- Design
- Population-based cohort, prediction model development
- Population
- 28,234 Dutch women after a first birth, followed up to 10 years
- Primary outcome
- 10-year incident hypertension
- Effect
- C-index 0.659 to 0.772 with pregnancy factors added (difference 0.113, 95% CI 0.092 to 0.132)
A Dutch population-based cohort linked primary care records to the national perinatal registry for 28,234 women having a first birth between 2007 and 2019, followed for up to 10 years. Over that time 639 developed hypertension, a cumulative incidence of 3.3%.
A model built from sociodemographic and cardiovascular factors alone had a C-index of 0.659. Adding pregnancy-related factors raised it to 0.772, a difference of 0.113 (95% CI 0.092 to 0.132), driven mostly by hypertensive disorders of pregnancy. The improvement came from better identification of women who went on to develop hypertension; classification of those who did not was unchanged.
The point for obstetric practice is that pregnancy is a cardiovascular stress test whose result is often lost at discharge. This model has not yet been validated outside the Netherlands, but the direction supports recording hypertensive disorders of pregnancy clearly in the discharge letter and in primary care notes.
- Record pre-eclampsia, gestational hypertension and their severity in the discharge summary sent to primary care.
- Advise women with a hypertensive disorder of pregnancy to have blood pressure checked at least yearly.
- Ask about hypertensive disorders in past pregnancies when assessing any woman's cardiovascular risk.
- Treat the model as research-stage until it has been validated in other populations.
Why it matters
A woman's obstetric history is one of the strongest early clues to later hypertension, and it is usually missing from adult risk scores.
Don't overread it
This is a prediction model from one country, not evidence that screening on it improves outcomes.
The statistics, in plain English
The C-index measures how well a model ranks who will and will not develop the outcome: 0.5 is a coin toss, 1.0 is perfect. A rise from 0.66 to 0.77 is a meaningful improvement. The net reclassification gain was entirely among women who developed hypertension; for women who did not, the model performed no better.
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