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:
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.
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.
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.
Being exhausted is very common during the first trimester of pregnancy, as well as during the last few months before delivering. This is most likely caused by rising levels of the hormone progesterone in early pregnancy, Moss said.
Women may notice they feel more sluggish and sleepy than usual as early as one week after conception, suggests the American Pregnancy Association.
It makes sense that the body feels wiped out more easily during the early phases of pregnancy because blood volume increases to supply the developing placenta and fetus with nutrients, which causes a woman's heart to work harder.
Moss said she dislikes the term "morning sickness" because the queasiness and throwing up can strike any time of day or night. Women may begin to feel sick to their stomachs between the sixth and twelfth weeks of pregnancy, and some women may start to feel relief by week 14, she said.
The bouts of nausea and vomiting affect 70 to 85 percent of pregnant women, according to The American Congress of Obstetrics and Gynecology (ACOG). These symptoms are likely triggered by the hormonal changes of pregnancy.
To ease the symptoms, Moss recommends eating small, frequent meals, resting as much as possible, choosing blander foods without strong smells and drinking ginger tea. Other remedies include eating a few crackers in the morning before getting out of bed, consuming high-protein snacks, such as yogurt, and avoiding spicy and fatty foods, according to ACOG. [Related: Pregnancy Diet & Nutrition: What to Eat, What Not to Eat]
In the early weeks of pregnancy, a woman may not yet be showing, but her abdominal area may feel softer and fuller, Moss said. This is likely caused by increased levels of the hormone progesterone, she explained.
During the early months of pregnancy, a woman may feel like she is on an emotional roller coaster as changes in hormone levels affect her body and mind.
"It's normal for women to feel on edge, like they are having premenstrual (PMS) symptoms," Moss said. For some women, this may make them act a little more irritable than usual, while others get a little more down or weepy, she explained.
Besides adjusting to shifting hormone levels, a woman's moodiness can also be caused by some of the physical changes of early pregnancy, such as fatigue and morning sickness, as well as the emotional changes in her life, including the stress of becoming a parent, worries over having a healthy baby and financial concerns about adding a new family member.
Changes in urination and bowel movements
Beginning about six weeks into the first trimester and throughout her pregnancy, a woman may need to pee more frequently.
Frequent bathroom visits happen in early pregnancy because the kidneys are working harder to filter the extra fluids in the body, such as an increased volume of blood. As the months pass and the fetus grows and develops in a woman's uterus, it can put pressure on her bladder, causing a need to urinate more often than usual, according to the March of Dimes.
Constipation may be caused by extra progesterone, which can slow down the digestive system so that more nutrients can reach the fetus. Pregnancy hormones can also relax muscles that push waste products through the intestines. Being physically active, drinking lots of liquids, and increasing dietary fiber can all help ease constipation, suggests the Mayo Clinic.
Headaches and back pain
Getting headaches is a common symptom during the first trimester, Moss said. They could be a sign of hunger or dehydration, or may even be caused by caffeine withdrawal, she explained.
Lower back pain, felt more as an achiness, is another complaint of women in early pregnancy. Backaches may be more common during the second and third trimesters, as the growing uterus puts pressure on nerves and blood vessels in the back and pelvis, and also as pregnancy weight gain changes a woman's center of gravity and her posture, according to ACOG.
Some women may feel dizzy or lightheaded during the early months of pregnancy. The wooziness can be related to low blood sugar or dehydration, Moss said, as well as to blood shifts in the body, especially when a woman changes position, for example from sitting to standing, or when she gets out of bed. If a woman faints, she should contact her health provider, she advised.
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