Morning sickness symptoms can start as early as two weeks after conception which means that nausea with or without vomiting is often among the very first signs of pregnancy. It is estimated to be experienced by up to 90 percent of all pregnant women and usually is not a cause of concern. In fact, a recent study has shown that morning sickness can reduce the risk of miscarriage although absence of pregnancy nausea does not necessarily increase the risk of pregnancy loss either. What causes morning sickness is not fully understood but most health experts believe that it is related to a hormone known as human chorionic gonadotropin (HCG). This hormone is produced shortly after conception which explains the early onset of morning sickness symptoms. Pregnancy nausea may be also related to the rising levels of hormones estrogen and progesterone which are believed to play a role in slowed digestion, and increased sense of smell and taste in pregnant women. As a result, many pregnant women experience food aversions and nausea when exposed to certain odors. Sometimes only the thought of certain foods or odors can trigger nausea. Other theories suggest that morning sickness may encourage pregnant women to avoid foods that may be harmful to the baby and increase consumption of foods high in nutrients which are crucial for healthy pregnancy and healthy fetal development.
Morning sickness symptoms vary greatly from one woman to another and from pregnancy to pregnancy but they typically include nausea which is sometimes accompanied by vomiting. The name suggests that morning sickness is experienced in the morning, however, nausea can strike at any time during the day and even at night. The good news is that it usually improves or goes away completely on its own by the beginning of the second trimester although it can persist throughout pregnancy in some cases.
Mild to moderate pregnancy nausea with or without vomiting is completely normal and cannot harm the baby. Severe nausea and vomiting are very rare but should be taken very seriously because they can signal the so-called hyperemesis gravidarum, a severe form of morning sickness. It is not a sign of pregnancy complication, however, it can cause serious complications for both the mother and baby if left untreated. You are highly recommended to contact your doctor if having severe morning sickness and finding no relief with the usual home treatments or if being unable to keep anything down more than 24 hours, passing small and infrequent amounts of urine, or if feeling dizzy or weak because you may need treatment with intravenous fluid or/and medications to control morning sickness.
In rare cases, severe morning sickness can be a sign of molar pregnancy, a condition in which an abnormal tissue known as mole begins to grow inside the uterus instead of an embryo. Molar pregnancy cannot progress normally and requires removal of the abnormal growth to prevent potentially serious complications. Next to severe morning sickness, symptoms of molar pregnancy typically include vaginal bleeding and passage of grape-like tissue.