Medicines mainly affect male fertility in the following four ways:

(1). Directly affect the gonad and spermatogenesis (for example, tumor chemotherapy drugs).

(2). Affect the normal secretion of hormones.

(3). Impair the function of ejaculation.

(4). Negative effects on male sexuality (for examples, some types of antihypertensive drugs, antidepressants, etc).

Although some medicines may have adverse effects on male reproduction, they generally do not directly affect fetal development.

The formation of sperm is related to many factors, and the normal sperm itself has an abnormality rate of about 10 percent, so for most medicines, men do not need to stop while trying to have a baby. If unsuccessful in trying for a family, you might consider whether medicine is a factor.

The sperm development cycle is generally three months. If anti-metabolic drugs (such as anti-tumor drugs, immunosuppressants) are used during this period, sperm quality may be affected, especially alkylating agents which can directly damage the DNA. Therefore, men who take these two types of drugs need to stop taking them for three months before trying for a baby. Some experts even recommend stopping the drug for a longer period (9 to 12 months) to reduce the risk.

For men taking other anti-metabolic drugs -- including methotrexate, mycophenolate mofetil and sulfasalazine -- it is also recommended they stop the drug for three months prior to trying for a family.

Available data shows that the effects of drugs on male offspring are still relatively small, while the risks of some drugs are still unknown.

Therefore, it is recommended that if taking high-risk drugs (mainly anti-metabolic drugs) that affect male fertility:

1. If you only take this kind of medicine in a short period, for the sake of safety, you can stop taking the medicine for three months before trying for a family (it may be slightly adjusted according to the metabolic characteristics of the different medicines).

2. If you need to take medicines for a long time, you might consider changing to the same kind of medicines with a lower risk, or continue to take medicines with the informed consent of the patient and continue to plan for a family.