The impact of guidelines on mild hypertension in pregnancy: time series analysis

Objective To determine the impact of a national strategy to promote implementation of a guideline on the management of mild, non-proteinuric hypertension in pregnancy.

Design Simple, interrupted time series analysis.

Setting Four maternity units in Scotland.

Population Women delivering a live or stillborn baby.

Methods Dissemination of the guideline under the auspices of a national clinical effectiveness programme, supported by a national launch meeting and feedback from a survey of obstetricians highlighting aspects of care that could be improved.

Main outcome measures Appropriateness of initial investigation and subsequent clinical management, and costs of guideline development and implementation activities.

Data collection Twenty-four months pre-intervention and 12 months post-intervention data were abstracted from a random sample of case notes.

Results Initial investigation was consistent with recommendations for 59.9% out of 1263 women and subsequent clinical management for 67.6% out of 1081 in whom a diagnosis could be made from available data. There were no significant changes in the appropriateness of initial investigation (10.6%; 95% confidence interval [CI] -0.1% to 19.3%; decreasing by 1.2% per month post-implementation, 95% CI -2.5% to 0.1%) or clinical management (-0.3%; 95% CI -8.7% to 11.2%). Guideline development and implementation cost an estimated pound2784 per maternity unit in Scotland.

Conclusions Clinical care of mild hypertension in pregnancy remains highly inconsistent. The lack of the intervention effect may be related to the complexity of the guideline recommendations and the nature of the implementation strategy.