The embry0/fetal-maternal unit is very vulnerable to exogenous influences

The risk of congenital defects acquired  during pregnancy is 4% in the normal population (without additional medication or other noxious agents).

For certain substances/drugs this risk is slightly to massively increased. Depending on the substance, the vulnerability may be present only for a certain period of the pregnancy or for the entire pregnancy, i.e. both the embryonic and foetal period. The extent of the physical and especially mental defects often only becomes apparent in the course of postnatal development, sometimes over years.. Any effects up to 14 days after conception is subject to the all-or-nothing law, i.e. if the pregnancy continues, the conceptus from that time shows no defects.

Substances/groups with an increased risk of intrauterine defects of the conceptus (teratogenicity) regardless of the extent:

ACE inhibitors


Antidepressants (paroxethine and others)

Benzodiazepines (cardiac damage is slightly above 4% depending on the examination tool; extent of developmental disorders is unknown)

Quinolone antibiotics

Chloramphenicol (antepartum)

Coumarin derivatives

Drugs: tobacco smoking, cannabis, cocaine, heroin

Epilepsy medication (valproate and others)

Folic acid antagonists (methothrexate and sulfonamides)

Iodine salts

Ergot alkaloids

Opioids (latest data on tramadol in 1st trim.)

Prostaglandin synthesis inhibitors: Paracetamol ONLY in very long term use (weeks), in short time no problem; all NSAIDs should NOT be used from the 20th week of pregnancy onwards because of the premature closure of D. arteriosus Botalli.

Sex hormones



Vit. A in high doses (> 5000 IU/day)

Vitamin A acid derivatives

The list makes no claim to completeness. 


Please find specific informations on the extent of the defects and the sensitive gestational age in the corresponding SAPP monographs or therapy recommendations.

If possible, a benefit/risk should be discussed with the woman before each pregnancy.

Especially in the case of severe pre-existing diseases and those requiring therapy (such as epilepsy), women should receive intensive and interdisciplinary care before and during pregnancy.