SUN-LB12 Prenatal Trenbolone Exposure and External Genital Malformation: A Case Report

Background Trenbolone is a synthetic anabolic steroid used for muscle growth in livestock. Human use is not FDA approved. The active metabolite, 17β trenbolone is 3 times more potent an androgen than testosterone propionate. Prenatal trenbolone exposure in rats results in female offspring with external genital malformations including an increased anogenital distance (AGD). We now report a case of prenatal trenbolone exposure in humans. Clinical Case A 10 hour old baby delivered vaginally at 37 6/7 weeks of gestation with a birth weight of 3615 grams was admitted to the NICU for concern of ambiguous genitalia. Baby was born to 30 year old G6P3 mother who was HIV positive and adequately treated with Triumeq. She had irregular cycles prior to conception and pregnancy recognized at 14 weeks. Unlike her previous pregnancies, during this pregnancy she had acne and mildly increased facial hair. Prenatal cell-free DNA screening was 46XX and ultrasound showed female genitalia. The 9 year old half-sister and 5 year old brother are healthy. No family history of early neonatal deaths. On arrival blood glucose was 55 mg/dL (45-90). On exam baby had no obvious facial dysmorphic features or midline defects. Hand creases were normal and no extremity edema was noted. Genitalia appeared symmetrical and, showed prominent soft tissue of clitoris without corpus enlargement. No gonads were palpable in the groin or labioscrotal folds. Significant posterior labioscrotal fusion was noted. Anogenital ratio was 0.8 (normal <0.5). A single orifice at the base of the clitoral hood was noted, consistent with likely urogenital sinus. Additional history provided by mother included her disclosure of use of 200 mg of IM trenbolone weekly for 5 weeks, for muscle building, prior to her knowledge of being pregnant. Multidisciplinary care included pediatric endocrinology, genetics, pediatric urology, and pediatric infectious disease. Labs at 24 hours of life: Sodium - 139 mmol/L (131-144), Potassium - 5.3 mmol/L (3.2-5.7), Serum glucose - 75 mg/dL (45-90), Random cortisol - 34.1 mcg/dL (1.0-10.0), 17 hydroxyprogesterone - 124 ng/dL (<460), CAH diagnostic panel - normal with exception of elevation in Progesterone - 3400 ng/dL (5-53), Newborn screening - normal, Chromosomal analysis - 46,XX and absent SRY, Ultrasound pelvis - normal Müllerian structures and bilateral intra-abdominal gonads present. Baby was hemodynamically stable, voided well, gained weight by discharge on DOL 4. Baby was stable on follow-up in endocrinology clinic on DOL 10. Surgical repair of anatomic malformation to be performed at 6 months of age by urology team. Conclusion To our knowledge, this is the first report of virilization of female offspring following human prenatal exposure to trenbolone. Women must be cautioned that trenbolone poses risks of external genital malformation to the developing fetus.