Abstract：
A pregnant female in her early 30s presented with cyanosis and oxygen saturation of 78%. She ingested isopropyl nitrate mistaking it for cannabidiol. Her arterial blood gas showed a methaemoglobin of >30% (outside the measuring range). She was treated with 120 mg of methylthioninium chloride (2 mg/kg) and symptoms improved. Her pregnancy progressed but was induced at 36 weeks because her child was small for gestational age. Methaemoglobinaemia is a rare presentation in pregnancy. There have been no reported cases of isopropyl nitrate-induced methaemoglobinaemia in pregnancy. Historically, intra-amniotic methylthioninium chloride was used in amniocentesis but use stopped after links to fetal malformations and neonatal death were made. There is no evidence outlining the risks of isopropyl nitrate in pregnancy and limited data on fetal effects from maternal exposure to intravenous methylthioninium chloride. This case adds to the evidence that treating methaemoglobinaemia may outweigh the risks of maternal exposure to methylthioninium chloride.
摘要：
一名30岁出头的怀孕女性表现为紫癜和78％的氧饱和度。她摄入了硝酸异丙酯，误认为是大麻二酚。她的动脉血气显示高铁血红蛋白>30％（超出测量范围）。她接受了120mg的甲基噻嗪（2mg/kg）治疗，症状得到改善。她的怀孕进展，但在36周时被诱导，因为她的孩子小于胎龄。高铁血红蛋白血症是妊娠期罕见的表现。在妊娠期间没有报告硝酸异丙酯诱导的高铁血红蛋白血症病例。历史上,羊膜腔内使用氯化甲基亚硫酸用于羊膜腔穿刺术,但在与胎儿畸形和新生儿死亡联系后停止使用.没有证据概述妊娠中硝酸异丙酯的风险，关于母体暴露于静脉注射甲基亚乙基氯化物对胎儿的影响的数据有限。这种情况增加了证据，表明治疗高铁血红蛋白血症可能超过母体暴露于氯化甲基亚硫的风险。
