Methylmercury (MeHg) exposure poses significant risks, especially for pregnant women in Indonesia, where fish consumption is a common dietary habit. This study used a physiologically based toxicokinetic model and reverse dosimetry to estimate MeHg exposure levels and assess health risks in pregnant Indonesian women. The model was validated against biomarker data, with observed MeHg blood levels of 1.69 µg/L and 0.8 µg/L. The results from reverse dosimetry estimated a mean daily MeHg intake of 2.88 µg/day. Sensitivity analysis identified clearance rates and volume of distribution as key factors influencing MeHg levels in maternal and fetal compartments. The majority of the population had a hazard quotient below one, indicating safe exposure levels, however, a subset exceeded this threshold, indicating potential health risks. The study emphasizes the need for continuous monitoring and risk management strategies to reduce MeHg exposure in sensitive populations, particularly pregnant women.