It’s important to remember that pregnancies differ from person to person. This page should give you a general idea of what to expect at each stage. If you have any questions or would like to confirm your pregnancy, please schedule a free appointment today at the Community Women’s Centers. We have three convenient locations located in Center City Philadelphia and Bucks County.
The following is a week-by-week explanation of pregnancy from Week 1 to Week 40.
Week 1-2
A lot is happening behind the scenes, you just can’t see it yet. This is when your body is ovulating, and your uterus is getting all ready to possibly conceive. This is apparent by the thickening of the uterine wall and the release of an unfertilized egg (called ovulation).
First Trimester | Weeks 3 - 14
With Week 3 comes the big moment. This is when ovulation and implantation can occur. When the one single sperm meets the egg, there you have it…conception. At conception, the fetus’ eye color, hair color, gender, and more have already been determined.
Right now, the fetus is called an embryo, and some major things are happening this week. The embryo’s brain, spinal cord, heart, and gastrointestinal tract are all being developed.
Week 4 | Now is the time to take a pregnancy test. Most women discover their pregnancies between weeks 4-7. At this stage, pregnancy symptoms may start to develop such as a missed period or breast tenderness.
Additionally, your embryo is beginning to experience some major growth here. The beginning stages of the nervous system, skin, nails, hair, mammary glands, sweat glands, and enamel for teeth begin to develop. Also, the foundations of the heart, lungs, skeletal, liver and much more are being laid. Even the beginnings of the arms and legs begin to develop this week.
Week 5 | You may begin feeling a little bit of morning sickness during this week. It’s a good time to make your appointment and schedule a free pregnancy test with us. If you are pregnant, at this state, your embryo looks a little bit like a tadpole. It has a steady heartbeat, and the eyes and ears are just beginning.
Week 6 | You may begin to experience more pregnancy symptoms by week 6. Heartburn, some light cramping, and light bleeding are super normal this week.
Your breasts may still be tender, and you might even notice some changes in the way they appear. Your embryo is beginning to develop fingers and toes. Plus, a little nose, jaw, and palate have begun. Also, the lungs and brain are continuing to develop.
Week 7 | You may still be experiencing morning sickness, and maybe some possible weight gain. However, you may have lost a couple of pounds due to morning sickness or gained a few pounds.
Each person is different. At this point, you might be having some mood swings and some unique food cravings, too. Your embryo is developing a tongue, hair follicles, and eyelids. Every essential organ that a human being needs to survive has already begun to form at this point.
Week 8 | It’s a good time to either begin or continue your prenatal care during week 8. Begin taking prenatal vitamins, continue with healthy eating and lifestyle choices. Before you were pregnant, your uterus was the size of a fist. By week 8, it’s the size of a grapefruit!
Your embryo now contains every body part that an adult has, but they are not developed. The facial features begin to become more defined, and its muscles are even able to contract. Heart development is complete.
Week 9 | While you still may not look pregnant from the outside, you may now begin to feel bloated and your pants may start to feel snug. Some of the pregnancy symptoms may have disappeared, and others may have surfaced.
Now called a fetus, it is ready for some major weight gain. The fetus can also start sucking its thumb this week.
Week 10 | In Week 10, your fetus moves, kicks, and swallows. Your newly pregnant body is still experiencing pregnancy symptoms.
The fetus’ kidneys, liver, brain, and lungs are now actually functioning. Plus, they are beginning to kick their newly developed legs this week.
Week 11 | Your fetus is super active at this point. The skeleton is beginning to harden, and your fetus’ head is almost half of its entire length. Your body is continually changing along with the ever-changing fetus.
Many women also notice hair and fingernail growth during this time in pregnancy. However, not all women will show their pregnancies at this point. Some may notice a small bump, and for some women no bump is noticeable.
Week 12 | Your fetus is continually growing, as well. Its kidneys can now secrete urine and the facial features become more recognizable. Gender can be determined by blood tests.
You are almost out of your first trimester at this point. Your ever-growing uterus is expanding, and depending on if this is your first pregnancy or not, you may already be needing maternity clothes.
Week 13 | Your fetus now has its very own fingerprints.
You are almost done with the first trimester of pregnancy. You might notice some stretch marks here and there as your body is meeting the demands of the growing fetus.
Week 14 | Because of your fetus’ developing brain, it can now make facial expressions with facial muscles. Its liver and spleen have also begun to develop more.
Congratulations! You made it into the second trimester!
Your early pregnancy symptoms may start to subside a little bit, and you might start feeling more like yourself again. Amen! Your breasts are preparing for lactation and may have become swollen and tender.
Second Trimester | Weeks 15 - 27
Week 15 | You can actually see your fetus’ skeleton on an X-Ray if it were taken this week.
Most women will have gained 5 pounds by this point. Don’t worry if you’ve gained more or less. But, continued prenatal visits are good to ensure you have a healthy weight gain and the fetus is developing appropriately.
Week 16 | Fetal movement may now be felt by the mother. Your fetus’ circulatory and urinary systems are beginning to function now, along with some other body systems.
You may be experiencing that “pregnancy glow” due to the increased blood volume and overactive oil glands.
Week 17 | Your fetus’ hearing is beginning to develop, and fetal heart tones are heard with a stethoscope. Most women see a noticeable baby bump by now. Your other internal organs are having to move because of your growing uterus.
Week 18 | Your fetus’ genitals are now beginning to form externally. It could be possible to distinguish between males and females on an ultrasound.
Your growing fetus needs some extra room. You may also notice some dizziness. This is due to possible low blood pressure caused by your cardiovascular system being affected by the pregnancy.
Week 19 | As other parts of the fetus’ development continue, hair is beginning to develop on the fetus’ head, and eyebrows. Due to the growing fetus, you may experience round ligament pain. This is super normal and happens when your ligaments must stretch to compensate for the growing fetus.
Week 20 | Your fetus is beginning to produce meconium (which then becomes the big first diaper change after birth).
You have made it halfway through your pregnancy! Yay! Typical weight gain at this point is between 8-10 lbs.
Week 21 | Your fetus is now swallowing amniotic fluid and the digestive system is continuing to develop.
Most women really enjoy this time in pregnancy. You are over the first trimester and your belly is not too big to keep you from doing most things.
You may have been able to feel the fetus move at this point. Continue a healthy diet and light exercise. Enjoy this time!
Week 22 | The fetus has a hand grasp and startles reflex.
You may notice some swelling in your feet or legs at the end of the day. If so, just take some breaks during the day to give your feet a rest.
Week 23 | Your fetus is beginning to start a rapid weight gain and looks more and more like a newborn baby.
The fetus is totally laying on your bladder. You may notice you have to use the bathroom more often.
Week 24 | Your fetus’ brain is developing super-fast and is also starting to develop taste buds during this time. With the continued growth of your fetus, you might begin to feel itchy as your skin stretched. Stretch marks are very normal. Lotion is a great option to help ease any itchiness associated with dry skin.
Week 25 | Your fetus’ gender should be distinguishable with ultrasound by now (or even before if the fetus will cooperate).
The uterus is approximately the size of a soccer ball.
Week 26 | Your fetus’ lungs are continuing to develop, and it is able to respond to sound and light.
Most women at this time have gained between 16-22 lbs. Continue with a healthy diet and regular prenatal visits to ensure you are experiencing a healthy pregnancy.
Week 27 | You should be feeling your fetus kicking and moving around all the time. You may also be feeling movements like hiccups. Keep track of the movements because a sharp decrease or no movement could be a sign of potential distress on the fetus.
If you have any questions, contact your doctor. Your fetus may be able to open its eyes at this point and has a regular sleep and wake cycle. Let’s just hope it’s the same as yours.
Third Trimester | Weeks 28 - 40
Week 28 | The fetus is taking up more space and your organs have to adjust. So, you may notice some constipation or some leg cramps. Your fetus is continuing to gain weight and even has eyelashes and eyebrows. You are now in the home stretch…the third trimester!
Week 29 | The fetus is experiencing some amazing brain development. Make sure to continue to eat foods high in folic acid and other vitamins. Plus, continue taking those prenatal vitamins.
The average weight gain at this point is between 19-25 lbs. Prenatal massage is a good way to relax overextended muscles and ligament pain.
Week 30 | The fetus is continually growing and is now able to distinguish between light and dark inside the womb.
You may be experiencing some insomnia. This is very normal since it can be hard trying to find a comfortable position to sleep. A pregnancy pillow may help you find some rest.
Week 31 | Your fetus is continuing to gain weight and develop its lungs.
During this time, you might have noticed a yellowish substance leaking from your breast. This is totally normal. It’s called colostrum, and it’s what your body makes in the beginning stages of lactation (breast feeding).
Week 32 | You may experience Braxton Hicks contractions during this time. They are completely normal and it’s your body’s way to “practice” labor. If you are not aware if you are experiencing Braxton Hicks contractions or real labor, contact your doctor. Your fetus is continuing to gain weight and develop its lungs.
Week 33 | Some women can get a little nervous that their “water” will break. Amniotic fluid is odorless and colorless.
If you are unsure if your bladder had a leak or if your amniotic sac has ruptured, try smelling it to tell the difference. If you are still unsure, contact your doctor. Your fetus’ bones are all beginning to harden, except for the skull, which needs to remain moldable for delivery.
Week 34 | Your fetus’ central nervous system is still developing, and it’s still gaining a consistent amount of weight.
Make sure to still do light exercise like walking and allow yourself to rest when you become tired. Your body is working hard, and self-care is important.
Week 35 | The fetus is pretty much done growing by this point. It will continue to gain weight, but the kidneys are totally developed. You should be able to feel the fetus move consistently.
Week 36 | The fetus should be positioned with its head down towards the pelvis.
People may begin to tell you that you’ve “dropped.” That just means that the fetus is now engaged in the pelvis. It helps with the shortness of breath but might keep you up at night with trips to the bathroom.
Week 37 | Your fetus is continually enjoying its womb for the time. But move out day is approaching.
Getting close to delivery! Braxton Hicks contractions may still be preparing you for labor, and the doctor may check to see if you are dilating.
Week 38 | All of the organs of the fetus are fully functioning, except the brain and lungs, which continue to develop after birth.
You may notice you have passed the mucus plug. It helps keep bacteria from entering the cervix during pregnancy. When you pass the mucus plug, it’s a great indicator that you may be dilating.
Week 39 | Your fetus is still gaining weight.
Although it’s normal to experience swelling during your pregnancy, make sure you are keeping a good eye on severe swelling as it could be a sign of preeclampsia (it can be a dangerous condition). Check with your doctor if you have any questions.
Week 40 | Full Term! You and your doctor have probably already talked about birthing possibilities and what to do if you go over 40 weeks. Your pregnancy has been a continual journey of preparation for labor.
Most full-term babies are between 19-21 inches long and weigh between 6 ¾ and 10 pounds.
The trusted and caring team at the Community Women’s Center can provide the information you need to make the choice that is right for you! Schedule an appointment today.