Your baby this week
Your baby may startle at loud noises and gets hiccups, which you might feel as small rhythmic jumps. Most of the amniotic fluid is now made up of your baby's urine.
At 25 weeks your baby's hair is growing and may be taking on its color and texture, though both can change after birth. Hands are getting more skilled: your baby makes fists and grabs their feet. The ligaments and joints supporting the spine are strengthening. For you, sleep may get harder; lying on your left or right side with a pillow between your knees and under your belly can help. Guidance from the UK's NHS is to go to sleep on your side from 28 weeks, because lying on your back in later pregnancy can reduce blood flow to the baby. If you wake on your back, simply roll onto your side.
By the numbers
Week 25 covers days 175 to 181 counted from the first day of your last period, which is 63% of a 40-week pregnancy. About 105 days remain until a 40-week due date. Since last week, an average baby gains about 4 oz (113 g). By date of conception, your baby is about 23 weeks old.
Pregnancy is dated from the first day of your last period, so conception happens around week 2. Your due date is 280 days (40 weeks) from that day, and an early ultrasound may adjust it.
Your body
Sleep can get harder to come by. When lying on your side, try a pillow between your knees or under your belly.
Tests and to-dos this week
Keep up your monthly checkups and get the glucose test done by 28 weeks. Write down questions about labor and delivery as they come to mind.
Glucose screening for gestational diabetes · weeks 24–28 · test
Done earlier if you have risk factors.
Coming up: Tdap (whooping cough) vaccine (from week 27). Full prenatal visit schedule
Tips for the second trimester
- Most healthy pregnant people are advised to get about 150 minutes of moderate activity a week, such as walking or swimming.
- Your recommended weight gain depends on your pre-pregnancy BMI, and gain usually speeds up in the second trimester.
- Once you feel your baby regularly, learn their usual pattern; a change in pattern matters more than any count.
- The flu shot is recommended at any point in pregnancy during flu season.
Call your provider or labor and delivery right away if you have:
- vaginal bleeding or leaking fluid
- regular contractions or pelvic pressure before 37 weeks
- a severe headache, vision changes, or sudden swelling of the face or hands
- a fever of 100.4 °F (38 °C) or higher, or painful urination
- after 24 weeks, your baby moving less or differently
In an emergency, call 911.
Last week and next week
Last week (24): The lungs keep maturing.
Next week (26): Your baby's eyes open for the first time this week.
Frequently asked questions
How big is the baby at 25 weeks?
About the size of an English cucumber: about 13.8 in (35 cm) · 1.7 lb (778 g), measured head to heel. These are rounded averages, and every baby grows at their own pace.
How many months is 25 weeks pregnant?
25 weeks is in month 6 and the second trimester. About 15 weeks (105 days) remain until a 40-week due date. Months are approximate; providers count weeks and days.
Why should I sleep on my side in pregnancy?
Later in pregnancy, lying on your back can press on major blood vessels and reduce blood flow to the baby. The NHS advises going to sleep on your side from 28 weeks; if you wake on your back, just roll over.
What's the next test or appointment after week 25?
Next up: Tdap (whooping cough) vaccine, from week 27. Your provider may schedule things differently depending on your health and local practice.
Sources
- WHO Fetal Growth Charts (Kiserud et al., PLoS Med 2017)
- INTERGROWTH-21st crown-rump length standard (Papageorghiou et al., 2014)
- Hadlock et al.: In utero fetal weight standard (Radiology 1991)
- NHS: Week-by-week guide to pregnancy
- NHS: Pregnancy symptoms you need to get help for
- ACOG: How Your Fetus Grows During Pregnancy
- ACOG: Routine Tests During Pregnancy
- ACOG: Prenatal Genetic Screening Tests
- CDC: Vaccine Recommendations Before, During, and After Pregnancy
- Office on Women's Health: Prenatal care and tests
- Hungarian Decree 26/2014 (IV. 8.) EMMI on prenatal care
- NNGYK (Hungary): 2026 vaccination methodology letter
- ACOG – Group B Strep and Pregnancy (Committee Opinion 797)
- ACOG – The Rh Factor
Last reviewed: November 14, 2026 · Kitpebble editorial team
This page is for general information. It isn't medical advice or a diagnosis and doesn't replace your OB-GYN or midwife. Sizes are rounded averages. Our editorial policy