What to Expect With Pregnancy, Week by Week

You're pregnant! Congrats! As your little one grows, you can expect a number of changes in your own body.

Here's what's happening week-by-week with you and your baby's development. And for more info, check out the For American Pregnancy Association's website or pick up a copy of the tried-and-true What to Expect When You're Expecting.

First Trimester

You may not be showing quite yet but your body (and your baby) are undergoing rapid change. This is the phase when you're likely to experience common pregnancy symptoms, including morning sickness. Read about each week to learn how to manage these early challenges and how to start prepping for your little one's arrival.

Week 1: Your first week of pregnancy occurs before you're actually pregnant.

(Imagine that!) In fact, technically, this first week marks the last period you'll have before conceiving. The reason this week "counts" as part of your pregnancy is really to create a standardized way of measuring women's pregnancy lengths, since many women may not know when they conceived and because conception may not actually take place on the day of intercourse.

Week 2: This week also occurs pre-conception. Your period will likely be gone by now and your body is preparing for ovulation. Doctors rely on a standardized measure of cycle length (28 days) and of the day ovulation occurs (day 14).

Your cycle may be longer and you may ovulate on day 14, 18 or even 25 of your cycle. No matter if your cycle falls within the parameters of your doctor's measurements or not, it doesn't really matter. He or she will be able to adjust your due date as your baby grows.

Week 3: The official start of your pregnancy is the hallmark of this week. Both ovulation (when your egg descends) and implantation (when your egg is fertilized and burrows into your uterus) usually occur during this week. Some women may feel mild cramping, nausea, tiredness and tender breasts this week, which could be mistaken for premenstrual symptoms. You may even notice light bleeding from the implantation of the embryo into your uterine wall, but not every woman experiences this.

Week 4: The most telltale sign that you've conceived is, of course, a positive pregnancy test. For many pregnant women, this week will be the one in which you'll miss your period and get the proverbial plus sign on the at-home urine test. (For those with longer cycles, you may need to wait until later in the week or even the following one to take a test.)

Like the previous week, you may experience common symptoms like tender breasts or nipples, some spotting, fatigue and upset stomach, if you haven't already. This is a good time to call your doctor to schedule your first pregnancy visit, which will likely occur around week 8.

Week 5: If you didn't get a positive pregnancy test last week, this week you likely will if you did indeed conceive. Your symptoms may continue to worsen, especially fatigue and nausea.

(Know that "morning sickness" is just a catchy term — you may actually feel sick all day long. Awesome, right?)

You may also notice some bloating. The rapid hormonal changes within your body are to blame for these side effects.

But while you may feel uncomfortable, know that these signs just mean that your body is actively growing your baby, which an amazing thing. Now is a good time to start taking prenatal vitamins, if you haven't already — these supplements contain folic acid, which is critical to supporting your baby's growing spine and brain.

Week 6: By this week, you probably aren't actually showing yet, but you may notice that your clothes aren't fitting quite like they used to pre-pregnancy. As your uterus changes in size to prepare for your growing baby, your waist will get thicker, making you want to swap your favorite jeans for comfy sweats.

Your changing uterus may also cause some light spotting — if you're experiencing bleeding in early pregnancy, it's a good idea to give your doctor a call just in case. Week six is an important week because it's the end of the high-risk miscarriage period, allowing you to rest a little easier knowing that your little one is most likely staying put in your womb for the long haul.

Week 7: If you've been lucky enough to escape the more common pregnancy symptoms like nausea, tiredness and breast changes, this week may change all that. If an upset stomach is plaguing you, try to eat small meals, snack on salty crackers and drink water to stay hydrated.

By keeping your stomach balanced — not too full and not too empty — you should be able to fight the nausea. You may also notice that certain foods or smells trigger your nausea, which is normal.

In most cases, pregnancy sickness and even vomiting won't hurt you or your baby. But if you're constantly throwing up and having a hard time keeping any food down, this could be a sign of a more serious condition and you should call your doctor just in case.

Week 8: Your first prenatal appointment will most likely occur this week, allowing you to see your bean-sized baby on an ultrasound and hear his or her heartbeat.

The excitement of actually "meeting" your child can often, at least temporarily, alleviate your uncomfortable pregnancy symptoms, reminding you that all the physical distress is well worth it. This week, your uterus has grown to the size of a grapefruit, making your clothing little tighter, and your breasts are beginning to prepare for lactation.

Week 9: As your baby continues to grow, more pregnancy symptoms may arise this week, including frequent urination, heartburn, digestive issues (yay, gas!) and lower back pain. You may experience mood swings, as well. If you still haven't faced morning sickness yet — and some lucky women don't — this week could be the week it appears. For those who battled it since the beginning and those who felt it later alike, know that the nausea will typically subside in about a month from now.

Week 10: By this week, your baby is just over an inch long and the average onlooker won't know you're pregnant. But your body continues to change in subtle ways, making getting dressed in your normal clothes an increasing challenge.

Your breasts may have grown a full cup size at this point and you might notice some darkening of your nipples, which will continue over the course of your pregnancy. (Your body is making sure that your newborn baby will be able to easily find your nipples if you choose to breastfeed. Cool, huh?) Your other symptoms may persist or intensify at this time, with a couple more added into the mix: Constipation, darkening of your veins, sensitive or bleeding gums and abdominal discomfort.

Read more: Pregnancy in Your 30s — Everything You Need to Know

Week 11: You're entering the home stretch of the (very tiring!) first trimester.

Luckily, a positive side effect is on the horizon, stronger skin and nails. Your pregnancy hormones will make both grow quicker and healthier, giving you luxurious locks and longer nails. If you've had particularly rough morning sickness, you may learn that you've lost weight or gained very little over the course of your pregnancy so far. This is normal but it's a good idea to talk with your doctor about it.

Week 12: In just two weeks your baby has tripled in size, reaching just over three inches in length. Your body changes are not quite as pronounced, yet.

However, you may notice your morning (or all-day) sickness subsiding this week, making you feel a bit more like your pre-pregnancy self. You may also notice some additional skin changes, particularly dark patches on your face. (Not to worry — just like your darker nipples, these patches should fade after delivery.)

Week 13: You've made it to the last week of your first trimester!

While you may still feel tired all the time, know that you're about to get a kick of energy over the next few weeks as your second trimester begins.

Your body is continuing to grow with baby, particularly your breasts and belly, and you may notices changes to your skin, like stretch marks and even some itching. Applying cream to your belly should alleviate some of the discomfort.

Second Trimester

Pregnant couple having tea together in kitchen

Signs That a Baby Is Getting Ready to Come

Learn More

As morning sickness wanes and your growing belly is still manageable, these weeks comprise the most comfortable phrase of pregnancy. This is the time to pick out those cute maternity duds and show off that bump. You may also get a chance to say hello to your growing baby on an anatomy scan between 18 to 22 weeks.

Week 14: Welcome to the second trimester! This week, your baby is measuring around four inches — but your waistline has probably expanded well beyond that.

Use your changing body as a fun opportunity to splurge on cute clothes that compliment your mom-to-be bod.

And while those pesky pregnancy symptoms are likely fading away, this week may bring some mood swings. Blame those rapidly changing hormones when you find yourself crying during (yet another!) commercial for laundry detergent.

Week 15: By this week, most women have gained about five pounds, but some may gain less or more. (Especially if this is not your first pregnancy, you may feel like your body has been changing at super speed this time around!)

Around this time, it's a good idea to change your sleeping position to on your side. Lying down on your stomach can put too much pressure on your growing baby and being on your back for too long can do the same to the blood vessels attached to your baby. Sticking a pillow between your knees while you sleep can be a good way to relive any lower pain you may have from being on your side.

Week 16: This week brings some major excitement — it's the time when you may be able to feel your baby quote-unquote kick for the first time.

Sometime between now and week 20 you'll notice fluttery feelings in your belly, or even a sensation that seems like it would be gas bubbles. That's your baby moving around. This week, you may also notice you have that so-called pregnancy glow as your blood volume continues to increase.

Week 17: The morning (or constant) sickness you felt in the early weeks has likely turned into an insatiable appetite by this week.

As your baby grows, so will your hunger. Go with your cravings while keeping a healthy balance as much as you can.

At the same time, as your uterus continues to expand to accommodate your baby, your internal organs are getting pushed in new directions. This can cause heartburn and indigestion. Smaller meals can alleviate these digestive annoyances. You may also notice allergy symptoms like a runny nose or itchy eyes this week, which is typical at this stage in your pregnancy.

Read more: The Biggest Myths About Working Out During Pregnancy, Debunked

Week 18: This week may be your next opportunity to see your baby if your doctor performs an ultrasound. Typically scheduled between 18 and 20 weeks, this scan gives you the chance to see your baby (sometimes in 3-D!) and allows your doctor to look at important bodily features, like your baby's heart, brain and spine.

And, of course, the sex of baby, if you so desire to know. You may also notice some changes in your legs and feet: At this point in your pregnancy, you may experience leg cramps and swelling. Keeping your legs elevated can help relieve the latter.

Week 19: You're almost to the halfway point and by now your uterus has grown so much that it has just about reached your belly button. (Go on, give it a feel.) If you haven't noticed fluttery movements from your baby yet, you likely will by this week.

On the less exciting side, you may have noticed some skin changes.

Not only will your nipples have darkened, but you may notice a vertical line reaching from your belly button to your vagina (called linea negra) that's common among pregnant women.

Your armpits, parts of your face and even your perineum may appear darker too. (Luckily, you probably can't see that last one unless you're really flexible.) You may also experience round ligament pain in your lower abdomen as this tendon increases in size and becomes tighter.

Week 20: At the halfway point, your baby is just about seven to eight inches long. You're likely gained about 8 to 10 pounds yourself by now and you can expect to gain a half to a full pound a week for the rest of your pregnancy.

By this week, you're actually rocking the bump, which is fun transition from looking (and feeling) super bloated without actually looking pregnancy yet. If you have an innie belly button, it may pop out and become an outie around this time. (It will go back in after delivery but the shape may be different than your pre-pregnancy navel.)

Week 21: This week is one of the best of pregnancy. You've got the bump out and proud, you're well past the nausea phase, your energy has come back and you've just recently seen your little one on the big screen. Now's a great time to get back into a fitness routine (talk to your doctor beforehand, of course) or start getting the nursery ready, before you're too big to want to move. (Kidding… kind of.)

One downside to this week is that you may start to notice some vein swelling in your legs and, yes, your vagina and booty, as the pressure from your baby and uterus pushes blood down. Like many symptoms, these will go away after delivery but you can alleviate the discomfort by elevating your legs and feet and by not standing up too fast when getting out of bed in the morning.

Week 22: As you head toward the third trimester, your baby has reached a pound in weight and around 10 inches in length.

Your bump is growing too, leading to one of the more annoying pregnancy symptoms — unsolicited belly grabs. If old ladies can't seem to keep their hands off of you, know that it's perfectly acceptable to either say no as a wayward hand comes your way or quickly scoot away.

Another important hallmark of this week has to do with preterm labor, a scary prospect for any expecting parent. Doctors can now do a simple pap smear-like test for this in which they check for fetal fibronectin, a protein only found in vaginal secretions up to 22 weeks and again at 38 weeks. If you're worried about preterm labor, this test can help alleviate concerns.

Week 23: Progesterone is doing a number on you this week, making eating and thinking a little more difficult. On the food front, the hormone causes your digestive system to slow down, which can make you feel perpetually bloated (like you didn't feel big enough already).

As far as your brain is concerned, progesterone is responsible for making you feel a bit fuzzy or absent minded. If you're losing your keys more than normal or find yourself walking out of the house without your shoes on, blame your hormones.

Week 24: While no one likes to talk about preterm birth, the good news is that, by this week, your baby is considered viable outside of the womb if he or she decides to come early.

Knowing this information helps many women breath a sign of relief just in case the unexpected happens.

As far as your body is concerned, this week may bring itchy or dry skin, particularly your tummy, but even your eyes too. Your doctor will also order a gestational diabetes test between now and 28 weeks to ensure your levels are within range.

Week 25: As you near the end of the second trimester, you're probably feeling a whole lot of action going on in your belly. Your baby's startle reflex has developed and he or she can also get the hiccups, making for some crazy-awesome sensations in your body.

Below the belly, you may notice some not-so-awesome side effects of your growing body, like hemorrhoids (sexy). You, or your partner, may have noticed also noticed that you now snore, as well. These unpleasant side effects are just part of carrying a baby in your belly and they won't last forever.

Week 26: By now, you've probably put on about 16 to 22 pounds and your baby continues to grow and change each day. He or she can hear and see (as much as one can see when suspended in liquid) and soon your baby's movements will get a bit more coordinated and feel less like sneak attack jabs.

Sleep may be tougher for you now with all that activity going on in your uterus, and those frequent trips to the bathroom as baby squishes cozily against your bladder. Just know that you're still getting more sleep than you will with a newborn, so enjoy it while you can.

Week 27: Welcome to the last week of your second trimester!

Your baby has grown to almost two pounds by now and you're feeling that growth as everyday movements (and sleeping) may become a little more challenging. Persistent symptoms like heartburn, swelling, dizziness and bloating remain and will continue until your delivery.

But anything out of the ordinary should always be discussed with your doctor. For instance, restless leg syndrome can affect many women by this week and while it could be just a benign part of pregnancy, it could also be a sign of an iron deficiency, so it's definitely something to bring up.

Third Trimester

You're getting close now! This phase can be the most tedious as you anxiously wait for your baby to arrive.

Exercise and even walking around may be more difficult as your baby grows in size so take this time to relax, decorate the nursery and prepare for parenthood. Your little one is almost here!

Week 28: To kick off your third trimester, literally, your doctor may suggest that you begin counting your baby's kicks. Some babies move more than others but having an idea of the frequency and schedule of these kicks can be a good indicator that everything is all good in the womb. You'll start having more frequent prenatal visits now that you're in the last portion of pregnancy — typically every two weeks until you hit 36 weeks — allowing you to confirm with your doctor that your baby is doing just fine.

Week 29: If you're feeling like you're ready to pop already, you're not alone.

But, on the flip side, if you're not as big as other expecting friends or family members at this stage in your pregnancy, don't sweat it. Every woman carries different depending on body type, height and pre-pregnancy weight. Your doctor will assure you that however big you've gotten (or not) is right for you.

No matter your bump size, constipation is likely your biggest pain point, literally, by this week.

Your growing uterus and the progesterone pumping through your body are doing a number on your digestive system, squishing your organs, slowing things down and stopping you up. Walking and eating fiber-rich foods should help.

Week 30: Ten more weeks to go, meaning that you're 75 percent of the way through your pregnancy. By this point, may women feel like they end can't come soon enough. Heartburn, gas, trouble sleeping and having to pee all the time make pregnant life far less glamorous than those glowing second trimester days. Your breast may also start feeling tender again as your body gears up for milk production.

Week 31: As your body prepares for labor, this week you may start to feel what are called Braxton-Hicks contractions, which are essentially a warm-up for the big show (but not nearly as painful, thankfully).

Your breasts are continuing to prep too and you may even notice some pre-delivery leakage of colostrum, the nutrient-rich substance your baby will eat before your milk supply rushes in a day or a few days after delivery. Having these side effects crop up when you least expect it is good practice for what it's like to having a baby. You just never know when he or she might spit up, wake up or, later, throw a tantrum. Think of rolling with these body changes as helpful prep for parenthood.

Week 32: By now, your uterus sits five inches above your belly button, leaving little room for the rest of your internal organs.

While you've likely noticed digestive issues (from constipation to heartburn) now you may feel some shortness of breath as your (still growing!) belly presses on your diaphragm. Speaking of growing, you're probably gaining about a pound a week now as your baby fattens up and gets ready to meet you.

Read more: 12 Safe Exercises to Stay Fit During Pregnancy

Week 33: These final weeks of pregnancy can drag, even more so than the first trimester, especially since you're now carrying extra weight around.

You may notice this week that your wrists and hands ache or feel numb — blame the excess fluid in your body for causing pinched nerves and general discomfort.

If you've been lucky enough to escape lower back pain, it may appear now too. Try to avoid standing for too long and, if you haven't already, ditch the high heels to take pressure off of your lower back. Your doctor may also be able to suggest a supportive brace you can wear if the pain is super intense.

Week 34: Your baby now weighs around four to five pounds and has reached 17 inches in length, on average. Between now and week 36, the volume of amniotic fluid will peak and then decrease, getting reabsorbed into your body, which will give your baby a little more room to kick and move around.

In fact, by this week, your baby should have flipped around to situate his or her head downward to get ready for heading out the birth canal.

(You may even feel your little one hiccuping right in your pubic area, which is quite the experience!) Your doctor can check your little one's position at your next appointment. This week, he or she will also order a group strep B test to check for a potential bacterial infection hat affects 25 percent of women.

Week 35: Yep, you're about ready to pop, as they say, this week.

You may feel increasingly clumsy and off-balance, teetering around with that belly. Being off-kilter is completely normal—your center of gravity is way off from what you're used to — and the pregnancy brain fog doesn't make getting around any easier. You might notice an increased need to pee all the time (yes, even more than weeks past), as your growing baby continues to put pressure on your bladder as he or she packs on the ounces.

Week 36: One month until your meet your baby! It's easy to get restless now that you're really in the final countdown.

But remember that the longer your baby stays put in your womb, the healthier he or she will be when delivery does happen.

Right now, your baby's head is wedged right above your cervix and you may have felt him or her "drop" this week as your delivery date gets closer. Braxton-Hicks contractions may also get more frequent or intense, making you wonder if this is it. Luckily, your doctor will have you come in for weekly appointments from here on out, giving you some extra peace of mind.

Week 37: This week marks an important milestone: If you go into labor now, your baby will be considered full-term. Of course, as over pregnancy as you might be, the longer he or she is cooking in your womb, the better. You'll notice that your body is prepping for labor as your cervix may begin to dilate (get bigger) and efface (soften).

Braxton-Hicks may kick up as well, giving you a taste of labor. You may even pass your mucus plug—the gooey stopper for your little one's hot tub that keeps bacteria out of the placenta—this week. (But it might not come out until you're actually in labor—everyone's body is different.) The week may also bring a newfound burst of energy as your body pumps up for the big show, which could happen anytime now.

Week 38: You're really in the final stretch now. Your belly is maxed out and your baby is ready to join you in the world. You may notice some increased swelling in your feet these days and more Braxton-Hicks. Sleep may be elusive as you get up to pee and struggle to find a comfortable position.

It's all a waiting game now so try to be patient as you ready yourself for labor. Pass the time by getting a manicure, packing your hospital bag or grabbing lunch with friends while you're still baby-free.

Week 39: Not much to do this week except wait.

You won't notice too many changes in your body at this stage as you wait for labor to kick in. Your pelvic area may feel achy from the added pressure from your baby's head over the past week weeks and you've likely perfected your pregnancy waddle. If you're having a scheduled caesarean, your doctor may book it for this week so that your body doesn't go into labor naturally before your surgery.

Week 40: Your baby will most likely make his or her debut this week, bringing your pregnancy to its official end. While pregnancies typically last 40 weeks, some women don't give birth until 41 or even 42 weeks, depending on how the baby is doing in the womb and what their doctors suggest. You may have your last prenatal visit this week and your doctor may schedule a non-stress test to check your baby's movements and the fluid level in your womb to determine if you might need to be induced.

No matter what, you will meet your child very soon and officially become a parent. Congratulations!

Read more: 11 Quotes That Will Inspire You to Love Your Postpartum Body