- Design
- Prospective national surveillance cohort (UKOSS)
- Population
- 210 pregnancies in 209 women with cardiomyopathy diagnosed before pregnancy, 2021–2024
- Primary outcome
- Obstetric, neonatal and cardiovascular outcomes
- Effect
- No maternal deaths; heart failure 10%, arrhythmia 8%; median delivery 38.1 weeks; 20% of babies admitted to neonatal unit
The UK Obstetric Surveillance System collected every pregnancy in a woman with a cardiomyopathy diagnosed before conception, from June 2021 to May 2024. It found 210 pregnancies in 209 women: about half had dilated cardiomyopathy, a fifth hypertrophic, 11% a previous peripartum cardiomyopathy and 5% arrhythmogenic right ventricular cardiomyopathy.
There were no maternal deaths. Ten per cent had a recorded episode of heart failure and 8% an arrhythmia during pregnancy. Median gestation at delivery among singletons was 38.1 weeks, and a fifth of babies with data went to the neonatal unit.
This matters for counselling. Many women with cardiomyopathy are told, or assume, that pregnancy is off the table. In a well-resourced system with joint cardio-obstetric care, most of these pregnancies reached near term. The cohort is descriptive: it shows how women who chose pregnancy fared, not how a woman with a poor ejection fraction would fare.
In practice: plan with a cardiologist before conception, review drugs that are contraindicated in pregnancy, and watch for heart failure through the third trimester and the weeks after birth. In India, where peripartum cardiomyopathy is not rare and joint clinics are scarce outside large centres, early referral is the step most within reach.
- Refer women with any cardiomyopathy to a joint cardiology–obstetric clinic before conception where possible
- Review ACE inhibitors, ARBs, sacubitril-valsartan and other drugs unsuitable in pregnancy at the planning visit
- Ask about breathlessness, orthopnoea and palpitations at every antenatal visit and in the postnatal weeks
- Plan delivery at a unit with cardiology and high-dependency cover
- Women with previous peripartum cardiomyopathy need the same specialist planning in any later pregnancy
Why it matters
It challenges the reflex that cardiomyopathy means advising against pregnancy.
Don't overread it
This describes women who chose pregnancy under UK specialist care; it cannot predict risk for an individual with severe dysfunction.
The statistics, in plain English
These are raw percentages from a complete national count, with no comparison group. With 209 women, a 10% heart-failure rate means about 21 women; small subtypes such as arrhythmogenic cardiomyopathy (11 women) are too few to give a reliable risk for that type.
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