Pregnancy Nausea and Vomiting - Causes and Treatment

Nausea and vomiting in the first trimester of pregnancy are so common events that can almost be considered as a physiological manifestation. In this text we will address the causes and treatments for simple pregnancy sickness and for the so-called hyperemesis gravidarum.

Pregnancy nausea
Pregnancy nausea

Morning sickness

Morning sickness is so common and so typical of early pregnancy that it loses only to menstrual delay as the symptom that most causes women to go to a pharmacy to buy a pregnancy test. About 70% to 80% of women experience morning sickness in the first trimester. Nausea may come with or without vomiting; occur mainly in the morning, but may manifest at any time of the day.

Pregnancy sickness usually occurs in the 5th or 6th week, usually lasting up to the 12th week, which marks the beginning of the 2nd trimester of pregnancy.

Some less fortunate women remain nauseated until the 18th week, at which time 90% of pregnant women no longer have them. Of these, about 10% maintain nausea during later stages of pregnancy, and may last until the third trimester.

The severity of pregnancy sickness varies greatly. Some women feel almost nothing; others complain of mild nausea in short periods, often without vomiting; there are also cases where nausea and vomiting are frequent, making the first trimester very difficult; at the end of the spectrum there are still cases of hyperemesis gravidarum, a picture of nausea and vomiting so frequent that they impede feeding and lead the pregnant woman to dehydration. I will address the hyperemesis gravidarum later in this text.

Why do you get nauseous during pregnancy?

The exact mechanism that leads pregnant women to feel sick during the entire first trimester of pregnancy is unknown. It is known, however, that the rapid hormonal changes of early pregnancy (estrogen, progesterone and hCG) play an important role in the picture. Some studies have shown that the higher the levels of the hCG hormone, the greater the incidence of nausea during pregnancy.

Pregnancy hormones, especially progesterone, also act on the motility of the gastrointestinal tract. Pregnant women have a "lazy stomach", which takes time to empty, which in addition to favoring the onset of nausea, also causes a feeling of early satiety, preventing the ingestion of large amounts of food. The pregnant woman feels "stuffed" very easily.

Risk factors

Although the causes for nausea are not completely elucidated, some factors are widely recognized as being at risk for the development of nausea and vomiting:
  • Women who experience nausea more easily, such as during movements or after stimuli to strong smells and tastes, increased risk of severe nausea during pregnancy.
  • Very anxious or pregnant women also present a higher incidence and intensity of nausea.
  • Pregnant women with a history of migraine are at higher risk.
  • Some studies suggest the hypothesis that women who have Helicobacter pylori bacteria may be at increased risk of nausea during pregnancy.
  • Pregnant women of twins have a higher incidence and greater intensity of nausea.


In most pregnant women, nausea is intermittent. There is a common alternation between hunger and nausea throughout the day. Ideally, the pregnant woman should try to eat when the sickness disappears.

Although uncomfortable, pregnancy sickness rarely causes any problems to the fetus. Most pregnant women are able to feed during periods of relief from nausea, thus maintaining adequate nutrient intakes.

Associated with nausea, it is possible that the pregnant woman presents changes in her nose and taste. Previously worshiped foods may lose all their appeal. On the other hand, it is common to have desires to eat foods that were never chosen before. It could happen, for example, that women who do not eat red meat will have desires for hamburgers, or pregnant women who are fueled by chocolate, simply can not eat a single candy.

When to see a doctor

In contrast to the other types of nausea and vomiting, in typical pregnancy nausea there are no other associated gastrointestinal or systemic symptoms such as fever, diarrhea and severe cramps. The presence of these symptoms should be reported to the physician.

Another sign of severity is uncontrollable vomiting, making the pregnant woman unable to feed or drink fluids. Pregnancy sickness can be so intense that it causes weight loss and dehydration of the pregnant woman. If you are pregnant, have frequent vomiting and have lost at least two pounds on account of these, seek a doctor, as we may be facing the diagnosis of hyperemesis gravidarum.

Hyperemesis gravidarum

Hyperemesis gravidarum is an abnormal presentation of morning sickness. It is a severe form of nausea and vomiting of pregnancy. Hyperemesis gravidarum occurs in 0.5% to 2% of pregnancies and is characterized by frequent vomiting, not responsive to treatment, associated with dehydration, hydroleleolytic alterations and weight loss. Because the mother can not feed herself or drink fluids, hospital admission may be necessary so that fluids and some nutrients can be given intravenously.


The first trimester of pregnancy is the most important because it is when the fetus is forming. At this stage it is imperative to avoid taking any kind of medicine or substance without the explicit authorization of your obstetrician.

In most pregnant women morning sickness does not require medication, only some changes in diet and some lifestyle habits:
  • Avoid large meals. The stomach of the pregnant woman empties more slowly, so small portions are better tolerated. Eating too much and staying on a full stomach may precipitate nausea.
  • Pregnancy sickness tends to be intermittent throughout the day. Try to feed yourself whenever you are feeling well. Hunger can trigger nausea. Be sure to feed yourself for fear of vomiting.
  • Avoid eating and lying down right after. Avoid eating near bedtime.
  • Eat what you want. It's better to eat anything than anything.
  • Ask someone to prepare the food. Some pregnant women lose hunger and begin to get sick when they need to prepare their own meal.
  • Try to always be well hydrated. If you have vomiting, try to replace lost fluids when motion sickness is gone. Again, take small volumes at a time. Cold liquids are best tolerated.
  • Recognize the nausea triggers and avoid them. Strong smells, for example, are often poorly tolerated. Other common triggers are heat, humidity, noise and being on the move, like riding a car or plane.
  • Avoid fatigue. It is common to have exercise intolerance in the first trimester. If you are an active person, do not try to maintain the same load of exercise you performed before you were pregnant. You do not have to be completely sedentary, but the ideal is not to get bored at this stage.
  • Ginger, lemon or watermelon are usually very well tolerated by pregnant women. Avoid spicy, greasy foods.
  • If your nausea does not come when you wake up, but rather after getting out of bed, keep a pack of crackers on the headboard to eat one or two before getting up. This "calms" the stomach.

The most important thing is to recognize what makes you good and what hurts you. The above tips work for most women, but you may have to figure out which tips are right for you.

If your nausea does not improve at all with the usual measures, you may need to use some medications to control them. The list of possible drugs is vast, however, as some can be sold without a prescription, I will not list them here so as not to stimulate self-medication, which is even more serious when done by a pregnant woman in the first trimester.

Myths about pregnancy sickness

- Is not the woman who is sick is at greater risk of miscarriage?

Not necessarily. Theoretically a troubled pregnancy would not produce adequate levels of hormones and the symptoms of nausea and vomiting would be less intense. However, it is common to have a normal pregnancy without having to go through the suffering of nausea. Therefore, it is not correct to create expectations about the success of pregnancy simply by the presence or absence of nausea.

- The sickness of pregnancy may harm the fetus?

No. Except in the most serious cases, requiring hospitalization, the fetus suffers nothing from its occasional nausea and vomiting.

- The sickness does not disappear after the end of the 1st quarter means something wrong in pregnancy?

No. Some pregnant women have nausea throughout their pregnancy, although this is not the most common. Any motion sickness that lasts beyond the 20th week should be assessed by the obstetrician, which does not necessarily mean that there is any problem with the pregnant woman.

- Sucking ice often improves sickness?

Yes and no. As already mentioned, these little tips may be the solution for some pregnant women and a complete failure for others. The advantage of ice is that, ultimately, it is water in small amounts, which favors the hydration of the pregnant without causing distension of the stomach.

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