We report a case of unexpected severe hypertriglyceridemia (140N) diagnosed at 33 weeks during a second gestation. The risk of acute pancreatitis indicated plasmapheresis (three procedures) with reduction of hypertriglyceridemia (6N) and no impact on fetal well-being. Immediate recurrence led to induction of labour at 34 weeks. Spontaneous regression occurred after delivery. We demonstrated reduced lipoprotein lipase activity with no mutation for apolipoprotein E, nor lipoprotein lipase in favour of a potential pregnancy-induced inhibitor of lipoprotein degradation.