Aspirin is frequently consumed during pregnancy, often without prescription or awareness by patients and doctors.
Aspirin, acetylsalicylic acid, is the most frequently consumed drug in pregnancy, taken mostly without a prescription because of headache or a minor ailment. Numerous preparations containing acetylsalicylic acid are freely available over the counter under a variety of proprietary names, and in many cases pregnant women and their doctors may be unaware that aspirin is being taken.
Bremer et al. (Wed,) studied this question.