What size is my baby this week?

What size is my baby this week? Is this normal in pregnancy? What symptoms should I have in the first, second, third trimester?

We compiled the answers in a comprehensive list! Here’s a week-by-week guide on baby size and common pregnancy symptoms from conception to birth. Keep in mind that every pregnancy is unique, so this is a general overview.

Weeks 1-4: Early Development

Week 1 (Conception):  

Baby Size: Still a twinkle in your eye!

Symptoms: You may not notice any symptoms yet. Some women experience very mild cramping or spotting.

Week 2:  

Baby Size: About the size of the period at the end of this sentence. The embryo is in the process of implanting into the uterine wall.

Symptoms: You might start to notice signs of early pregnancy like fatigue, changes in mood, or very early signs of nausea. 

Week 3:  

Baby Size: About the size of a poppy seed. The embryo is developing into a blastocyst.

Symptoms: Early symptoms such as tender breasts, frequent urination, and heightened sense of smell may start to appear.

Week 4:  

Baby Size: Approximately the size of a sesame seed. The embryo is now called a baby and is developing rapidly.

Symptoms: Missed period, morning sickness, fatigue, and frequent urination. You might also notice increased sensitivity in your breasts.

 Weeks 5-8: Major Development

Week 5:  

Baby Size: About the size of a peppercorn. Major organs are beginning to form.

Symptoms: Morning sickness, mood swings, food aversions, and increased urination.

Week 6:  

Baby Size: Roughly the size of a lentil. The fetal heartbeat may start to be detectable via ultrasound.

Symptoms: Nausea, fatigue, and possibly light spotting as implantation completes.

Week 7:  

Baby Size: Around the size of a blueberry. Facial features and limb buds are becoming more defined.

Symptoms: Continued morning sickness, breast tenderness, and potential food cravings or aversions.

Week 8:  

Baby Size: About the size of a kidney bean. The baby’s organs are continuing to develop.

Symptoms: Nausea and vomiting may persist, along with increased fatigue and frequent urination.

Weeks 9-12: Growth and Development

Week 9:  

Baby Size: Roughly the size of a grape. Facial features are becoming more distinct.

Symptoms: Morning sickness may begin to lessen, but fatigue and frequent urination continue.

Week 10:  

Baby Size: About the size of a kumquat. The baby is starting to make movements, though they’re not felt yet.

Symptoms: You might feel slightly more energetic. Other symptoms like breast tenderness and occasional nausea may still be present.

Week 11:  

Baby Size: Around the size of a fig. The baby is developing reflexes and may start to move.

Symptoms: Nausea might be decreasing. You might notice more visible changes, like a growing belly and possible weight gain.

Week 12:  

Baby Size: About the size of a lime. The baby’s organs are nearly fully developed.

Symptoms: Symptoms like nausea may be significantly reduced. You might experience increased appetite and energy.

Weeks 13-16: Second Trimester Begins

Week 13:  

Baby Size: Roughly the size of a peach. The baby is becoming more active and features are more defined.

Symptoms: Many women experience a decrease in nausea and fatigue. Increased appetite and visible changes in the body continue.

Week 14:  

Baby Size: About the size of a lemon. The baby’s limbs are now fully formed, and fine hair (lanugo) starts to develop.

Symptoms: You may notice your belly growing more, and you might experience round ligament pain as your uterus expands.

Week 15:  

Baby Size: Around the size of an apple. The baby is starting to move more, but you may not feel it yet.

Symptoms: Increased energy levels and continued growth of the belly. Some women might experience back pain or constipation.

Week 16:  

Baby Size: About the size of an avocado. The baby’s facial features are becoming more recognizable.

Symptoms: You may start to feel fetal movements, especially if this isn’t your first pregnancy. Continued changes in appetite and body shape.

 Weeks 17-20: Mid-Pregnancy

Week 17:  

Baby Size: Roughly the size of a turnip. The baby is growing rapidly and developing more distinct features.

Symptoms: You may feel more energetic and less nausea. You might experience the “quickening,” or first fetal movements.

Week 18:  

Baby Size: About the size of a bell pepper. The baby’s sensory organs are becoming more developed.

Symptoms: Continued fetal movement, possible changes in skin and hair, and noticeable weight gain.

Week 19:  

Baby Size: Around the size of a mango. The baby’s skin is becoming less transparent.

Symptoms: You might experience more pronounced fetal movements, backaches, and continued weight gain.

Week 20:  

Baby Size: About the size of a banana. This is the halfway point, and the baby is growing quickly.

Symptoms: You might notice more pronounced kicks and movements. Possible swelling of ankles and feet.

Weeks 21-24: Growth and Development

Week 21:  

Baby Size: Roughly the size of a carrot. The baby’s skin is becoming less wrinkled and more pigmented.

Symptoms: Increased movement and continued physical changes like a growing belly and potential stretch marks.

Week 22:  

Baby Size: About the size of a spaghetti squash. The baby is starting to develop fat layers and its movements are more pronounced.

Symptoms: You may experience more back pain, leg cramps, and possibly heartburn as the uterus expands.

Week 23:  

Baby Size: Roughly the size of a large mango. The baby’s lungs are developing, and it may start to practice breathing movements.

Symptoms: Continued physical discomfort, including backaches and leg cramps. You may also notice changes in sleep patterns.

Week 24:  

Baby Size: About the size of an ear of corn. The baby is gaining weight and developing more distinctive features.

Symptoms: You might experience more pronounced fetal movements and increased physical discomfort as your body adjusts to the growing baby.

 Weeks 25-28: Third Trimester Begins

Week 25:  

Baby Size: Roughly the size of a cauliflower. The baby’s brain is developing rapidly.

Symptoms: Increased back pain, frequent urination, and possible shortness of breath as the uterus expands.

Week 26:  

Baby Size: About the size of a head of lettuce. The baby’s eyes are fully formed, and it may start to have sleep patterns.

Symptoms: Possible swelling of hands and feet, increased fatigue, and continued physical discomfort.

Week 27:  

Baby Size: Roughly the size of a cucumber. The baby’s brain and lungs are maturing.

Symptoms: You may notice more pronounced fetal movements and continued physical symptoms like heartburn and back pain.

Week 28:  

Baby Size: About the size of an eggplant. The baby’s body is beginning to fill out.

Symptoms: Increased physical discomfort, including back pain and swelling. Braxton Hicks contractions are possible starting around now, and get more likely the further into pregnancy you go.

Weeks 29-32: Preparing for Birth

Week 29:  

Baby Size: Roughly the size of a butternut squash. The baby’s lungs and brain continue to mature.

Symptoms: You might experience more frequent Braxton Hicks contractions, swelling in your extremities, and difficulty sleeping.

Week 30:  

Baby Size: About the size of a cabbage. The baby is growing!

Symptoms: Increased discomfort and pressure on the pelvis. Possible shortness of breath and frequent urination.

Week 31:  

Baby Size: Roughly the size of a pineapple. The baby is becoming more active and its movements may be more pronounced.

Symptoms: Continued physical discomfort, including backaches and pelvic pressure. You might notice more pronounced swelling.

Week 32:  

Baby Size: About the size of a squash. The baby is developing fat stores and preparing for birth.

Symptoms: Braxton Hicks contractions may increase. You might also experience increased fatigue and difficulty finding a comfortable sleeping position.

Weeks 33-36: Final Stretch

Week 33:  

Baby Size: Roughly the size of a pineapple. The baby’s organs are maturing and preparing for life outside the womb.

Symptoms: You might experience increased pelvic pressure, back pain, and possible difficulty with breathing as the baby moves downward.

Week 34:  

Baby Size: About the size of a cantaloupe. The baby is becoming more cramped and its movements might feel different.

Symptoms: Continued physical discomfort, frequent urination, and possible leakage of colostrum from your breasts.

Week 35:  

Baby Size: Roughly the size of a honeydew melon. The baby is gaining weight and its organs are maturing.

Symptoms: You may experience more frequent Braxton Hicks contractions and possible difficulty sleeping.

Week 36:  

Baby Size: About the size of a large cantaloupe or a watermelon. The baby is considered near-term and preparing for birth.

Symptoms: Increased pelvic pressure as the baby moves downward, possible nesting instincts, difficulty sleeping, swelling, and feeling very ready for the baby to be out!

The Waiting Game: Full Term

Week 37:

Baby Size: Roughly the size of a bunch of Swiss chard or a stalk of celery. The baby’s lungs are almost fully mature.

Symptoms: Increased pelvic pressure, difficulty sleeping, changes in discharge, high potential for Braxton Hicks

 Week 38:

Baby Size:  About the size of a small pumpkin. The baby is gaining weight and the body is filling out with fat.

Symptoms:  Possible Water Break: Your water might break, which can be a sign that labor is imminent.

Increased Cervical Dilation: Cervix may be dilating in preparation for labor.

Intensified Braxton Hicks: More noticeable and frequent practice contractions.

Fatigue: Increased tiredness as your body prepares for labor.

Discomfort: Greater difficulty finding comfortable sleeping positions or moving around due to the baby’s size.

 Week 39:

Baby Size:  About the size of a watermelon. The baby’s organs are fully developed, and it’s getting ready for life outside the womb.

Symptoms:  Labor Signs: Watch for signs of labor such as regular contractions, back pain, or the loss of the mucus plug.

Lightening: The baby might “drop” further into the pelvis, which can relieve some upper abdominal pressure but increase pelvic discomfort.

Contractions: Contractions may become more regular and intense as labor approaches.

Nesting Instincts: A burst of energy and urge to prepare the home for the baby’s arrival.

 Week 40: Full-Term

Baby Size:  About the size of a small pumpkin or a large watermelon. The baby is considered fully developed and ready for birth.

Symptoms:  Labor Contractions: Contractions will be regular and progressively stronger, signaling the onset of labor.

Water Breaking: This may happen just before or during labor, though not all women experience this.

Increased Cervical Dilation: Cervix should be more dilated and effaced.

Possible Loss of Mucus Plug: It may come out in one piece or as a discharge over several days.

Physical Discomfort: Increased pelvic pressure, lower back pain, and difficulty sleeping as labor approaches.

 Week 41: Post-Term

Baby Size:  The baby is still the size as a small pumpkin, though it may continue to gain a bit more weight.

Symptoms:  Ongoing Labor Symptoms: If labor hasn’t started, you may continue to experience Braxton Hicks contractions and increased discomfort.

Monitoring: Your healthcare provider will likely monitor you and the baby more closely to assess readiness for labor and delivery.

Possible Induction: If labor hasn’t started by this point, induction may be considered.

 Week 42: Post-Term, Delivery Imminent 

Baby Size:  Newborn size! The baby is likely fully developed.

Symptoms:  Continued Physical Discomfort: Due to the baby’s size and your body preparing for birth.

Signs of Labor: As in previous weeks, watch for signs like regular contractions and water breaking.

Labor Induction: If labor has not started naturally, your healthcare provider may discuss options for induction.