Appropriate advice should be made available to women with epilepsy; special advice on contraception and pre-conception and also greater levels of care are required in pregnancy, labour and postnatally.
Most pregnant women with epilepsy have a normal pregnancy and childbirth.However, there is an increased risk of teratogenicity associated with the use of anti-epileptic drugs (AEDs), especially if used during the first trimester and also if the patient takes two or more AEDs.
Lamotrigine has been increasingly prescribed in pregnancy over older AEDs such as carbamazepine and sodium valproate.
Once an unplanned pregnancy is discovered it is usually too late for changes to be made to the epilepsy treatment regimen. The risk of harm to the mother and fetus from convulsive seizures outweighs the risk of continued therapy.
Liver enzyme (cytochrome P-450) induction reduces the efficacy of the combined oral contraceptive pill, combined contraceptive patch, combined contraceptive vaginal ring and progestogen-only contraceptive pill and this may place women at greater risk of unplanned pregnancy.Women should be counselled about the increased risk of pregnancy (contraceptive failure) and any harmful effects of medication on the fetus.
- Women with a history of epilepsy, who are not taking anticonvulsants, may use any method. Women taking anticonvulsants that do not induce liver enzymes (eg, gabapentin, levetiracetam, valproate and vigabatrin) may use any method without restriction.
- Women taking anticonvulsants that induce liver enzymes (eg, phenytoin, carbamazepine, barbiturates, primidone, topiramate and oxcarbazepine) may use depot medroxyprogesterone acetate, copper intrauterine contraceptive devices, the levonorgestrel-releasing intrauterine system, barrier methods and natural family planning methods.
- The progestogen-only contraceptive pill and the progestogen implant are not recommended as reliable contraception in patients taking enzyme-inducing AEDs.
- Intramuscular medroxyprogesterone acetate (Depo-Provera®) can be used but should be scheduled every 10 weeks rather than 12-weekly.
- The use of additional barrier methods should be discussed with women and girls taking enzyme-inducing AEDs and oral contraception or having depot injections of progestogen.
- If women choose a combined contraceptive method, they should use a preparation containing at least 50 micrograms of oestrogen.Tricycling the packs, with no withdrawal bleed for 3-4 packs and then a reduced pill-free interval of only four days, is also recommended.
- Any oestrogen-based contraceptive can result in a significant reduction of lamotrigine levels and lead to loss of seizure control.
- Breakthrough bleeding does not necessarily indicate low serum hormone concentrations and risk of ovulation; nevertheless, women with breakthrough bleeding may increase their dose of ethinylestradiol above 50 micrograms daily.
- After appropriate counselling some women may choose sterilisation as a permanent method of contraception.
- The effectiveness of levonorgestrel, and possibly ulipristal, is reduced in women taking enzyme-inducing drugs (and possibly for four weeks after stopping).
- A copper intrauterine contraceptive device can be offered instead, or the dose of levonorgestrel should be increased to a total of 3 mg taken as a single dose (unlicensed dose).
Women with epilepsy may have a lower fertility rate than average but the evidence is poor. While personal choice and/or societal pressure may play some role in this, women with epilepsy also appear to have a higher incidence of menstrual irregularities, polycystic ovarian disease and reproductive endocrine disorders. All of these may reduce fertility. These are thought to arise both from neuro-endocrine disturbances related to seizure activity as well as the alteration of endogenous sex steroid metabolism in the presence of enzyme-inducing AEDs.There is an increase in polycystic ovaries and hyperandrogenism associated with valproate therapy.
The risk of congenital malformation is higher in babies if the mother has epilepsy. Most women with epilepsy should continue their medication during pregnancy as uncontrolled seizures also carry a maternal risk.
There is an increased risk of teratogenicity associated with the use of AEDs (especially if used during the first trimester and particularly when taking two or more AEDs). Valproate is associated with the highest risk of major and minor congenital malformations (in particular neural tube defects) and long-term neurodevelopmental effects.
Valproate should not be used during pregnancy or in women of child-bearing age unless there is no safer alternative and only after a careful discussion of the risks. If valproate is to be used during pregnancy, the lowest effective dose should be prescribed in divided doses or as modified-release tablets to avoid peaks in plasma-valproate concentrations. Doses greater than 1 g daily are associated with an increased risk of teratogenicity. There is also an increased risk of teratogenicity with phenytoin, primidone, phenobarbital, lamotrigine and carbamazepine. Topiramate carries an increased risk of cleft palate if taken in the first trimester of pregnancy. There is not enough evidence to establish the risk of teratogenicity with other AEDs.
One study found that fetal valproate exposure has dose-dependent associations with reduced cognitive abilities at 6 years of age. There was a beneficial association of periconceptional folate with the child's IQ.
Fetal valproate exposure is associated with an increased likelihood of difficulty with adaptive functioning and with attention deficit hyperactivity disorder (ADHD).
Performance IQ has also been found to be significantly lower in children exposed to carbamazepine during pregnancy than in unexposed children.
There are relatively few data regarding the safety of the newer AEDs during pregnancy. However, a study in Denmark found that first-trimester exposure to lamotrigine, oxcarbazepine, topiramate, gabapentin or levetiracetam compared with no exposure was not associated with an increased risk of major birth defects.
Fetal anticonvulsant syndrome
Children exposed to valproate have more distinctive facial features; however, a subtle and distinctive facial phenotype is also seen in children exposed to carbamazepine. Nearly half of unexposed children had some of the facial features associated with AED exposure, showing that many of these features may be seen as part of normal variation and that the diagnosis of the fetal anticonvulsant syndrome is difficult to make on the basis of facial appearance alone.
Associated features include tall/broad forehead, trigonocephaly (premature fusion of the metopic suture, leading to a triangular-shaped forehead), medial deficiency of eyebrows, infraorbital grooves, epicanthic folds, broad nasal bridge, anteverted nose, abnormal philtrum, thin upper lip, everted lower lip, micrognathia, small mouth, dysplastic ears, hypoplastic digits, arachnodactyly, clinodactyly, flat feet and hypoplastic nails.
- Women who want to become pregnant should be referred to a specialist for advice in advance of conception. For some women, the severity of seizure or the seizure type may not pose a serious threat and drug withdrawal may be considered. Treatment may be resumed after the first trimester. If treatment with AEDs must continue throughout pregnancy then monotherapy is preferable at the lowest effective dose.
- The choice of anti-epileptic therapy should also be carefully considered in prepubescent girls who may later become pregnant.
- Discuss the risk of AEDs causing malformations and possible neurodevelopmental impairments in an unborn child. Assess the risks and benefits of treatment with individual drugs.
- It should be emphasised that the likelihood of a woman who is taking AEDs having a baby with no malformations is at least 90%. It is very important that women do not stop taking treatment just because of concern over harm to the fetus and without a thorough specialist assessment of individual need.
- Folic acid:
- To reduce the risk of neural tube defects, folate supplementation is advised before conception and throughout the first trimester.
- 5 mg per day of folic acid before any possibility of pregnancy should be advised in order to lower the risk of neural tube defects in the offspring.
The concentration of AEDs in the plasma can change during pregnancy. Doses of phenytoin, carbamazepine and lamotrigine should be adjusted on the basis of plasma-drug concentration monitoring. The dose of other AEDs should be monitored carefully during pregnancy and after birth and adjustments made on a clinical basis.
Women who have seizures in the second half of pregnancy should be assessed for eclampsia before any change is made to anti-epileptic treatment.
There is an increased risk of complications during pregnancy and labour. Care of pregnant women and girls should be shared between the obstetrician and the epilepsy specialist. All pregnant women and girls with epilepsy should notify their pregnancy to the UK Epilepsy and Pregnancy Register - see website under 'Further reading & references', below.
- An increase in seizure frequency is generally unlikely in pregnancy or in the first few months after birth. The risk of a tonic-clonic seizure during the labour and the 24 hours after birth is low.
- The fetus may be at relatively higher risk of harm during a generalised tonic-clonic (GTC) seizure (although the absolute risk remains low) and the level of risk may depend on seizure frequency. However, miscarriage, trauma related to falls, fetal hypoxia and acidosis are all possible sequelae of maternal seizures. There is no evidence that focal, absence or myoclonic seizures affect the pregnancy or developing fetus adversely unless the mother falls and sustains an injury.
- Status epilepticus carries a high mortality rate for mother and fetus, and generalised seizures occurring during labour can result in fetal bradycardia.
- Other potential antenatal problems seen more frequently in women with epilepsy are hyperemesis gravidarum, gestational hypertension, mild pre-eclampsia, vaginal bleeding and anaemia.
- Difficulties during labour and delivery include premature labour, failure to progress and an increased rate of caesarean sections.
Antenatal and intrapartum care
- Pregnant women taking AEDs should be offered a high-resolution ultrasound scan to screen for structural anomalies, performed at 18-20 weeks of gestation; however, earlier scanning (11-13 weeks) may allow major malformations to be detected sooner.
- Fetal growth should be monitored in women taking topiramate or levetiracetam.
- Genetic counselling should be considered if one partner has epilepsy, particularly if the partner has idiopathic epilepsy and a positive family history of epilepsy.
- Intrapartum care should include the following:
- Women should deliver in a centre with adequate facilities for maternal and neonatal resuscitation.
- Women should continue to take their anti-epileptic medication in labour.
- Birthing pools are not recommended for women with epilepsy.
- Intravenous access (in case of seizure).
- Hyperventilation and maternal exhaustion should be avoided.
- GTC seizures are associated with hypoxia. Continuous cardiotocography (CTG) tracing is recommended in the event of a seizure.
- An intravenous benzodiazepine (eg, lorazepam or diazepam) is recommended to terminate any seizures.
- In the event of benzodiazepine being used to terminate the seizure, loss of baseline variability of the fetal heart rate tracing can be expected for approximately one hour.
- Withdrawal effects in the newborn may occur with some AEDs, especially benzodiazepines and phenobarbital.
- If doses have been increased during pregnancy, toxicity may occur and medication requirement is likely to fall in the puerperium.
- Routine injection of vitamin K at birth minimises the risk of neonatal haemorrhage associated with AEDs.
- Breast-feeding for most women taking AEDs is generally safe and should be encouraged.
- One study found no adverse effects of AED exposure via breast milk observed at age 6 years and found that those children who had been breast-fed exhibited higher IQ and enhanced verbal abilities.
- The total amount of drug transferred to infants via breast milk is usually much smaller than the amount transferred via the placenta during pregnancy. However, repeated administration of a drug such as lamotrigine via breast milk may lead to accumulation in the infant.
- Primidone, phenobarbital and the benzodiazepines may cause drowsiness in breast-fed babies.
- Maternity services should be aware of the risk of postpartum seizures, particularly in the setting of sleep deprivation. Ensuring women get adequate sleep and take their medication is very important.
- Mothers may be anxious about the prospect of having a seizure whilst caring for a baby at home alone. Although the risk to the infant from maternal seizures is generally low, women with juvenile myoclonic epilepsy are a particular concern. The myoclonic jerks tend to be more frequent in the early morning, often around the time of infant waking.
- To reduce the risk of injury if the mother has a seizure, advice should include:
- Change or feed the baby on the floor.
- Avoid baby slings.
- Where possible, minimise climbing of stairs.
- Avoid bathing the baby when alone.
Did you find this information useful?
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- Epilepsy Action
- Epilepsy Society
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