Is methylmethacrylate toxic during pregnancy and breastfeeding?--- a systematic review

Introduction: Methyl methacrylate (MMA) is commonly used in the fields of dentistry and orthopaedic surgery. However, there remain concerns for the occupational hazards of MMA, particularly during pregnancy and breastfeeding. Methods: We performed a systematic review of studies on effects that MMA may have in pregnancy in the context of exposure during orthopaedic surgery and dentistry. Review articles, studies lacking statistical data, single case reports and other evidence level V studies were excluded. Results: Nine studies were included. One basic science study demonstrated an increase in neuronal cell lysis and shrunken cell bodies when neocortical neurons were exposed to MMA monomer. Three animal studies exposed pregnant rodents to MMA via intraperitoneal injection or inhalation. Exposed fetuses in two studies had an increase in gross abnormalities such as hemangiomas, while there was no increase in teratologic effects in the third study. In dental workers exposed to MMA, two retrospective cohort studies did not find a statistically significant increase in birth defects or miscarriage. After exposure to MMA during total joint arthroplasty, two studies found that MMA levels were undetectable in the mothers’ serum or breast milk. One study measuring the airborne levels of MMA during simulated joint arthroplasty found that concentrations never exceeded 1% of the recommended limit set forth by the Occupational Safety and Health Administration (OSHA). Conclusions: Potential teratologic effects of MMA cannot be excluded by existing evidence. However, the typical MMA exposure levels for dental and orthopaedic personnel appear to be substantially less than currently proposed exposure limits.