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The Pregnancy Hub

33 weeks pregnant

Get to know your growing baby and the changes you may be feeling.

Choose your week

Week 33

Know your due date?

Enter the due date from your care team to find your estimated week today. Your date stays in this browser tab.

Illustration of a pineapple

Third trimester

About the size of

a pineapple

Approximate length

17.2 in / 43.7 cm Head to heel

Your baby

Your baby's bones are becoming firmer, while the skull bones remain flexible to allow movement during birth and continued growth afterward. Development continues in the weeks ahead. The pineapple comparison is an approximate size reference and should not be used to decide whether a baby would be ready for birth now.

Your body

You may notice tightening sensations sometimes described as practice contractions. However, at this stage it is important not to diagnose contractions yourself. Regular or frequent tightening, pelvic pressure, a persistent low backache or a change in discharge may need assessment for preterm labor. Contractions do not have to be very painful to deserve a call.

This week

Taking early contractions seriously

Contact your maternity care team right away about possible labor symptoms before 37 weeks, vaginal bleeding or leaking fluid. Do not wait for contractions to match a rule intended for labor at term. Ask where to go if the team advises assessment and what to do if you cannot reach them. For preparation when you are feeling well, save contact numbers and think through transportation and childcare. Packing can wait if symptoms arise: getting assessed matters more than arriving with a complete hospital bag. Your clinician can explain which signs apply to your circumstances.

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Looking ahead

A question for your next visit

What symptoms should make me call before 37 weeks, and where should I go for assessment?

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A little context for these comparisons

These are approximate sizes for each week, not measurements of your baby. Babies and produce both come in different sizes, and the illustrations are not shown to scale.

Before week 20, length is measured from head to bottom. From week 20, it includes the legs, from head to heel. That change explains the jump in length between weeks 19 and 20.

When to get help

If your baby’s usual movements slow down, stop, or change, contact your maternity care team right away.

Seek medical care right away for warning signs such as a severe or persistent headache, vision changes, chest pain, trouble breathing, severe belly pain, vaginal bleeding, leaking fluid, or thoughts of harming yourself or your baby. These are examples, not a complete list. If you cannot reach your care team, seek urgent medical care. Call 911 for a medical emergency.

Read the CDC urgent maternal warning signs (opens in a new tab)
About this guide

Approximate measurements and development information draw on the NHS weekly guides. Linked US health resources support care and preparation topics. The topics are suggestions for discussion, not a schedule of required appointments or tests. Your own care plan may differ.

Every pregnancy is different. Your care team can help you understand your baby’s growth and any symptoms you’re experiencing.