ABSTRACT
In the early stages of pregnancy, nausea and vomiting are extremely common, aff ecting more than half of all pregnancies. HG represents the most extreme form of this condition. In HG, vomiting is persistent, resulting in more than 5% weight loss and ketosis. Electrolyte imbalances are also common. Th ese include low levels of magnesium, phosphate and potassium. Urea and creatinine levels may be raised and liver function tests (LFTs) may be grossly abnormal. However, jaundice is very uncommon. HG is thankfully uncommon, aff ecting about 0.5%–1% of pregnancies. In the patient discussed, due to a previous episode, the risk may unfortunately be as high as 15%. Th is is a distressing condition, usually leaving the pregnant woman exhausted and away from family and work. As was the case in her fi rst pregnancy, it can be quite diffi cult to treat, requiring treatments that may potentially harm the growing fetus. HG is associated with a transient hyperthyroidism. Th is may be due to thyroid stimulation by hCG, which has molecular similarities to TSH. Th is hyperthyroidism does not need treating and will normally resolve by the 18th week of the pregnancy. Higher levels of hCG, such as are found in multiple and molar pregnancy, are also associated with HG. Th e severity of symptoms seems to be related to higher levels of TSH and hCG.
