The nausea and vomiting that affects some pregnant women between the sixth and fourteenth weeks of pregnancy is called morning sickness (hyperemesis gravidarum), but it can occur at any time of the day. Its severity varies markedly, with about one third of pregnant women having no morning sickness, one half having it badly enough to vomit at least once, and in 5% the condition is serious enough result in prolonged bed rest or even hospitalisation, when it is called hyperemesis gravidarum.
Morning sickness is caused by the unusually high levels of oestrogen present in the mother’s bloodstream during the first three months of pregnancy. Although it usually ceases after about three months, it may persist for far longer in some unlucky women. Severe cases may be associated with twins, and it is usually worse in the first pregnancy.
Because morning sickness is a self-limiting condition, treatment is usually given only when absolutely necessary. A light diet, with small, frequent meals of dry fat-free foods, is often helpful. A concentrated carbohydrate solution (Emetrol) may be taken to help relieve the nausea. Supplements of vitamin B6 and ginger (either as pieces or capsules) have also been shown to help. Only in severe cases, and with some reluctance, will doctors prescribe more potent medications. In rare cases, fluids given by a drip into a vein are necessary for a woman hospitalised because of continued vomiting.
Morning sickness has no effect upon the development of the baby.