- Design
- Prospective national surveillance cohort (UKOSS), 2021–2024
- Population
- 210 pregnancies in 209 UK women with cardiomyopathy diagnosed before pregnancy
- Primary outcome
- Obstetric, neonatal and cardiovascular outcomes
- Effect
- No maternal deaths; heart failure 10%, arrhythmia 8%; median delivery 38.1 weeks; 20% neonatal unit admission
The UK Obstetric Surveillance System collected every notified pregnancy in a woman with cardiomyopathy diagnosed before conception between June 2021 and May 2024. There were 210 pregnancies in 209 women: about half had dilated cardiomyopathy, a fifth hypertrophic, 11.5% previous peripartum cardiomyopathy, 5% arrhythmogenic right ventricular cardiomyopathy and the rest other types.
There were no maternal deaths. Heart failure was documented in 10% of women and an arrhythmia in 8%. Median gestation at delivery among singletons was 38.1 weeks, and 20% of babies with data were admitted to the neonatal unit.
This is reassuring for counselling, but it describes women already known to services and managed in a system with joint cardio-obstetric care. It does not tell you the risk for an individual with poor ventricular function, and the abstract does not break outcomes down by type.
In practice: these women should be planned for before conception and seen in a combined clinic. One in ten developing heart failure is not rare — it is the reason for scheduled cardiac review across pregnancy and the early postpartum weeks.
- Refer women with any cardiomyopathy for pre-conception cardiology and obstetric review.
- Plan surveillance for heart failure and arrhythmia through pregnancy and the first postpartum weeks.
- Counsel that a neonatal unit admission is likely for about one baby in five.
- Ask about previous peripartum cardiomyopathy specifically — it was 11.5% of this cohort.
- Agree a delivery plan in advance, including place of birth and anaesthetic input.
Why it matters
It gives counselling numbers for a group often told only that pregnancy is high risk.
Don't overread it
These are women already under specialist care in the UK; outcomes elsewhere, or in severe disease, may be worse.
The statistics, in plain English
No deaths among 209 women does not mean the risk is zero — with this many women, a true risk of about 1 in 70 could still produce no deaths by chance. The 10% and 8% are simple proportions without adjustment, so they describe this cohort rather than predict any one woman's course.
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