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Pregnancy And Birth



This article provides a useful overview of the issues about medication use during pregnancy.


Pregnancy and Medicines

This article includes general information on medicines in pregnancy, including prescription medicines, non-prescription medicines, natural remedies and recreational drugs. Some suggestions for treating common problems in pregnancy are given. Always talk to your doctor, pharmacist or midwife about medicines in pregnancy.

  • Most medicines cross the placenta and go into the blood of the foetus.
  • The foetus cannot always get rid of the medicine as easily as the mother can, so they may receive higher doses than the mother.
  • Medicines can affect the foetus at any stage through the pregnancy, not just the first trimester.
  • Remedies you take during pregnancy or breast feeding may affect your baby, but some medicines are thought to be safe in pregnancy and breast-feeding. Your pharmacist or doctor can advise you on what you can take.
  • If you take regular medicines talk to your doctor before becoming pregnant so that you can plan the safest use of your medicine during your pregnancy.
  • Do not stop your regular medicines without talking to your doctor. Depending on why you have been prescribed the medicine, you and/or your baby will often have lower risk if your medical condition is under control with medicines.
  • The dose of some medicines can change during pregnancy.
  • It is hard to know with many medicines and natural remedies if they are absolutely safe in pregnancy because it would not be ethical to do studies during pregnancy for most remedies.
  • By the time you have had a positive pregnancy test you may be anywhere from three weeks to two or three months pregnant. This means you may have taken medicines or had alcohol without realising you were pregnant.
  • If you are trying to become pregnant let your doctor or pharmacist know you may be pregnant if you are being prescribed or sold any medicines.
  • Folic acid helps prevent spina bifida and should be taken for at least a month before pregnancy plus the first three months of pregnancy.
  • Iron may be needed in pregnancy &endash your midwife or doctor will often arrange a blood test to check if you need an iron supplement.
  • Extra calcium may be needed in pregnancy, particularly if your diet is low in dairy products.


Up to 15,000 babies were affected by thalidomide use during pregnancy in the 1950s, a medicine that was promoted for morning sickness. Since then there has been a lot more caution in recommending drugs in pregnancy.

What Effects Can Medicines Have?

Medicines can cause:

  • smaller baby size (e.g. smoking)
  • limb defects (e.g. thalidomide)
  • addiction (e.g. morphine)
  • brain problems (e.g. alcohol)
  • heart or kidney problems (e.g. alcohol)
  • other malformations e.g. cleft palate
  • problems with blood flow to the baby (e.g. anti-inflammatories)
  • behavioural problems (e.g. alcohol)
  • contractions of the uterus (e.g. castor oil)
  • miscarriage (e.g. misoprostol)
  • premature delivery

Sometimes problems can be delayed, for example stilboestrol was given during pregnancy several decades ago and it wasn't until after the offspring reached puberty that it was discovered to cause problems with the reproductive system.

Regular Medicines

If you are taking regular medicines through your doctor and you are thinking of starting a family, talk to your doctor first before trying to get pregnant. Your doctor may want to take you off that medicine or switch you to a safer medicine for your pregnancy and this should be done first, before you become pregnant. Your doctor can also talk through with you any issues for becoming pregnant while on your medicine. For some medicines the doses can be different in pregnancy.


Women with epilepsy usually continue antiepileptic medicine during their pregnancy as there is can be a greater risk if the medicine is not taken. Some of these medicines can cause a increase in malformations, with around 7% of babies of mothers with epilepsy affected compared with 2% to 3% for the general population. Often folic acid is taken through the whole pregnancy in addition to the epilepsy medicine. Your doctor may change your medicine or reduce your medicine dose if you are planning to become pregnant.


It is important that women with diabetes continue using their insulin/diabetes medicines during pregnancy. It is recommended that you discuss plans for pregnancy, you may be advised to try to get your blood levels well-controlled to an agreed level before and during the pregnancy.


Talk to your doctor about the best treatment for your depression before becoming pregnant if possible.


Inhalers continue to be used during pregnancy &endash both the preventer (steroid) and reliever (bronchodilator). The doctor will try to ensure your asthma control is the best possible during your pregnancy.

Other conditions

there are many other conditions that require special planning before pregnancy. The main points to note are:

  • If you are thinking of starting a family talk to your doctor first so that medication and health issues can be discussed.
  • If you have accidentally become pregnant and you are on regular medicines talk to your doctor immediately so you can plan the medicine use in your pregnancy.
  • Do not stop taking your regular medicines without talking to your doctor first ; in many cases an uncontrolled medical condition can be much higher risk for the mother and/or the baby than the medicine itself.



Medicines Available Without a Prescription

Often it is thought that medicines available from the supermarket, pharmacy, drugstore or petrol station are very safe. However, these medicines can still get through to the foetus, and it is best to ask your pharmacist, doctor or midwife before taking anything at all. As an example, ibuprofen (Nurofen, Motrin, Act-3) or aspirin (Aspro, Disprin) can be particularly dangerous in the third trimester, potentially causing problems with the foetal blood flow. Aspirin is generally not recommended during any stage of pregnancy.

Most medicines available without a prescription are for more minor illnesses that will go away by themselves. So, try to avoid taking anything and just put up with the problem, if you can.

Common Complaints in Pregnancy

Morning Sickness ; if you have especially bad morning sickness your doctor can prescribe some medicines for it. Do not take anything without your doctor's advice. Acupressure or pyridoxine (Vitamin B6) may be helpful. Do not take more pyridoxine than is recommended.

Pain and fever - paracetamol (acetaminophen) is thought to be safe for short-term use for pain and fever in pregnancy and breast feeding. However, it is important not to take more than the recommended dose. Avoid anti-inflammatories such as ibuprofen, ketoprofen, diclofenac and aspirin, especially in the third trimester. Even rub-on products containing methyl salicylate may possibly cause problems for the foetus.

Constipation - bulk-forming laxatives e.g. Metamucil are usually considered safe in pregnancy. Increase the amount of fruit and vegetables you are eating, drink plenty of water, try to get exercise every day and give your body time to "respond to the urge". Prunes or prune juice can also help. Avoid castor oil.

Cold or Flu paracetamol can usually be taken for pain and fever. Drink plenty of water. Use a saline nose spray or steam inhalation for a blocked nose. If you can, put up with the symptoms, if you can't put up with the symptoms ask your pharmacist or doctor what to take. Don't take anything without checking first.

Haemorrhoids wipe the area with antibacterial soothing towelettes such as Wet Ones, avoid being constipated, and ask your pharmacist, doctor or midwife what they recommend for you.

Indigestion some indigestion remedies are safe your pharmacist, doctor or midwife can advise you. It can also help to eat small amounts more often rather than big meals, avoid eating just before going to bed, avoid spicy or fatty foods, avoid alcohol and caffeine, and prop yourself up in bed &endash make the top of the bed higher or use extra pillows.

Vaginal Thrush many vaginal thrush products (e.g. clotrimazole) do not seem to cause any problems in pregnancy, but check with your health professional. You may be advised not to use an applicator for insertion. Thrush is common in pregnancy and you can help to avoid it by avoiding tight clothing, synthetic underwear and pantyhose (tights). Vaginal douches may also increase the risk of vaginal infections.

Infections antibiotics have been widely used in pregnancy, and many have not been associated with any malformations or problems, e.g. amoxycillin (Amoxil) and ampicillin. Cephalosporins are also thought to be safe. Tetracyclines (e.g. Vibramycin, doxycycline, minocycline) are not recommended during pregnancy. Let your doctor know you are/may be pregnant if you are being prescribed antibiotics.


Natural Products Herbal Remedies, Vitamins, Minerals

Do not assume that these are safe just because they are natural. A couple of examples of problems are high doses of Vitamin A causing malformations and raspberry leaf causing contractions.


Alcohol can cause foetal alcohol syndrome. This is usually related to heavy alcohol use.

The symptoms of foetal alcohol syndrome include changes in appearance of the face, behavioural problems, mental retardation, heart problems, kidney problems, and many more problems. These problems can be with your child for life.

Avoid binge-drinking, and ideally do not have any alcohol at all. Even in the first weeks before you are certain you are pregnant, alcohol can have a bad effect, so if you are trying to become pregnant you are best to avoid alcohol. Your doctor or midwife can tell you more.

In practice many woman have had small amounts of alcohol with no adverse outcomes,however the lowest safe amount is unknown.


Cigarette smoking is not recommended during pregnancy because it is harmful to the baby, e.g. causing lower birth weight. Discourage others from smoking around you. There are many different chemicals in cigarettes (not just nicotine). If you are pregnant and want to quit smoking try cold turkey if you can, but if you need help, talk to your pharmacist or doctor about whether or not you should use nicotine replacement.

Other recreational drugs

Caffeine (e.g. from coffee, tea and soft drinks) should be used in moderation. High doses may not be wise.

Amphetamines can cause slower growth, premature delivery and brain problems.

Cocaine ; women using cocaine during pregnancy have higher risk for early delivery, miscarriage, premature detachment of the placenta, slower growth of the foetus, malformations of the foetus as well as other problems.

Narcotics e.g. morphine, codeine and heroin can cause withdrawal reactions in babies when born.

Marijuana ; it is hard to know the effects on the baby of marijuana because often pregnant women using marijuana are also using other substances such as alcohol and tobacco, and may have poor diets. However, there may be a link with childhood leukaemia, and the growth of the foetus may be slower than usual. Marijuana should not be used during pregnancy or breast feeding.



Some vaccinations should not be taken in pregnancy, so tell your doctor if you think you may be pregnant.




  • Check with your doctor, midwife or pharmacist before using anything in pregnancy.
  • If you are on regular medication try to plan your pregnancy with your doctor.
  • Do not stop taking regular medication without your doctor's advice.
  • If trying to become pregnant try to avoid medicines and recreational drugs such as alcohol.

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