Fetal growth and premature delivery in pregnant women on antiepileptic drugs.

OBJECTIVE: To evaluate the effects of epilepsy and antiepileptic drugs (AEDs) used during pregnancy on fetal growth and preterm delivery. METHODS: This study included singleton liveborn infants born to women enrolled in the North American Antiepileptic Drug Pregnancy Registry between 1997 and 2016. Data were collected prospectively through telephone interviews. The prevalence of preterm birth (<37 weeks) and small for gestational age status (SGA) among infants exposed prenatally to AEDs when used by women with epilepsy (WWE) or women without epilepsy (WWOE) was compared with that among infants unexposed to AEDs and born to WWOE. Multivariate log-binomial regression models were used to estimate relative risks (RRs) and 95% confidence intervals (CIs). RESULTS: The study population included infants born to 6,777 AED-WWE, 696 AED-WWOE, and 486 no-AED-WWOE. The risk of prematurity was 6.2% for no-AED-WWOE, 9.3% for AED-WWE (RR = 1.5, 95% CI = 1.0-2.1), and 10.5% for AED-WWOE (RR = 1.5, 95% CI = 1.0-2.4). Prenatal exposure to AEDs in WWE and WWOE was associated with a mean lower birth weight of 110 and 136g, respectively, as compared to no-AED-WWOE. The prevalence of SGA was 5.0% for no-AED-WWOE, 10.9% for AED-WWE (RR = 2.0, 95% CI = 1.3-3.0), and 11.0% for AED-WWOE (RR = 1.9, 95% CI = 1.2-2.9). Within users of AEDs in monotherapy, the prevalence of SGA ranged from 7.3% for lamotrigine to 18.5% for topiramate. INTERPRETATION: Women on AEDs during pregnancy, whether for epilepsy or for other neuropsychiatric indications, are at a higher risk of delivering prematurely and giving birth to SGA newborns. The risk may vary by drug. Ann Neurol 2017;82:457-465.

Advantages and problems with pregnancy registries: observations and surprises throughout the life of the International Lamotrigine Pregnancy Registry.

PURPOSE: The International Lamotrigine Pregnancy Registry monitored for a signal of a substantial increase in the frequency of major congenital malformations associated with lamotrigine exposures in pregnancy over an 18-year period. Key methodological lessons are discussed. METHODS: The strengths and weaknesses of the Registry were assessed using quantifiable methodological and operational parameters including enrollment, completeness of exposure and outcome data reporting, and lost to follow-up. The choice of comparator groups and stopping rules for registry closure were critically evaluated. RESULTS: The reliance on voluntary reporting was associated with a clustered geographical distribution of registered pregnancies. The enrollment rate increased over time with new approvals and indications for lamotrigine and publication of interim data. Reporter burden was minimized through a streamlined data collection approach resulting in a high level of completeness of exposure and primary outcome data. Lost to follow-up rates were high (28.5% overall) representing a major limitation; incentives to increase the completeness of reporting failed to reduce rates. A lack of an internal comparator group complicated data interpretation; but external comparisons with multiple external groups allowed an assessment of consistency of outcome data across multiple data sources. A lack of a priori closure criteria prolonged the life of the Registry, and consideration of regulatory guidelines on this subject is encouraged at the time of conception of future registries. CONCLUSIONS: A successful pregnancy exposure registry requires ongoing flexibility and continuous re-assessment of enrollment, recruitment, and retention methods and the availability of comparison data, throughout its lifecycle.

Ascertainment of malformations in pregnancy registries: Lessons learned in the North American AED Pregnancy Registry.

BACKGROUND: Pregnancy registries, designed to assess the safety of medications and vaccines for the exposed mother and fetus, have been developed since the 1990s. Malformations present in the exposed liveborn or stillborn infant or fetuses in elective terminations are the outcome of greatest concern. The experiences of the North American AED (antiepileptic drug) Pregnancy Registry (NAAPR) can be used to identify the challenges and limitations of a pregnancy registry in identifying congenital malformations. METHODS: The NAAPR enrolls pregnant women who are taking one or more AEDs for any medical condition, but primarily to prevent seizures, and an unexposed comparison group. Participants are interviewed by clinical research coordinators (CRCs) at enrollment, later in pregnancy and postpartum. Malformations are identified in the mother's reports and her infant's medical records through age 12 weeks. A teratologist, blinded to exposure status, evaluates each potential malformation identified. RESULTS: Among 10,982 pregnancies enrolled between 1997 and 2022, 282 malformations were identified in the 9677 AED-exposed and 15 among the 1305 unexposed infants. Isolated malformations, such as cleft palate, accounted for 84% of the malformations identified. Increased frequencies of oral clefts and myelomeningocele were associated with exposure to several different AEDs. Copies of reports from many diagnostic studies were not obtained and very few pregnancy losses had autopsies. CONCLUSIONS: The evaluation of the AED-exposed infants in a pregnancy registry is indirect. Improvements rely on the rapport established with the mothers by the CRCs and the mothers' willingness to assist in obtaining information from her infants' physicians.

Risks and management of pregnancy in women with epilepsy.

Most women with epilepsy today can conceive and bear normal, healthy children, but their pregnancies present an increased risk for complications. Pregnancy can exacerbate seizure frequency in some women with epilepsy, and both maternal epilepsy and in utero exposure to antiepileptic drugs can increase the risk of adverse outcomes in children born to women with epilepsy. These outcomes include fetal loss and perinatal death, congenital malformations and anomalies, neonatal hemorrhage, low birth weight, developmental delay, and childhood epilepsy. After reviewing these risks, this article concludes with practical recommendations for reducing these risks and optimizing the management of pregnant women with epilepsy.

Association between topiramate and zonisamide use during pregnancy and low birth weight.

OBJECTIVE: To assess the possible effects of topiramate and zonisamide use during pregnancy on fetal growth. METHODS: The study population was the singleton liveborns born to women who enrolled in the North American Antiepileptic Drug Pregnancy Registry between 1997 and 2012. Data were collected through telephone interviews at enrollment, 7 months of gestation, and postpartum. The prevalence of small for gestational age at birth among neonates exposed to topiramate and to zonisamide when either was used as monotherapy during pregnancy was compared with that among neonates exposed to lamotrigine monotherapy, a weight-neutral therapy, and the most common antiepileptic drug in the Registry. Relative risks (RRs) and 95% confidence intervals (CIs) were estimated with multivariable log-binomial regression to control for potential confounders. RESULTS: Data were available for 347 topiramate, 98 zonisamide, and 1,581 lamotrigine-exposed neonates. The mean gestational length was 39 weeks for all comparison groups. Prenatal exposure to topiramate or zonisamide was associated with a mean lower birth weight of 221 and 202 g, respectively, and a mean lesser neonatal length of 1 cm as compared with lamotrigine exposure (p<.01). The prevalence of small for gestational age was 6.8% for lamotrigine, 17.9% for topiramate (RR 2.4, 95% CI 1.8-3.3) and 12.2% for zonisamide (RR 1.6, 0.9-2.8). Similar results were found when a group of 457 unexposed neonates was used as the reference. CONCLUSIONS: Topiramate and zonisamide have been shown to reduce weight in adults. Our finding of a decrease in mean birth weight and length among neonates exposed in utero raises concern. LEVEL OF EVIDENCE: II.

Teratogenicity and antiepileptic drugs: potential mechanisms.

Congenital malformations often the most concerning risk of taking antiepileptic drugs (AEDs) during pregnancy for both the patient and the physician. This chapter reviews aspects of the association between AEDs and congenital malformations, including a historical perspective, type and patterns of congenital malformations, possible confounding factors, and potential mechanisms of teratogenicity. The role of folic acid in preventing birth defects in the general population and in setting of taking AEDs is also presented. One of the most serious congenital malformations, spina bifida (SB), and its association with intrauterine valproate exposure, is discussed in depth.

Clinical care of pregnant women with epilepsy: neural tube defects and folic acid supplementation.

Women with epilepsy (WWE) have a risk of bearing children with congenital malformations that is approximately twice that of the general population. Most antiepileptic drugs (AEDs) have been associated with such risk. Valproate and carbamazepine have been associated specifically with the development of neural tube defects (NTDs), especially spina bifida. Other factors may contribute to the risk, including concomitant diseases such as diabetes mellitus, occupational exposure to teratogens, excessive prepregnancy weight, and various nutrient deficiencies. In the general population, maternal folate deficiency, in particular, has been linked with the development of NTDs, and periconceptional folate supplementation with a reduction of risk. It is unclear whether folate supplementation has a comparable protective effect for WWE. Data concerning the risk for congenital malformations associated with the newer AEDs (gabapentin, felbamate, lamotrigine, levetiracetam, oxcarbazepine, tiagabine, topiramate, and zonisamide) are still limited. Several pregnancy registries for women taking AEDs have been established. Comprehensive postmarketing surveillance, regionally or nationally, might be the ideal method of monitoring medication safety, but government support for such an undertaking has for the most part been lacking. Despite uncertainty about the efficacy of periconceptional folate supplementation in WWE, these women should receive such supplementation at dosage levels recommended for the general population of women of childbearing age. Seizure control must not be neglected in a pregnant woman with epilepsy since seizures are associated with harm to the fetus as well as the mother. Risk may be minimized by using a single AED at the lowest effective dosage.

Management issues for women with epilepsy: neural tube defects and folic acid supplementation.

For infants exposed to antiepileptic drugs (AEDs) in utero, the risk for congenital malformations is approximately 4 to 6%, twice the rate reported in the general population. A variety of malformations have been reported in association with prenatal exposure to AEDs. However, a particular association of valproate and carbamazepine with neural tube defects (NTDs)--specifically, with spina bifida aperta (SB)--has been identified. The prevalence of SB is approximately 1 to 2% with valproate exposure and 0.5% with carbamazepine. Reported risk factors for NTDs include previous pregnancy with an NTD, maternal insulin-dependent diabetes mellitus, various nutritional deficiencies and occupational exposures, and high prepregnancy weight. Deficiencies of folate have been implicated in the development of birth defects, including NTDs. The value of periconceptional folic acid supplementation for women in the general population is accepted. However, it is unclear whether folic acid supplementation protects against the embryotoxic and teratogenic effects of AEDs because animal and human studies and case reports have shown variable results. Nevertheless, folic acid supplementation is recommended for women with epilepsy as it is for other women of childbearing age. Even with supplementary folic acid, women taking valproate or carbamazepine should undergo perinatal diagnostic ultrasound to rule out NTDs.