Isotretinoin exposure and pregnancy outcome: an observational study of the Berlin Institute for Clinical Teratology and Drug Risk Assessment in Pregnancy

Apart from thalidomide, retinoids like isotretinoin are the strongest teratogens in humans known today. The overall risk of birth defects is estimated as up to 30% after exposure during embryogenesis. In spite of well established pregnancy prevention programs, pregnancies still occur during isotretinoin therapy in many countries including Germany. A detailed investigation of the incidence and outcome of these pregnancies would fill an important gap.

The Berlin Institute for Clinical Teratology documents prospectively the course of drug-exposed pregnancies when contacted for individual drug risk assessment. Datasets of isotretinoin exposed pregnancies recorded between 1993 and 2008 were evaluated as to the outcome of pregnancy.

A total of 108 pregnancies exposed to systemic isotretinoin (median dosage 20 mg/day) during the contraindicated period were registered. 76% (69/91) of the pregnancies with known outcome were electively terminated—mainly for fear of medication risk. No terminations due to abnormal prenatal ultrasound findings were reported. Spontaneous abortions occurred in five pregnancies. Of 18 live births including 1 pair of twins 1 major birth defect (small ventricular septal defect) was observed. None of the infants showed symptoms of retinoid embryopathy. 70% (48/69) of the patients with data on contraception did not use any method, in 30% contraception failed. There was no evidence that poor maternal education was a major cause for the omission of contraception documented in 48 women.

Inadvertent isotretinoin exposure during the first 2 weeks post conception does not necessarily require discussion of termination of pregnancy, as the risk of major birth defects appears to be much lower than it becomes beyond this period. Nevertheless, additional efforts are required to improve the effectiveness of contraception while on isotretinoin treatment considering psycho-social aspects such as improved self-confidence, unexpected new partnership and sexual activity and incorrect perception of infertility.