Recurrence after severe hypertensive disease: 14.9% overall, 22.9% if it began before 28 weeks

Design

Retrospective cohort, US Premier Inpatient database, 2015-2020

Population

560,295 people with two or more pregnancies; 11,433 with severe HDP in the index pregnancy

Primary outcome

Severe HDP in a subsequent pregnancy

Effect

14.9% recurrence, RR 16.0 (95% CI 15.2-17.0); onset before 28 weeks 22.9%, RR 23.1 (19.1-27.9)

A retrospective cohort used the US Premier Inpatient database to follow 560,295 people with two or more pregnancies between 2015 and 2020. Severe hypertensive disorder of pregnancy (HDP) was defined as pre-eclampsia with severe features, superimposed pre-eclampsia, HELLP syndrome or eclampsia, identified from ICD-10 codes.

Of 11,433 people with severe HDP in the index pregnancy, 14.9% had severe HDP again (RR 16.0 against those with no HDP). Onset before 28 weeks carried the highest risk: 22.9% recurrence, and 4.7% recurrence before 28 weeks again. HELLP recurred in 4.6% and eclampsia in 1.1% of those who had had them.

These are the numbers most counselling has lacked. Earlier estimates varied widely, and a woman asking what happens next time can now be given a figure matched to the timing and type of her disease.

Use them at the postnatal review and at pre-pregnancy counselling, and make sure the next pregnancy starts with aspirin, early booking and a plan for blood pressure surveillance.

• Record gestation at onset and the phenotype (severe features, HELLP, eclampsia) in the discharge summary.
• Quote about 1 in 7 recurrence after severe HDP, and nearer 1 in 4 if onset was before 28 weeks.
• Advise early booking and low-dose aspirin before 16 weeks in the next pregnancy.
• Check blood pressure, renal function and metabolic risk at the postnatal visit; the cardiovascular risk outlasts the pregnancy.

Why it matters

Recurrence counselling after severe pre-eclampsia can now be specific to when the disease began, rather than a vague 'you are at higher risk'.

Don't overread it

Diagnoses came from billing codes in one hospital network, and people who had no further pregnancy or delivered elsewhere are not captured.

The statistics, in plain English

A relative risk of 16 sounds alarming because the comparison group, people with no hypertensive disease, has a very low baseline rate. The absolute figure, 14.9%, is the one to give a patient. The very large relative risks for recurrent HELLP (61) and early-onset disease (185) rest on small numbers of events, which is why their confidence intervals are so wide.

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