Ketones are substances that are found in the blood when the body starts to use protein for energy, as opposed to carbohydrates. They are an indicator that the body is short of sugar.
A woman suffering from severe morning sickness will often have ketones in her urine, primarily because she is unable to digest enough carbohydrate to prevent the body from using protein for energy.
Additionally, if a woman is in labour with ketones in her blood, she is likely to feel sick and shaky, and it can slow her labour down. For this reason, a glucose drip may be used if ketones are present.
Ketones are detected via a simple urine test, which is a standard check that all midwives carry out at a woman's prenatal checks. If ketones are present, they will be entered as 'trace' on a woman's notes, or '+' if small amounts are detected.
To counteract the presence of ketones, the woman will be advised to eat as regularly as possible to prevent the body from taking energy from the wrong reserves. Women who simply cannot digest food due to pregnancy sickness may be offered intravenous fluids if her condition is particularly severe.
The levels of ketones in a woman's blood are closely monitored throughout pregnancy as, when found in combination with sugar, this can be a sign of diabetes.