From the FDA Drug Label
Use in Specific Populations 8. 1 Pregnancy Pregnancy Category C: There are no adequate and well-controlled studies in pregnant women. In nonclinical studies in mice, rats, and rabbits, gabapentin was developmentally toxic when administered to pregnant animals at doses similar to or lower than those used clinically. Gabapentin should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus When pregnant mice received oral doses of gabapentin (500 mg, 1000 mg, or 3000 mg/kg/day) during the period of organogenesis, embryo-fetal toxicity (increased incidences of skeletal variations) was observed at the two highest doses The no-effect dose for embryo-fetal developmental toxicity in mice was 500 mg/kg/day or approximately ½ of the maximum recommended human dose (MRHD) of 3600 mg/kg on a body surface area (mg/m2) basis In studies in which rats received oral doses of gabapentin (500 to 2000 mg/kg/day), during pregnancy, adverse effect on offspring development (increased incidences of hydroureter and/or hydronephrosis) were observed at all doses. The lowest effect dose for developmental toxicity in rats is approximately equal to the MRHD on a mg/m2 basis When pregnant rabbits were treated with gabapentin during the period of organogenesis, an increase in embryo-fetal mortality was observed at all doses tested (60 mg, 300 mg, or 1500 mg/kg). The lowest effect dose for embryo-fetal developmental toxicity in rabbits is less than the MRHD on a mg/m2 basis
Gabapentin use during pregnancy is not recommended unless the potential benefit justifies the potential risk to the fetus. The FDA drug label indicates that gabapentin has been shown to be developmentally toxic in nonclinical studies, and there are no adequate and well-controlled studies in pregnant women.
- Pregnancy Category C indicates that gabapentin should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.
- Developmental toxicity has been observed in mice, rats, and rabbits at doses similar to or lower than those used clinically.
- Embryo-fetal toxicity has been observed in mice and rats, and embryo-fetal mortality has been observed in rabbits.
- The clinical significance of these findings is unknown 1.
From the Research
Gabapentin should be used during pregnancy only when the potential benefits outweigh the risks, and only under close medical supervision. The most recent and highest quality study, published in 2024 2, suggests that prenatal exposure to gabapentin is associated with an increased risk of preterm birth, preeclampsia, small-for-gestational-age, and NICU admission. Another recent study, published in 2023 3, also raises concerns about the safety of gabapentin use during pregnancy, particularly with regards to the risk of congenital anomalies and neurodevelopmental outcomes.
Key considerations for the use of gabapentin during pregnancy include:
- The potential risks of birth defects, particularly neural tube defects, and neonatal complications
- The importance of close medical supervision and regular prenatal monitoring, including ultrasounds and possibly blood level monitoring of the medication
- The need to weigh the potential benefits of gabapentin use against the potential risks, particularly for women with epilepsy or other conditions that may require continued treatment during pregnancy
- The possibility of alternative medications with better safety profiles during pregnancy, which may be considered depending on the individual's condition and needs.
It is essential to note that the evidence on the safety of gabapentin use during pregnancy is not yet conclusive, and more research is needed to fully understand the potential risks and benefits. However, based on the current evidence, it is recommended that gabapentin be used during pregnancy with caution and only when necessary, and that women who are pregnant or planning to become pregnant should consult their healthcare provider to discuss the potential risks and benefits of gabapentin use in their individual situation 2, 3.