Hyperemesis Gravidarum

hyperemesis gravidarum 1

Dr James Nicopoullos, Consultant Gynaecologist and Subspecialist in Reproductive Medicine & Surgery at The Lister Hospital, London talks about the condition Hyperemesis Gravidarum.


” Hyperemesis is an extreme form of morning sickness. At least 50% of women suffer from some nausea and vomiting but in a small proportion it becomes so severe that it leads to an inability to tolerate enough oral fluids to maintain hydration, which can lead to dehydration and occasionally weight loss, imbalances in important electrolytes in the body (such as sodium and potassium) and poor nutrition. Dehydration can cause a rise in heart rate as the body tries to compensate, a drop in blood pressure and dizziness. The key symptoms always begin in the first trimester, most commonly at six to eight weeks of pregnancy and they tend to resolve in the majority by week 14-16.

“The reason why some women suffer and others do not is poorly understood. It may be as a consequence of hormonal, mechanical and psychological factors. The early pregnancy hormone Human Chorionic Gonadotropin (hCG) stimulates the thyroid gland and levels of hCG and thyroid hormones seem to correlate with the severity of symptoms in some, but not all, women. Pregnancy also naturally leads to certain mechanical changes that predispose to the symptoms, so are exacerbating factors but are unlikely to be the underlying cause (such as changes in pressure in the oesophagus and slower emptying of stomach contents).”

Can it harm the baby at all?

“Serious consequences to both mother and baby are rare with Hyperemesis Gravidarum (HG) and only occur if poorly treated. For mum, the main concern is nutritional deficiencies. In particular Vitamin B1 (Thiamine) deficiency can cause “Wernicke’s Encephalopathy” where there can be significant visual disturbance and confusion and lead to learning difficulties if left untreated. This is exceptionally rare, as most will be treated with the appropriate fluid to avoid this and supplemented with Thiamine. On the rare occasion that a woman suffers Wernicke’s emcephalopathy this leads to a fetal death in 40% of cases.

“On occasion, the persistent vomiting and dehydration can lead to low sodium levels, which can (rarely) cause seizures and respiratory problems. The often violent retching, can lead to a “Mallory Weiss Teat”, a small tear in the oesophagus, and bleeding.

“Thankfully, in general, HG shows no increase in risk to baby with no increase in congenital birth defects. If severe and leading to maternal weight loss and nutritional problems, the pregnancy should be monitored a little more closely to assess fetal weight, as this can decrease.

“If the dehydration is significant, there is an increase in the risk of potentially life-threatening blood clots. This is another reason for a low threshold for admission so preventative measures can be taken if needed.”

How can expectant mothers ease their symptoms to help minimise the impact in their lives?

“The most important factor is probably tackling the symptoms as early as possible when they are easier to deal with and before they have a chance to cause significant dehydration and any nutritional problems. It is therefore vital that women seek guidance from their Doctor or hospital sooner rather than later and that the medical practitioners have a good understanding of HG, how it can impact on couples and the treatment options.

“Just as important is the emotional support we can offer and the reassurance that the symptoms will improve with time. Any underlying causes of nausea (such as urine infections or taking iron supplements) should be excluded and one of the many safe anti-sickness medications should be discussed and offered.  If fluids are not being tolerated and the woman is becoming dehydrated, there should be a low threshold to admit to hospital and offer the respite of intravenous fluids and anti-sickness medications until feeling better. This can also allow assessment for any electrolyte imbalances (such as low sodium) and allow nutritional supplementation. This is often only needed for a few days but can often be required several times over the course of the early pregnancy until the symptoms resolve.”

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