First Trimester

Week 1-2

Your body is ovulating, and your uterus is getting ready to possibly conceive by the thickening of the uterine wall and the release of an unfertilized egg (called ovulation).

Week 3

This is the week fertilization occurs. When one single sperm unites with the egg, you have conception or fertilization. At conception, the new human’s eye color, hair color, gender and more have already been determined. Now the journey down the fallopian tube toward the uterus begins.  Our next stop is implantation.  Right now, the new human is called an embryo.1

At this stage, the amount of HCG (pregnancy hormone) in urine can vary a great deal from woman to woman. So, if you do a pregnancy test too soon, you may get a false negative or an unclear result like a faint line.

Week 4

As we implant into the uterus, the placenta starts to form. The placenta is the organ that serves as our DoorDash and Waste Management company throughout the rest of our stay in the uterus. As the tiny human’s development continues to move rapidly, so do hormone levels.  This increase in hormones accounts for pregnancy symptoms such as a missed period and breast tenderness. But many women don’t have any symptoms yet.

Week 5

Hormone levels continue to rise, and you may be growing more aware of pregnancy-related symptoms, including fatigue, sore or swollen breasts, nausea, and the need to pee more often. This week in development, we look a little bit like a tadpole. However, our heart has begun to beat and is steady, and our brain and nervous system are beginning.

It’s a good time to come see us. Since ovulation times are different for every woman, it’s important to have accurate, medical grade pregnancy testing which we do free of charge. You may have your first limited OB ultrasound this week as well. It is the best way to determine due date, gestational age or how far along you are.

Week 6

It has been only 4 weeks since conception, and we are already beginning to develop arms and legs. Our head and neck are center stage this week as the muscles, bones, and glands start to shape. As well as continued brain development. You may see the heartbeat this week during the ultrasound.

You may begin to experience more pregnancy symptoms. Your breasts may still be tender, and you might even notice some changes in the way your nipples appear. Heartburn and some light cramping and light spotting are super normal this week. It’s counterintuitive but eating small meals throughout the day can help you keep nausea at bay. Snacking on lightly seasoned or unseasoned foods and drinking ginger tea can also help.

Week 7

This week our face begins to take distinctive form as it continues to grow. Indentions that will be our nostrils (nose holes) are visible and the retinas (back part of our eye which is how we see) start to take shape.  Also, the beginnings of our legs are more noticeable, and our little arms have developed hands, which look more like paddles at this stage.  

You may still be experiencing morning sickness which can lead to weight loss. It is normal to have random mood swings and some interesting and unusual cravings. You may have a heightened sense of smell which can make you feel queasy and need to stay away from certain foods. Some foods to avoid now for health reasons are: Swordfish, cold deli meats, raw oysters, homemade cookie dough, bean sprouts, extra-large coffees, unpasteurized juices, and queso fresco.

Week 8

At this stage we are now the size of a kidney bean and have many of the body parts that an adult has, but these parts are not fully developed yet. Our legs now have feet (also resemble paddles) but individual fingers have begun to separate which means our hands no longer look like paddles. The nervous system has begun to work and small movements can be seen on the ultrasound.  Although you typically won’t feel them until week 16. The facial features like eyes, nose and upper lip are more defined. Also, the beginnings of our ears are seen. 

If you have not begun your prenatal care, now is the time to start. Keep taking prenatal vitamins and 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. Breasts are typically tender and larger by now.

Week 9

This week toes are now visible as well as longer arms that now have elbows. On the face the eyelids form. We have grown about a quarter of an inch which puts us the length of the diameter or a U.S. penny. 

Your body is not only growing this embryo, but also a new organ – the placenta, which is attached to your uterus and connected to the embryo through the umbilical cord. The placenta is developed enough now to take over most of the critical job of producing hormones that help growth and development.

You may not look pregnant on the outside, but you may now begin to feel bloated and your pants may start to feel snug. Some of your pregnancy symptoms may have disappeared, and others may have surfaced.

Week 10

We are ever-changing and now begin to kick our developing legs and wave arms freely. There are now eyelids forming that will cover the eyes as protection during continued development. At the end of this week, the eye lids will be fused, which means they won’t open, until week 27.  The umbilical cord is clearly seen.  

The thickening in your midsection is most likely due to slight weight gain and bloating. You may have more vaginal discharge. It should be odorless or mild-smelling and clear or milky white. You can wear panty liners if you need to, but don’t use tampons or douche.

Week 11

This week is the beginning of the fetal period (from embryo). All vital organs should be in place, and many have already started to function. Your fetus is super active at this point. The skeleton is beginning to harden, and our head is half of our entire length.  Teeth buds appear, and red blood cells are being made in the liver.  External genitalia has started to form.  We measure about 2 inches in length from head to rump.  

Your body is continually changing too. Many women also notice hair and fingernail growth during pregnancy. However, not all women look pregnant at this point. Some may notice a small bump when it won’t be noticeable in others.

Week 12

As our head continues to take shape, facial features become more recognizable. Fingernails are now forming. We have grown to about 2 ½ inches. You are almost done with the first trimester of pregnancy.

Your uterus is expanding and depending on if this is your first pregnancy or not, you may already be needing looser clothes. Your uterus has grown enough that your healthcare provider can now feel the top of it low in your abdomen, above your pubic bone. Your doctor may use a special device called a doppler which when placed over this same area so you can hear your baby’s heartbeat.

Second Trimester

Week 13

This week in development, we have started swallowing amniotic fluid and excreting urine, recycling the full volume of fluid every few hours. Skeletal bones are hardening, and our skin is still pretty thin. Skin will start to thicken before long. Fingers move independently and now have fingerprints visible. At this point, females have all the eggs she will ever produce in her tiny ovaries.  

You might notice some stretch marks here and there as your body is meeting the demands of your growing bodies. Moisturizing these areas are a must! 

Week 14

We can now make facial expressions with facial muscles and may be caught on ultrasound sucking our thumb. Their spleen has become more developed and is making red blood cells. The fetus starts to make sucking and chewing movements. The body’s growing faster than the head, which now sits upon a more distinct neck. The arms are growing more in proportion to the rest of their body which is the size of a lemon.

The early pregnancy symptoms may start to subside a little bit. Your energy is likely returning, your breasts may feel less tender, and hopefully queasiness may have eased by now.

Week 15

The legs have grown longer than the arms now, and the fetus can move all joints and limbs. Taste buds are forming, and nerves are being connected to the brain. The fetus has hair forming on their eyebrows, eyelids, head, and has well-defined fingers and toes with nails present. Because of continued bone development, the skeleton can be seen on an X-Ray if it were taken this week.

Most women will have gained 5 pounds by this point. Continued prenatal visits are good to ensure you have a healthy weight gain and everything is developing appropriately.

Week 16

Our head is more erect and now we look more like we will after delivery.  The eyes can move around and sense light.  The eyelids are still fused as a protective layer during the rest of eye development.  Skin has started to thicken this week as well.  

You should have less nausea, fewer mood swings, and “glowing” skin which contributes to an overall sense of well-being. This pregnancy glow is due to the increased blood volume and overactive oil glands in the skin.

Week 17

Toenails are starting to form. Activity in the womb is increasing with our ever-developing muscles. We are working our muscles to stay strong and healthy. At any time from now, you may start to feel these movements which are called “quickening” at first.  

Most women see a noticeable ‘baby bump’ by now. This is because your other internal organs are having to move over because of your growing uterus. As your belly grows, your center of gravity changes. You may begin to occasionally feel a little unsteady on your feet.  Slow down a little when standing up and take it easy if necessary when feeling this way. Use furniture or a friend to help steady yourself as needed. 

Week 18

Genitals are more specified and pronounced. It could be possible to distinguish between male and female on an ultrasound, depending on positioning. Our ears are now in their final position and are functioning. Also, the digestive system has started working this week. 

Your growing fetus needs some extra room so consider switching to maternity clothes if you have not already. You may also notice some dizziness, too. Drinking plenty of water to stay well hydrated should help. Eating healthy snacks every three hours will keep your blood sugar level steady, so you’re less likely to be starving at dinnertime.

Week 19

Your baby’s brain is designating specialized areas for smell, taste, hearing, vision, and touch. Arms and legs are in proportion to each other and the rest of the body now. At this point growth is able to slow down a little. We now have a protective coating for our skin to prevent hard scratched from nails and damage from the amniotic fluid (like when we prune from a long swim or bath). 

Due to the growing fetus, you may experience ligament pain. This is super normal and

happens when your ligaments that hold the uterus stretch as the uterus grows with baby.

Week 20

You are halfway through the pregnancy! We have developed a sleep/wake cycle and may be awakened by noises or your activities.  Many of the taste buds can now transmit taste signals to the brain, and swallowing molecules of the food you eat that passed through your blood into your amniotic fluid. Researchers aren’t sure if they can taste these molecules, but some research indicates that what you eat during pregnancy can influence the foods your baby will prefer later. We are now a little over 6 inches from head to rump.  

Week 21

The hair on our head starts to grow with color now.  Also, a fat layer is forming that will plump up the skin. The initial fluttering movements have turned into full-fledged kicks and nudges. You may also discover a pattern to the activity.

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.

Week 22

Hair is now visible on our head and eyebrows. For males, the testicles have started to drop down. We are about 7 ½ inches long from head to rump and weigh around 1 pound. 

Your Increased oil production may cause you to develop acne and 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

This week we start to gain weight rapidly and look more and more like a newborn baby. Our hearing is more developed, and we better hear sounds from the outside world, although they’re muffled by layers of skin, uterus, and amniotic fluid. 

Your growing uterus is totally laying on your bladder. You may notice you have to use the bathroom more often.

Week 24

Our brain is developing very quickly. The body is filling out proportionally, and soon will start to plump up. The skin is still translucent, but that will start to change as well.

With continued growth, you might begin to feel itchy as your skin stretches. Stretch marks are very normal. Apply lotion to help ease the itchiness. Your nesting instinct may be kicking in. Make the most of it. In addition to organizing, cleaning, and preparing your baby’s space, think about child-proof safety in your home.

Week 25

Our gender should be distinguishable with an ultrasound by now (or even before if we will cooperate). It is possible at this point that you notice movement when talking or other familiar sounds are heard.

Your hair may look full and more lustrous than ever. It’s not that you’re growing more hair, but thanks to hormonal changes the hair that you’d normally shed is sticking around longer than usual. Pale skin is a sign that you may be iron deficient. It’s common during pregnancy, so you’ll be tested for it around this time.

Week 26

We may have started to inhale and exhale small amounts of amniotic fluid, which is essential for lung development. Also, we can respond with changes in heartbeat, breathing, and movement.

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. If your lower back seems a little achy lately, you can thank both your growing uterus – which shifts your center of gravity, stretches out and weakens your abdominal muscles, and may be pressing on a nerve – as well as hormonal changes that loosen your joints and ligaments.

Week 27

Our eyelids, which have been fused shut, can now open and close, and may blink in response to light. You should be feeling us kicking and moving around all the time. You may also be feeling movements like the hiccups, too. They may be common from now on. Each episode usually lasts only a few moments.

Yes, your feet are spreading due to fluid retention and looser ligaments. So, buy a few pairs of comfortable, roomy shoes.

Third Trimester

Week 28

This week, our brain is adding billions of new nerve cells. The senses of hearing, smell, and touch are developed and functional. We are continuing to gain weight and even has eyelashes. We are very active now, and your healthcare provider may ask you to spend some time each day counting kicks and will give you specific instructions on how to do this.

You’ll most likely have a checkup every two weeks until 36 weeks, then switch to once-a-week visits until you deliver.

Week 29

Brain development continues. Make sure to continue to eat foods high in folic acid and other vitamins. Plus, continue taking those prenatal vitamins.

Your baby’s bones are soaking up lots of calcium as they harden, so be sure to drink your milk (or find another good source of calcium, such as cheese, yogurt, or enriched orange juice). About 250 milligrams of calcium are deposited in your baby’s skeleton each day.

The average weight gain at this point is between 19-25 lbs.

Week 30

The pupils can constrict and expand, allowing and now able to distinguish between light and dark inside the womb and able to see dim shapes. Also, red blood cells are being made in the bone marrow.

You may be experiencing some insomnia, fatigue and mood swings. This is very normal since it can be difficult trying to find a comfortable position to sleep. Sleeping with a pregnancy pillow can help you find some rest.

Week 31

This week we have finished most of our major development; so we continue to gain weight, develop its lungs, and probably moving a lot.

Have you noticed the muscles in your uterus tightening now and then? Many women feel these random contractions – called  Braxton Hicks contractions – in the second half of pregnancy. Often lasting about 30 seconds, they’re irregular, and at this point, should be infrequent and painless. They are completely normal and it’s your body’s way to “practice” labor. During this time, you might have also 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

The baby toenails and fingernails have grown in, along with real hair (or at least respectable peach fuzz).

You’re gaining about a pound a week, and roughly half of that goes right to your little one. They will gain a third to half of their birth weight during the next seven weeks as they fatten up for survival outside the womb.

Week 33

The bones in your baby’s skull overlap and will compress into a bullet-like shape so he can fit through the birth canal. The rest of the bones are all beginning to get hard.

It’s typical to be short of breath as your growing uterus puts pressure on your diaphragm and pushes up against your lungs. 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 sack has ruptured, try smelling it to tell the difference. If you are still unsure, contact your doctor.

Week 34

The baby’s central nervous system is still developing, and it’s still gaining a consistent amount of weight.

A woman’s body is continually preparing for delivery with each passing week. It is important to still do light exercise like walking and allow yourself to rest when tired. By this week, fatigue has probably set in again, though maybe not with the same coma-like intensity of the first trimester.

Week 35

The baby is pretty much done growing by this point. It will continue to gain weight, but the kidneys are totally developed. While there is less room for the baby to kick, you should still be able to feel us move consistently.

Soon the baby will descend into your pelvis, giving your lungs more room but putting more pressure on your bladder.

Week 36

Most babies at this point are head down towards the pelvis.

People may begin to tell you that you’ve “dropped.” That just means that the baby is now engaged in the pelvis. It helps with the shortness of breath you may have been experiencing but might keep you up at night with trips to the bathroom.

Now that your baby is taking up so much room, you may have trouble eating a normal-size meal. Smaller, more frequent meals are often easier to handle at this point.

Week 37

Your due date is getting close now. Spending the next two weeks in the womb allows your baby’s brain and lungs to fully mature. Because it’s so snug in your womb, your baby isn’t doing a lot of somersaults anymore, but the amount of kicking should remain about the same.

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 our organs are fully functioning, except the brain and lungs, which continue to develop after birth.

You may notice you pass 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 baby is still gaining weight. They continue to build a layer of fat to help control body temperature after birth. At a prenatal checkup, your provider might do an internal exam to see whether your cervix has started ripening which means softening, effacing (thinning out), and dilating (opening). 

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.

Call your provider if you think your water has broken. Sometimes there’s a big gush of fluid, but sometimes there’s only a small gush or a slow leak.

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.

Babies of all ethnicities are born with reddish-purple skin that changes to pinkish-red in a day or so. The pink tint comes from the red blood vessels that are visible through your baby’s still-thin skin. Because your baby’s blood circulation is still maturing, his hands and feet may be bluish for a few days. Over the next six months, your baby’s skin will develop its permanent color.

It’s hard to say for sure how big your baby will be, but the average newborn weighs about 7 1/2 pounds and is about 20 inches long. About half of all newborns are late arrivals – usually because their due date was off.