When the baby makes the mother sick: cause of morning sickness found

What exactly is hyperemesis gravidarum?
What causes excessive morning sickness?
What are the symptoms of hyperemesis gravidarum?
How many pregnant women are affected by excessive nausea?
Is hyperemesis gravidarum dangerous?
What use are the findings to those affected?

Breakthrough in study - When the baby makes the mother sick: cause of morning sickness found

Being pregnant is no walk in the park. Many expectant mothers struggle in the first few weeks in particular, as seven to eight out of ten women worldwide suffer from nausea and vomiting. Some of them even suffer so much that they can't keep a bite down for weeks, sometimes months. A prominent example: Kate Middleton. During all three pregnancies, the wife of the British Crown Prince was dependent on anti-nausea medication and was given fluids via a drip to combat dehydration.

Until now, not much could be done to combat this extreme form of morning sickness, also known as hyperemesis gravidarum (HD). This could now change. An international team of researchers claims to have found the cause of HG and gives hope for future treatment options.

What exactly is hyperemesis gravidarum?

Some expectant mothers are particularly affected by morning sickness. This extreme form is called hyperemesis gravidarum. Those affected vomit excessively or the vomiting cannot be stopped. HG usually starts in the sixth week of pregnancy and persists for weeks. Improvement often only occurs from the 20th week, in some cases even later.

What causes excessive morning sickness?

What causes hyperemesis gravidarum was unclear for a long time. Now, however, an international team of researchers claims to have found the answer. As part of a study, they claim to have discovered that a hormone is the culprit. The hormone is called GDF15. It is a so-called growth differentiation hormone, which is produced in low concentrations in many organs. The receptors for GDF15 are located in the area of the brain that is also responsible for nausea and vomiting. During pregnancy, the fetus ensures an increased concentration of the hormone in the womb through its own production of GDF15.

The study results suggest that the GDF15 concentration is a significant factor in pregnancy nausea. And: The severity of the condition is probably dependent on the amount of GDF15 that the woman had in her body before pregnancy. "We now know that women suffer from nausea during pregnancy when they are exposed to higher concentrations of the hormone GDF15 than they are used to," says study leader Marlena Fejzo from the University of Southern California.

The results have now been published in the journal "Nature". There were earlier indications that GDF15 could be the cause, but these have not yet been investigated further.

What are the symptoms of hyperemesis gravidarum?

Pregnant women affected by hyperemesis gravidarum vomit more than five times a day, regardless of whether there is anything in their stomach or not and regardless of the time of day. Eating and drinking becomes a torture.

How many pregnant women are affected by excessive nausea?

The number of pregnant women affected by hyperemesis gravidarum is estimated at 0.5 to 2 percent. It mainly affects young, slim women who do not smoke and expectant mothers who are expecting twins.

Is hyperemesis gravidarum dangerous?

As the expectant mothers cannot keep anything down, they lose weight, some of them considerably. A loss of more than five percent of body weight due to hyperemesis gravidarum is not uncommon. Pregnant women also struggle with dehydration.

The consequences include deficiency symptoms, weakness and circulatory problems. If HG persists beyond the 20th week of pregnancy, the risk of pre-eclampsia also increases. HG is the most common cause of women being admitted to hospital in the first three months of pregnancy.

What use are the findings to those affected?

Up to now, pregnant women suffering from hyperemesis gravidarum have been able to do little about the symptoms. This is partly because many medications cannot be taken during pregnancy and partly because the cause of the condition was unknown. The latest findings now offer a starting point for the development of appropriate medication. According to the researchers, it would be conceivable to administer the hormone before pregnancy or a drug that blocks the effect of GDF15 in the brain.

Sources: Nature, University Hospital Freiburg, Deutsche Hebammen Zeitschrift, Science, BBC