Pregnancy brings with it important concerns about prescription and non-prescription drugs. Not every medication poses a risk to the unborn baby, but some do. Only a limited number of drugs have been shown conclusively to be dangerous during pregnancy, but many others have to be used with caution. All teratogenic drugs should be avoided at all costs before and during pregnancy.
What are teratogenic drugs?
Drugs which cause malformations are known as teratogens. Other drugs that are dangerous may still cause neurological (brain) and behavioural problems without causing malformations in the baby. A teratogen is an agent that can disturb the development of the developing fetus or embryo. Teratogens can halt the pregnancy (cause a miscarriage) or, alternatively, permit the pregnancy to proceed but produce a congenital defect.
What are some common drugs that are dangerous during pregnancy?
There are a number of drugs – including prescription and non-prescription drugs, legal and illegal drugs – that are dangerous if used during pregnancy. These include the following:
• A few antihypertensive drugs e.g. captopril, lisinopril
• Acne medications like isotretinoin
• Alcohol ingested chronically or in binges
• Antiepileptic agents like Phenobarbital
• Some antibiotics like tetracycline and streptomycin
• Anticoagulant (blood thinner) e.g. warfarin
• Anti-depressant drugs e.g. lithium
• Anticancer agents like methotrexate
• Cocaine
• Diethylstilbestrol
• Thalidomide
What determines how a dangerous drug affects the fetus?
How a dangerous drug taken during pregnancy affects the developing fetus depends on a number of factors. These include the time in pregnancy when the drug was taken, the amount of the drug taken and the individual characteristics of the pregnant woman. Women who are taking teratogenic drugs, and who become pregnant or plan to become pregnant, should see their obstetrician as soon as possible to get specialist advice. All pregnant women should first consult with their obstetrician before taking any medication including over-the-counter drugs and herbal drugs. Yes, some herbal medications are dangerous if used during pregnancy. Folic acid taken in pregnancy is very safe and beneficial to the developing fetus.
Drugs use for medical conditions during pregnancy
Drug therapy during pregnancy poses a serious challenge for the obstetrician. While many drugs may have harmful effects and should be avoided, there are several medical conditions that require treatment with drugs. Under treatment of these diseases can be equally harmful. Ideally, all pregnant women with various medical conditions should see their obstetrician prior to a planned pregnancy, or shortly after an unplanned pregnancy, to discuss treatment options. Sometimes it may be possible to use alternate medications that are not as harmful as the current medication. Pregnant women on medication for chronic conditions should not just stop using their medication once they are pregnant. They should see their healthcare provider first. Individuals using anti-depressant medications should see their obstetrician prior to becoming pregnant. They should not alter their medication without consultation with their obstetrician.
Safety of drugs during pregnancy
Several drugs have been used for many years during pregnancy and have been shown to be safe, but the drug manufactures fail to recommend them during pregnancy. It is wise to discuss with your obstetrician the merits of a particular drug during pregnancy. Some drugs are approved for use in some countries and not others. For instance, some drugs are approved for use in European countries while the same drug is not approved for use in the USA. A number of clinical studies have now established that a number of drugs can be used safely during pregnancy. It is important for doctors and others dealing with distributing medications to keep up to date with current medical research. Some healthcare providers still give outdated information to patients who are pregnant and need medications.
Conclusion
Many pregnant women are concerned with the effects of drugs used during pregnancy. There are indeed a small number of drugs that are definitely teratogenic and some that are dangerous. It is wise to consult with your obstetrician before using any drug during pregnancy. If you have a medical condition, then your obstetrician will decide on the best available drug to use because not treating a medical condition can be very dangerous as well. Various studies have clearly established that a number of drugs are safe to use during pregnancy. Your obstetrician will be the best person to give advice on the safety or risk of specific drugs during pregnancy.
Ask Your Doctor is a health education column and is not a substitute for medical advice from your physician. The reader should consult his or her physician for specific information concerning specific medical conditions. While all reasonable efforts have been made to ensure that all information presented is accurate, as research and development in the medical field are ongoing, it is possible that new findings may supersede some data presented.
Dr. Hodge is an Obstetrician/Gynaecologist and Family Doctor who has over thirty-five years in clinical practice. Dr Hodge has a medical practice in The Johnson Building in The Valley (Tel: 264 4975828).
