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There are an estimated 40,000 people in Ireland with epilepsy of whom about 10,000 are women of child-bearing age.
The following are guidelines on the basic management of women with epilepsy
(WWE) who become (or are planning to become) pregnant.
The goal of epilepsy treatment in any women of reproductive years is to control seizures at the minimum dose of anti-epileptic medication possible.
If an Anti-Epileptic Medications (AED) is needed, monotherapy is preferable to polytherapy.
Any changes to AEDs should ideally be made 6 months before any planned pregnancy
(ideally before conception or before stopping contraception)
The choice of AED for pregnant women with epilepsy requires assessment of balance of risks between teratogenicity and seizure control.
Seizure activity during pregnancy varies greatly between individuals and can be different from pregnancy to pregnancy in the same woman. Approximately 25% of women with epilepsy will have fewer seizures during pregnancy, 53% will have no change in seizure activity, and 23% will have an increase in seizure activity.
Any woman taking an AED planning on becoming pregnant should be taking folic acid 5mg per day prior to conception.
Studies do vary but the generally accepted risk of a major congenital abnormality for a woman taking AEDs is between 4-15 % (i.e. taking one AED, risk is 4%, 2 or more and risk is 15%)
The risk of seizures increases by between 20-30% during pregnancy. This is important to emphasise as some patients may skip taking their medication to try to protect the developing baby. Most malformations occur at an early stage in pregnancy before WWE knows she is pregnant.
It is important to point out to patients that an epileptic seizure can be as detrimental to a developing baby as their medication can. WWE should enter pregnancy having complete seizure control or as few seizures as possible.
Why the frequency of seizures increases during pregnancy is multifactorial but includes reasons such as decreased serum AED concentration because of vomiting, non-compliance with medication and a lack of sleep. There is also variation in the metabolism of AEDs during pregnancy which will alter the effectiveness of the medication.
Seizure exacerbation may occur at any time in WWE who are pregnant but most occur at the end of the first and beginning of the second trimesters.
Whether it is planned or unplanned when a woman presents to a doctor with a confirmed pregnancy the following steps should be taken:
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Do not alter the doses of AntiEpileptic Medications
Refer to a neurologist
Start Folate 5mg/day if not already taking this
By the time the woman presents to a doctor it is probably already later than the period of greatest teratogenicity.
Reducing or stopping the doses at this stage will only increase the risk that the mother will have a seizure.
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Serum AED levels should be taken at least once in each trimester (and a baseline serum level taken pre at first visit)
Common conditions to monitor are Hyperemesis Gravidarum where the patient may not able to absorb the AED and patients who are not sleeping well as this will decrease their seizure threshold.
If a patient had a seizure at any stage during a pregnancy it is important to assess for any factor that may have lowered their seizure threshold.
Patients should follow the general rules of care for seizures (e.g. first aid with regard to seizures) such as not having baths or swimming alone.
The risk of a pregnant woman having convulsive seizures is highest during this trimester.
Ten milligrams of Vitamin K should be given orally four weeks prior to the Estimated Date of
Delivery (EDD) for patients who are on enzyme inducing AEDs (Phenytoin, Phenobarbitol,
Primidone, Carbamazepine, Oxcarbazepine and Topiramate at doses of >200mg/day).
In Ireland all newborn infants receive an intramuscular injection of Vitamin K the day after they are born but it is especially important that children of mothers who were taking hepatic enzyme inducers receive this to reduce the risk of haemorrhage in the newborn.
Also if patients taking hepatic enzyme inducers are at risk of preterm labour a higher dose of corticosteroid should be used to induce foetal lung maturation.
It is strongly recommended that women with epilepsy have their labour in a maternity hospital and not at home.
Although seizure frequency is unlikely to increase for most women during pregnancy, the probability of a seizure during labour is 9 times greater than at any other time in pregnancy, and 1% to 2% of women with epilepsy will have a seizure in the intrapartum period.
Normal doses of AED’s should be given around the time of (and during) labour.
Avoid pethidine if possible
If AEDS have been increased during pregnancy, one may need to reduce the does again in the 4-6 weeks after delivery.
The following is just a brief synopsis of the basic principles involved in the treatment of status epilepticus during pregnancy.
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Establish the ABCs, and check vital signs, including oxygenation.
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Assess the foetal heart rate or foetal status.
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Rule out eclampsia.
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Administer a bolus of lorazepam (0.1 mg/kg, up to 5-10 mg) at no faster than
2 mg/min (or 2mg iv and no more than 8mg in 24 hours)
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Load phenytoin (20 mg/kg, ie, 1-2 g) at no faster than 50 mg/min, with cardiac monitoring.
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If this is not successful, load phenobarbital (20 mg/kg, ie, 1-2 g) at no faster than 100 mg/min.
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Check laboratory findings, including electrolytes, AED levels, glucose, and toxicology screen.
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If fetal testing results are non-reassuring, move to emergent delivery.
Most AEDs are excreted in breast milk but breast-feeding is still recommended as the best feeding option for babies. Doses of AEDs secreted in breast milk should not have any effect on the developing baby.
Some babies may become drowsy particularly if the mother is taking phenobarbitol, in which case breast feeding should be discontinued.
Currently there is insufficient evidence about the safety of AEDs during pregnancy and their risk of malformations.
Any woman with epilepsy who becomes pregnant should be registered to the Irish Epilepsy and Pregnancy Register: telephone 1800320820 or www.epilepsypregnancyregister.ie
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