What is it about ?
Many of the substances that a pregnant woman takes enter the baby’s blood through the placenta. This is also the case for drugs. A pregnant woman should be very careful with the medicines she takes since some are harmful to the baby. Women who want to get pregnant should also be careful, because some substances stay in the blood for a long time.
What do I need to know?
If you are pregnant or breastfeeding, you are advised to only take medications that are really necessary and known to work during pregnancy or while breastfeeding. Although the substances are passed to the baby through the placenta, it is of course important to always take the medicines you need, usually in the lowest dose possible to treat the symptoms.
It is during the first trimester of pregnancy that the fetus is most exposed to the risk of malformations. During the second and third trimesters, the side effects of the drugs show up in other forms, such as growth retardation or abnormal organ maturation. Some drugs have an effect on mental functioning, which does not become apparent until later in life.
Why is it advisable to take folic acid?
Adequate dietary intake of folate, and, in supplement form, folic acid, is important for the normal development of the fetus. Taking folic acid supplements decreases the risk of birth defects, especially what we call “neural tube defects” such as spina bifida or lack of brain development (anencephaly).
Dietary intake of folic acid is low. However, folic acid should be present in sufficient amounts during the first few weeks of pregnancy, when the baby’s organs are forming. Therefore, it is advisable to take 0.4 mg of folic acid per day as soon as you plan to become pregnant, starting no later than 2 months before the start of your pregnancy and continuing treatment until the 12th.th week of pregnancy.
If a neural tube defect has been found in a previous pregnancy or in a close relative, the recommended dose of folic acid is increased to 4 mg per day.
The dose is 1 mg if you are taking certain anti-seizure drugs (valproic acid, carbamazepine, phenytoin and topiramate).
How common are neural tube defects?
Each year, around 115,000 babies are born in Belgium. In Europe, neural tube defects affect around 1 in 1,000 babies, which corresponds to around 115 children per year in Belgium.
What can you do ?
If you are planning to become pregnant, see your general practitioner. He will discuss with you the medicines that you need to adapt or stop (for example, medicines against acne, certain medicines against hypertension,…). On your side, you can start taking 0.4 mg of folic acid, certainly when you stop the pill. The ideal is to start at least 2 months before trying to get pregnant. Never take any medication while pregnant or breastfeeding without first seeking the advice of your doctor.
What can your doctor do?
Your doctor will assess which medications you need and which are best or least for you. At the same time, he will take a blood test to check if you have received the necessary vaccines. If not, your doctor can still give them to you before you become pregnant.
Want to know more?
- Valproic acid – CBIP – Belgian Center for Pharmacotherapeutic Information
- Carbamazepine – CBIP – Belgian Center for Pharmacotherapeutic Information
- Phenytoin – CBIP – Belgian Center for Pharmacotherapeutic Information
- Topiramate – CBIP – Belgian Center for Pharmacotherapeutic Information
Sources