What Are The Fetal Anti-Convulsant Syndromes ?

Today many people have heard of Fetal Valproate Syndrome, due to the concerns regarding sodium valproate however this is just one of the 26 anti-epileptic drugs taken in the UK today. Some of these are also known to have the risk of affecting the fetus leaving the child disabled when the mother took anti-epileptic medication during pregnancy.  It is a syndrome that effects the child on every level, the physical body, cognitive disabilities and mental health issues.


Fetal Anti-Convulsant Syndrome is caused when a mother uses anti-convulsant medication during pregnancy (also known as Anti-Epileptic Drugs, or AEDs:  AEDs are not only used to treat epilepsy but are also used to treat pain, migraine, bi-polar and other mental health conditions).

One of the challenges that can occur for the pregnant mother with epilepsy is that some mothers tend to have more severe seizures during pregnancy.  It is because of this that some doctors will up the dosage during the pregnancy which can make the fetus more susceptible to problems during pregnancy. The risk of disability varies according to the specific drug taken; however there are some patterns to be seen in them all. Fetal anti-convulsant syndrome(s) are/is not a 'genetic' condition in the usual sense but current opinion is that it is in the way these drugs are metabolised by some pregnant women, and/or their affected children, predisposes the unborn baby to damage. This variation in metabolism probably is genetically determined but there is, as yet, no test at present to determine which mothers, taking this medicine, is at risk.  Seizures too will carry their own risks to the foetus, so these issues have to be weighed up before making any choices.  Different drugs carry more risks of the mother conceiving a child with FACS than others.  Sodium Valproate is regarded as by far the worst, with up to 35 – 40% likelihood of the child conceived being effected. For women who have had one child diagnosed with fetal anti-convulsant syndrome, the risk of having a second affected baby may be as high as 55%.  The risk of anti-convulsant syndrome is believed to be higher when the mother takes more than one AED.


The first crucial period in pregnancy extends, from fertilization until the end of the first trimester.  As it is during this period that fetus develops its main organs, and it is during this time, that abnormalities and malformations occur. Congenital malformations are abnormalities of development that are present at birth, however others may become apparent when an MRI is done, often due to a concern about that persons wellbeing.


It is well documented that anti-convulsant medication causes congenital abnormalities.  Most statistics given today originate with the pregnancy and epilepsy register.   The onus of this is upon major congenital abnormities during the first six weeks of the baby’s life, so statistics emerging from this can cause concern if they are used to determin the figures of those with fetal anti-convulsant syndrome.  There is now a growing awareness of neurodevelopment disorders occurring at a much higher frequency.  In sodium valproate is the best recorded drug; these have been given as high as 35 – 40%. Other drugs are also associated with neurodevelopmental delay, however the figures of these has yet to be determined.  Just a few of the common challenges associated with FACS are: skeletal problems, heart defects, spinal bifida, kidney damage.  Neurodevelopmental delay including learning difficulties, autism spectrum, language delay; also often overlooked are mental health problems. The disabilities presented by FACS often cause further health problems and can result in serious health conditions and on occasion even death.  Itis for this reason that  it recommended that a diagnosis is sought The mothers of these children are often disabled themselves.  However not only are the mothers disabled carers, but the children are often overlooked in their role also as disabled young carers.


There is no real test for fetal anti convulsant syndrome, but it is possible to scan for malformations with, types 1 and II ultra-scan sound, Fetal anomaly screening, Fetoscopy, heart scans for the foetus other scans as well as blood tests.  This can be specifically requested where a mother has been taking anti-epileptic drugs, especially if they have had other children with fetal anti convulsant syndrome. It is believed that taken folic acid during the first four months of pregnancy may have some preventative value.  It is also recommended that the baby is given 1mg of vitamin K at birth.  Those with dysmorphic features should be noted and be followed up by the new-born hearing screening programme.

The information provided by OACS is to empower so that those taking anti-convulsant medicines can make informed choices about the medication that is used during pregnancy. 

It is important to speak to your doctor before choosing to stop or changing any medication

© Copyright of Organisation of Anti-Convulsant Syndrome (O.A.C.S) 2/2014 Registered Charity no. 1116497