In general, medicines taken by a pregnant woman do not enter the fetus, but in some cases they can do so, causing damage or birth defects.

The biggest risk of damage to the fetus is during the first weeks of pregnancy, when the most important organs are developing.

However, researchers do not know whether taking medications during pregnancy will have negative effects on the baby afterwards.

It is thought that many over-the-counter medications that can be purchased at pharmacies and other businesses, and others prescribed by your health care provider, are safe if taken during pregnancy, although no medication has been proven to be absolutely safe when you are pregnant .

If you do not know for sure if you can take an over-the-counter product, ask your doctor.

Some medications are not safe during pregnancy. Even medications prescribed by your health care provider before becoming pregnant can be harmful to both you and the developing fetus during pregnancy.

Make sure all your doctors and other health professionals who provide services know that you are pregnant, and never take any medication during pregnancy unless they tell you to.

Also remember that other things such as caffeine, vitamins and herbal tea can affect the developing fetus.

Ask your doctor about reducing your caffeine intake and about the vitamins you should take.

Never use any herbal product without  consulting your doctor first if you are pregnant.

Which over-the-counter and prescription medications are unsafe during pregnancy?
The Food and Drug Administration (FDA) of the United States has a system to classify medicines as to how safe they are during pregnancy.

This system classifies both over-the-counter medications that you can buy at a pharmacy or other store, such as those prescribed by your doctor, but most medications have not been studied in pregnant women to determine if they cause harm to the fetus in developing.

Always consult a doctor if you have questions or concerns about a medication.

The FDA classifies the drugs in the following way according to their safety during pregnancy:

Category A – medications that have been evaluated for safety during pregnancy, and are considered safe. This includes medications such as folic acid, vitamin B6, and thyroid medications (levothyroxine) in prescribed doses. Category B – medicines that have been used a lot during pregnancy and do not seem to cause serious birth defects or other problems. This includes antibiotic medications such as amoxicillin, medications for nausea such as ondansetron, diabetes medications such as metformin and regular insulin and NPH.

Category C – drugs with a greater chance of causing problems for the mother or the fetus. It also includes medicines whose safety studies have not yet been completed.

Most of these medications are not being studied in terms of their safety. These medications usually contain warnings that indicate they should be used only if the benefits of taking them outweigh the risks. This is something that a woman should discuss carefully with her doctor.

This category includes medications such as fluconazole for vaginal yeast infections, albuterol for asthma, and fluoxetine and sertraline for depression

Category D – drugs that have obvious risks to the fetus, including: alcohol, lithium (used to treat manic depression), phenytoin (Dilantin) for epileptic seizures, and most chemotherapy drugs for treatment of cancer. In some cases chemotherapy drugs are administered during pregnancy.

Category X – medications that have been shown to cause birth defects and should never be taken during pregnancy.

This includes medications to treat skin conditions such as Isotretinoin (Accutane) for the treatment of cystic acne and psoriasis (Tegison or Soriatene), a sedative (thalidomide), and a medication called diethylstilbestrol to prevent spontaneous abortion that was used until 1971 in the United States and 1983 in Europe.

During pregnancy, aspirin (acetylsalicylic acid) or other medications containing salicylate are not recommended, especially during the last three months.

In rare cases, the doctor may recommend that she use this type of medication under careful control.

Acetylsalicylic acid, a common ingredient in many over-the-counter pain relievers, can extend pregnancy and cause serious bleeding before and after delivery.

Should I avoid taking medication during my pregnancy?

Whether or not you should continue taking medications during your pregnancy is a serious question. If you stop taking a medication that you need, this could harm both you and your baby.

An example of this is if you have an infection called toxoplasmosis, which can be contracted by handling cat fecal matter or eating infected meat. This infection can cause problems in the brain, eyes, heart, and other organs of the developing fetus. This infection should be treated with antibiotics.

For pregnant women who have HIV, the Centers for Disease Control and Prevention (CDC) recommends the use of a combination drug against HIV. Studies show that women with HIV who take these drugs during pregnancy reduce by two thirds the risk of transferring HIV to their babies.

If a diabetic woman does not take her medication during pregnancy, she has an increased risk of spontaneous abortion and stillbirth.

If asthma or hypertension (high blood pressure) is not controlled during pregnancy, this can cause problems for the fetus. Consult a doctor if the benefits of taking a medication outweigh the risks to you and your baby.

Can natural medicines, or herbal remedies, be taken during pregnancy?
Although some herbal remedies claim to help her with her pregnancy, there have been no studies to check whether these claims are true.

Also, there have been very few studies to determine how safe and effective herbal remedies are.

Some of the popular herbs are Echinacea, Ginkgo biloba, and St. John’s Wort. Do not take any herbal product without first consulting your doctor.

These products may contain agents that can harm you and the developing fetus, and cause problems in your pregnancy.