The early signs of pregnancy usually begin for most women during the first few weeks following conception, and some even before their first missed menstrual cycle. The symptoms will vary in intensity and type, although a missed menstrual period is usually the first sign of pregnancy noticed by most women.

Here are the other most common signs and symptoms of early pregnancy:

- Tender Breasts: Besides a missed period, swollen or tender breasts may be experienced within the first few weeks of pregnancy. Some women also report a feeling of fullness or heaviness, as well as a tingling sensation in the breasts in the first month or so following conception.

- Nausea: Nausea, often accompanied by vomiting, and queasiness are one of the early signs of pregnancy known as "morning sickness," although these symptoms can appear any time of the day or night contrary to the popular name. As early as two weeks after conception, some women may begin feeling queasy or notice an aversion to certain foods or aromas. Rising estrogen levels, which actually cause the stomach to empty slower, may be to blame for feeling nauseous during the early weeks and months of pregnancy.

- Unusual Fatigue: In addition to increased estrogen, levels of another hormone, progesterone, also rapidly increase, causing an unusual feeling of tiredness. This coupled with a decline in blood sugar and blood pressure all work together to deplete one's energy. Changes in hormone levels may also contribute to frequent headaches early in pregnancy.

- Constipation: Increased progesterone may also cause constipation as digested foods tend to pass through the intestines slower than normal.

- Frequent Urination: Frequent urination is a symptom of pregnancy that usually will continue on throughout the entire pregnancy due to hormone levels and increased pressure on the bladder.

- Bleeding and/or Cramping: Some pregnant women will experience a small amount of vaginal bleeding which is referred to as implantation bleeding, or some abdominal cramping similar to those felt during menstruation. Implantation bleeding occurs 10 to 14 days following fertilization as the newly fertilized egg attaches itself to the thickened lining of the uterus.

- Mood Swings: The first three months of pregnancy are often characterized by frequent mood swings or periods of irritability due to the influx of hormones.

- Feeling Faint, or Dizzy: Low blood sugar levels, a drop in blood pressure, and the dilation of blood vessels may cause feelings of dizziness or faintness.

- Changes in Eating Habits: Food cravings are a rather common sign of early pregnancy, with many women finding themselves liking certain foods they never did before, or even having an aversion to those that were once favorites. Cravings, like most symptoms of pregnancy, are due to the increase and fluctuation of hormone levels.

- Increased Basal Body Temperature: Basal body temperature, the temperature of the body upon first awakening in the morning, increases slightly after a woman ovulates, and stays at that increased level until their next menstrual cycle. If the increase lasts longer than 14 days, this may be an accurate indication of pregnancy.

It's important to remember that many early signs of pregnancy are slight, subtle changes that you may not recognize right away. Alternately, most symptoms are not totally unique to pregnancy and may actually be due to a number of other conditions or illnesses. The best way to find out what may be causing your symptoms is to take a home pregnancy test, and then make an appointment with your health care provider.