11 Aug Occurrence of pregnancy and pregnancy outcomes during isotretinoin therapy (Q10-23)
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Occurrence of pregnancy and pregnancy outcomes during isotretinoin therapy (Q10-23)
Q10-23
Overview
What is the issue?
- Isotretinoin, marketed under the name Accutane but available as a generic drug, is a widely used drug to treat severe, cystic acne.
- This drug is known to cause birth defects and there is uncertainty regarding the level of pregnancy prevention implemented by users.
- While there are pregnancy prevention programs in place, prior to our study adherence to these programs was uncertain.
What was the aim of the study?
- This study sought to determine the adherence to pregnancy prevention programs in 4 participating provinces: British Columbia, Saskatchewan, Manitoba and Ontario.
- The study examined several outcomes over time in women who used isotretinoin, including: the frequency of exposed pregnancies, the number of these pregnancies that reached end of term, and the number that resulted in fetal abnormalities.
How was the study conducted?
- Using administrative data between 1996 and 2011, 4 historical cohorts of female isotretinoin users (aged 12 – 48 years old) were constructed.
- Two definitions of pregnancy were used: one only counted cases with documented pregnancy outcomes (high-specificity definition), and the other included individuals recorded as having received prenatal care (high-sensitivity definition).
- Pregnancies were detected during isotretinoin treatment only and up to 42 weeks after treatment. To identify congenital malformations, live births were followed for 1 year.
What did the study find?
- Of the 59 271 female patients examined, only 24.3% (Saskatchewan) to 32.9% (Manitoba) of participants received prescriptions for oral contraceptives while being treated with isotretinoin. This is compared to 28.3% to 35.9% in the 12 months before taking isotretinoin.
- During treatment, there were 186 pregnancies during treatment according to the high-specificity definition of pregnancy, compared to 367 pregnancies using the high-sensitivity definition.
- Up to 42 weeks after treatment, there were 1473 pregnancies detected, of which 1331 (90.4%) were terminated spontaneously or by medical intervention.
- Among the 118 live births, 11 (9.3%) infants were born with congenital malformations. Pregnancy rates during isotretinoin treatment remained stable during the study period.
Implications
- Clinicians should adhere more closely to prescribing advice and suggest safer acne treatments before isotretinoin. The isotretinoin pregnancy prevention program in Canada should be strengthened.
Key message
- There is low compliance to the isotretinoin pregnancy prevention program in Canada.
Manuscripts
Henry D, Dormuth C, Winquist B, Carney G, Bugden S, Teare G, Lévesque LE, Bérard A, Paterson JM, Platt RW. Occurrence of pregnancy and pregnancy outcomes during isotretinoin therapy. CMAJ. 2016 Jul 12;188(10):723-30