Penamecillin, an acetoxymethyl ester of benzylpenicillin, is a prodrug processed to benzylpenicillin by esterases.[1] It has no detectable teratogenic risk to the fetus.[2]
^Czeizel AE, Rockenbauer M, Sørensen HT, Olsen J (1999). "The Safety of Penicillin V: Oral Penamecillin Use During Pregnancy The Importance and Limitation of Recall Bias". Congenital Anomalies. 39 (4): 267–279. doi:10.1111/j.1741-4520.1999.tb00566.x. ISSN0914-3505.