8.1Pregnancy Pregnancy Exposure Registry
There is a pregnancy exposure registry that monitors pregnancy outcomes in women exposed to AEDs, such as oxcarbazepine, during pregnancy. Encourage women who are taking oxcarbazepine during pregnancy to enroll in the North American Antiepileptic Drug (NAAED) Pregnancy Registry by calling 1-888-233-2334 or visiting http://www.aedpregnancyregistry.org/. Risk Summary Although oxcarbazepine is closely related structurally to carbamazepine, which is considered to be teratogenic in humans, available human data from published literature and ongoing pregnancy registry studies on use of oxcarbazepine during pregnancy have not demonstrated an increased prevalence of major congenital malformations with first trimester exposure.
However, all published studies reviewed have important methodological limitations, including unmeasured confounding and a small number of exposed cases (see Data). There are risks to the mother and fetus associated with partial onset seizures (see Clinical Considerations ). There are no data on the risks associated with the use of oxcarbazepine and miscarriage or other adverse maternal outcomes. Increased incidences of fetal structural abnormalities and other manifestations of developmental toxicity (embryolethality, growth retardation) were observed in the offspring of animals treated with either oxcarbazepine or its active 10-hydroxy metabolite (MHD) during pregnancy at doses similar to the maximum recommended human dose (MRHD).
In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2% to 4% and 15% to 20%, respectively. All pregnancies have a background risk of birth defect, loss, or other adverse outcomes. Clinical Considerations Disease-associated Maternal and/or Embryofetal Risk Epilepsy, with or without exposure to antiepileptic drugs, has been associated with several adverse outcomes during pregnancy, including preeclampsia, preterm labor, antepartum and postpartum hemorrhage, placental abruption, poor fetal growth, prematurity, fetal death, and maternal mortality.
The risk of maternal or fetal injury may be greatest for patients with untreated or poorly controlled convulsive seizures. Women with epilepsy who become pregnant should not abruptly discontinue antiepileptic drugs, including oxcarbazepine, due to the risk of status epilepticus or severe seizures, which may be life-threatening [see Warnings and Precautions (5.6)]. Maternal Adverse Reactions An increase in seizure frequency may occur during pregnancy because of altered levels of the active metabolite of oxcarbazepine.
Monitor patients carefully during pregnancy and through the postpartum period [see Warnings and Precautions (5.10)]. Data Human Data Data from a published retrospective cohort study and ongoing pregnancy registry studies on the use of oxcarbazepine during pregnancy have not demonstrated an increased prevalence of major congenital malformations with first trimester exposure. A retrospective cohort study conducted in Nordic countries (Denmark, Finland, Iceland, Norway, and Sweden) from 1996-2020 found that there was no increased prevalence of major congenital malformations when pregnancies exposed to oxcarbazepine during the first trimester were compared to pregnancies exposed to lamotrigine (adjusted risk ratio =1.09; 95% CI 0.83 to 1.44; n pregnancies exposed to oxcarbazepine= 1,313, n exposed cases = 58).
In an ongoing pregnancy registry that included data from over 40 countries from 1999 to 2022 and 443 pregnancies exposed to oxcarbazepine, oxcarbazepine exposure during the first trimester was not associated with major congenital malformations (adjusted odds ratio =1.09; 95% CI 0.56 to 2.13, n exposed cases = 10). However, there are important methodological limitations of these studies including unmeasured confounding factors and a small number of exposed cases in the registry.
Animal Data When pregnant rats were given oxcarbazepine (0, 30, 300, or 1000 mg/kg/day) orally throughout the period of organogenesis, increased incidences of fetal malformations (craniofacial, cardiovascular, and skeletal) and variations were observed at the intermediate and high doses (approximately 1.2 and 4 times, respectively, the MRHD on a mg/m 2 basis). Increased embryofetal death and decreased fetal body weights were seen at the high dose.
Doses ≥300 mg/kg/day were also maternally toxic (decreased body weight gain, clinical signs), but there is no evidence to suggest that teratogenicity was secondary to the maternal effects. In a study in which pregnant rabbits were orally administered MHD (0, 20, 100, or 200 mg/kg/day) during organogenesis, embryofetal mortality was increased at the highest dose (1.5 times the MRHD on a mg/m 2 basis). This dose produced only minimal maternal toxicity.
In a study in which female rats were dosed orally with oxcarbazepine (0, 25, 50, or 150 mg/kg/day) during the latter part of gestation and throughout the lactation period, a persistent reduction in body weights and altered behavior (decreased activity) were observed in offspring exposed to the highest dose (less than the MRHD on a mg/m 2 basis). Oral administration of MHD (0, 25, 75, or 250 mg/kg/day) to rats during gestation and lactation resulted in a persistent reduction in offspring weights at the highest dose (equivalent to the MRHD on a mg/m 2 basis).
