More than 80 percent of women have some degree of nausea during their first three months of pregnancy. Even though pregnancy-related nausea and vomiting is incredibly common, it's rare for the condition to be so severe that it requires medical attention.
Morning sickness seems to stem from sensitivity to the hormone human chorionic gonadotropin, or hCG, which peaks in the first trimester of pregnancy. Some women have normal levels of this hormone, but will be very sensitive to it, and others will have higher levels.
In the vast majority of cases, morning sickness is more bothersome than dangerous. Many of my patients worry that if they’re not able to keep food down or losing a little weight they’re starving their baby. That is not the case. The baby is good at taking what it needs from your system.
The bigger concern is hydration levels, as your body needs fluids to function properly. Plus, the more dehydrated you get, the more nauseated you feel, creating a vicious cycle. This is why morning sickness is most common in the morning – your body is the most dehydrated when you first wake up.
When it’s more than just morning sickness
For a minority of women, morning sickness isn’t just annoying – it can become a severe condition known as hyperemesis gravidarium (HG). While there is no single definition of HG, when a patient has lost 5 percent or more of her pre-pregnancy weight or hasn’t been able to keep anything down for 24 hours (including water), they require intervention.
Because of their inability to keep up their intake of foods or liquids, women may become dehydrated and develop electrolyte imbalances and nutritional deficiencies. Constantly vomiting can reduce levels of important vitamins and minerals, such as thiamine (vitamin B1), potassium and magnesium.
Another common symptom is that women with HG have an extreme sensitivity to smell. It’s not just food and cooking smells; it can also be perfumes or just about anything. Women may also be sensitive to light, noise and temperature changes.
If certain changes, like sipping water and avoiding troublesome foods, don’t help the condition, mothers with HG might be admitted to the hospital. Most women will just get an IV of fluids to rehydrate their bodies, but occasionally they’ll be given anti-nausea medications. While some women’s symptoms of HG may begin to improve by the 15th to 20th week of pregnancy, others may have frequent relapses throughout their pregnancy or have symptoms until they deliver.
Am I at risk of getting HG?
If a woman has HG during her first pregnancy, she’s extremely likely to have the condition in subsequent pregnancies. The condition also tends to run in families and can be inherited from a woman’s mother or father’s mother.
Besides genetics, other known risk factors for HG include being pregnant with multiples, such as twins or triplets; being pregnant with a girl; or having a history of motion sickness or migraines. These three risk factors only slightly increase a woman’s risk for HG, and it doesn’t necessarily mean that if a woman is carrying a boy she won’t get the condition.
If you’re an expectant mother and think you may be experiencing HG, I’d recommend making an appointment with your obstetrician to discuss treatment options.