The third trimester is the final part of pregnancy, when many begin to prepare more concretely for childbirth and the time immediately following. When you search for "when does the 3rd trimester start", it is typically because you want a clear week indication and to know what you can practically do from then on. Most divisions place the start of the 3rd trimester around pregnancy week 28, and it lasts until birth. Some sources may vary slightly in their division, so if you are in doubt, you can always base it on your due date and ask your midwife or doctor.

For many, the 3rd trimester starts at week 28+0, meaning when you have completed 27 weeks and are entering week 28. This is a widespread division in both pregnancy apps and patient-oriented information. At the same time, it is worth knowing that pregnancy weeks can be counted slightly differently in everyday life (e.g., "I am in week 28" can mean 27+something). If you want to be completely precise, use the format week+day (e.g., 28+3).

Practical tip: Find your due date, and use a due date calculator or your maternity record to see when you hit 28+0. This makes planning things like birth preparation, maternity leave, and shopping more manageable.

The 3rd trimester runs from approximately week 28 until birth. Many pregnancies end around the due date period (typically around week 40), but this can vary, and birth can happen both before and after term. Therefore, it is most practical to think of the third trimester as "week 28 onwards".

• Weeks 28 to 32: Focus on energy, sleep, and getting the most important appointments sorted (midwife visits, possibly birth preparation).
• Weeks 32 to 36: Pack the essentials and make a short list of contact details and transportation plans.
• Week 36 onwards: Make time for more rest, and keep an eye on changes in movements and symptoms.

In the third trimester, many experience that their belly is bigger, and everyday life requires more breaks. This can include more pelvic pressure, more need to urinate, or getting out of breath more easily. Braxton Hicks contractions may also increase. This is common but should always be assessed in conjunction with how you are feeling and what you are used to.

Practical tip: Write small notes in your calendar about sleep, hydration, and the baby's movements. This makes it easier to explain changes if you need to contact healthcare professionals.

Here, it often brings the most peace of mind to choose a few specific preparations:

• Agree on who to contact with questions outside opening hours (e.g., the labor ward's number).
• Make a simple packing list well in advance (ID, charger, comfortable clothes, practical toiletries).
• Think practically about maternity leave: paperwork, transport, and who can help in the first few days.
• Consider everyday comfort if you experience more heaviness in your lower back and pelvis: short walks, rest, and support when standing.

Contact healthcare professionals if you experience anything that seems different or worrying to you. As a general and often used guideline, you should react to, for example:

• Bleeding or sudden, severe pain
• Rupture of membranes or suspicion of amniotic fluid
• Persistent headache, vision disturbances, or sudden swelling
• Fever or signs of infection
• Significant change in the baby's movements

If you are in doubt, it is always okay to call and have the situation assessed.

As your belly grows, support and comfort can make everyday life easier, especially around your lower back and pelvis. Some pregnant women benefit from a support belt, which can relieve pressure during activity: Support Belts and specifically Maternity Support Belt.

If you also notice that your breasts are changing and becoming more sensitive, a pregnancy and nursing bra without underwire can be relevant for support without pinching: Pregnancy Bra & Nursing Bra and specifically Gel-Support Maternity Nursing Bra.