All about Vomiting in Early Pregnancy & Hyperemesis Gravidarum!

Vomiting in early pregnancy, also known as the morning sickness is a common condition experienced by most pregnant women. As well as in medical practice, in many cultures, vomiting and nausea after a missed period is used as a sign of pregnancy and therefore is a normal phenomenon. However, when the vomiting becomes excessive requiring hospital admission and replacement of fluid in the hospital it is known as hyperemesis gravidarum or excessive vomiting in pregnancy.

Vomiting in pregnancy may be due to several causes. The early pregnancy itself is known to precipitate vomiting because of the high levels of human chorionic gonadotrophin (hCG), which is known to cause vomiting. The level of hCG may be higher than usual and therefore the twin pregnancy, vomiting more profuse in twin pregnancy and pre-eclampsia (a state where the blood pressure becomes high in pregnancy associated with loss of protein in urine). Many medical diseases can precipitate vomiting in pregnancy. The commonest causes include urinary tract infections, viral and bacterial gastroenteritis (infection of the bowels), hepatitis, diabetes mellitus and ketoacidosis and raised intracranial pressure (increased pressure within the skull – described in detail in the hub “Headache – When should you start worrying”). Certain supplements given in pregnancy (e.g. – iron tablets as ferrous sulphate) and most of the drugs prescribed for other illnesses can precipitate vomiting in pregnancy. In addition the rare but life threatening causes such as bowel obstruction and acute pancreatitis should always be thought about at least by a physician. In addition psychological problems and excessive stress experienced during the pregnancy may manifest as the physical symptom of vomiting.

Several mechanisms (pathophysiological processes) had been postulated to explain how vomiting occurs in early pregnancy. The most accepted mechanism is the high levels of hCG and oestrogen seen in early pregnancy. The one-way sphincter (valve) controlling the entry of food into the stomach from the oesophagus is said to become weaker in pregnancy due to high progesterone levels. Emptying of the stomach after a meal is also seen to be delayed due to the effect of progesterone. The pressure exerted by the pregnant uterus on the stomach may also contribute to vomiting.

Vomiting can lead to several complications in pregnancy. Due to the nausea and loss of appetite, pregnant women tend to eat less and due to this starvation there is a risk of developing a condition known as ketoacidosis which may be life threatening. Excessive vomiting can also lead to dehydration which can be as severe as a state of shock. Imbalances in the levels of sodium, potassium and acid-base imbalances may also occur, leading to various complications. The failure of the kidneys and the liver are also important to consider in severe vomiting and dehydration. The pregnant women may also complain of a numbness of the extremities which should be taken very seriously. This is due to a vitamin deficiency (thiamine – a vitamin of B complex) and if this is left without treatment can lead to confusion altered state of consciousness (Wernicke’s encephalopathy) which is reversible with treatment and state of psychosis (known as Korsocoff psychosis) which is irreversible.

Once admitted to a hospital the pregnant women should undergo a number of investigations including, dip-stick test for pregnancy (urinary hCG), urine full report and urine culture, urinary ketone bodies, random blood sugar level, level of electrolytes (sodium, potassium and chloride) in serum. An ultrasound scan may be necessary to exclude a twin pregnancy and t look for gestational trophoblastic disease (an abnormal pregnancy where there is no viable foetus but there are high levels of hCG in blood and a risk of progression to a state like cancer). Thyroid functions may be assessed due to the commonly associated hyperthyroidism (abnormally high activity of thyroid gland) with hypermemsis gravidarum. In addition, if there is suspicion plain radiograph (X-ray) of the abdomen may also be necessary to look for bowel obstruction.

A mother with excessive vomiting in pregnancy should be advised to strictly rest in a bed. Avoidance of certain items of food and smells that may induce vomiting may be necessary during this period. Intake of frequent and small meals may be helpful. The fluids lost with vomiting should be replaced with oral fluids (fluids taken via mouth). Intravenous fluids may be necessary if the oral fluid intake is not sufficient. An injection of thiamine is always warranted to prevent Wernicke’s encephalopathy and Korsocoff psychosis described above. If the vomiting becomes troublesome, antiemetic drugs can be used to alleviate vomiting including:

–      Maxalone (metaclopramide) 10mg intramuscular and intravenous infusions

–      Promethazine thecolate (Avamine / Phenagon) 25mg

–      Stematic (Proclorperazine) 25mg as a suppository

Other drugs that are shown to be useful include prednisolone, vitamin B6 (pyridoxine – known to reduce nausea). Acupuncture is seen to improve nausea and vomiting in some patients. In addition to the above treatment, reassurance of the mother and psychological support are known to be helpful in most of the instances. In case, if vomiting and dehydration becomes unresponsive (refractory) to regular treatment and extremely sever to a state which may be a threat to the life of the mother, termination of the pregnancy remains as the last option to save the life of the mother.

The first twelve weeks of pregnancy is crucial in the development of all the systems of the embryo. Any insult to the embryo within this period can lead to abnormalities in the foetus and the child later on. Vomiting in early pregnancy is said to occur as a protective mechanism avoiding intake of teratogenic substances (substances that may be harmful to the embryo) by the mother. However, excessive vomiting again can be harmful and should be managed properly so that the outcome of the pregnancy would be a healthy mother and a healthy baby.