Epilepsy in Pregnancy

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Definition

-  Management of Epilepsy prenatally, antenatally, during pregnancy & post partum

 

Features

-  Aim of Mx is to control seizures & minimise risk to mother & fetus

-  Most common neurologicall disorder to effect pregnancy

-  0.5% of women of child bearing age

-  Slight increase in risk of fetal abnormalities

-  All anticonvulsants cross placenta & are teratogenic

-  3.5% risk on no medication

-  6-7% risk on monotherapy

-  15%+ if on 2+ medications

-  Some combinations (Carbamazepine + Phenytoin) up to 50%

-  Sodium Valproate: overall risk 6.2% (dose dependant), neural tube defects, developmental delay, cardiac anomalies

-  Carbamazapine: overall risk 2.2%, neural tube defects, developmental delay

-  Phenytoin: congenital heart defects, orofacial defects

-  Risk of child developing Epilepsy 5-20% if mother only (or other first degree relative only)

-  25%+ if x2 first degree relatives

-  No increased risk of obstetric complications if managed appropriately

-  Seizure frequency increases by 25-30% in pregnancy

-  Esp if poorly controlled or on Lamotrogine

-  1-2% women have seizure during labour

-  1-2% women have seizure within 24hrs post partum

 

Ix

-  +/- baseline Phenytoin levels if unstable

 

Mx

-  Pre-conception

-  Neurologist R/V to determine if Rx still required & which is most appropriate (risk of teratogenicity vs seizure)

-  Usually risk of seizures > risk of teratogenicity

-  If free from seizures for 3yrs may consider stopping 6/12 prior to pregnancy (but should not drive for this time)

-  Carbamazapine drug of choice

-  Monitor seizure activity

-  Folic acid 5mg PO Daily 12+ weeks prior until second trimester

-  Pregnancy

-  Early booking & antenatal assessment

-  US

-  12-14/40 US (NT) to confrm dates & assess for anencephaly

-  Detailed morphology scan (second trimester) with Obstetrician/FDU

-  Ongoing growth scans if polytherapy

-  36/40 consider Vitamin K

-  20mg PO Daily until delivery if on Phenytoin, Carmamazepine or Topiramate (not for Sodium Valproate)

-  Appropriate Mx of hypermesis gravidarum to maintain therapy

-  Labour

-  Continue Anticonvulstants in labour

-  Increased risk of seizure up to 24hrs post partum

-  Morphine preferable over Pethidine for analgesia (as can lower seizure threshold)

-  Seizure Mx

-  MET call

-  BLS, maintain airway

-  Diazepam 10mg IV

-  +/- MgSO4

-  Monitor for next 72hrs

-  Recurrent seizures near term then consider elective LUSCS

-  Puerperium

-  Neonatal Vitamin K strongly recommended 0.1mg/kg IM at birth

-  Breast feeding encouraged but some drug levels may require monitoring

-  Dosage may require down titration over 3-4 weeks

 

 

 

References

 

www.hutchon.net/NFMMSIG/epilepsy.htm