Epileptic seizure control during and after pregnancy in Australian women

Transfer of anticonvulsants and lithium into amniotic fluid, umbilical cord blood & breast milk: A systematic review & combined analysis

OBJECTIVE

Data on the ability of anticonvulsants and lithium to enter fetal and newborn circulation has become increasingly available; here we estimated penetration ratios in a series of matrices from combined samples of pregnant/breastfeeding women treated with anticonvulsants or lithium.

METHODS

We conducted a systematic literature search in PubMed/EMBASE for studies with concentrations of anticonvulsants/lithium from maternal blood, amniotic fluid, umbilical cord blood and/or breast milk. Penetration ratios were calculated by dividing the concentrations in amniotic fluid, umbilical cord plasma or breast milk by the maternal concentrations. When data from multiple studies were available, we calculated combined penetration ratios, weighting studies' mean by study size.

RESULTS

Ninety-one eligible studies for brivaracetam, carbamazepine, clonazepam, ethosuximide, gabapentin, lacosamide, lamotrigine, levetiracetam, lithium, oxcarbazepine, perampanel, phenobarbital, phenytoin, pregabalin, primidone, topiramate, valproate, vigabatrin and zonisamide were identified. For amniotic fluid, the highest penetration ratios were estimated for levetiracetam (mean 3.56, range 1.27-5.85, n = 2) and lowest for valproate (mean 0.11, range 0.02-1.02, n = 57). For umbilical cord plasma, oxcarbazepine had the highest ratio (mean 1.59, range 0.11-4.33, n = 12) with clonazepam having the lowest (mean 0.55, range 0.52-0.59, n = 2). For breast milk, the highest ratios were observed for oxcarbazepine (mean 3.75, range 0.5-7.0, n = 2), whereas the lowest were observed for valproate (mean 0.04, range 0.01-0.22, n = 121).

DISCUSSION

We observed substantial variability between anticonvulsants and lithium regarding their ability to enter fetal/newborn circulation. Assessing concentrations of anticonvulsants and lithium in maternal samples can provide a surrogate of fetal/infant exposure, although patterns of concentration-dependent effects for maternal/neonatal safety are lacking.

Economic Evaluation of the Community Benefit of the Australian Pregnancy Register of Antiseizure Medications

BACKGROUND AND OBJECTIVE

The Raoul Wallenberg Australian Pregnancy Register (APR) was established to collect, analyze, and publish data on the risks to babies exposed to antiseizure medications (ASMs) and to facilitate quality improvements in management care over time. It is one of the seveal prospective observational pregnancy registers of ASMs that has been established around the world. Although the APR and other registries have contributed to knowledge gain that has been applied to decrease adverse pregnancy outcomes, their cost-effectiveness remains unknown. Here, we aimed to evaluate the economic impacts of the APR from both societal and health care system perspectives.

METHODS

Using decision analytic modeling, we estimated the effectiveness (prevention of adverse pregnancy outcomes) and costs (costs of adverse pregnancy outcomes and the register itself) of the APR over a 20-year time horizon (2000-2019). The comparator was set as the adverse pregnancy outcomes collected by the APR between 1998 and 2002 (i.e., no APR derived improvements in care). In the scenario analysis, we conservatively assumed a 2.5% and 5% contribution of the APR to the savings in health care and societal costs. Adverse pregnancy outcomes included stillbirth, birth defects, and induced abortion. All cost data were derived from published sources. Health and economic outcomes were extrapolated to the total target Australian epilepsy population. The primary outcomes of interest were the return of investment (ROI) for the APR and incremental cost-effectiveness ratio (ICER) for cost per adverse outcome avoided.

RESULTS

Over the 20-year time horizon, the ROI from the APR from a societal perspective was Australian dollars (AUD) 2,250 (i.e., every dollar spent on the program resulted in a return of AUD2,250). Over this time, it was estimated that 9,609 adverse pregnancy outcomes were avoided, and health care and societal costs were reduced by AUD 191 million and AUD 9.0 billion, respectively. Hence, from a health economic point of view, the APR was dominant, providing cost saving ICERs from both perspectives.

DISCUSSION

Following its inception 20+ years ago, the APR has represented excellent value for investment for Australia, being also health-saving and cost saving from a societal and a health care perspective. With the growing number of marketed ASMs, the APR is expected to continue to have a major impact in the foreseeable future.

Seizure control in successive pregnancies in Australian women with epilepsy

OBJECTIVES

To investigate control of epileptic seizures during pairs of successive pregnancies in antiseizure medication (ASM)-treated women with epilepsy.

MATERIALS AND METHODS

Analysis of seizure freedom rates during 436 pairs of successive pregnancies in Australian women with epilepsy, in nearly all instances long-standing epilepsy.

RESULT

There was a higher rate of seizure-free second pregnancies compared with first paired pregnancies (63.1% vs. 51.4%; Relative Risk (R.R.) = 1.2277; 95% CI 1.0930, 1.3789) and of seizure-free pre-pregnancy years before second as compared with first paired pregnancies in the same women (63.6% vs. 52.4%; R.R. = 1.2616; 95% CI 1.1337, 1.4040). In 108 women whose ASM therapy was unaltered throughout both of their pregnancies, the seizure-freedom rate was higher in the second of the paired pregnancies (82.4% vs. 69.4%; R.R. = 1.1867, 95% CI 1.0189, 1.3821).

CONCLUSIONS

Altered ASM therapy after the first of a pair of successive pregnancies did not fully account for the better overall seizure control in the corresponding second pregnancies. Some additional factor may have been in operation, possibly a greater preparedness to undertake a further pregnancy if seizures were already fully controlled.