After the first trimester, a miscarriage is much less likely. And for many moms-to-be, early pregnancy symptoms like morning sickness and fatigue have faded away. If you’re feeling more energetic now and haven’t been exercising, it’s a good time to start a regular pregnancy fitness routine.
How big is your baby? We give the answer a real-world twist in this handy, week-by-week, food-inspired guide.
In this illustration, you’ll notice that your growing baby takes up quite a bit of room these days. In the third trimester, you might be peeing more often or have leg cramps as he presses on nerves in your hips and back.
Get more information, expert advice, and support from our community of parents to guide you through your pregnancy and beyond:
At the start of this week, you ovulate. Your egg is fertilized 12 to 24 hours later if a sperm penetrates it – and this simple biological occurrence begins a series of increasingly complicated processes that leads to a new human life, if all goes well. Over the next several days, the fertilized egg will start dividing into multiple cells as it travels down the fallopian tube, enters your uterus, and starts to burrow into the uterine lining.
Your baby has started moving around, though you won’t feel movement yet. Nerve cells are branching out, forming primitive neural pathways. Breathing tubes now extend from his throat to his developing lungs.
Your baby is almost fully formed. She’s kicking, stretching, and even hiccupping as her diaphragm develops, although you can’t feel any activity yet.
Your baby resembles a tadpole more than a human, but is growing fast. The circulatory system is beginning to form, and the tiny heart will start to beat this week.
Your baby can move her joints, and her skeleton – formerly soft cartilage – is now hardening to bone. The umbilical cord is growing stronger and thicker.
The patterning on your baby’s scalp has begun, though the hair isn’t visible yet. His legs are more developed – find out when you’re likely to feel your baby kick! His head is more upright, and his ears are close to their final position.
Your baby’s ears are getting better at picking up sounds. After birth, she may recognize some noises outside the womb that she’s hearing inside now.
This is the last week of your first trimester. Your baby’s tiny fingers now have fingerprints, and her veins and organs are clearly visible through her skin. If you’re having a girl, her ovaries contain more than 2 million eggs.
Follow your baby’s development week by week, from conception to labor, in these amazingly detailed, doctor-reviewed images.
Capture your precious pregnancy & baby milestone photos by marking them with beautifully crafted artwork & personalized text. Share & treasure forever!
AAFP. 2011c. Your baby’s development: The third trimester. American Academy of Family Physicians. http://familydoctor.org/familydoctor/en/pregnancy-newborns/fetal-health/your-babys-development-the-third-trimester.html [Accessed October 2016]
Your baby’s brain impulses have begun to fire and he’s using his facial muscles. His kidneys are working now, too. If you have an ultrasound, you may even see him sucking his thumb.
See an incredible illustration of what your developing baby looks like at 16 weeks.
Your baby’s physical development is complete, but he’s still busy putting on fat he’ll need to help regulate his body temperature in the outside world.
See an incredible illustration of what your developing baby looks like at 14 weeks.
You’re probably gaining about a pound a week. Half of that goes straight to your baby, who will gain one-third to half her birth weight in the next seven weeks in preparation for life outside the womb.
Your baby is now considered late-term. Going more than two weeks past your due date can put you and your baby at risk for complications, so your provider will probably talk to you about inducing labor.
MedlinePlus (ADAM). 2015. Fetal development. https://www.nlm.nih.gov/medlineplus/ency/article/002398.htm [Accessed October 2016]
Capture your weekly baby bump growth, bubs first kick, first steps, messy moments or first day at school. Add our adorable artwork & treasure the special moment forever. Parents-to-be & new parents, this adorable app is made for you!
Your baby’s wrinkled skin is starting to fill out with baby fat, making her look more like a newborn. Her hair is beginning to come in, and it has color and texture.
See an incredible illustration of what your developing baby looks like at 18 weeks.
It’s getting snug inside your womb! Your baby’s kidneys are fully developed, and his liver can process some waste products.
Mayo Clinic. 2014a. Fetal development: The 1st trimester. http://www.mayoclinic.org/healthy-lifestyle/pregnancy-week-by-week/in-depth/prenatal-care/art-20045302 [Accessed October 2016]
Your baby can swallow now and his digestive system is producing meconium, the dark, sticky goo that he’ll pass in his first poop – either in his diaper or in the womb during delivery.
If you’re past your due date you may not be as late as you think, especially if you calculated it solely based on the day of your last period. Sometimes women ovulate later than expected.
Find the best gear for your baby. See the 2018 Moms’ Picks winners.
ACOG. 2015. FAQ156. Prenatal development: How your baby grows during pregnancy. American College of Obstetricians and Gynecologists. http://www.acog.org/Patients/FAQs/Prenatal-Development-How-Your-Baby-Grows-During-Pregnancy#one [Accessed October 2016]
Your baby is now inhaling and exhaling amniotic fluid, which helps develop his lungs. These breathing movements are good practice for that first breath of air at birth.
Your baby’s eyelids are still fused shut, but she can sense light. If you shine a flashlight on your tummy, she’ll move away from the beam. Ultrasounds done this week may reveal your baby’s sex.
This is the last week of your second trimester. Your baby now sleeps and wakes on a regular schedule, and her brain is very active. Her lungs aren’t fully formed, but they could function outside the womb with medical help.
Your baby’s basic physiology is in place (she even has tiny earlobes), but there’s much more to come. Her embryonic tail has disappeared. She weighs just a fraction of an ounce but is about to start gaining weight fast.
Your ball of cells is now officially an embryo. You’re now about 4 weeks from the beginning of your last period. It’s around this time – when your next period would normally be due – that you might be able to get a positive result on a home pregnancy test.
Mayo Clinic. 2015. Fetal development: The 2nd trimester. http://www.mayoclinic.org/healthy-lifestyle/pregnancy-week-by-week/in-depth/fetal-development/art-20046151 [Accessed October 2016]
Your baby’s nose, mouth and ears are starting to take shape, and the intestines and brain are beginning to develop.
Your baby is gaining about an ounce a day. She’s also losing most of the fine down that covered her body, along with the vernix casosa, a waxy substance that was protecting her skin until now.
Plus: See our ultimate pregnancy to-do list for the second trimester
Your baby’s central nervous system is maturing, as are her lungs. Babies born between 34 and 37 weeks who have no other health problems usually do well in the long run.
Our complete pregnancy guide gives you expert info and advice about your growing baby and the changes in your body, by week and…
Your baby now looks almost like a miniature newborn. Features such as lips and eyebrows are more distinct, but the pigment that will color his eyes isn’t present yet.
At 39 weeks, your baby will be considered full-term. In the illustration, you can see the mucus plug sealing your uterus and how squished your intestines are now.
Your baby cuts a pretty long and lean figure, but chubbier times are coming. His skin is still thin and translucent, but that will begin to change soon too.
Your baby has doubled in size since last week, but still has a tail, which will soon disappear. Little hands and feet that look more like paddles are emerging from the developing arms and legs.
Your baby’s muscles and lungs are busy getting ready to function in the outside world, and his head is growing to make room for his developing brain.
Your baby’s senses – smell, vision, touch, taste and hearing – are developing and she may be able to hear your voice. Talk, sing or read out loud to her, if you feel like it.
Meeting your baby for the first time is so exciting – but exactly what will lead up to that moment is unpredictable, and it’s natural to feel nervous. Here’s some help as you prepare for the big day. Find out how you’ll know you’re in labor and what to expect from delivery, understand your childbirth choices, and more.
The bones in your baby’s skull aren’t fused yet. That allows them to shift as his head squeezes through the birth canal. They won’t fully fuse until adulthood.
Your due date is very close, but though your baby looks like a newborn, he isn’t quite ready for the outside world. Over the next two weeks his lungs and brain will fully mature.
See an incredible illustration of what your developing baby looks like at 15 weeks.
OWH. 2010. Stages of pregnancy. U.S. Office on Women’s Health. http://www.womenshealth.gov/pregnancy/you-are-pregnant/stages-of-pregnancy.html [Accessed October 2016]
Now nestled in the nutrient-rich lining of your uterus is a microscopic ball of hundreds of rapidly multiplying cells that will develop into your baby. This ball, called a blastocyst, has begun to produce the pregnancy hormone hCG, which tells your ovaries to stop releasing eggs.
Mayo Clinic. 2014b. Fetal development: The third trimester. http://www.mayoclinic.org/healthy-lifestyle/pregnancy-week-by-week/in-depth/fetal-development/art-20045997 [Accessed October 2016]
How big is my baby? Week-by-week fruit and veggie comparisons
See an incredible illustration of what your developing baby looks like at 17 weeks.
Your embryo has completed the most critical portion of development. His skin is still translucent, but his tiny limbs can bend and fine details like nails are starting to form.
See an incredible illustration of what your developing baby looks like at 12 weeks.
Your baby is flexing his arms and legs, and you may be able to feel those movements. Internally, a protective coating of myelin is forming around his nerves.
See an incredible illustration of what your developing baby looks like at 27 weeks.
The so-called honeymoon phase of pregnancy is over and parenthood is visible on the horizon has begun. Now’s the time to do things like sign up for a childbirth class, choose a doctor for your baby, and create a baby registry.
This week your baby’s reflexes kick in: His fingers will soon begin to open and close, toes will curl, and his mouth will make sucking movements. He’ll feel it if you gently poke your tummy – though you won’t feel his movements yet.
Your baby’s eyesight is developing, which may enable her to sense light filtering in from the outside. She can blink, and her eyelashes have grown in.
Your baby is surrounded by a pint and a half of amniotic fluid, although there will be less of it as she grows and claims more space inside your uterus.
But if you don’t go into labor on your own by your due date, your healthcare provider will probably do tests (such as a sonogram and a non-stress test) to make sure you can safely continue your pregnancy
In this illustration, you can see how big – and yet, how tiny still – your baby is as you begin your second trimester.
Your baby can now turn his head from side to side. A protective layer of fat is accumulating under his skin, filling out his arms and legs.
AAFP. 2011a. Your baby’s development: The first trimester. American Academy of Family Physicians. http://familydoctor.org/familydoctor/en/pregnancy-newborns/fetal-health/your-babys-development-the-first-trimester.html [Accessed October 2016]
Your baby’s movements have gone from flutters to full-on kicks and jabs against the walls of your womb. You may start to notice patterns as you become more familiar with her activity.
Are you curious about your baby’s eye color? Her irises are not fully pigmented, so if she’s born with blue eyes, they could change to a darker color up until she’s about a year old.
AAFP. 2011b. Your baby’s development: The second trimester. American Academy of Family Physicians. http://familydoctor.org/familydoctor/en/pregnancy-newborns/fetal-health/your-babys-development-the-second-trimester.html [Accessed October 2016]