Hormone changes Pathophysiology of vomiting in pregnancy * An increase in the circulating level of the hormone estrogen. However, there is no consistent evidence of differences in estrogen levels and levels of bilirubin between women that experience sickness and those that do not. Related to increased estrogen levels, a similar form of nausea is also seen in some women who use hormonal contraception or hormone replacement therapy. * An increase in progesterone relaxes the muscles in the uterus, which prevents early childbirth, but may also relax the stomach and intestines, leading to excess stomach acids and gastroesophageal reflux disease (GERD). * An increase in human chorionic gonadotropin. It is probably not the HCG itself that causes the nausea. More likely, it is the HCG stimulating the maternal ovaries to secrete estrogen, which in turn causes the nausea. Defense mechanism<unk>  may be an evolved trait that protects the fetus against toxins ingested by the mother. Evidence in support of this theory includes: *<unk>  is very common among pregnant women, which argues in favor of its being a functional adaptation and against the idea that it is a pathology. * Fetal vulnerability to toxins peaks at around 3 months, which is also the time of peak susceptibility to<unk> . * There is a good correlation between toxin concentrations in foods, and the tastes and odors that cause revulsion. Women who have no<unk>  are more likely to miscarry. This may be because such women are more likely to ingest substances that are harmful to the fetus. In addition to protecting the fetus,<unk>  may also protect the mother. A pregnant woman's immune system is suppressed during pregnancy, presumably to reduce the chances of rejecting tissues of her own offspring. Because of this, animal products containing parasites and harmful bacteria can be especially dangerous to pregnant women. There is evidence that<unk>  is often triggered by animal products including meat and fish. If<unk>  is a defense mechanism against the ingestion of toxins, the prescribing of anti-nausea medication to pregnant women may have the undesired side effect of causing birth defects or miscarriages by encouraging harmful dietary choices. Also<unk>  is a defense mechanism because when analyzing embryonic growth, several critical periods are identified in which there is mass proliferation and cell division resulting in the development of the heart and central nervous system that are very sensitive. In that period, the fetus is most at risk from damage to toxins and mutagens. These developments occur through week 6-18 which is in the same time frame in which the most nausea and vomiting of pregnancy (NVP) occurs. This relationship between the time at which the embryo is most susceptible to toxins lines up exactly with when the most severe NVP symptoms are seen, suggesting that this NVP is an evolutionary response developed in the mother, to indicate the sensitivity of the fetus hence making her wary to her health and in turn protecting the fetus.
Morning sickness
Q fever
Ski sickness
Relapsing fever
Brain fever
Fever of unknown origin
Enterotoxemia
Heat illness