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| Over-the-counter medicines in pregnancy |
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Written by Helen Marshall, NetDoctor pharmacist
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Most women are aware that during pregnancy they need to avoid as
many non-essential medicines as possible.
Yet these same women are just as
likely to suffer from minor ailments as anyone else, as well as being more likely to suffer pregnancy-related symptoms such as constipation or heartburn.
So should you have to grin
and bear those headaches, coughs and colds? Or are there over-the-counter
medicines that are actually safe to use in pregnancy?
The problem caused by medicines taken by the mother is that they
can cross the placenta and enter the baby's bloodstream. This is because the
medicine particles are small enough to cross the placental barrier along with
the nutrients needed for the baby's development. The effect any medicine has on
the developing baby depends on the medicine itself and the trimester of
pregnancy the medicine is taken in.
How does a medicine affect the developing baby?
The trimester of pregnancy is often very important. Some
medicines can be dangerous to take in the first three months but safe in the
second or third, or vice versa.
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The first trimester is the period of greatest risk for the
baby. This is because during this stage the baby's organs are developing.
Medicines taken during this time have the potential to affect this development,
which could result in malformations or birth defects. If a defect is very
severe this could cause a miscarriage.
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During the second trimester medicines can interfere with the
development of the baby's nervous system, or with the growth of the baby,
resulting in a low birth weight. However, generally, experts believe that the
second trimester is the safest period to take medicines.
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Medicines taken in the final three months of pregnancy can
cause complications such as breathing difficulties for the baby after birth.
This is because the medicine remains in the baby's body after birth, and the
newborn baby may not be able to cope with the medicine in its bloodstream the
way the mother can.
Medicines taken by the mother can also indirectly affect the
baby by interfering with the environment within the womb. Some medicines can
cause contractions of the womb, decreasing the blood supply to the baby, while
others may cause early, delayed or even prolonged labour, all of which pose a
threat to the baby.
How do we know which medicines are safe?
The answer is that often we don't. Pharmaceutical companies
rarely perform clinical trials or actual studies of their medicines on pregnant
women. As a result, few medicines are actually licensed for use during pregnancy.
Most information we get about safety in pregnancy often comes from
practical experience with the medicine over time. Often, when a medicine has
been in wide use for many years without causing adverse effects on pregnancies,
we can conclude that it is not harmful. Information will also come from women
who have been accidentally exposed to a medicine during pregnancy and from
animal studies.
So some medicines are known to be safe while others are known to
be definately harmful. But in a large number of cases there isn't the firm
evidence to conclude safety or risk. This applies to all medicines, be they
prescription only or over-the-counter.
Taking any medicine during pregnancy is all about weighing up
the pros and cons. The decision should, ideally, be made by your doctor, who
will be able to weigh up the benefits of a particular medicine to the mother
against the risks of that same medicine to the baby. If the benefits outweigh
the risks, then the medicine may be given to the mother. If the risks to the
baby are too great, then alternative treatment options need to be sought. The final
decision about taking a medicine should be made in conjunction with you.
Is there anything I can take to treat minor ailments?
The best way to minimise any risks for your baby is
to avoid all non-essential medicines, especially in the first trimester. However, what follows is a general
overview of what you can and can't take safely to treat common minor illnesses.
Remember: always consult your doctor or pharmacist before taking any medicine during pregnancy.
Constipation
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Try dietary measures such as drinking more fluids and eating more fibre first. If these are not effective, there are
over-the-counter laxatives that can be taken in pregnancy.
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Bulking agents such as ispaghula (Fybogel), methylcellulose,
bran and sterculia are safe.
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The stimulant laxatives senna and cascara are
also safe.
Heartburn and indigestion
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Antacids are generally safe, though sodium bicarbonate is
absorbed into the bloodstream and so should be avoided in pregnancy, since
your sodium intake should not be too high.
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Medicines such as Gaviscon that contain alginates are safe,
and can be especially useful for heartburn caused by the pressure of the baby
on the stomach. They form a raft on the stomach contents and prevent them
passing back up the food pipe.
Pain such as headache or backache
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Try non-drug methods first. A head massage can help relieve headache, while backache can be eased by gentle stretching to relieve tight muscles, or a soak in a warm bath.
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Paracetamol is generally regarded as safe for short-term use in all three trimesters. It is widely used in all stages of pregnancy for pain relief and reducing fever.
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Aspirin and non-steroidal anti-inflammatory drugs (NSAIDs) such as
ibuprofen are not recommended during pregnancy, as there are safer
alternatives available. They should particularly be avoided in the last
trimester, because they can delay labour, increase the length of labour and cause complications in the newborn baby. Painkilling doses of aspirin can also increase the risk of bleeding in the
mother and baby if taken in the third trimester. Evidence suggests these medicines should also be avoided in the first trimester and by women attempting to conceive, as they may increase the risk of miscarriage or malformations.
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Codeine and dihydrocodeine can affect the baby's breathing if
taken in the last trimester, or during labour in large amounts. Heavy use may
also cause a withdrawal syndrome in the newborn infant. However, small doses
for a short period of time to treat specific pain can be taken in the
first and second trimesters, but only on the advice of a doctor. Be aware that some over-the-counter painkillers contain codeine or dihydrocodeine. Consult your doctor or pharmacist before taking
any medicines during pregnancy.
Hay fever and allergies
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For hay fever, first try as much as possible to reduce your exposure to the allergens that trigger it.
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If this isn't possible, you can safely use sodium cromoglicate nasal spray or eye drops in all three trimesters.
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Alternatively, short-term use of nasal sprays containing corticosteroids such as
beclometasone is unlikely to cause any harm. With long-term use sufficient
can be absorbed to impair the growth of the baby, so these
should only be used after discussing any risks with your doctor or pharmacist.
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Products containing antihistamines, such as brompheniramine,
meclozine, diphenhydramine, doxylamine, cetirizine and loratadine should generally be
avoided, as there is insufficient information about their safety. However,
chlorphenamine is generally considered safe to take during all three
trimesters, if the measures mentioned above fail. Consult your doctor or pharmacist before taking any medicines
during pregnancy.
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Antihistamine nasal sprays and eye drops should be avoided.
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Nasal decongestants, such as pseudoephedrine, phenylephrine,
xylometazoline, oxymetazoline should also be avoided as there is insufficient
evidence of their safety. Steam inhalations should provide some relief from nasal congestion.
Coughs and colds
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Cough and cold remedies often contain a combination of several
ingredients, including painkillers, antihistamines and decongestants (see above), so it is important to make sure
that each ingredient is safe before taking them. Consult your doctor or
pharmacist before taking any medicines during pregnancy.
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The cough expectorant guaifenesin to help loosen a
chesty cough can be used, though drinking lots of water is just as effective
for this. You could also try using steam inhalations to help liquify mucus and make it easier to cough up. Cough medicines containing iodine as an expectorant should be
avoided, as the iodine can impair the functioning of the baby's thyroid gland.
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The cough suppressant dextromethorphan has been in widespread use and is generally considered safe to use during pregnancy, providing it is only taken for short periods
of time and using the smallest dose possible. However, it is probably best to avoid it in the first
trimester. Cough suppressants containing codeine should be avoided in the third trimester.
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Soothing cough mixtures such as simple linctus, or sucking lozenges containing honey or
glycerol to coat the throat, are the safest option to reduce coughing. Consult your doctor or
pharmacist before taking any medicines during pregnancy.
Diarrhoea
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Short bouts of diarrhoea won't do your baby any harm, but
diarrhoea lasting longer than a few days can cause dehydration. This can be
avoided by taking rehydration salts such as Dioralyte, which are safe to use in
pregnancy.
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Kaolin mixture can also be used to increase the bulk of the
stools.
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Loperamide to stop diarrhoea should be avoided, as there is
insufficient information available to decide if it is safe or not.
Vaginal thrush
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There is not a great deal of information available about
antifungal medicines such as clotrimazole (Canesten) or fluconazole (Diflucan
1). They should only be used after discussion of the risks and benefits with
your doctor.
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If you are advised to use a vaginal preparation, take care
with vaginal applicators or avoid using them altogether.
Eczema, dermatitis and skin allergies
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Moisturisers or soothing products such as calamine lotion
should be your first port of call as these are completely safe.
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Steroid creams such as hydrocortisone can be used during
pregnancy, but avoid using them on large areas of skin, for long periods of
time, or under dressings, as significant amounts may be absorbed into the bloodstream.
Folic acid
This is the only over-the-counter medicine that is really
important to take, both prior to and during pregnancy. One 400 microgram tablet
should be taken every day by women planning a pregnancy and for the first 12
weeks of pregnancy. This is to help the development of the baby's spinal cord
and nervous system and prevent neural tube defects such as spina bifida. Taking
folic acid daily also helps prevent birth defects such as cleft lip and cleft
palate.
A higher daily dose (5mg) of folic acid is recommended if you or your partner has spina bifida, or if you have had a previous child born with neural tube defects. Discuss this with your doctor.
For medicines not covered here ask the advice of either your
pharmacist or doctor. The best way to minimise risk is to minimise your intake
of all unnecessary medicines. Remember that herbal remedies are not necessarily
safe in pregnancy. If in doubt ask!
Quick recap
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Are you pregnant and taking any medicines?
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Have you told your doctor or pharmacist that you are pregnant?
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If you are pregnant, are you taking your folic acid
tablets?
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Generally, avoid all medicines during pregnancy if possible.
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Always consult you doctor or pharmacist if you are pregnant and
starting a new medicine.
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Remember some over-the-counter medicines and medicines from the supermarket
can be harmful to your baby.
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Herbal remedies are not necessarily safe alternatives. Ask your doctor or pharmacist for advice about taking these while pregnant too.
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If you experience any unusual effects after taking your
medicine, inform your doctor or pharmacist immediately.
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Your doctor needs to weigh up the risks versus the benefits of
giving a medicine during pregnancy.
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Everybody is different - one woman may take a harmful medicine
and have a healthy baby and another women may take a so-called safe medicine
and end up having a child with a birth defect.
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Birth defects can occur naturally, even if you do not take any
medicines, and no one can really explain why they occur.
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References
Nathan A. General care of pregnant women. Pharmaceutical Journal 2003;270:338-340.
Briggs G, Freeman R, Yaffe S. Drugs in Pregnancy and Lactation. Seventh edition.
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Last updated 11.04.2007
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