Reduction of the teratogenic effects of phenytoin by folic acid and a mixture of folic acid, vitamins, and amino acids: a preliminary trial

Serum NGF levels may be associated with intrauterine antiepileptic exposure-related developmental problems

OBJECTIVE

It has been shown that maternal epilepsy and antiepileptic drug use during pregnancy have adverse developmental outcomes in children. The aim of this study was to investigate the developmental outcomes of maternal epilepsy and prenatal antiepileptic exposure. We also looked for the associations between serum levels of glial cell-derived neurotrophic factor (GDNF) and nerve growth factor (NGF) and developmental outcomes.

METHODS

This is a retrospective, nonrandomized, case-controlled study. Fifty-three children aged two to six years old with maternal epilepsy were included in the case group. Fifty-three age- and gender-matched children without maternal epilepsy were included in the control group. Developmental assessment was conducted using the Denver II Developmental Screening Test (DDST-II). Serum levels of NGF and GDNF were measured using an enzyme-linked immunosorbent assay (ELISA) kit.

RESULTS

Multiple regression analysis revealed that prenatal antiepileptic exposure was significantly associated with lower global developmental scores (B = -7.5, confidence interval (CI): -13.1; -1.9, p = 0.009) while periconceptional folate use was associated with a reduced risk for adverse developmental outcomes (B = 6.6, CI: 0.91; 12.3, p = 0.024). Children with prenatal antiepileptic exposure are at increased risk for global developmental delay (GDD) particularly for language domain (p = 0.018). We found a statistically significant positive correlation between NGF levels and global developmental scores (r = 0.302, p = 0.009). Serum levels of GDNF in children with maternal epilepsy were significantly lower than the children without maternal epilepsy (p = 0.025).

CONCLUSIONS

Prenatal antiepileptic exposure was related with the increased risk of GDD while periconceptional folate use was related with lower risk. Clinicians should inform all women in reproductive age with epilepsy about the possible benefits and risks of antiepileptic drug use during a possible pregnancy. Periconceptional folate use has protective effect on child development, and all women on antiepileptic drugs should be encouraged for periconceptional folate use. Serum NGF levels may be a promising biomarker for monitoring global development delay in at-risk population.

Folic acid prevents congenital malformations in the offspring of diabetic mice

It is well known that maternal diabetes causes various congenital malformations. Although there are many reports that folic acid (FA) administration in pregnancy reduces the risk of birth defects including neural tube defects (NTDs), a precise analysis on the preventive effect of FA against diabetic embryopathy has not been done yet. In this study, we analyzed the preventive effects of FA on congenital malformations including NTDs, cardiovascular, and skeletal malformations using a diabetic mouse model. Female mice were rendered hyperglycemic by streptozotocin and then mated. Pregnant diabetic mice were treated daily with FA (3 mg/kg body weight) or saline between gestational days (GD) 6 and 10. On GD 18, fetuses were examined for congenital malformations. FA did not affect plasma glucose levels. In the DM control group, the incidence of NTDs, cardiovascular, and skeletal malformations was 28.4%, 28.5%, and 29.7%, respectively. In the FA-treated group, the corresponding proportions reduced to 6.0%, 2.5% and 12.5%, respectively. A whole-mount TUNEL revealed an increased apoptosis in the hindbrain region of embryos from DM control group on day 9.5, and the apoptosis was decreased by FA treatment. Maternal plasma homocysteine levels on GD 9.5 were significantly lowered in DM control group compared with those in non-DM group, and FA treatment did not show a significant effect. These results indicate that FA is effective for the prevention of various diabetic embryopathy including NTDs, cardiovascular, and skeletal malformations, and suggested that this effect is independent from homocysteine metabolism and possibly mediated by decreasing the abnormal apoptosis during organogenesis.

Efavirenz use during pregnancy and for women of child-bearing potential

BACKGROUND

Efavirenz is the preferred non-nucleoside reverse transcriptase inhibitor for first-line antiretroviral treatment in many countries. For women of childbearing potential, advantages of efavirenz are balanced by concerns that it is teratogenic. This paper reviews evidence of efavirenz teratogenicity and considers implications in common clinical scenarios.

FINDINGS

Concerns of efavirenz-induced fetal effects stem from animal studies, although the predictive value of animal data for humans is unknown. Four retrospective cases of central nervous system birth defects in infants with first trimester exposure to efavirenz have been interpreted as being consistent with animal data. In a prospective pregnancy registry, which is subject to fewer potential biases, no increase was detected in overall risk of birth defects following exposure to efavirenz in the first-trimester.

DISCUSSION

For women planning a pregnancy or not using contraception, efavirenz should be avoided if alternatives are available. According to WHO guidelines for resource-constrained settings, benefits of efavirenz are likely to outweigh risks for women using contraception. Women who become pregnant while receiving efavirenz often consider drug substitution or temporarily suspending treatment. Both options have substantial risks for maternal and fetal health which, we argue, appear unjustified after the critical period of organogenesis (3-8 weeks post-conception). Efavirenz-based triple regimens, initiated after the first trimester of pregnancy and discontinued after childbirth, are potentially an important alternative for reducing mother-to-child transmission in pregnant women who do not yet require antiretroviral treatment.

CONCLUSION

Current recommendations for care for women who become pregnant while receiving efavirenz may need to be re-considered, particularly in settings with limited alternative drugs and laboratory monitoring. With current data limitations, additional adequately powered prospective studies are needed.

Effects of Seizures and Their Treatment on Fetal Brain

PURPOSE

To describe the effects of pregnancy on seizures, the effects of seizures during pregnancy on the fetus, and the effects of antiepileptic drugs (AEDs) on fetal brain and development.

METHODS

The available literature was reviewed and summarized.

RESULTS

There is a paucity of prospective studies. Retrospective studies indicate that, during pregnancy, alterations in seizure frequency can occur in an unpredictable fashion. Generalized tonic-clonic seizures may have adverse effects on the fetus. It is unclear whether complex partial seizures or absence seizures have negative consequences. AEDs may have potentially detrimental effects on the fetus and its subsequent development, but the full spectrum and clinical significance are under investigation. Monotherapy is strongly encouraged.

CONCLUSIONS

Dealing with the pregnant epileptic patient is a difficult and challenging task. Although there are several risks for the mother and the fetus, most epileptic women bear normal, healthy children.

Neurodevelopmental effects of antiepileptic drugs

Although the vast majority of children born to women with epilepsy are normal, these children are at increased risk for both anatomic and cognitive impairments. Current evidence suggests that the defects are the result of in utero antiepileptic drug (AED) exposure combined with a genetic predispositon. However, the exact mechanisms underlying these effects remain to be delineated. AED polytherapy increases the risk, but it remains uncertain if specific AEDs pose an overall greater threat. Most women with epilepsy cannot avoid AEDs during pregnancy because of the greater risks posed by seizures to the mother and fetus. Therefore, current recommendations emphasize definitive diagnosis and the use of AED monotherapy at the lowest effective dose if treatment is indicated. Prenatal folate and multivitamins should also be given routinely to women of childbearing age who require AED therapy.

Drug and environmental factors associated with adverse pregnancy outcomes. Part II: Improvement with folic acid

OBJECTIVE

To provide a comprehensive review of periconceptional folic acid supplementation and factors affecting folate supplementation trials.

DATA SOURCES

A MEDLINE search was conducted through December 1997. Additional sources were obtained from Current Contents and citations from the references obtained. Search terms included folate, folic acid, neural tube defect, spina bifida, and anencephaly.

STUDY SELECTION

Relevant animal and human studies examining the effects of folate were reviewed.

DATA EXTRACTION

Data collected included: type of study, folate dosing, dietary folate intake, serum and red blood cell folate concentrations, type of defect(s) studied, vitamin usage, parental risk factors, factors affecting trial results.

DATA SYNTHESIS

Nine key factors have been identified that affect outcomes of folic acid supplementation trials. Daily doses of 0.8 mg decreased the occurrence and doses of 4 mg decreased the recurrence of neural tube defects in randomized clinical trials. Since lower folic acid doses were effective in nonrandomized trials, research is needed to determine the lowest effective dosage. Other benefits involving pregnancy outcome are suggested.

CONCLUSIONS

Women of childbearing age should take a daily folic acid supplement to reduce the risk of pregnancies resulting in infants with a neural tube defect and other potential adverse pregnancy outcomes. Further health benefits from folic acid supplementation are reviewed in Part III of this series.

Folic acid improves phenytoin pharmacokinetics

Phenytoin (PHT) therapy to control seizures decreases serum folate levels in half of epileptic patients, thus increasing the risk of folate depletion. Supplementation with folic acid prevents deficiency but also changes PHT pharmacokinetics. Kinetic monitoring of PHT when folic acid is provided as a supplement has not been reported in women of child-bearing age. This study of six fertile women examined the interdependence of PHT and folic acid in a randomized crossover study of two treatments: treatment 1 consisted of 300 mg sodium PHT per day and treatment 2 consisted of 300 mg sodium PHT plus 1 mg folic acid per day. Dietary folic acid intake was calculated daily. During treatment 1, serum folate level decreased 38.0 +/- 18.6% (mean +/- standard deviation) and serum PHT concentration was in the low therapeutic range (43.92 +/- 14.52 mumol/L). During treatment 2, serum folate level increased 26.0 +/- 33.4%, and serum PHT level (39.04 +/- 14.16 mumol/L) was similar to that in treatment 1. Only one subject attained PHT steady state during treatment 1, but four subjects achieved steady state during treatment 2. Dietary folate intakes during treatments 1 and 2 were not significantly different. This study suggests an interdependence between PHT and folic acid and supports the observation that fertile women treated with PHT require folic acid supplementation to maintain a normal serum folate level.

Serum folic acid levels in epileptic mothers and their relationship to congenital malformations

Folic acid levels during pregnancy and in pre-pregnancy were determined in 51 epileptic mothers and those of matched controls. The serum folic acid (SF) levels of epileptic mothers were significantly lower than those of controls in all study periods. The SF levels of mothers of malformed offspring were significantly lower than those of mothers of normal offspring in the 1st and 2nd trimesters of pregnancy. These results suggest that SF concentrations are implicated in congenital malformations in the offspring of epileptic mothers.