When hyperemesis gravidarum is severe and/or inadequately treated, it may result in:[1]
Symptoms can be aggravated by hunger, fatigue, prenatal vitamins (especially those containing iron), and diet.[4] Some women with hyperemesis gravidarum lose as much as 10% of their body weight.[5] Many sufferers of HG are extremely sensitive to odors in their environment; certain smells may exacerbate symptoms. This is known ashyperolfaction. Ptyalism, or hypersalivation, is another symptom experienced by some women suffering from HG.
Hyperemesis gravidarum tends to begin somewhat earlier in the pregnancy and last significantly longer than morning sickness. While most women will experience near-complete relief of morning sickness symptoms near the beginning of their second trimester, some sufferers of HG will experience severe symptoms until they give birth to their baby, and sometimes even after giving birth.[6]
Causes
While there are numerous theories regarding the cause of HG, the cause remains controversial. It is thought that HG is due to a combination of factors which may vary between women and include: genetics,[1] body chemistry, and overall health.[7]
One factor is an adverse reaction to the hormonal changes of pregnancy, in particular, elevated levels of beta human chorionic gonadotropin.[8][9] This theory would also explain why hyperemesis gravidarum is most frequently encountered in the first trimester (often around 8 – 12 weeks of gestation), as hCG levels are highest at that time and decline afterward. Another postulated cause of HG is an increase in maternal levels of estrogens (decreasing intestinal motility and gastric emptying leading to nausea/vomiting).[1]
Although the pathophysiology of HG is poorly understood, the most commonly accepted theory suggests that levels ofhCG are associated with it.[10] Leptin may also play a role.[11]