Adherence to anti-hypertensive medication in pregnancy

Objectives: To assess adherence to anti-hypertensive medication by pregnant women and to identify the factors associated with adherence or lack thereof. 

Study Design: Observational study in 100 pregnant women with either chronic hypertension or gestational hypertension who were being treated with at least one anti-hypertensive medication and attending antenatal clinics at one of two maternity hospitals. In-depth interviews were conducted with a subset of 27 women from the same group. Quotes from interview transcripts were used to illustrate the quantitative results. 

Main Outcome Measures: BP control, self-reported adherence, complexity of medication regimen. 

Results: Participants (mean age 33 [±4.9] years; mean gestation 29 (±7) weeks) had a median blood pressure (BP) of 130/80 mmHg (IQR: 16/15). Sixty-five women had chronic hypertension, of whom 13 were diagnosed during pregnancy, before 20 weeks gestation. Thirty-five women had gestational hypertension. Ninety-two per cent of participants had sub-optimal adherence. There were no significant differences in adherence scores between participants with chronic hypertension and their counterparts. The main contributors to sub-optimal adherence were intentionally putting up with medical problems before taking any action, confusion about the medication, and making changes to the recommended medication regimen to suit lifestyle. 

Conclusions: Nine out of ten pregnant women using anti-hypertensives self-reported some degree of suboptimal adherence, intentionally and/or unintentionally. Health professionals, including pharmacists, general practitioners and obstetricians, have a role in promoting optimal medication adherence.