Pregnancy & Birth

Pregnancy Timeline:
Week by Week

From conception to delivery, pregnancy is a 40-week adventure into parenthood. Every trimester, you and your baby will experience new milestones — changes in your body, evolving pregnancy symptoms, and the size of the fetus.

At NewYork-Presbyterian, our board-certified obstetricians and gynecologists are familiar with what to expect. We’ve created a timeline that takes you through your pregnancy week by week, so you can know what’s coming and get excited about the journey.

Woman throughout pregnancy timeline

How Many Weeks is a Pregnancy?

Pregnancy typically lasts for 40 weeks or 280 days. Most doctors start the pregnancy countdown from the first day of your last menstrual period (LMP).

Pregnancy is divided into three stages called trimesters:

  • First trimester (1 to 13 weeks)
  • Second trimester (14 to 26 weeks)
  • Third trimester (27 to 40 weeks) 

Throughout all three trimesters, subtle to significant changes will occur in your body and in your baby’s development. This week-by-week pregnancy timeline offers a preview of what you can expect over time.


The first 13 weeks of pregnancy can be an exciting and nerve-wracking time. While a missed period might be your first early pregnancy symptom, there are other signals from the body that you’re pregnant. Throughout the pregnancy timeline, various symptoms will arise. You may experience all or none of them. 

Week 3

Congratulations! You’ve officially conceived. Your baby-to-be is a tiny cell, quickly dividing and growing. You probably won’t be able to confirm the pregnancy through a test quite yet, but your body may start exhibiting signs of conception. 

3-week pregnancy symptoms:

  • A heightened sense of smell, caused by hormonal fluctuations
  • Lower abdominal pressure
  • Metallic taste in your mouth 
  • Light spotting
  • Nausea or mild queasiness
  • Breast tenderness

Baby’s size: No bigger than a tip of a pin

Week 4

A home pregnancy test from a local pharmacy can confirm pregnancy if your period is late. If the test yields a positive result, you can schedule an appointment to see an obstetrician 2 to 4 weeks later (at 6 to 8 weeks gestation). A doctor can confirm the pregnancy through a blood or urine sample. 

Your body: The placenta and amniotic sac are starting to form within the uterus.

4-week pregnancy symptoms:

  • Tender breasts
  • Abdominal pressure
  • Implantation bleeding

Your baby is a rapidly transforming ball of cells or blastocyst. 

Baby’s size: No bigger than a poppy seed

Week 5

At this point, most women have noticed a missed period and have taken steps to confirm their pregnancy through an at-home test. 

Your body: First trimester symptoms may kick in and be harder to ignore. 

5-week pregnancy symptoms:

  • Sore breasts
  • Frequent urination
  • Morning sickness
  • Cramps
  • Fatigue
  • Mood swings

Your baby is already beginning to resemble a fetus. The brain, spinal cord, and heart are starting to form.

Baby’s size: As big as an apple seed

Week 6

You may be preparing for your first prenatal visit. Be sure to keep track of your symptoms and any questions you have for your doctor. 

Your body: While you won’t have a baby bump yet, you may experience bloating and other symptoms, including cravings for foods you’ve never wanted before.

6-week pregnancy symptoms: 

  • Bloating and gas
  • Fatigue
  • Morning sickness/nausea
  • Cramping/spotting
  • Mood swings
  • Sore breasts
  • Frequent urination

Your baby’s heart has started to beat. The baby’s body resembles a tadpole with tiny eyes and eyelids.

Baby’s size: Your baby has doubled in size since last week from an apple seed to a sweet pea.

Week 7

Your body: To prepare for breastfeeding, fat and blood flow begins to build up in your breasts. Your bra size might go up a whole cup, and your nipples may be extra sensitive. The area around the nipple (areola) will expand and grow darker. Hormonal acne breakouts are expected at this stage. 

7-week pregnancy symptoms:

  • Bloating and gas
  • Heartburn
  • Acne
  • Fatigue 
  • Morning sickness/nausea
  • Extra saliva
  • Cramping/spotting
  • Mood swings
  • Darkened areola
  • Increased breast size
  • Sore breasts
  • Frequent urination

Your baby: In addition to forming all the essential organs — heart, lungs, liver, intestines — small, paddle-shaped clusters are developing at the end of your baby’s arms and legs. These will eventually become feet and hands. 

Baby’s size: As big as a blueberry

Week 8

At your prenatal doctor’s visit, you will be able to see your baby via an ultrasound and see and/or hear the fetal heartbeat. 

Your body: In addition to physical pregnancy symptoms, you may start to experience vivid dreams. 

8-week pregnancy symptoms:

  • Strong sense of smell
  • Mild cramping
  • Constipation
  • Fatigue
  • Morning sickness/nausea
  • Spotting (Let your doctor know) 
  • Sore breasts
  • Frequent urination

Your baby is officially a fetus. Its posture is starting to straighten out, and the beginnings of a face are forming, including ears, a nose, and lips. 

Baby’s size: As big as a raspberry

Week 9

Your body: The uterus is growing to make room for your developing fetus, so you might find it hard to button your pants due to bloating. 

9-week pregnancy symptoms:

  • Nasal congestion
  • Headaches
  • Fatigue
  • Morning sickness/nausea
  • Mood swings
  • Sore breasts
  • Frequent urination 
  • Bloating/gas
  • Constipation

Your baby’s reproductive organs have begun to form. Its tadpole tail has disappeared, replaced by two tiny legs. 

Baby’s size: As big as a cherry or a green olive

Week 10

10-week pregnancy symptoms:

  • Veins, visible around the breast and belly
  • Dizziness
  • Headaches 
  • Growing breasts
  • Morning sickness
  • Fatigue
  • Mood swings
  • Increased vaginal discharge (Consult your doctor if it’s tinged with blood or colored)

Your baby’s eyes are open now. The webbing that was once in between the toes and fingers is completely gone. Already the brain is making cognitive connections that your baby will use in future music and math classes. 

Baby’s size: As big as a strawberry

Week 11

Your body: New pregnancy symptoms can include leg cramps at night, which may disrupt your sleep. Also, the appearance of linea nigra, a dark line that develops down the center of your stomach. Linea nigra is caused by fluctuating hormones and will disappear after you give birth. 

11-week pregnancy symptoms:

  • Frequent urination
  • Nausea
  • Bloating/gas
  • Skin darkening down the center of the abdomen, or the linea nigra

Your baby is becoming active but is still too small for you to feel any of its movements. Its head is large compared to its body, accounting for almost half of its body. Irises and fingernails are forming. 

Baby’s size: As big as a lime

Week 12

By 12 weeks, your risk of miscarriage significantly drops, so you can start sharing the news about your pregnancy. And if you haven’t heard it already, you’ll be able to see your baby’s heartbeat during the 12-week checkup. 

Your body: Hormones begin to level out, meaning your fatigue and morning sickness may subside. The need to frequently urinate will fade as your uterus shifts away from the floor of your pelvis to a more centered and frontal part of your stomach. 

12-week pregnancy symptoms:

  • Headaches
  • Nausea
  • Fatigue

Your baby’s organs are rapidly developing, and your teeth, fingers, and toes. 

Baby’s size: As big as a plum

Week 13

Your body: Toward the end of the third trimester, some of your initial pregnancy symptoms may diminish. Hopefully, you are putting on weight, and your morning sickness symptoms are gone. 

13-week pregnancy symptoms:

  • Spider veins, due to increased blood flow
  • Heartburn
  • Constipation

Your baby’s kidneys are developed enough to produce urine. If your baby is female, hundreds of eggs have already formed in her ovaries. 

Baby’s size: As big as a lemon


The second trimester is, for many, the “golden period” of pregnancy. Second-trimester symptoms tend to be less severe. Morning sickness will subside, energy returns, and your baby bump will be visible for the world to see. 

Weeks 14 to 26 offer many exciting milestones. While some expectant parents find out the sex of the baby at 10 weeks via a blood test, you may now (if you choose) have the opportunity to learn its sex via an ultrasound. 

Week 14

Your body: At 14 weeks, you will begin to gain weight more rapidly. As your baby grows, your abdomen may start to feel sore. 

14-week pregnancy symptoms:

  • Increased appetite
  • Increased energy levels
  • Round ligament pain
  • Breast growth
  • Nasal congestion

Your baby may be sucking its thumb. Its body is covered with peachy-soft hairs, or lanugo, to keep it warm. It measures in length about 4 inches from the top of the head to its bottom. 

Baby’s size: As big as a peach

Week 15

Your body: You may experience bleeding gums due to hormone fluctuations. Be sure to schedule a dental visit if needed.

15-week pregnancy symptoms: 

  • Swollen/bleeding gums
  • Nosebleeds
  • Round ligament pain
  • Heartburn

Your baby is flexing its muscles — forming fists, adapting facial expressions, and moving around more. 

Baby’s size: As big as a pear

Week 16

Your baby can now hear your voice. 

Your body: Continued weight gain and breast size. Around this time, you might start to feel your baby kick. 

16-week pregnancy symptoms:

  • Increased breast size
  • Itchy, dry eyes
  • Radiant skin, aka “pregnancy glow” 
  • Constipation
  • Backaches
  • Bleeding gums

Your baby is almost 5 inches long. Eye movement is increasing, and even though the eyes remain closed, they are becoming sensitive to light.

Baby’s size: As big as an avocado

Week 17 

Your body: Continued weight gain and increase in breast size. You may start producing more fluids — vaginal discharge, sweat, and nasal mucus. 

17-week pregnancy symptoms: 

  • Rapid weight gain
  • Increased breast size
  • Snoring
  • Night sweats
  • Stretch marks 

Your baby is practicing breathing by sucking and swallowing. Eyelashes, eyebrows, and hair are starting to grow. 

Baby’s size: As big as a large onion

Week 18

Your body: Your uterus is about the size of a cantaloupe, and you are visibly pregnant to the outside world. 

18-week pregnancy symptoms: 

  • Baby kicks
  • Backaches
  • Swollen feet and hands (edema)
  • Leg cramps 
  • Sleep issues
  • Varicose veins
  • Nosebleeds
  • Bloating/gas

Your baby is becoming more active. Expect lots of kicks and flutters. 

Baby’s size: As big as a cucumber

Week 19

Your body: At this stage in pregnancy, it is normal to experience leg cramps — uncomfortable spasms that shoot down your calves, especially while you are trying to sleep. 

19-week pregnancy symptoms:

  • Leg cramps/spasms 
  • Hip pain 
  • Round ligament pain
  • Backaches

Your baby: A waxy coating called vernix caseosa (vernix means “cheese”) develops over your baby’s body. A layer of fat develops beneath the skin, providing a layer of warmth. Your baby’s hair continues to grow. 

Baby’s size: As big as a mango

Week 20

You’re halfway there. Congratulations! 

Your body: As your baby’s size increases, your appetite does too. The second trimester is when most mothers start to gain weight. Talk to your doctor about what is considered a normal amount of weight gain. At this point, many mothers-to-be start to have to swell around the ankles. 

20-week pregnancy symptoms: 

  • Swollen feet/ankles
  • Leg cramps
  • Increased energy levels
  • Heartburn

Your baby is around 6 ½ inches from the crown of the head to its bottom. It may average growing a pound a week from this point on. 

Baby’s size: As big as a banana

Week 21

Your body: You may start to have Braxton Hicks contractions. These contractions are normal and will often subside if you switch positions. Notify your doctor if the pain doesn’t stop or if there’s fluid or bleeding from the vagina. 

21-week pregnancy symptoms:

  • Braxton Hicks contractions
  • Heartburn
  • Indigestion
  • Stretch marks
  • Backaches

Your baby: Teeth are starting to form under the gums. Bone marrow creates lots of red blood cells to deliver oxygen to your baby. Meconium, an early form of stool passed by newborns, is produced in the intestines and passed inside the uterus. 

Baby’s size: As big as a green bell pepper

Week 22

Your body: Your milk ducts will have developed entirely at the end of the second trimester. You may experience leakage from your breasts. And don’t be surprised by changes to your belly button. Your “innie” could turn into an “outie” this week. Don’t worry, the change is not permanent. 

22-week pregnancy symptoms: 

  • Leaky breasts 
  • Your “innie” becomes an “outie” 
  • Stretch marks
  • Backaches

Your baby’s hormones and sex organs are developing. For girls, the ovaries, uterus, and vagina are formed. For boys, the testes have begun to drop down. Your baby’s sense of smell, taste, and touch are coming online. 

Baby’s size: As big as a coconut

Week 23

Your body: Due to swelling, your feet may no longer fit comfortably in your favorite shoes. 

23-week pregnancy symptoms:

  • Swollen ankles and feet 
  • Backaches
  • Braxton Hicks contractions
  • Bleeding gums

Your baby weighs about a pound. Strong connections in the neuropathways of the brain are forming. Its lungs practice breathing by taking in amniotic fluid. 

Baby’s size: As big as a grapefruit

Week 24

Your body: Swollen feet and ankles, backaches, and leg cramps are the norm at this stage in pregnancy. Swelling can cause tingling and numbness in the extremities, including the wrists. Developing carpal tunnel syndrome may be an unpleasant side effect. 

24-week pregnancy symptoms:

  • Leg cramps
  • Swollen feet and ankles
  • Backaches
  • Carpal tunnel syndrome/wrist and finger pain
  • Stretch marks
  • Aching lower abdomen

Your baby: The wrinkles on your baby’s previously pruned skin are smoothing out. 

Baby’s size: As big as a cantaloupe

Week 25

Your body: Your uterus is about the size of a soccer ball. The weight of it pressing down on the rectum can result in hemorrhoids. 

25-week pregnancy symptoms:

  • Frequent urination 
  • Hemorrhoids 
  • Sleeping issues 
  • Constipation
  • Braxton Hicks contractions
  • Heartburn
  • Restless leg syndrome

Your baby’s skin is becoming less translucent. In addition to kicks and increased movement, you may feel tiny hiccups inside your tummy. 

Baby’s size: As big as an eggplant

Week 26

Your body: Between nighttime trips to the bathroom, leg cramps, baby kicks, and a beach ball-sized tummy, expect to have trouble sleeping. To combat insomnia, consider cutting out caffeine entirely (if you haven’t already), limit fluids before bedtime, and implement a gentle daily exercise or mediation routine. 

26-week pregnancy symptoms:

  • Sleep troubles
  • Leg cramps
  • Frequent urination
  • Swelling
  • Migraines
  • Blurred vision

Your baby’s eyes are open for the first time. They may appear blue at first but may darken to brown six months to a year after birth. 

Baby’s size: As big as an acorn squash


The third trimester is a challenging time, physically and emotionally. In addition to bodily discomfort, you may be experiencing anxiety about the birth and becoming a parent. Be candid with your doctor about these feelings. As your due date approaches, you’ll be meeting with your doctor more regularly to monitor your health and pregnancy progression. 

Here are some third-trimester symptoms not to ignore:

  • Vaginal bleeding
  • Dramatic increase in vaginal discharge
  • Intense vomiting for over 24 hours
  • Consistent contractions before 36 weeks
  • Severe pain or cramping in your lower abdomen
  • Severe back pain
  • Burning during urination
  • Sudden facial swelling
  • Chills or fever
  • High blood pressure, a possible sign of preeclampsia
  • Consistent, intense headaches
  • Lack of fetal movement
  • Blurred vision/seeing spots

Week 27

Your body: The uterus has expanded to the size of a basketball. Edema or swelling of the hands, feet, and ankles may kick into high gear. To combat edema, stay hydrated and alternate between standing and sitting. Due to increased sweating, many women also develop heat rash on the lower abdomen, inner thighs, and beneath the breasts. 

27-week pregnancy symptoms:

  • Edema, or swelling of the feet, ankles, and hands. 
  • Leg cramps
  • Hemorrhoids
  • Constipation
  • Backaches

Your baby has adapted sleep patterns — regular waking periods vs. snoozing. The vital organs, including the brain, are continuing to develop. 

Baby’s size: As big as a cabbage

Week 28

Your body: Get used to being uncomfortable. Some women at this stage develop sciatica — pain, and tingling cascading from the back of their buttocks and down the leg. This is caused by the baby’s head pressing on the sciatic nerve as it shifts to a head-down position.

28-week pregnancy symptoms:

  • Sciatica
  • Sensitive, itchy skin
  • Leaking breasts
  • Braxton Hick contractions

Your baby weighs over 2 pounds, and is beginning to cough, sneeze, and hiccup inside the womb. 

Baby’s size: As big as a head of lettuce

Week 29

Your body: Your baby is getting big and putting pressure on your pelvis, bladder, and intestines. Pelvic pain and heartburn will be normal, as will the frequent need to urinate. 

29-week pregnancy symptoms:

  • Frequent urination
  • Pelvic pain
  • Hemorrhoids
  • Heartburn 
  • Headaches
  • Hip and/or back pain 

Your baby is growing strong and may be punching and kicking more frequently and powerfully than ever. 

Baby’s size: As big as a cauliflower 

Week 30

Your body: It is becoming more challenging to find a comfortable sleeping position at this point in your pregnancy. Dreams may become increasingly vivid due to hormones, anxiety, and a disrupted sleep schedule. 

30-week pregnancy symptoms: 

  • Disrupted sleep
  • Swelling
  • Hip, back, and pelvic aches
  • Bloating/gas

Your baby weighs around 3 pounds

Baby’s size: As big as a zucchini

Week 31

Your body: Your expanding uterus moves your internal organs around, compressing the space around the lungs and diaphragm. 

31-week pregnancy symptoms:

  • Braxton Hicks contractions
  • Leaky breasts
  • Backaches
  • Frequent need to urinate 

Your baby: All five of your baby’s senses are fully developed. 

Baby’s size: As big as a bunch of broccoli

Week 32

Your body: At this stage, your baby might turn into the head-down position, getting ready for birth. Don’t worry if it hasn’t. There’s still time for the flip to occur. 

32-week pregnancy symptoms: 

  • Darker areolas/nipples
  • Braxton Hicks contractions
  • Leaky breasts
  • Heartburn
  • Vaginal discharge
  • Constipation 

Your baby: The fine hair, or lanugo, is falling away from your baby’s skin. As it grows and space in the uterus shrinks, its movements will slow down.

Baby’s size: As big as a large, yellow squash

Week 33

Your body: As your metabolic rate rises, you may experience hot flashes or periods of feeling overheated. 

33-week pregnancy symptoms: 

  • Hot flashes/overheated
  • Backaches
  • Clumsiness
  • Braxton Hicks contractions

Your baby’s bones are hardening, except for the soft spot in the skull. Antibodies are being passed from you to your baby, assuring the development of a strong fetal immune system. 

Baby’s size: As big as a butternut squash

Week 34

Your body: Your growing baby continues to press down on your ligaments and pelvis. 

34-week pregnancy symptoms:

  • Dry, itchy eyes
  • Edema, swollen feet, and ankles
  • Backaches
  • Leg cramps
  • Braxton Hicks contractions

Your baby weighs in at a hearty 5 pounds. Due to limited real estate in the uterus, you may witness a hand or foot pushing against the inside of your stomach. 

Baby’s size: As big as a pineapple

Week 35

Your body: If your baby has dropped or “lightened” into the head-down position, there is more pressure on your bladder. This could result in a sudden lack of bladder control or incontinence. The upside? There will be more space around the lungs, so your shortness of breath could dissipate. 

35-week pregnancy symptoms:

  • Incontinence
  • Braxton Hicks contractions
  • Hemorrhoids
  • Pelvic and hip pain
  • Headaches
  • Constipation 

Your baby’s growth rate is increasing, gaining a ½ pound or more a week. Its body may have dropped into the head-down position. 

Baby’s size: As big as a spaghetti squash

Week 36

Your body: Your breasts may start leaking a yellowish, milky substance called colostrum. At this stage, most women start seeing their doctor once a week.

36-week pregnancy symptoms:

  • Leaking colostrum from the breasts
  • Pelvic pressure/discomfort
  • Frequent need to urinate
  • Itchy tummy
  • Edema

Your baby: Weighing around 6 pounds, your baby will be considered full-term.

Baby’s size: As big as a papaya

Week 37

Your body: You may experience a bit of spotting. The cervix is very delicate at this stage and can be irritated during sex, causing it to bleed. Do contact your doctor if there are more than a few drops of blood.

37-week pregnancy symptoms:

  • Light spotting
  • Heartburn
  • Braxton Hicks contractions
  • Nausea
  • Pelvic and abdominal pressure

Your baby, at about 6 ½ pounds, is just about full-grown with a robust immune system. 

Baby’s size: As large as a head of Romaine lettuce

Week 38

Your body: At 38 weeks, you could go into labor at any time. Be on the lookout for the mucus plug that appears as blood-tinged vaginal discharge. It’s a signal that your labor might begin soon. 

38-week pregnancy symptoms:

  • Blood-tinged vaginal discharge
  • Swollen feet
  • Braxton Hicks contractions
  • Leaky breasts
  • Diarrhea 

Your baby is practicing sucking and opening its tiny hands — reflexes that will serve it well during breastfeeding and bottle feeding. The brain regulates the heart rate and breathing patterns.

Baby’s size: As big as a mini watermelon

Week 39

The body: Your typical third-trimester symptoms will continue. Any new ones could be signals that your baby is coming soon. Braxton Hicks contractions are likely to increase in frequency and intensity. Sharp sensations in your vagina and pelvis can appear as your baby presses down on certain nerves. 

39-week pregnancy symptoms:

  • Braxton Hicks contractions
  • Appearance of mucus plug
  • Pelvic pressure  
  • sharp sensations in the vagina and pelvis

The baby is in position for delivery

Baby’s size: As big as a honeydew melon

Week 40

The body: Your body is ready to embark on the final stages of birth, and you’ll soon get to meet your new son or daughter. The symptoms will be the same as in week 39.

40-week pregnancy symptoms:

  • Braxton Hicks contractions
  • Appearance of mucus plug
  • Pelvic pressure  
  • sharp sensations in the vagina and pelvis

The baby: Your baby may not come on the estimated due date. If it gets too comfortable, your doctor may suggest inducing labor. Though the process is different than having the baby come on its own, the result is the same: a healthy childbirth. 

Baby’s size: As big as a small pumpkin

Trust the Pregnancy Experts at NewYork-Presbyterian

NewYork-Presbyterian consistently delivers more babies than any other hospital in New York City and Westchester combined. Our expert obstetrician-gynecologists collaborate with experienced nurses, nurse practitioners, obstetric anesthesiologists, diagnostic sonographers, and certified midwives to bring you the best experience possible. From pre-conception counseling and family planning, to prenatal care, delivery, and postpartum services, our maternal teams administer expertise in a nurturing atmosphere. 

NewYork-Presbyterian is here for you and your baby.