The links between maternal histamine levels and complications of human pregnancy.

Previous literature published since 1910 on maternal blood histamine levels and complications of pregnancy have been reviewed, showing links between hyper-histaminemia occurring in specific gestational complications including preeclampsia, spontaneous abortion, preterm labour and hyperemesis gravidarum. These complications may present with symptoms similar to those of experimentally induced high blood histamine or hyper-histaminemia in non-pregnant humans. Maternal levels of histamine in normal pregnancy decrease below values found in healthy non-pregnant women. However, in some complications of pregnancy, maternal blood histamine levels rise above those associated with normal pregnancy and may exceed normal non-pregnant circulating levels. These links between circulating maternal histamine levels and specific complications of human pregnancy suggest that further investigations to evaluate the outcome of managing maternal blood histamine levels during such complications may be warranted.