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Learn what to expect with your body and your baby's growth over the 40 weeks of your pregnancy.


Week 1 - A happy thought

Your pregnancy begins with the first day of your last menstrual period.

Your body makes follicles each menstrual cycle which contain about 20 eggs. One of these eggs (called an ovum), is released about 2 weeks after your period begins, and travels down your fallopian tube awaiting fertilization. It is important that you begin taking 0.4 milligrams (400 micrograms) of folic acid each day before conception occurs to help decrease the risk of neural tube defects, such as spina bifida.


Week 2 - Conception

By the end of this week, the egg will most likely have traveled down the fallopian tube to become fertilized. It’s hard to know exactly when conception occurs, so your due date is estimated by taking the first day of your last menstrual period, subtract 3 months, and add 7 days. Therefore, the length of pregnancy is approximately 40 weeks, or 280 days.

Week 3 - A zygote

Baby: The sperm has now joined the egg to create a zygote, which is about the size of a pin head. This group of cells multiplies and grows rapidly. 

Mom: You haven’t missed a period yet, so you are not even aware you are pregnant.

Week 4 - Baby is the size of a poppy seed

Baby: By the end of the first month, your fertilized egg is now called an embryo and is approximately ¼ inch long — smaller than a grain of rice.

Mom: You may notice some light spotting when the embryo implants itself into the lining of your uterus.

Week 5 -Size: apple seed

Baby:  Your baby’s brain, spinal cord, and heart have begun to form; and baby’s arm and leg buds appear. 

Mom:  You may notice changes in your body early in pregnancy, such as bloating, darkened nipples, and breast tenderness. These changes occur from increasing progesterone levels (which are vital to maintain a healthy pregnancy). Wear whatever is comfortable and makes you feel good.

Week 6 - Size: black peppercorn

Baby:  Baby’s heart can now be seen and heard with ultrasound, and facial features are forming. 

Mom: Your hCG (human chorionic gonadotropin) levels should be high enough now to give you a positive pregnancy test.

If you haven’t already done so, schedule your first prenatal appointment. Click here if you need a provider. (This link will take you to a provider directory on


Week 7 - Size: blueberry

Baby:  Your baby’s fingers and toes are developing, and eyelids have formed. 

Mom:  Your breasts may continue to be tender and swollen.  You may also need to urinate more frequently since blood volume increases during pregnancy. These are some of the prenatal blood tests you may expect at your prenatal visit:  determine your blood type and Rh (Rhesus) factor, blood count, test for hepatitis B, HIV, rubella, and syphilis. The physical exam will most likely include a pelvic exam, cultures for gonorrhea and chlamydia, Pap test, test for human papillomavirus (HPV), and possibly an ultrasound, depending on the week of pregnancy. 

Week 8 - Size: grape

Your baby is starting to move.

Baby: By the end of your 8th week, your baby is now a fetus and is nearly one inch long and weighs ¼ ounce. 

Mom:  You may now be experiencing morning sickness (which can occur at any time of the day, not just mornings). Contact your health care provider if nausea and vomiting are persistent and you are unable to keep fluids down for 24 hours. Small, frequent meals may help combat nausea.

Week 9 - Size: strawberry

Baby: Baby’s intestines are forming, and 20 buds appear in preparation for future teeth. 

Mom:  You may be experiencing mood swings, sleepiness, and fatigue since progesterone levels remain high. Try going to bed earlier to get a good night’s rest.

Week 10 - Size: mandarin orange

Baby:  Bones and cartilage are developing, and soft nails are forming on fingers and toes. Heartbeat may be detected with a hand-held fetal Doppler. 

Mom:  Cravings or distaste may be occurring for certain foods. Make sure you’re eating healthy foods, drinking lots of water, and avoiding alcohol and illicit drugs. If taking prescription medicines, make sure your health care provider knows, so they can advise you on what is best for you and baby. Your prenatal visits will likely happen every 4 weeks until week 28 or so, and then they will become more frequent.

Week 11 - Size: lime

Baby:  Bones are starting to harden, and muscle development has begun. 

Mom:  Now is the time to evaluate workplace and environmental hazards you may be in contact with.

Risk of miscarriage is the highest in the first 3 months of pregnancy. 

Week 12 - Size: plum

Baby:  Nerves and muscles begin to work together, and baby can even make a fist. Eyelids close to protect the developing eyes and will not open again until the 28th week. Baby is now almost 3 inches long and weighs almost an ounce. 

Mom:  Your uterus is now the size of an orange, and you have probably gained 2-4 pounds. You may also feel short of breath, too, as your baby grows.

Week 13 - Size: peach

Baby:  Now called a fetus, the baby’s spleen starts working to produce red blood cells, sex hormones are being made, and the vocal cords are forming. 

Mom:  Most moms find the second trimester of pregnancy easier than the first. Some symptoms like nausea and fatigue may be going away, but other new, noticeable changes to your body are happening. Talk to your health care provider about any concerns you may have. 

Now is the time to quit smoking, if you are a smoker and have not quit yet. Smoking while pregnant triples your baby’s risk of dying unexpectedly and suddenly. It also increases the chances of your baby being born too early and too small to be healthy. It is never too late to quit — the sooner the better. Your healthcare provider probably has resources for smoking cessation.