Minoxidil pills are safe and effective for women with hair thinning. While there are no known instances of birth defects from pregnant women using minoxidil pills, due to a lack of clinical data on this subject, it recommended to stop taking minoxidil pills if pregnant. A dose of 0.25mg (aka Very Low Dose Oral Minoxidil) is ideal to minimize the risks of undesired hair growth elsewhere on the body.