Animal studies have revealed increased incidences of fetal structural abnormalities and other manifestations of developmental toxicity (embryolethality, growth retardation), fetal malformations (craniofacial, cardiovascular, and skeletal), embryofetal death, decreased fetal body weight, and maternal toxicity. There is no evidence to suggest that teratogenicity in these studies was secondary to maternal toxicity.

There are no controlled data in human pregnancy. Oxcarbazepine and its active metabolite, MHD, cross the human placenta. Oxcarbazepine is structurally related to carbamazepine, which is considered to be a human teratogen. Due to this finding and the results of animal studies, it is likely that oxcarbazepine is a human teratogen.

Clinical response should be monitored carefully in women receiving this drug during pregnancy to ensure that adequate seizure control is maintained; determination of changes in MHD plasma concentrations should be considered, as levels may gradually decrease throughout pregnancy.

To monitor the outcomes of in utero exposure to this drug, physicians are encouraged to recommend that pregnant patients taking oxcarbazepine enroll in the North American Antiepileptic Drug (NAAED) Pregnancy Registry by calling the toll free number 1-888-233-2334. Patients must enroll themselves. Information on the registry can also be found at the website http://www.aedpregnancyregistry.org/.

AU TGA pregnancy category D: Drugs which have caused, are suspected to have caused or may be expected to cause, an increased incidence of human fetal malformations or irreversible damage. These drugs may also have adverse pharmacological effects. Accompanying texts should be consulted for further details.

US FDA pregnancy category C: Animal reproduction studies have shown an adverse effect on the fetus and there are no adequate and well-controlled studies in humans, but potential benefits may warrant use of the drug in pregnant women despite potential risks.

This drug should only be given during pregnancy when benefits outweigh risks.

AU TGA pregnancy category: D
US FDA pregnancy category: C

Comments:
-The prevalence of malformations in the offspring of women with epilepsy is 2 to 3 times that of the general population. The prevalence appears increased in patients on polytherapy.
-The risk of having an abnormal child due to antiepileptic medicines is considered to be outweighed by the dangers of uncontrolled epilepsy to the mother and fetus.
-Women on antiepileptic drugs should receive pre-pregnancy counseling regarding the risk of fetal abnormalities.
-Antiepileptic drugs should be continued during pregnancy and monotherapy should be used if possible at the lowest effective dose for at least the first 3 months of pregnancy
-Effective antiepileptic therapy should not be interrupted.
-Folic acid supplementation (5 mg daily) should be commenced 4 weeks prior to and continue for 12 weeks after conception.
-Specialist prenatal diagnosis, including detailed mid-trimester ultrasound should be offered.
-Vitamin K1 should be administered in the last few weeks of pregnancy and to the newborn as a preventative measure against bleeding disorders.

See references

Use is not generally recommended; a decision should be made about whether to discontinue nursing or to discontinue the drug in nursing women, taking into account the importance of the drug to the mother.

Excreted into human milk: Yes

Comments: The effects in the nursing infant are unknown. If used during breastfeeding, particularly in infants that are exclusively breastfed and in mothers on combination anticonvulsant therapy, the infant should be monitored for drowsiness, adequate weight gain, and developmental milestones.

Limited information suggests that oxcarbazepine would not be expected to cause adverse effects in breastfed infants, particularly if the infant is over 2 months of age.

The active metabolite of oxcarbazepine, 10-monohydroxy (MHD), is also excreted into human breast milk; The milk to plasma ratio has been estimated to be 0.5 for both.

See references