Drugs in pregnancy

When using drugs during pregnancy, it is necessary to take into account not only the indications and contraindications on the part of the mother, but also the potential teratogenicity of individual drugs, possibly also the indications on the part of the fetus.

Factors of Teratogenicity
Potentially teratogenic drugs also have different effects on the fetus in different periods of pregnancy. Approximately until the end of '''5. week after the last menstruation''' (i.e. a week after the woman discovers that she is not menstruating) taking medicines is practically without risk to the embryo. In the remaining first trimester (approx. until the 15th week after the last menstruation), organogenesis takes place, during which there is a risk of congenital developmental defects. During the second and third trimester, the risk for the fetus is relatively reduced ; there is a certain risk of impaired growth and functional development. On the contrary, it is necessary to take into account that during lactation many drugs pass into the milk. During the first trimester, there are risky drugs, e.g. some antiepileptics (phenytoin, carbamazepine, valproate), lithium, warfarin, retinoids, danazol, cytostatics. During the second and third trimester, risky drugs are e.g. ACEIs, β-blockers, thyrostatics, benzodiazepines and barbiturates, NSAIDs, tetracyclines, warfarin, cytostatics.

Another effect is the different permeability through the placenta. Low molecular weight substances pass through; high molecular weight (e.g. heparin). Sometimes it is advantageous if the substance penetrates the placenta, and this can be used for fetal therapy.

Principles of pharmacotherapy in pregnancy
It is necessary to have a responsible approach and choose the appropriate drugs at the right time, adjust the dose (often even increase) and shorten the exposure as much as possible. .

Drug Classification
According to the FDA, drugs are divided into 5 classes based on use during pregnancy and lactation :


 * A – drugs that are tested on a group of pregnant women without established teratogenicity,
 * B – drugs that are tested on animals without established teratogenicity,
 * C - drugs that are teratogenic in animals, unknown in humans,
 * D – drugs that are teratogenic in humans, but can be given in critical conditions because of their irreplaceability (immunosuppressants, antiepileptics, cytostatics),
 * X – drugs for which the risk outweighs the benefit.

Examples
Here are examples of drugs that may or may not be suitable during pregnancy:

Analgesics
Nonsteroidal antirheumatic drugs (e.g. ibuprofen) can cause premature constriction of the fetal ductus arteriosus.

Antiasthmatics
Most can be done without increased risk to the fetus.

Antidepressants
They are risky, especially monoamine oxidase inhibitors.

Other unsuitable medicines
Relatively inappropriate drugs include diuretics', hormones and sedatives.

Unsuitable Herbs
Sage, linden, ivy, senna leaf

Nausea
Common symptom when occurring 1-2 times a day. Non-pharmacological influence by more frequent intake of smaller portions of low-calorie cold food. Antacids (Tums, Rennie, Maalox, Anacid, etc.) should only be used intermittently, not long-term. The effect of vitamin B6 and ginger extracts (Avioplant, Ginger; max. 250 mg per day) is unconfirmed.

Fever
During pregnancy, lowering the temperature above 38 °C is appropriate due to the risk of damage to the fetus.

Warning
The given text is only informative and can in no way be considered as a flawless treatment guide (see Disclaimer).

Related Articles

 * Teratogens
 * Fetal alcohol syndrome
 * Congenital developmental defects
 * Screening for birth defects