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Safety of medications taken during pregnancy.

Introduction

Some medications and drugs are known to cause fetal harm if taken during pregnancy. Medications should only be taken if the expected benefits to the mother are greater than the risk to the mother and baby. Essential medications should be taken in the lowest possible dose and for the shortest possible time during pregnancy. The risks of the fetus. malformation They are greatest during the first trimester (the first 12 weeks of gestation). The effect of withdrawal on the newborn baby should be carefully evaluated if medications such as antidepressants are taken during the third trimester (after 28 weeks).

In rare cases, problems have also been reported when the male partner has taken medications such as finasteride.

Drug licensing authorities classify drugs according to their risk in pregnancy. Data is limited; Many available medications have not yet been evaluated or classified, and unclassified medications may or may not be safe during pregnancy. Scheduled drugs may be reclassified as new information becomes available.

Consult the most current and approved fact sheet for the individual medication when considering prescribing a medication to a pregnant woman.

Australian TGA classification

When prescribing medications in pregnancy, it is helpful for healthcare professionals to access the Australian Government Department of Health. Therapeutic Comprehensive resource from the Goods Administration (TGA), prescribing medicines in pregnancy database.

The definitions of each category are copied below (TGA website accessed August 27, 2019).

Category A

A large number of pregnant women and women of childbearing age have taken category A medications, with no proven increase in the frequency of malformations or other direct or indirect harmful effects on the fetus.

Category B

Drugs assigned to Category B are subcategorized based on animal data, with human data missing or inadequate.

Category B1: Medicines that have been taken only by a limited number of pregnant women and women of reproductive age, without an increase in the frequency of malformation or other direct or indirect harmful effects on the human fetus. Animal studies have shown no evidence of increased occurrence of fetal harm.

Category B2: Medicines that have been taken only by a limited number of pregnant women and women of childbearing age, without an observed increase in the frequency of malformations or other direct or indirect harmful effects on the human fetus. Animal studies are inadequate or may be lacking, but available data show no evidence of increased occurrence of fetal harm.

Category B3: Medicines that have been taken only by a limited number of pregnant women and women of childbearing age, without an increase in the frequency of malformation or other direct or indirect harmful effects on the human fetus. Animal studies have shown evidence of increased occurrence of fetal damage, the significance of which is considered uncertain in humans.

Medicines in Category B do not imply greater safety than medicines in Category C.

Category C

Category C drugs are drugs that, due to their pharmacological effects (risk based on the mechanism of action of the drug), have caused or may be suspected of causing harmful effects on the human fetus or newborn without causing malformations. These effects may be reversible.

Category D

Medications in category D are absolutely not contraindicated During pregnancy. However, there is an increased risk of malformations. Category D drugs have caused, are suspected of causing, or may be expected to cause, an increase incidence of human fetal malformation or irreversible damage. These medications can also have adverse pharmacological effects.

Category

Medications in Category teratogenic)

Category

New Zealand approved data sheets are the official source of information for these prescription drugs, including approved uses and risk information. See the New Zealand individual data sheet on the Medsafe website.