Pregnancy causes some physical changes as early as 10 days after conception. Changing hormone levels modify how your body's systems work to accommodate your growing baby.
First Trimester
Early signs of pregnancy occur in weeks one to 12, or the first trimester. Your first physical signs may be slight uterine cramping and spotting. These occur during implantation when the embryo burrows into the uterine lining and begins to develop a placenta. Your breasts may become swollen and feel tender. Your menstrual cycle will stop and you will feel tired. Both progesterone and estrogen levels rise steadily during your pregnancy. Hormonal changes early in pregnancy can cause changes in blood pressure that can make you feel dizzy or cause headaches. You may also suffer mood swings. Food will move more slowly through your stomach and intestines and cause nausea and constipation. You may have a heightened sense of smell, which will make some foods--even ones you love-- less appetizing. On the other hand, you may crave other foods.
Second Trimester
By week 13, the beginning of the second trimester, you may be adjusted to the early changes and have regained some of your energy. Now, as the baby begins to grow more rapidly, you may start to feel aches in you back, abdomen or groin. You may also begin to feel your baby move inside you.
The most visible signs of pregnancy are stretch marks and changes in skin color. The skin around your nipples may darken. You may notice a dark line running from your belly button to your pubic hair. Some women develop patches of darker skin on their faces, called the "mask of pregnancy." Stretch marks are permanent, but changes in skin pigment go away after you have the baby. Your hands, fingers or ankles may swell because of fluid retention. You may experience a tingling sensation in your hands and feet, which are symptoms of carpal tunnel syndrome. This will usually go away after delivery.
Third Trimester
Between weeks 29 and 40, you are in the last trimester of pregnancy. Your baby is taking up a lot of space beneath your rib cage and may be putting pressure on your stomach, lungs and bladder. Pressure on the lungs can cause shortness of breath. You've probably noticed that you need to urinate more beginning in the first trimester, but with the weight of the baby on your bladder, you may feel that you are spending all your time in the bathroom. You might have heartburn due to the pressure the baby is putting on your stomach. Your belly is very large now and your belly button may be pushed out. Your breasts may be leaking a pre-milk fluid called colostrum. Near delivery, your baby may "drop" lower into your pelvis where she needs to be for vaginal delivery. You may feel "practice" uterine contractions called Braxton Hicks from time to time. The good news is is that all of these wonderful, strange and annoying physical signs of pregnancy are "cured" by the delivery of your baby.
