BackgroundGPs have been shown to be important providers of medical care during pregnancy, however, little evidence exists on their awareness of pregnancy when prescribing medication to women.AimTo assess GPs’ awareness of pregnancy and its association with prescribing medication with potential safety risks.Design and settingPopulation-based study using confirmed pregnancy records linked to GP records from the PHARMO Perinatal Research Network.MethodGPs’ awareness of pregnancy, defined as the presence of a pregnancy confirmation in the GP information system during pregnancy, was assessed from 2004 to 2020. GP prescriptions of medication with potential safety risks were selected during pregnancy and its association with GPs’ awareness of pregnancy was assessed using multivariable logistic regression.ResultsA pregnancy confirmation was present in the GP records for 48% (n= 67 496/140 976) of selected pregnancies, increasing from 28% (n= 34/121) in 2004 to 63% in 2020 (n= 5763/9124). During 3% (n= 4489/140 976) of all pregnancies, the GP prescribed highly hazardous medication with teratogenic effects that should have been (temporarily) avoided. Pregnancy was GP confirmed for only 13% (n= 585/4489) at the first occurrence of such a prescription. Comparative analyses showed that women without a pregnancy confirmation were 59% more likely to be prescribed this highly hazardous medication (odds ratio [OR] 1.59, 95% confidence interval [CI] = 1.49 to 1.70) compared with those with a confirmed pregnancy.ConclusionResults of this study indicate a potential issue with GP awareness about pregnancy status at the time medication with potential safety risks is prescribed. Although pregnancy registration by GPs improved over the years, inadequate use still seems to be made of the available information systems for appropriate drug surveillance.