Morning sickness or also called pregnancy-related nausea and vomiting indicated the most common medical condition observed during pregnancy, with up to 80% of pregnant women experiencing this problem to some extent. Morning sickness may be one of the earliest signs of a positive pregnancy. 

Despite the name, morning sickness can happen at any time of the day or night. Nausea and vomiting are limited to the morning in only 2% of pregnant women. Some experts even suggest that morning sickness should be renamed as “morning, noon and night sickness” or directly “all-day sickness”. It is so common that it is usually acknowledged as a sign of normal pregnancy.

Especially during the first three months of pregnancy, many people have morning sickness or nausea-like symptoms. But some people can have nausea and vomiting throughout the three trimesters of pregnancy. Home remedies, such as snacking during the day and sipping ginger tea or taking medicine under the doctor's supervision, might help relieve nausea. 

It might take place as soon as waking up, often as retching rather than actual vomiting, therefore it usually does not disturb the total health of a pregnant woman.

Causes:

The cause of morning sickness is not known and hasn't been established yet, though hormonal changes might play a significant role. Rarely, a medical condition not related to pregnancy, such as thyroid or gallbladder disease, can also cause serious nausea or vomiting and mimic a pregnancy like morning sickness. 

Sometimes a severe form of morning sickness is termed hyperemesis gravidarum. When nausea and vomiting cause serious fluid loss or loss of more than 5% of pre-pregnancy body weight and severe electrolyte imbalance it is termed a hyperemesis gravidarum. Hyperemesis gravidarum may also lead to hospitalization.

An increase in the levels of estrogen and progesterone levels may cause morning sickness. As progesterone also relaxes the stomach and intestines, it can result in excess stomach acids and, subsequently, gastroesophageal reflux disease and also gastrointestinal disorders like indigestion or constipation. Since these hormones trigger active reflux at night, symptoms are commonly worse in the morning.

Human chorionic gonadotropin (HCG) may also lead to nausea and vomiting by stimulating another endogenous hormone-like vasopressin. Since vasopressin is an emetic, increased sensitivity of the physiological mechanisms for vasopressin release could be a possible mechanism for morning sickness.

Hypoglycemia or low blood sugar caused by the energy requirements of the placenta or the growing baby is another theory of pregnancy-related nausea and vomiting. Fasting hypoglycemia or low blood sugar can develop in anyone with an empty stomach. Thus, it is inevitable that this type of hypoglycemia is related to morning sickness in a pregnant woman when she awakens.

Morning sickness may appear as an evolutionary adaptation or trait that protects pregnant mothers (and their unborn child) from various types of food that may cause food poisoning. Therefore pregnant women with morning sickness do not have an affinity for potentially contaminated food such as eggs, poultry or meat.

Management of morning sickness:

As pregnancy-related nausea and vomiting affect a large fraction of pregnant women, healthcare providers and patients should be aware of the information on various treatment options available and these should be sculptured individually for each pregnant woman for their ease. 

Timing of the treatment of morning sickness is critical because early treatment can stop the development of hyperemesis gravidarum and reduce the time absent from work, hospitalization, and emotional distress. Both women and healthcare providers should be aware that the benefits of safe treatment modalities outweigh any theoretical risks to the fetus.

Some of the treatment options are an adequate diet, drinking at least two liters of fluids per day, taking prenatal vitamins, and antacids, intake of fibers for constipation, as well as spitting out excessive saliva and mouth washing. Herbal products such as ginger and vitamin B6 can also be used safely, although the medical literature shows varying degrees of effectiveness.

The growing baby is another theory of pregnancy-related nausea and vomiting. Fasting hypoglycemia or low blood sugar can develop in anyone with an empty stomach. Thus, it is inevitable that this type of hypoglycemia is related to morning sickness in a pregnant woman when she awakens.