When Does Nausea Start in Pregnancy?

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Nausea in pregnancy, more commonly known as morning sickness, typically begins between the sixth and eighth week of pregnancy, notes Parents magazine. While not impossible, it's uncommon for nausea to begin before the sixth week.

Morning sickness is often one of the first symptoms women experience during pregnancy. Many women do not know they are pregnant until about half way through the first trimester, and this is when nausea begins to develop. The severity of nausea varies from woman to woman but is generally considered a normal symptom of pregnancy and poses no risk to mother or baby.

What Causes Morning Sickness?
The exact cause of morning sickness is unknown, but many medical experts agree that nausea develops due to hormonal changes within the mother's body. In particular, estrogen and progesterone levels can be as much as 100 times higher during pregnancy. The rise in these hormones can cause nausea in the early stages of pregnancy until the body adjusts to the change. Additionally, human chorionic gonadotropin (hCG) is a new hormone produced in the body soon after conception, which may lead to nausea in some women, states Medical News Today.

A non-hormonal cause for nausea is the increased sensitivity to smells that many women experience during pregnancy. If women are already sensitive to certain smells, such as to foods or perfumes and colognes, then this increases drastically during pregnancy and can trigger a nausea response.

When Does Nausea Occur?
Though it's often called "morning sickness," nearly 80 percent of women experience nausea at some time during the day other than morning, according to Parents magazine. Chances are that if a woman is feeling queasy anytime during the early stages of pregnancy (and she is not suffering an illness) it can be attributed to the pregnancy. A majority of women experience nausea beginning at six weeks and ending by the 14th week. Mothers can celebrate the beginning of the second trimester by saying "goodbye" to the unpleasantness of nausea. However, some women experience morning sickness throughout the entire pregnancy.

Complications With Morning Sickness
Medical professionals consider morning sickness a normal part of pregnancy. It is typically mild though unpleasant. However, one to two percent of pregnant women experience hyperemesis gravidarum, which is a severe form of morning sickness, as stated by Medical News Today. This condition presents with severe vomiting and the inability to keep fluids down. As a result, women can become dehydrated and lose weight, both of which pose risks to the pregnancy. Hyperemesis gravidarum is easily treatable by a medical professional, and symptoms often go away on their own by the fifth month of pregnancy.

Nausea is a normal, though not enjoyable, symptom of pregnancy. For most women this symptom only occurs in the early stages and goes away as the pregnancy progresses. Even severe nausea and vomiting tend to clear up by the middle stages of pregnancy. If a pregnancy is confirmed and nausea is not present, this is completely normal as well. Some women do not experience any nausea throughout the entire course of their pregnancy. Though there are some common symptoms, every woman and every pregnancy is different.