Lithium

(Date of issue: May 2015. Version: 2)

This factsheet has been written for members of the public by the UK Teratology Information Service (UKTIS). UKTIS is a not-for-profit organisation funded by Public Health England on behalf of UK Health Departments. UKTIS has been providing scientific information to health care providers since 1983 on the effects that medicines, recreational drugs and chemicals may have on the developing baby during pregnancy.

What is it?

Lithium (Camcolit®, Liskonum®, Priadel®, Li-liquid®) is used to treat depression, mania, and bipolar disorder, and occasionally to prevent a specific type of headache called cluster headache.

Is it ‘safe’ to take lithium in pregnancy?

There is no ‘yes’ or ‘no’ answer to this question. When deciding whether or not to take lithium during pregnancy it is important to weigh up how necessary lithium is to your health, against the possible risks to you or your baby, some of which will depend on how many weeks pregnant you are. Remaining well is particularly important during pregnancy and while caring for a baby. For some women, treatment with lithium in pregnancy may be necessary.

This leaflet summarises the scientific studies relating to the effects of lithium on a baby in the womb. It is advisable to consider this information before taking lithium if you are pregnant.

Your doctor is the best person to help you decide what is right for you and your baby.

What if I have already taken lithium during pregnancy?

If you have taken or are taking any medicines, it is always a good idea to let your doctor know that you are pregnant so that you can decide together whether you still need the medicines that you are on and if so, to make sure that you are taking the lowest dose that works and only for as long as you need to.

It is very important that you do not suddenly stop taking lithium as this could be dangerous to you, and also to your unborn baby if you are pregnant. Do not make any change to your medication without first talking to your doctor.

Can taking lithium in pregnancy cause birth defects in the baby?

A baby’s body and most internal organs are formed during the first 12 weeks of pregnancy. It is mainly during this time that some medicines are known to cause birth defects.

There is no evidence that women who take lithium in pregnancy are more likely overall to have a baby with a birth defect than women who don’t. A possible link between exposure to lithium in the womb and the baby being born with a heart defect has been suggested but has not been confirmed.

Heart defects
It is not yet clear whether taking lithium during early pregnancy increases the chance of having a baby with a heart defect. It is known that about one in every 100 babies is born with a heart defect, regardless of whether or not their mother took medicines during pregnancy. This is called the “background population risk”. A small number of studies have shown that babies exposed to lithium in the womb were more likely to have heart defects than other babies, although other studies have not agreed with this finding. Some of these studies however, also showed that heart defects were more common in babies of women with illnesses which lithium is sometimes prescribed to treat, but who had either stopped their treatment before pregnancy or were taking another type of medication for their condition. This suggests that factors other than lithium may underlie any increased risk of heart defects.

An early study of babies who had been exposed to lithium in the womb identified two babies with a very rare heart defect called Ebstein’s anomaly and suggested a possible link with lithium. However, because of the way in which the information in this study was collected and analysed it is not possible to rule out that this was pure chance (and therefore unrelated to the lithium). Because Ebstein’s anomaly is so rare, thousands of pregnant women would need to be studied together to accurately assess whether or not lithium may cause this heart defect. Lithium is however not used very commonly and although more recent studies have not found any evidence that lithium causes Ebstein’s anomaly, they were not able to include enough women to rule out a link.

More research is needed to accurately assess whether taking lithium in pregnancy increases the chance of birth defects in the baby.

Can taking lithium in pregnancy cause miscarriage?

There is currently no strong evidence that lithium use in pregnancy increases the risk of miscarriage. Only two studies have investigated this, and while one showed a possible link between lithium use and miscarriage, the other did not. However, in the study that did show a possible link, the group of women taking lithium were studied from an earlier stage of pregnancy (when miscarriage is more likely) than the group of women who they were being compared to, who were taking other medicines. This difference may explain why more miscarriages were recorded in the women taking lithium. Because miscarriage rates have been studied in only a small number of pregnant women taking lithium, more research into this subject is required.

Can taking lithium in pregnancy cause preterm birth?

Studying whether lithium use in pregnancy increases the risk of a baby being born preterm is difficult. This is because bipolar disorder in the mother (one of the main illnesses that lithium is used to treat) has itself been shown to increase the chance of the baby being born preterm.  Two studies that did not take into account the effects of bipolar disorder in the mother both showed that women taking lithium were more likely to have a preterm birth. However, one study that did account for the underlying illness in the mother showed no link between lithium use in pregnancy and preterm birth. There is therefore currently no strong evidence that taking lithium in pregnancy increases the chance of preterm birth, but more research into this subject is required.

Can taking lithium in pregnancy cause my baby to be smaller or larger than expected at birth?

One study has suggested that babies born to women who took lithium in pregnancy were likely to have higher birth weights than babies born to women not taking lithium. Other studies have, however, not agreed with this finding. There is no evidence that taking lithium in pregnancy is linked to the baby being smaller than expected for the stage of pregnancy when they are born.

Can taking lithium in pregnancy cause stillbirth?

The single study that investigated this found that rates of stillbirth were slightly higher in women who were treated with lithium in pregnancy compared to women taking other medicines. More information needs to be collected on this subject.

Can taking lithium in pregnancy cause learning and behavioural problems in the child?

A baby’s brain continues to develop right up until the end of pregnancy. It is therefore possible that taking certain medicines at any stage of pregnancy could have a lasting effect on a child’s learning or behaviour.

Three small studies all found that children who were exposed to lithium in the womb were no more likely to have problems with thinking, learning, and behaviour than children who were not exposed to lithium. Although these findings are reassuring, only small numbers of children exposed in the womb to lithium have been studied, and there are many areas of child development that have not yet been assessed.  More research is therefore required before we can say whether lithium use in pregnancy can cause changes in thinking, learning and behaviour in exposed children.

Can taking lithium in pregnancy cause problems in the baby after birth (‘neonatal complications’)?

There are case reports in the scientific journals of newborn babies whose mothers took lithium in pregnancy suffering from various problems including floppy muscles, fast heart rate, breathing difficulties, low blood sugar, excessive sleepiness, shaking, and jaundice. No studies have investigated how likely these problems are.  It is also not clear whether the chance of a baby having these problems might be linked to the level of lithium in the mother’s bloodstream around the time of delivery (see below).

As a precaution, close monitoring of your baby after birth is advised, especially if you took lithium within 24-48 hours of your baby being born. It is also recommended that all babies whose mothers took lithium in pregnancy have blood taken to check their lithium levels after birth.  This will guide doctors as to whether your baby needs any monitoring or treatment to prevent them from developing problems associated with high levels of lithium.

Why has my doctor advised that I stop my lithium around the time of my baby’s birth?

During childbirth, lithium is not cleared from the mother’s body as effectively as it would normally be. If the levels of lithium are high in the mother’s bloodstream, more lithium will cross the placenta and may cause toxic effects in the baby after birth. To reduce the risk of toxicity in both you and your baby after birth, your doctor may advise you not to take any further doses of lithium once you are in ‘active’ labour until your baby has been born. If you think you are in labour it is important that you are assessed by your doctor before missing any doses of lithium.

Will I or my baby need extra monitoring?

Most women will be offered a scan at around 20 weeks of pregnancy to look for birth defects as part of their routine antenatal care. Taking lithium in pregnancy would not normally require extra monitoring of your baby before birth. 

Because of the normal bodily changes that occur as your pregnancy progresses, your doctor will wish to closely monitor the levels of lithium in your bloodstream to assess whether your lithium dose needs to be adjusted for it to remain both effective and within the recommended levels. You will therefore be asked to have a blood test every four weeks up until the 36th week of pregnancy, after which your blood levels will be tested weekly. You should not change the dose of any prescribed medicine without first consulting your doctor.

Your baby may also be monitored after birth and is likely to have a blood test to check his or her lithium levels as discussed in the section above.

Are there any risks to my baby if the father has taken lithium?

We would not expect any increased risk to your baby if its father took lithium before, or at around the time you became pregnant.

Who can I talk to if I have questions?

If you have any questions regarding the information in this leaflet please discuss them with your health care provider. They can access more detailed medical and scientific information from www.uktis.org.  

General information 

Up to 1 out of every 5 pregnancies ends in a miscarriage, and 1 in 40 babies are born with a birth defect. These are referred to as the background population risks.  They describe the chance of these events happening for any pregnancy before taking factors such as the mother’s health during pregnancy, her lifestyle, medicines she takes and the genetic make up of her and the baby’s father into account.

Medicines use in pregnancy

Most medicines used by the mother will cross the placenta and reach the baby. Sometimes this may have beneficial effects for the baby.  There are, however, some medicines that can harm a baby’s normal development.  How a medicine affects a baby may depend on the stage of pregnancy when the medicine is taken. If you are on regular medication you should discuss these effects with your doctor/health care team before becoming pregnant.

If a new medicine is suggested for you during pregnancy, please ensure the doctor or health care professional treating you is aware of your pregnancy.

When deciding whether or not to use a medicine in pregnancy you need to weigh up how the medicine might improve your and/or your unborn baby’s health against any possible problems that the drug may cause. Our bumps leaflets are written to provide you with a summary of what is known about use of a specific medicine in pregnancy so that you can decide together with your health care provider what is best for you and your baby.   

Every pregnancy is unique. The decision to start, stop, continue or change a prescribed medicine before or during pregnancy should be made in consultation with your health care provider. It is very helpful if you can record all your medication taken in pregnancy in your hand held maternity records.

   

www.medicinesinpregnancy.org

Disclaimer: This information is not intended to replace the individual care and advice of your health care provider. New information is continually becoming available. Whilst every effort will be made to ensure that this information is accurate and up to date at the time of publication, we cannot cover every eventuality and the information providers cannot be held responsible for any adverse outcomes following decisions made on the basis of this information. We strongly advise that printouts should NOT be kept for any length of time, or for “future reference” as they can rapidly become out of date.

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