Tretinoin (topical)

8.1 Pregnancy Risk Summary Available data from published prospective observational studies and retrospective cohort studies over decades of use of topical tretinoin in pregnant women have not established a drug-associated risk of major birth defects, miscarriage, or adverse maternal or fetal outcomes (see Data) . In animal reproduction studies with pregnant rats, alterations in the vertebrae and ribs of offspring were observed with daily topical dosing of 0.1% Tretinoin Gel (microsponge) during organogenesis at 5 to 10 times the maximum recommended human dose (MRHD).

In animal reproduction studies with pregnant rabbits, fetal malformations, such as domed head and hydrocephaly, were observed in the offspring with daily topical dosing of 0.1% Tretinoin Gel (microsponge) during organogenesis at 10 to 19 times the MRHD [ see Data ]. The background risk of major birth defects and miscarriage for the indicated population is unknown. All pregnancies have a background risk of birth defect, loss, or other adverse outcomes. In the US general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2% to 4%, and 15% to 20%, respectively.

Data Human Data: Published data from prospective observational studies and retrospective cohort studies on the use of topical tretinoin products during pregnancy have not identified an association with topical tretinoin and major birth defects or miscarriage. The available studies have methodologic limitations, including potential misclassification of exposure, small sample size and in some cases, lack of physical exam by an expert in birth defects. Animal Data: For purposes of comparison of the animal exposure to systemic human exposure, the MRHD applied topically is defined as 1 gram of Tretinoin Gel Microsphere, 0.1%, applied daily to a 60 kg person (0.017 mg tretinoin/kg body weight).

Pregnant rats were treated with 0.1% Tretinoin Gel (microsponge) at daily dermal doses of 0.2, 0.5, and 1 mg/kg/day tretinoin on gestation days 6-15. Alterations were seen in the vertebrae and ribs of the affected offsprings at 0.5 mg/kg/day tretinoin, 5 to 10 times the MRHD based on body surface area (BSA) comparison. Pregnant rabbits were treated with 0.1% Tretinoin Gel (microsponge) at daily dermal doses of 0.2, 0.5, and 1 mg/kg/day tretinoin on gestation days 7-19. Doses were administered topically for 24 hours a day while wearing Elizabethan collars to prevent ingestion of the drug. Increased incidences of certain alterations, including domed head and hydrocephaly, typical of…