Why does morning sickness cause diarrhea?
Most of us are familiar with typical acute diarrheal illnesses like gastroenteritis. There is nausea, vomiting and diarrhea along with other symptoms like abdominal cramping. Nausea and vomiting are a common part of pregnancy, particularly early pregnancy, and is referred to as morning sickness. When diarrhea occurs then it is not entirely irrational to associate the frequent and watery stool with morning sickness.
Read more on morning sickness.
Diarrhea is a common occurrence during pregnancy but may not always be related to the changes in the body associated with pregnancy hormones and the growing fetus. In fact diarrhea in pregnancy may not be anymore common than diarrhea in non-pregnant women. However, as with other symptoms many pregnant women immediately associate diarrhea with pregnancy.
Diarrhea in Early to Mid Pregnancy
The elevation of certain hormones as a result of pregnancy can stimulate the vomiting centers in the brain and therefore result in morning sickness. While the pregnancy hormones can cause changes in bowel habit, constipation is more likely to occur. The hormonal change in pregnancy can have extensive effects in the body but it is not always clear how it may directly cause diarrhea in early pregnancy.
Changes in eating habits during pregnancy and even a predisposition to infections as a result of a weakened immune system in pregnant women may lead to diarrhea. Similarly anxiety and psychological stress may be other contributing factors to diarrhea in early pregnancy. Pre-existing bowel conditions may flare up in pregnancy but all of these factors are usually independent of morning sickness.
Therefore morning sickness and diarrhea may not be linked in that it is not caused by the same conditions or mechanisms. Furthermore both morning sickness and diarrhea are symptoms. Usually one cannot cause the other. Morning sickness causes upper gut symptoms while diarrhea is primarily a lower gut problem.
Diarrhea in Late Pregnancy
Constipation is more common in late pregnancy for several reasons. Apart from the effects of pregnancy hormones, the enlarged uterus can also press against the bowels in the cramped abdominal and pelvic cavities. Therefore there may be no specific pregnancy-related reason why diarrhea will occur in late pregnancy when it does arise. It may be due to the same causes as diarrhea in early to mid pregnancy or in non-pregnant women.
Morning sickness on the other hand is uncommon in late pregnancy but some women may experience it throughout pregnancy. Therefore when there is nausea, vomiting and diarrhea in late pregnancy then it may not be simply a matter of morning sickness with diarrhea due to pregnancy effects on the body. Other causes of nausea and vomiting with diarrhea should be considered.
The only exception is when diarrhea occurs prior to labor. The hormones that are released to cause uterine contractions may also have an effect on the movement through the bowels. These hormones known as prostaglandins increase bowel motility which may lead to diarrhea. Although it does not always occur, diarrhea can be one of several signs of labor.
Causes of Diarrhea with/without Morning Sickness
It is important to consider all possible causes of diarrhea in pregnancy. Whether the accompanying symptoms of nausea and vomiting is due to morning sickness or caused by the same conditions that cause diarrhea is not always clear. Pregnant women need to be particularly cautious as some conditions and medication can harm the fetus. Therefore immediate medical attention should always be sought for these symptoms in pregnancy.
Read more on diarrhea in pregnancy.
Gastroenteritis and Food Poisoning
Gastroenteritis is a common cause of nausea, vomiting and diarrhea. When the bugs or toxins that cause gastroenteritis are caused by eating contaminated food then it is referred to as food poisoning. It usually causes intense nausea, vomiting and severe diarrhea for a short period of time which just lasts for 2 to 3 days.
Viruses tend to cause outbreaks of the ‘stomach flu’ as it is often easily spread among people in close contact. Bacteria, protozoa and the toxins from these agents may also be responsible for gastroenteritis. Pregnant women who are traveling need to be particularly cautious, especially when visiting developing nations.
Medication and Supplements
Prenatal vitamin supplements usually do not cause any irritation of the digestive tract for most pregnant women. In high doses these supplements may be a problem. However, some women may experience gastrointestinal upsets with regular doses of prenatal vitamins.
A host of different medication can cause nausea, vomiting and/or diarrhea. This has to be considered when medication is commenced during pregnancy. Sometimes these side effects arise even with normal doses. However, overdosing must also be considered, whether intentional or accidental.
Overeating and Dietary Changes
Appetite may be reduced in early pregnancy particularly when there is persistent morning sickness. Many women experience gastrointestinal upsets with eating even small quantities of food in the early stages of pregnancy where morning sickness is at its worst. Sometimes this is related to food intolerance and malabsorption syndromes.
However, the opposite occurs later in pregnancy. The increased appetite and cravings in late pregnancy can lead to a host of digestive upsets. It may be a result of overeating or eating unusual or irritant foods in large quantities. This may lead to nausea, vomiting and diarrhea.
Anxiety and Psychological Stress
Symptoms like nausea and eve vomiting as well as diarrhea can occur with anxiety and psychological stress, which may or may not be related to pregnancy. It is well known that the hormonal changes in pregnancy can lead to mood swings and altered mental/emotional states like anxiety. Therefore diarrhea with morning sickness symptoms can be related to pregnancy in these instances.
Pre-Existing Bowel Conditions
The fluctuations in the body associated with pregnancy can causes some chronic conditions to ease or worsen. Therefore women with conditions like irritable bowel syndrome (IBS) and inflammatory bowel disease (IBD) may experience a worsening of these conditions during pregnancy. In early pregnancy when morning sickness is more likely to occur, these chronic diarrheal illnesses may exacerbate at the same time.