Hyperemesis gravidarum: when nausea becomes dangerous

Hyperemesis gravidarum, which causes severe nausea and vomiting, affects about 3% of pregnancies and is responsible for many hospital admissions .

Up until the 1950s, when intravenous hydration was introduced,   it was a leading cause of pregnancy deaths . It is now the second leading cause of hospitalizations during pregnancy, after the risk of preterm birth.

How does hyperemesis gravidarum differ from normal nausea?

Symptoms of hyperemesis gravidarum can include:

• extreme nausea and vomiting
• rapid weight loss
• dehydration
• electrolyte imbalance
• dizziness
• excessive salivation

Some women, in severe cases, may start vomiting blood or bile and may require intravenous hydration and medication.

Hyperemesis gravidarum isn’t controlled with small meals and munching on crackers like ordinary nausea, and it can last longer than the typical first trimester of pregnancy.

The symptoms can be very strong and therefore it is recommended to consult a doctor as soon as you suspect that you suffer from this pathology.

How is hyperemesis gravidarum treated?

It is difficult to find information on the safety of drugs that can treat hyperemesis gravidarum. In part this is due to the disaster of thalidomide which was prescribed in the 1950s to women with hyperemesis to relieve nausea. Thalidomide taken during pregnancy caused limb deformities in children.

This has obviously caused difficulties in developing and testing the drugs on pregnant women.

From the limited data available it has been seen that Ondansetron (Zofran) is effective in the treatment of the symptoms of hyperemesis in over 50 percent of the women who have undergone the treatment. Side effects , such as bowel obstruction , are rare and recent research has found no link to birth defects in the newborn .

However, it is known for certain that women with hyperemesis gravidarum who are losing weight and who are unable to tolerate food and vitamins for more than a week should be treated not only with intravenous fluids, but also with thiamine to avoid the rare but avoidable occurrence of Wernicke’s encephalopathy.

You need to know the cause in order to treat it

It is not yet known what causes hyperemesis gravidarum and for this reason a safe and effective treatment for all has not been found at the moment.

Currently, the main hypothesis is that pregnancy hormones cause nausea and vomiting, together with genetic and environmental factors that transform normal nausea into hyperemesis.

The genetic component is increasingly gaining ground as a hypothesis of cause. If a woman suffers from hyperemesis gravidarum during pregnancy, there is an approximately 80 percent risk of recurrence in a subsequent pregnancy. The greatest risk factor for hyperemesis gravidarum (besides having a previous pregnancy with hyperemesis) is having a sister who has had hyperemesis, which constitutes a 17-fold increased risk .

Once the biological and genetic causes associated with hyperemesis are identified, further research will be needed to develop therapies that target the causes of the condition.

The effects on the fetus

There are studies that have shown that malnutrition in early pregnancy can be linked to long-term health problems in the fetus.

Children exposed to hyperemesis gravidarum in utero have a 3-fold increased risk of neurodevelopmental delay.

There is a 4-fold increased risk of preterm birth and a 3.6-fold increased likelihood for women with hyperemesis to experience emotional disorders such as depression and anxiety.

The effects of hyperemesis gravidarum can also last long after birth . In fact, there is an increased risk of suffering from chronic postpartum disorders such as reflux, anxiety, depression, insomnia, fatigue and muscle pain, and many show all the symptoms of post-traumatic stress .

Hyperemesis gravidarum can also lead to Wernicke encephalopathy (WE), a serious neurological condition caused by a deficiency of thiamine (vitamin B1). A dozen cases were published in the medical literature between 2012-2014 , and recent maternal deaths caused by complications of hyperemesis (including Wernicke’s encephalopathy) have been documented in the United States, England and Africa .

A condition therefore that should not be underestimated at all.

In a survey of 800 women with hyperemesis, one in 7 women decided to terminate their pregnancy  because they saw no hope of relief from the condition.