Nausea and vomiting is a common complication of pregnancy and occurs in 70-80% of all pregnancies. The symptoms usually start 2-4 weeks after fertilization and peak between the 9th and 16th week of gestation. In the 22nd week of pregnancy, the symptoms usually resolve. In up to 10% of all pregnancies nausea and vomiting may persist until delivery, which is called emesis gravidarum. In 0.3-2% of all pregnancies, nausea and vomiting occur with a pathological intensity called hyperemesis gravidarum. The cause of nausea and vomiting during pregnancy is unknown, but it is believed that the stimulus is the placenta and not the fetus. Antihistamines have proven to be an effective therapy. Histamine is increasingly produced during pregnancy by mast cells in the endometrium and myometrium, but also by mast cells in the placenta and in the decidua. High expression of the histamine-producing enzyme histamine-decarboxylase (HDC) in the placenta and many histamine receptors at the feto-maternal transition in the decidua indicate a physiological role of the histamine during pregnancy. The antidote is diamine oxidase (DAO), which is produced in the decidua and trophoblast and breaks down histamine. DAO acts as a barrier to prevent excessive passage of histamine into the maternal and fetal circulation. DAO levels increase exponentially in the first 20 weeks of pregnancy to 1000 times the baseline before pregnancy. It has been shown that intravenous vitamin C significantly reduces blood histamine levels in both allergic and non-allergic disorders. Another study with the German Navy also proved that oral vitamin C administration can reduce nausea in seasickness. In an Australian study in 2016, it was shown that chewing gum was not inferior to ondansetron therapy in patients with postoperative nausea and vomiting (PONV). From the available literature, we conclude that high maternal histamine concentrations in early pregnancy may be a cause of nausea and vomiting, whereas DAO is not sufficiently expressed by the transfer of histamine from the decidua and trophoblast into the maternal circulation prevent. Vitamin C has been identified in controlled clinical trials as a way to lower blood histamine levels. Furthermore, chewing gum was already described as a treatment option for nausea and vomiting. The aim of this study is therefore to test whether chewing gum containing vitamin C in pregnant women with emesis gravidarum has the potential to reduce nausea and vomiting and to evaluate a possible association between maternal human chorionic gonadotropin (hCG) or histamine levels and the severity of nausea and vomiting in early pregnancy as well as the influence of other factors such as thyroxine and pyridoxine.
Age range
18 Years
Sex
FEMALE
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Modified PUQE (Pregnancy-Unique Quantification of Emesis and Nausea) Score
Timeframe: 1 month