Why do Pregnant Women Experience Nausea within the First Few Weeks of Their Pregnancy?
It has not been determined what is the exact cause of the nausea and vomiting that many pregnant women experience. It is estimated that approximately 70% of pregnant women suffer from this nausea that is commonly referred to as morning sickness. It has been theorized that the nausea and vomiting in the early stages of pregnancy may be the result of hormonal changes that occur due to the presence of the placenta and the fetus. It is also thought that the changes in the gastrointestinal system may also influence the development of morning sickness; hormones are thought to cause the stomach to empty more slowly.
For the majority of expectant women, pregnancy nausea in the first few weeks begins somewhere between the fourth and the eighth week. In most cases the nausea and vomiting will subside by the 14th to the 16th week. While it is referred to as morning sickness, the nausea and accompanying vomiting of early pregnancy can be present throughout the entire day.
Most experts concur that morning sickness does play a functional role in pregnancy. Many believe that morning sickness protects the fetus. It is theorized that unlike adults who have defenses against toxic substances the fetus does not have a well-developed defense system. While a small dose of toxins may have an adverse effect on an adult, the same does could be lethal to the fetus. Hence it is thought that nausea in pregnancy may occur when women are exposed to the smell or the taste of foods that may contain toxins, which would cause harm to the fetus.
It is also thought that pregnancy nausea in the early weeks may serve as a protection to the mother. During pregnancy, the immune system of the woman is suppressed most likely as a defense against rejecting the tissue of her unborn child. As a result, the consumption of foods, particularly animal products, could expose the pregnant woman to harmful parasites and/or bacteria that her system is unable to protect her from. Hence, her body may be trying to provide protection by rejecting those foods through nausea and vomiting.
Fortunately, the mild to moderate nausea that is occasionally accompanied by vomiting is not a threat to the health of the mother or the unborn child. Even if the pregnant woman does not experience a weight gain during the first trimester this is not considered dangerous to the well being of the baby or the mother. If the expectant mother is able to maintain a healthy diet and to stay well hydrated, the fetus will continue to develop healthily. In the majority of cases of morning sickness, the woman recovers her appetite and is able to maintain a healthy weight gain.
Particularly among young women who are pregnant for the first time and among women experiencing a multiple birth pregnancy, the level and length of morning sickness may be greater. There are women who continue to suffer from morning sickness well beyond their first trimester. A small percentage of women will continue to be plagued by nausea and vomiting for the entire pregnancy.
