Antiseizure Medication Concentrations During Pregnancy: Results From the Maternal Outcomes and Neurodevelopmental Effects of Antiepileptic Drugs (MONEAD) Study

IMPORTANCE

During pregnancy in women with epilepsy, lower blood concentrations of antiseizure medications can have adverse clinical consequences.

OBJECTIVE

To characterize pregnancy-associated concentration changes for several antiseizure medications among women with epilepsy.

DESIGN, SETTING, AND PARTICIPANTS

Enrollment in this prospective, observational cohort study, Maternal Outcomes and Neurodevelopmental Effects of Antiepileptic Drugs (MONEAD), occurred from December 19, 2012, to February 11, 2016, at 20 US sites. Enrolled cohorts included pregnant women with epilepsy and nonpregnant control participants with epilepsy. Inclusion criteria were women aged 14 to 45 years, an intelligence quotient greater than 70 points, and, for the cohort of pregnant women, a fetal gestational age younger than 20 weeks. A total of 1087 women were assessed for eligibility; 397 were excluded and 230 declined. Data were analyzed from May 1, 2014, to June 30, 2021.

EXPOSURE

Medication plasma concentrations in women taking monotherapy or in combination with noninteracting medications. The cohort of pregnant women was monitored through 9 months post partum, with similar time points for control participants.

MAIN OUTCOMES AND MEASURES

Dose-normalized concentrations were calculated as total or unbound plasma medication concentrations divided by total daily dose. Phlebotomy was performed during 4 pregnancy study visits and 3 postpartum visits for the pregnant women and 7 visits over 18 months for control participants. The primary hypothesis was to test pregnancy changes of dose-normalized concentrations from nonpregnant postpartum samples compared with those of control participants.

RESULTS

Of the 351 pregnant women and 109 control participants enrolled in MONEAD, 326 pregnant women (median [range] age, 29 [19-43] years) and 104 control participants (median [range] age, 29 [16-43] years) met eligibility criteria for this analysis. Compared with postpartum values, dose-normalized concentrations during pregnancy were decreased by up to 56.1% for lamotrigine (15.60 μg/L/mg to 6.85 μg/L/mg; P < .001), 36.8% for levetiracetam (11.33 μg/L/mg to 7.16 μg/L/mg; P < .001), 17.3% for carbamazepine (11.56 μg/L/mg to 7.97 μg/L/mg; P = .03), 32.6% for oxcarbazepine (11.55 μg/L/mg to 7.79 μg/L/mg; P < .001), 30.6% for unbound oxcarbazepine (6.15 μg/L/mg to 4.27 μg/L/mg; P < .001), 39.9% for lacosamide (26.14 μg/L/mg to 15.71 μg/L/mg; P < .001), and 29.8% for zonisamide (40.12 μg/L/mg to 28.15 μg/L/mg; P < .001). No significant changes occurred for unbound carbamazepine, carbamazepine-10,11-epoxide, and topiramate, although a decrease was observed for topiramate (29.83 μg/L/mg to 13.77 μg/L/mg; P = .18). Additionally, compared with dose-normalized concentrations from control participants, pregnancy dose-normalized median (SE) concentrations decreased significantly by week of gestational age: carbamazepine, -0.14 (0.06) μg/L/mg (P = .02); carbamazepine unbound, -0.04 (0.01) μg/L/mg (P = .01); lacosamide, -0.23 (0.07) μg/L/mg (P < .001); lamotrigine, -0.20 (0.02) μg/L/mg (P < .001); levetiracetam, -0.06 (0.03) μg/L/mg (P = .01); oxcarbazepine, -0.14 (0.04) μg/L/mg (P < .001); oxcarbazepine unbound, -0.11 (0.03) μg/L/mg (P < .001); and zonisamide, -0.53 (0.14) μg/L/mg (P < .001) except for topiramate (-0.35 [0.20] μg/L/mg per week) and carbamazepine-10,11-epoxide (0.02 [0.01] μg/L/mg).

CONCLUSIONS AND RELEVANCE

Study results suggest that therapeutic drug monitoring should begin early in pregnancy and that increasing doses of these anticonvulsants may be needed throughout the course of pregnancy.

Altered adult neurogenesis and gliogenesis in patients with mesial temporal lobe epilepsy

The hippocampus is the most common seizure focus in people. In the hippocampus, aberrant neurogenesis plays a critical role in the initiation and progression of epilepsy in rodent models, but it is unknown whether this also holds true in humans. To address this question, we used immunofluorescence on control healthy hippocampus and surgical resections from mesial temporal lobe epilepsy (MTLE), plus neural stem-cell cultures and multi-electrode recordings of ex vivo hippocampal slices. We found that a longer duration of epilepsy is associated with a sharp decline in neuronal production and persistent numbers in astrogenesis. Further, immature neurons in MTLE are mostly inactive, and are not observed in cases with local epileptiform-like activity. However, immature astroglia are present in every MTLE case and their location and activity are dependent on epileptiform-like activity. Immature astroglia, rather than newborn neurons, therefore represent a potential target to continually modulate adult human neuronal hyperactivity.

Changes in Seizure Frequency and Antiepileptic Therapy during Pregnancy

BACKGROUND

Among women with epilepsy, studies regarding changes in seizure frequency during pregnancy have been limited by the lack of an appropriate nonpregnant comparator group to provide data on the natural course of seizure frequency in both groups.

METHODS

In this prospective, observational, multicenter cohort study, we compared the frequency of seizures during pregnancy through the peripartum period (the first 6 weeks after birth) (epoch 1) with the frequency during the postpartum period (the following 7.5 months after pregnancy) (epoch 2). Nonpregnant women with epilepsy were enrolled as controls and had similar follow-up during an 18-month period. The primary outcome was the percentage of women who had a higher frequency of seizures that impaired awareness during epoch 1 than during epoch 2. We also compared changes in the doses of antiepileptic drugs that were administered in the two groups during the first 9 months of epoch 1.

RESULTS

We enrolled 351 pregnant women and 109 controls with epilepsy. Among the 299 pregnant women and 93 controls who had a history of seizures that impaired awareness and who had available data for the two epochs, seizure frequency was higher during epoch 1 than during epoch 2 in 70 pregnant women (23%) and in 23 controls (25%) (odds ratio, 0.93; 95% confidence interval [CI], 0.54 to 1.60). During pregnancy, the dose of an antiepileptic drug was changed at least once in 74% of pregnant women and in 31% of controls (odds ratio, 6.36; 95% CI, 3.82 to 10.59).

CONCLUSIONS

Among women with epilepsy, the percentage who had a higher incidence of seizures during pregnancy than during the postpartum period was similar to that in women who were not pregnant during the corresponding epochs. Changes in doses of antiepileptic drugs occurred more frequently in pregnant women than in nonpregnant women during similar time periods. (Funded by the National Institutes of Health; MONEAD ClinicalTrials.gov number, NCT01730170.).

Fetal loss and malformations in the MONEAD study of pregnant women with epilepsy

OBJECTIVE

To examine occurrence of severe adverse fetal outcomes (SAO), including fetal loss and major congenital malformations (MCMs), in pregnant women with epilepsy (PWWE) vs healthy pregnant women (HPW).

METHODS

The Maternal Outcomes and Neurodevelopmental Effects of Antiepileptic Drugs (MONEAD) study is an NIH-funded, prospective, observational, multicenter investigation of pregnancy outcomes for both mother and child, which enrolled women December 2012 through January 2016.

RESULTS

The 351 PWWE had 365 conceptions, and 105 HPW had 109 conceptions. SAOs occurred more often in PWWE (7.9%) vs HPW (1.9%) (p = 0.025) with odds ratio (OR) 4.45 (95% confidence intervals [CI] 1.04-19.01). There were no significant differences for fetal loss (2.8% vs 0%, p = 0.126) or MCMs (5.2% vs 1.9%, p = 0.185; OR 2.86, 95% CI 0.65-12.53) individually. No fetal losses in PWWE appeared to be related to acute seizures. Outcomes were not affected by periconceptional folate, unplanned/unwanted pregnancies, prior maternal pregnancy history, or antiepileptic drug (AED) blood levels, except for an AED level effect for fetal loss that appeared to be due to polytherapy. Combined maternal or paternal family history of MCM was marginally associated with increased SAOs (p = 0.046).

CONCLUSIONS

The findings provide additional information on risks of SAOs in PWWE, assessing effects of both AED levels and periconceptional folate. Group differences in average enrollment gestational age could have affected fetal loss results. Analyses are limited by small sample sizes as the MONEAD study was not powered for these secondary outcomes. The large majority of pregnancies in women with epilepsy do not have SOAs.

Changes in antiepileptic drug-prescribing patterns in pregnant women with epilepsy

OBJECTIVE

We analyzed current prescribing patterns for antiepileptic drugs (AEDs) in pregnant women with epilepsy (PWWE) at 20 USA tertiary epilepsy centers.

METHODS

The Maternal Outcomes and Neurodevelopmental Effects of Antiepileptic Drugs (MONEAD) study is an NIH-funded, prospective, observational, multicenter investigation of pregnancy outcomes for both mother and child, which enrolled women from December 2012 to January 2016. Inclusion criteria for PWWE included ages 14-45 years and up to 20 weeks gestational age. Exclusion criteria included history of psychogenic nonepileptic spells, expected intelligence quotient (IQ) <70, other major medical illness, progressive cerebral disease, and switching AEDs in pregnancy prior to enrollment.

RESULTS

Three hundred fifty-one PWWE were enrolled in the MONEAD study, which included 259 (73.8%) on monotherapy, 77 (21.9%) on polytherapy, and 15 (4.3%) on no AEDs. The most common AED monotherapy regimens were lamotrigine (42.1% of monotherapies), levetiracetam (37.5%), carbamazepine (5.4%), zonisamide (5.0%), oxcarbazepine (4.6%), and topiramate (3.1%). All other individual monotherapies were each <1%. The most common AED polytherapy combination was lamotrigine + levetiracetam (42.9% of polytherapies), followed by lacosamide + levetiracetam (6.5%), lamotrigine + zonisamide (5.2%), and all other remaining combinations (each <4%); only 5.2% of polytherapy subjects were on ≥3 AEDs (1.1% of total PWWE). Only four subjects (1.1%) were on valproate (1 monotherapy, 3 polytherapy).

CONCLUSIONS

The distribution of AED use likely reflects current prescribing patterns for PWWE cared for in USA tertiary epilepsy centers. This distribution has changed markedly since the turn of the century, but changes in the general population remain uncertain.

Sexual dysfunction, sex steroid hormone abnormalities, and depression in women with epilepsy treated with antiepileptic drugs

Women with epilepsy are believed to be at risk for sexual dysfunction. Disorders of sexual desire and sexual arousal, including dyspareunia, vaginismus, and lack of lubrication, affect an estimated 30 to 60% of women with epilepsy. In this study, 57 reproductive-aged women with either localization related (LRE) or primary generalized epilepsy (PGE) on antiepileptic drug (AED) monotherapy and 17 nonepileptic controls completed questionnaires examining sexual experience, arousability, anxiety, and symptoms, as well as an inventory of depression. An endocrine assessment was performed during the early follicular phase of the menstrual cycle. Sexual dysfunction was more common in women with LRE, in women receiving phenytoin, in women with low levels of estradiol and dehydroepiandrosterone sulfate, and in women with self-reported symptoms of mild depression. The mechanisms of sexual dysfunction in women with epilepsy are multifactorial, but AED choice appears to be one cause that is modifiable.