How many weeks pregnant will I be on that date?

Your weeks on the day of your trip or event

We count from your due date to the date you enter, and show the weeks and days, the trimester and the general flying notes for that week. Travelling? Add the return date too: health services advise checking how many weeks pregnant you will be on both the way out and the way back (CDC).

Flying in pregnancy: what to check

Airline rules and the doctor’s letter

• Many women find the middle of pregnancy, around 4 to 6 months, the most comfortable time to travel.
• After 28 weeks, airlines may ask for a letter from your doctor or midwife confirming your due date. It can take time and may cost money.
• Some airlines do not let you fly towards the end of pregnancy: labour is more likely after 37 weeks (NHS). Most allow flights until about 36 weeks, and some stop earlier for international flights (CDC).

Long flights

Journeys over 4 hours carry a small risk of blood clots. Drink water and move about every 30 minutes or so. Compression stockings can help with swelling (NHS).

Twins

With twins, labour is more likely from around 32 weeks (NHS), so your airline may have an earlier limit. Check with your airline and your midwife or doctor.

This is general information. Always check with your airline and your doctor or midwife before you book. We never say whether you can fly.

Cruises, ferries and car journeys

• Most cruise lines do not take passengers beyond 24 weeks, and some ask for a doctor’s note with your due date (CDC).
• Ferry companies have their own rules and may refuse to carry women late in pregnancy (NHS).
• In the car, wear the seatbelt with the cross strap between your breasts and the lap strap under your bump, not across it. Avoid long car journeys if you can (NHS).

Insurance and health care abroad

• Get travel insurance that covers pregnancy, an early birth and changing your return date (NHS).
• Take your pregnancy notes with you, so doctors abroad have your information.
• Check your destination for infections such as Zika before you book, and ask your GP or midwife about any vaccines.

Questions people ask

How do you work out how pregnant I will be on a date?

We count from your due date (40 weeks) to the date you enter. Check the weeks on your return date too (CDC).

Up to how many weeks pregnant can I fly?

Most airlines allow flights until about 36 weeks, but some stop earlier for international flights (CDC). With twins, labour is more likely from around 32 weeks (NHS). Always check your airline and ask your midwife or doctor.

When is the best time to travel in pregnancy?

Many women find the middle of pregnancy, between 4 and 6 months, the most comfortable time to travel (NHS).

Do I need a letter from my doctor to fly?

After 28 weeks, airlines may ask for a letter from your doctor or midwife confirming your due date. You may have to pay for it and wait for it (NHS).

Can I go on a cruise when pregnant?

Most cruise lines do not take passengers beyond 24 weeks, and some ask for a doctor’s note (CDC). Check with the cruise line before you book.

What about long flights?

Flights over 4 hours carry a small risk of blood clots. Drink plenty of water, move about every 30 minutes or so, and think about compression stockings (NHS).

Do I need special travel insurance?

Yes. Check that it covers pregnancy, an early birth and the cost of changing your flight home (NHS).

Sources

• NHS: Travelling in pregnancy · checked October 26, 2026
• CDC Yellow Book: Pregnant travelers · checked October 26, 2026