Pregnancy as a major determinant for discontinuation of antidepressants: an analysis of data from The Health Improvement Network.

backgroundPotential adverse effects of antidepressants during pregnancy have caused concern about their use. There are, however, very limited detailed data on patterns of antidepressant prescribing in pregnancy.

objectiveTo examine secular trends in prescribing during pregnancy, to assess whether pregnancy is a major determinant for stopping antidepressants, and to identify characteristics of those who stopped antidepressants during pregnancy.

methodIn this cohort study, we obtained data on 114,999 pregnant women (median age at delivery, 30.5 years [interquartile range, 26-34 years]) who had a live birth between 1992 and 2006 and 22,677 nonpregnant women from The Health Improvement Network primary care database, one of the largest sources of continuous anonymized primary care data in the United Kingdom and broadly representative of UK general practice. This database includes information on age, sex, medical diagnosis and symptoms, health promotion activities, referrals to secondary care, and prescriptions for each registered individual. The database also holds information about social deprivation as measured using quintiles of the Townsend score. We used Cox regression analysis to compare time to last prescription in pregnant versus nonpregnant women and to identify characteristics of those women who stopped antidepressants during pregnancy.

resultsAntidepressant prescribing in pregnancy increased nearly 4-fold from 1992 to 2006 (relative risk = 3.87; 95% CI, 1.73-8.66; P < .001). Since 2001, approximately 3% of the cohort received antidepressants at some stage during pregnancy. Selective serotonin reuptake inhibitors accounted for approximately 80% of the prescribed antidepressants. Antidepressants were more likely to be stopped in pregnant than in nonpregnant women, in particular during the first 6 weeks of pregnancy (hazard ratio = 5.19; 95% CI, 4.85-5.56; P < .001). Only 10% of women treated before pregnancy still received antidepressants at the start of the third trimester. In contrast, 35% of nonpregnant women were still treated after a similar time period.

conclusionsAlthough antidepressant prescribing in pregnancy increased nearly 4-fold from 1992 to 2006, pregnancy was a major determinant of cessation of antidepressant medication, and most women did not receive further antidepressant prescriptions beyond 6 weeks of gestation. This finding may be explained by concerns about potential adverse effects of the medications, even though these concerns need to be balanced against the potential harm of inadequate treatment of depression during pregnancy.