Hyperemesis Gravidarum vs Morning Sickness

? : @abbypayton

Nausea and vomiting of pregnancy is extremely common. One textbook cited that it occurs in up to 85% of all pregnancies! (1) If you are one of the lucky 15%, may I be the first to congratulate your superhuman motherhood-ness! However, if you are like the unfortunate majority rest assured that you are not alone 😉 Unfortunately, there is no known way to prevent morning sickness or hyperemesis gravidarum, but there are ways to manage the symptoms.

Morning Sickness

As the title suggests, in this post I will help you understand the differences between morning sickness and hyperemesis gravidarum. Before I get to that though, I want to clear up a common misconception. The term “morning sickness” can be very misleading. In fact, it’s wishful thinking! For most people, these symptoms persist throughout the day and/ or night! (2) Ok on to the good stuff…

Nausea and vomiting during pregnancy (NVP) or “morning sickness” is typically seen within the first 12-14 weeks of pregnancy but may continue throughout the entire pregnancy. Just as each pregnancy is different, NVP varies between individuals and can even vary between pregnancies! If you have experienced these symptoms, you know just how irritating they can be. In fact 25% of women may miss work as a result of their symptoms (3) (which can be pretty difficult if you are trying to keep it a secret from your coworkers 😉 )

The cause of morning sickness is thought to be multifactorial. Hormones like prostaglandin, low vitamin B6 (helps your body make red blood cells for you and baby), hyperolfaction (“pregnancy nose”), and human chorionic gonadotropin (what sets off most pregnancy tests ? ) are thought to be the offending agents. Prostaglandin relaxes the smooth muscles of the sphincter between your stomach and your esophagus – leading to heartburn and nausea ?. There are also psychological factors like stress and anxiety that may contribute as well.

Treatment varies with severity. Some nausea and vomiting in pregnancy (NVP) can be managed with drug free treatments which include frequent and small meals with high carbs and low fat content. There is also some research that shows that eating certain types of foods (salty food in the morning, and sour/tart beverages rather than water) may be better tolerated (4). Other treatments include acupuncture, acupressure, hypnosis, and ginger. If these are unsuccessful, there are a number of medications your physician can prescribe including antihistamines, dopamine antagonists, vitamin B6, and serotonin antagonists.

Hyperemesis Gravidarum

Before we get to the details, let’s first dissect the word. Hyper (over or beyond) emesis (vomiting) Gravidarum (associated with pregnant women). As the definition suggests, Hyperemesis Gravidarum is excessive nausea and vomiting in pregnancy.

Hyperemesis Gravidarum (HG) has a typical onset of 4-8 weeks of pregnancy and usually resolves at weeks 14-16. Unlike morning sickness, hyperemesis gravidarum (HG) only affects .5%-2% of pregnant women. (5) If you think of morning sickness on a scale of 1-10, 10 being the worst morning sickness… that is HG. It is associated with similar but more severe nausea, vomiting, and a weight loss greater than 5% of pre-pregnancy weight. The reason HG is dangerous is because excessive vomiting causes the body to lose essential fluids, electrolytes, and vitamins that can cause serious and sometimes life threatening problems. If severe enough, these electrolyte imbalances and nutritional deficiencies may require hospitalization to restore. (6)

Treatment for HG (like NVP) also varies with severity. As reported in the Journal of American Medicine, milder symptoms of nausea and emesis of pregnancy can be treated with ginger, pyroxidine (vitamin B6), antihistamines, and metoclopramide. For moderate symptoms vitamin B6 + Unisom (diclegis), promethazine (phenergan), and metoclopramide. For severe symptoms corticosteroids may also be beneficial.

In summary, if you are pregnant you are probably experiencing some level of nausea and/or vomiting. This is very common and can be treated with a number of medications or medication free remedies. If your vomiting and nausea is severe enough that you are losing a significant amount of weight, you may have HG and should consult with your physician.

I know this post has probably come close to home and reminded you of that not-so-wonderful aspect of pregnancy, but let me finish by telling you that the fact that we get nauseous in pregnancy is actually kind of amazing. This is because nausea in pregnancy has been hypothesized to serve an incredible function. It is thought that this hyper sensitivity to smells, tastes, and stimuli in general is useful in protecting the growing baby by helping us avoid potentially harmful or teratogenic (developmental malformation causing) foods and drinks. (7)


(1) Maltepe, C. (01/01/2013). Clinical pharmacology during pregnancy: 12: Updated guidelines for the management of nausea and vomiting of pregnancy and hyperemesis gravidarum Academic Press [Imprint].

(2) Association of Professors of Gynecology and Obstetrics : APGO Educational series on women’s health issues. Nausea and vomiting of pregnancy. Boston, Massachusetts: Jespersen & Associates, LLC, 2011.

(3) Vellacott I.D., Cooke E.J., and James C.E.: Nausea and vomiting in early pregnancy. Int J Obstet Gynecol 1988; 27: pp. 57-62

(4) Quinlan J.D., and Hill D.A.: Nausea and vomiting of pregnancy. Am Fam Physician 2003; 68: pp. 121-128

(5) ACOG (American College of Obstetrics and Gynecology) : Practice bulletin: nausea and vomiting of pregnancy. Obstet Gynecol 2004; 103: pp. 803-814

(6) Bottomley C., and Bourne T.: Management strategies for hyperemesis. Best Pract Res Clin Obstet Gynaecol 2009; 23: pp. 549-564

(7) Furneaux E.C., Langley-Evans A.J., and Langley-Evans S.C.: Nausea and vomiting of pregnancy: an endocrine basis and contribution to pregnancy outcome. Obstet Gynecol Surv 2001; 56: pp. 775-782