Your health care provider will typically mark the beginning of your first trimester from the start of your last period. This means you are not actually pregnant for the first couple of weeks from their calendar calculations. The reason the calculation is done this way is because it is nearly impossible to tell the exact day you conceived, but on average it occurs approximately 2 weeks after your last period.

Therefore, Week 3 is considered the first week in which you are actually fertilized (i.e., when the zygote - sperm plus egg - forms), and Week 4 is when the multiplying zygote (blastocyst) reaches your uterus and attaches itself and the placenta begins to form. At this time, the pregnancy hormone, human chorionic gonadotrophin (hCG), begins to surge and you may test positive with a home pregnancy test that can detect hCG days prior to your expected period.

Once you find out that you are pregnant, you are probably wondering what to expect in the months to come. Be prepared and informed for changes you might experience in the first trimester (Weeks 1 to 13 from the start of last menstrual period).

The first thing you need to know is that each pregnancy is different. However, to help manage your stress, you should be aware or what common changes might occur and what symptoms require a visit to your physician.

  • tiredness: This is perfectly normal since your body requires energy to support the growth of your baby. Try to get as much rest as you can. Sleeping on your left side may be beneficial and alleviate stress on the blood and nutrient supply to the baby.
  • breast changes: Swollen or tender breasts are common and the result of getting prepared for breast-feeding. Areolas may enlarge, darken, and become covered with small white bumps. Additionally, veins on the surface of the breast can become more prominent. These are perfectly normal changes.
  • nausea and vomiting: Often referred to as morning sickness even though it can last all day long. This is perfectly normal and occurs in more than half of all pregnant women in the first trimester and usually subsides in the second trimester, although some women experience it throughout their entire pregnancy. Avoid smells and foods that make you nauseous, eat small and frequent meals, and drink plenty of fluids. If your nausea is severe, contact your health care provider.
  • increased frequency of urination: This is common and a result of hormonal changes. If you suspect a urinary tract infection (burning, pain, or discharge), contact your health care provider.
  • dizziness: This can occur due to changes in your circulatory system and with increased blood flow to your uterus. Avoid prolonged standing and get up slowly from a lying or sitting position. Dehydration, stress, or low blood sugar levels may also be culprits for dizziness. Make sure to stay hydrated, snack frequently, and find ways to reduce your stress level. Alert your health care provider of any dizziness you are experiencing; although common, it can indicate other problems (such as anemia) in some cases.
  • varicose veins: These swollen veins can occur in pregnant women during all trimesters and are most often found in the legs. They are the result of increased blood volume, increased pressure on the leg veins by the uterus, and pregnancy hormones that can relax muscles. These may require treatment to remove them after pregnancy. To minimize you chances of getting varicose veins, avoid tight stockings, extreme weight gain, and heavy lifting. Try to exercise and keep your feet raised when you're sitting. Additionally, some women can get harmless spider veins on their thighs or ankles that usually vanish after pregnancy.
  • increased heart rate: An increased pulse rate during pregnancy can occur as a result of larger cardiac volume required for extra blood flow to your uterus.
  • heartburn, indigestion, and gastrointestinal problems: Pregnancy hormones relax muscle tone, including those in your digestive tract and bowels, causing indigestion, constipation, and bloating. Additionally, the relaxation of the ring separating your stomach and esophagus can cause stomach acid to flow upwards, resulting in the burning sensation of heartburn. Try eating smaller meals that are high in fibre at regular intervals, drinking plenty of liquids, stopping smoking (secondhand smoke should also be avoided during pregnancy), and avoiding gas-producing spicy, acidic, carbonated, or fried foods. Talk to your physician before taking any over-the-counter products.
  • excess saliva production: This is a harmless condition that can occur in the first few months of pregnancy, which normally disappears.
  • hemorrhoids: Hemorrhoids are similar to varicose veins but with veins swelling centralized to the rectum, either internally or externally, and lead to itching, pain, or bleeding. Although commonly experienced during pregnancy, talk to your physician about potential hemorrhoid remedies.
  • weight gain or loss: Most women will gain some weight during the first trimester, however, it is not uncommon for those experiencing morning sickness to actually lose weight. Although not optimal, weight loss should not be a problem during the first trimester and is usually associated with morning sickness. Fortunately, morning sickness usually disappears after the first trimester, allowing pregnant women to consume the extra roughly 350 to 450 calories per day they need during the second and third trimesters for fetal growth. Also, extreme weight gain is not healthy and can lead to a variety of complications. Regular visits with your doctor will help you assess your optimal target weight gain over time.
  • changes in taste and smell: Pregnant women commonly develop heightened sensitivity to smells and tastes. This normal occurrence may lead to unusual food cravings or avoidance of certain foods and smells. Use common sense and avoid triggers that bother you. Don't overindulge on cravings that you know are unhealthy for you - try to find a healthier alternative.
  • missed menstrual periods: Your period stops during the length of your pregnancy. In the first trimester, when most miscarriages occur, you should be particularly aware of unusual cramping or spotting. While this can be normal in the first several weeks of pregnancy, it is best that you contact and discuss with your doctor to help alleviate your stress.
  • mood changes: You may experience anxiety, elatedness, fear, joy, irritability, misgivings, moods swings, and even weepiness. These feelings are perfectly normal. Seek encouragement and understanding about your feelings with your friends, partner, family, and health care provider. Again, always remember to take good care of yourself and realize that the ups and downs you are feeling are a normal part of pregnancy.