The primary sign of pregnancy is missing a menstrual period or two or more consecutive periods, but many women experience other symptoms of pregnancy before they miss a period.
Missing a period does not always mean a woman is pregnant. Menstrual irregularities are common and can have a variety of causes, including taking birth control pills, conditions such as diabetes and polycystic ovary syndrome, eating disorders, and certain medications. Women who miss a period should see their health care provider to find out whether they are pregnant or whether they have another health problem.
Pregnancy symptoms vary from woman to woman. A woman may experience every common symptom, just a few, or none at all. Some signs of early pregnancy include:1
- Slight bleeding. One study shows as many as 25% of pregnant women experience slight bleeding or spotting that is lighter in color than normal menstrual blood.2 This typically occurs at the time of implantation of the fertilized egg (about 6 to 12 days after conception) but is common in the first 12 weeks of pregnancy.3
- Tender, swollen breasts or nipples. Women may notice this symptom as early as 1 to 2 weeks after conception. Hormonal changes can make the breasts sore or even tingly. The breasts feel fuller or heavier as well.1
- Fatigue. Many women feel more tired early in pregnancy because their bodies are producing more of a hormone called progesterone, which helps maintain the pregnancy and encourages the growth of milk-producing glands in the breasts. In addition, during pregnancy the body pumps more blood to carry nutrients to the fetus. Pregnant women may notice fatigue as early as 1 week after conception.4
- Headaches. The sudden rise of hormones may trigger headaches early in pregnancy.5
- Nausea and/or vomiting. This symptom can start anywhere from 2 to 8 weeks after conception and can continue throughout pregnancy. Commonly referred to as "morning sickness," it can actually occur at any time during the day.1
- Food cravings or aversions. Sudden cravings or developing a dislike of favorite foods are both common throughout pregnancy. A food craving or aversion can last the entire pregnancy or vary throughout this period.1
- Mood swings. Hormonal changes during pregnancy often cause sharp mood swings. These can occur as early as a few weeks after conception.6
- Frequent urination. The need to empty the bladder more often is common throughout pregnancy. In the first few weeks of pregnancy, the body produces a hormone called human chorionic gonadotropin, which increases blood flow to the pelvic region, causing women to have to urinate more often.7
Many of these symptoms can also be signs of other conditions, the result of changing birth control pills, or effects of stress, so they do not always mean that a woman is pregnant. Women should see their health care provider if they suspect they are pregnant.