Related to increased estrogen levels, a similar form of nausea is also seen in some women who use hormonal contraception or hormone replacement therapy. The nausea can be mild or induce actual vomiting, however, not severe enough to cause metabolic derangement. In more severe cases, vomiting may cause dehydration, weight loss, alkalosis, and hypokalemia. This condition is known as hyperemesis gravidarum and occurs in about 1% of all pregnancies. Nausea and vomiting can be one of the first signs of pregnancy and usually begin around the 6th week of pregnancy (counting gestational age from 14 days before conception).