%) | HDP 4,859 (8.1%) | Gestational Hypertension 146 (0.2%) | Preeclampsia 618 (1.0%) | HDP 764 (1.3%) | |
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|
|
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| CVD (CAD or Stroke) | |||||||
| Cases/Person-years | 820/1,737,169 | 40/53,413 | 95/109,544 | 135/162,957 | 1/4,487 | 18/19,296 | 19/23,783 |
| Excess cases per 100,000 person-years | --- | 28 | 40 | 36 | *** | 46 | 33 |
| Model 1 | 1.00 (ref) | 1.69 (1.23, 2.33) | 1.89 (1.53, 2.34) | 1.83 (1.52, 2.19) | *** | 2.21 (1.39, 3.53) | 1.88 (1.19, 2.96) |
| Model 2 | 1.00 (ref) | 1.53 (1.11, 2.11) | 1.74 (1.40, 2.15) | 1.67 (1.39, 2.01) | *** | 2.04 (1.27, 3.25) | 1.74 (1.10, 2.75) |
CAD: coronary artery disease; CVD: cardiovascular disease; HDP: hypertensive disorders of pregnancy; PY: person-years. Hazard ratios and corresponding 95% confidence intervals are provided for Models 1 and 2. Excess cases (rate differences) were calculated by subtracting the incidence (cases/person-years) in the unexposed from the incidence in the exposed. Tests for effect modification by preterm delivery in the fully adjusted model (Model 2) through likelihood ratio tests, comparing models with and without multiplicative interaction terms between HDP and preterm delivery: p=0.31 (for the three-category HDP exposure) and p=0.87 (for the binary HDP exposure).
Model 1 is adjusted for age at first birth (years), age at NHSII enrollment (years), race/ethnicity (Black, Hispanic/Latina, Asian, White [ref], other/multi-race), and parental education (<9, 9–11, 12, 13–15, ≥16 years [ref]).
Model 2 is additionally adjusted for physical activity at ages 18–22 (never, 1–3 [ref], 4–6, 7–9, 10–12 mo/yr), pre-pregnancy smoking (never [ref], past, current), pre-pregnancy BMI (<18.5, 18.5–24.9 [ref], 25–29.9, ≥30 kg/m2), pre-pregnancy alcohol consumption (none [ref], ≤1 drink/week, 2–6 drink/week, ≥1 drinks/day), pre-pregnancy Alternative Healthy Eating Index (AHEI) score (quintiles with the fifth quintile [ref] representing the healthiest diet category), pre-pregnancy oral contraceptive use (never [ref], <2, 2–<4, ≥4 years), pre-pregnancy hypercholesterolemia (no [ref], yes), and parental history of CAD and/or stroke before age 60 (CAD only for CAD model, stroke only for stroke model, CAD or stroke for CVD models; no [ref], yes).
These results are drawn from 6 different models—one model with hypertensive disorders in pregnancy and normotensive first pregnancies split out by term and preterm delivery (i.e. 4 exposure categories) and another model with preeclamptic, gestational hypertensive, and normotensive first pregnancies split out by term and preterm deliveries (i.e. 6 exposure categories); normotensive term served as the reference group. Results for women with normotensive preterm (n=4,352; 7.2%) are not shown above but were obtained within the same models: fully adjusted HR=1.41 (CI: 1.14–1.73).
Results not shown given only 1 CVD event among women with gestational hypertension and preterm delivery in first birth.