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When a woman finds out that she is pregnant, it can be the start of a remarkable, life-changing experience.
"The first changes a woman is most likely to experience when she is pregnant are a missed period followed by a positive pregnancy test," said Lia Moss, a certified nurse midwife at Northwestern Medicine, who delivers babies at Prentice Women's Hospital in Chicago.
Pregnancy tests, whether done at home or at a doctor's office, measure the amount of human chorionic gonadotropin (hCG) in a woman's urine or blood. This hormone is released when a fertilized egg attaches to the lining of the uterus. Urine pregnancy tests can detect levels of hCG about 10 days after conception, Moss said, while blood tests, usually done at a doctor's office, can detect a pregnancy about seven to 10 days after conception. Testing too soon can produce a false negative result.
Women typically have many of the early signs of pregnancy, with the most common symptoms being fatigue, breast tenderness, nausea and bloating, Moss told Live Science. But not all women will have the same symptoms in early pregnancy or will experience them to the same extent.
Of all the early signs of pregnancy, a select few women only have a missed period and a positive pregnancy test, Moss said. "Those women are very lucky."
"The first trimester can be very hard for some women," Moss said, but after that many mothers-to-be start feeling better. Moss likes to call the second trimester "the golden period of pregnancy," because, she said, that's when women often feel their best.
During the early stages of pregnancy, Moss encourages her patients to use whatever coping methods they can to help them adapt to the many changes happening in their bodies and to take good care of themselves, whether that means getting extra rest, booking a prenatal massage or simply taking a walk outside to lift their spirits.
Here are 10 clues that a woman may notice during her first trimester to indicate she may be pregnant:
Missed periodSlide 2 of 21
Often the first tipoff of pregnancy, a missed period might make a woman wonder if she could be expecting. However, there are other reasons for missing a period. Perhaps a woman is not keeping track of her menstrual cycle, or maybe its length is irregular from month to month. Other explanations for why a woman could be late include excessive exercise, gaining or losing too much weight, stress, illness or breastfeeding, according to the National Institutes of Health.Slide 3 of 21
Bleeding/spottingSlide 4 of 21
Two weeks after conception occurs, a pregnant woman may experience a scant amount of vaginal bleeding or light spotting, Moss said. The blood may be pink to brown in color, she said, and it may also be accompanied by mild cramping, so a woman may think she is about to start her period.
Known as implantation bleeding, it occurs when the fertilized egg attaches to the wall of the uterus. This slight bleeding tends to happen right around the time a woman may be expecting her period, but it's shorter and much lighter than menstrual bleeding.Slide 5 of 21
Breast tendernessSlide 6 of 21
Six weeks after a missed menstrual cycle or two weeks after conception, a woman may notice that her breasts feel fuller, and her nipples may be more sensitive, Moss said. This is caused by increased levels of the hormones progesterone and estrogen, as well as increased blood flow to this area, she explained. To feel more comfortable at night, some pregnant women may sleep in a light supportive sports bra, Moss suggested.
Another very early clue to pregnancy is that the skin surrounding a woman's nipples, known as areolas, might darken and get bigger. The release of early-pregnancy hormones is the reason for this change.Slide 7 of 21
FatigueSlide 8 of 21