Effect of paternal medication on offspring

It seems unlikely that the use of medication by the expectant father will pose a risk for his unborn child. However, little research has been done so far. The Teratology Information Service of Lareb, received many questions on this topic and that was the starting point for us, together with the Erasmus Medical Center hospital, to start a study on the safety of the use of immunosuppressive drugs by men who wish to start a family.

Immunosuppressive drugs
Some immunosuppressive drugs can cause DNA damage. In theory they could damage the DNA of sperm cells as well. As a result, an increased risk of harm to the offspring cannot be completely excluded. This applies for example to methotrexate and mycophenolate mofetil. Since there is no information about this possible risk, contraception must be used as a precaution. For men on chronic use of immunosuppressive drugs (for instance after organ transplant), this implies that they would not be able to conceive their own biological children.

Congenital abnormalities
Can medication use by the father actually lead to adverse effects in the unborn child? The answer to this question is unclear. Too little research has been done. So far, there are no indications for an increased risk of congenital abnormalities. But with the afore mentioned drugs, which can damage DNA, more research is needed in order to be sure (1).

Survival of the fittest
Until now no increased risk of abnormalities was seen after paternal drug use. Not even with medication that can be harmful to sperm cells. The most plausible explanation for this is the principle of 'survival of the fittest’. Fertilization with a damaged sperm cell will most probably end in an early miscarriage. This outcome is therefore included in the study.

(1) de Swart I, te Winkel B. Kans schade foetus door medicatie vader niet goed onderzocht. Risk of damage to fetus through paternal medication not studied properly. Pharm Weekbl 2018 ;8:153-13.