Morning sickness – causes, symptoms and other complications

Morning sickness

Nausea that is happening during the pregnancy is known as morning sickness. This name is a misnomer but it is known fact that the morning sickness can strike at any time of the day or night. There are many pregnant women who are affected by the morning sickness. This condition is most common during the first trimester but there are some cases when the morning sickness lingers throughout the pregnancy. In the most cases treatment is not needed. There are some home remedies such as snacking throughout the day and sipping ginger ale which can help you to get a relief from the nausea. There are rare cases when the morning sickness is so severe and in this case it is classified as hyperemesis gravidrum [1]. This type of morning sickness may need hospitalization and treatment with medications and intravenous fluids (IV fluids). Morning sickness is very common condition and it is affecting up to 75% of pregnant women at some time [2]. Also this condition can be accompanied with other symptoms of early pregnancy such as tiredness or fatigue. Nausea of the pregnancy usually is starting about the 6th weeks of the pregnancy but there are some women who can experience it earlier. It is known fact that experiencing certain smells or eating certain foods may bring on vomiting and nausea of the pregnancy. One of the risk factors for having morning sickness is being pregnant with twins or multiples due to the higher hormone levels [3]. Also there are other factors which can increase the risk of morning sickness such as a history of motion sickness and history of migraine headaches. Also women who are pregnant with girl have increased risk of developing morning sickness.

Morning sickness symptoms

This condition is characterized by nausea with or without vomiting. Morning sickness is most common during the first trimester and in some cases it begins as early as 2 weeks after conception. If you vomit blood, your heart races, you feel dizzy or faint when you stand up, then you should talk with your doctor. Also you should visit your doctor if you cannot keep down liquids, you pass only a small amount of urine or it is dark in color or the nausea and vomiting is severe.

Causes: It is not clear what the cause for morning sickness is but it is thought that the hormonal changes of pregnancy are playing a role in it. It is known fact that early in pregnancy, the levels of the hormones estrogen and hCG (human chorionic gonadotropin) rise. In the early pregnancy there is an enhanced sense of sensitivity and smell to odors which can also lead to nausea. Also it is possible that there are some women who have so – called sensitive stomach which means that they are more sensitive to hormonal changes of pregnancy than other women. There are not sure evidences but some doctors are thinking that morning sickness can result from an abnormal response to stress early in pregnancy. There are very rare cases when the severe or persistent nausea or vomiting can be caused by a medical condition which is not related to pregnancy such as liver or thyroid disease.

Morning sickness

Morning sickness risk factors

Morning sickness can affect every single person even if it is not pregnant. Morning sickness is more likely to happen if:

  • You are pregnant with twins or other multiples [3]
  • You experienced morning sickness during a previous pregnancy
  • You experienced vomiting or nausea from exposure to estrogen (in birth control pills, for example) before pregnancy, certain smells or tastes, migraines and motion sickness [4]

You are having increases chances of experiencing hyperemesis gravidarum if:

  • You experienced hyperemesis gravidarum during a previous pregnancy
  • You have a family history of hypermesis gravidarum [5]
  • You are pregnant with a girl

Complications: In the most cases the morning sickness is not causing complications for the mother or baby. Also in some studies is said that if you are underweight before the pregnancy and if the morning sickness is preventing you from gaining a healthy amount of weight during the pregnancy, then your baby can be born underweight [6]. There are rare cases when the frequent vomiting can lead to tears in the tube which is connecting the mouth to the stomach (esophagus).


[1] van Vliet R, Bink M, Polman J, et al. Patient preferences and experiences in hyperemesis gravidarum treatment: A qualitative study. Journal of Pregnancy. 2018.

[2] Gabra A. Risk factors of hyperemesis gravidarum: Review article. Health Science Journals. 2018;12(6):603.

[3] Mitsuda N, Eitoku M, Maeda N, et al. Severity of nausea and vomiting in singleton and twin pregnancies in relation to fetal sex: The Japan Environment and Children’s Study (JECS). Journal of Epidemiology. 2019;29(9):340–6.

[4] Verberg MFG, Gillott DJ, Al-Fardan N, Grudzinskas JG. Hyperemesis gravidarum, a literature review. Human Reproduction Update. 2005;11(5):527-39.

[5] NHS. Morning sickness ‘is inherited’. 2010. Retrieved from

[6] Li C, Zhu N, Zeng L, et al. Effect of maternal pre-pregnancy underweight and average gestational weight gain on physical growth and intellectual development of early school-aged children. Scientific Reports. 2018;8:12014.


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