Tramadol (versus unexposed)

Study	Reference
Bowie, 2022	Bowie Prescribed opioid analgesics in early pregnancy and the risk of congenital anomalies: a population-based cohort study. CMAJ 2022; 194:E152-E162
Ferrer, 2025	Ferrer Tramadol During Pregnancy: Risk of Adverse Pregnancy Outcome and Major Congenital Anomalies. A Comparative Study in the EFEMERIS Database. Pharmacoepidemiol Drug Saf 2025; 34:e70143
Gouraud, 2010	Gouraud, A. First trimester exposure to tramadol: A prospective comparative study Fundam. Clin. Pharmacol. 2010; 24:90-. Gouraud, A. Focused Conference Group: FC04 - Pharmacoepidemiology, current controversies and opportunities first trimester exposure to tramadol: A prospective comparative study Basic Clin. Pharmacol. Toxicol. 2010; 107:121-.
Källén, 2015	Källén Use of tramadol in early pregnancy and congenital malformation risk. Reprod Toxicol 2015; 58:246-51
Sørensen, 2022	Sørensen Exposure to Tramadol During Early Pregnancy and Risk of Spontaneous Abortion or Major Congenital Malformations. Obstet Gynecol 2022; 139:545-553