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27 Weeks Pregnant: The Second Trimester Ends

Medically reviewed by

Sarah Riffle, RN Jul 30, 2026

Line illustration of a pineapple: at 27 weeks pregnant your baby is about the size of a pineapple, roughly 23 to 25cm crown to rump

Line drawing of a 27-week foetus with fuller limbs as fat begins to build under the skin

Line drawing of a woman's torso at 27 weeks pregnant, showing the uterus inside a full rounded bump

Your baby is the size of a

Pineapple

~820g–1,000g

~23–25 cm / ~9.1–9.8 in

Key Takeaways

At 27 weeks pregnant, you are at the very end of the second trimester. According to Mayo Clinic, your baby's nervous system is continuing to mature, and your baby is gaining fat, which helps the skin look smoother.

Mayo Clinic gives no measurement at 27 weeks. It places the baby at about 230 millimetres and 820 grams at week 26, and about 250 millimetres and 1,000 grams (1 kilogram) at week 28 — so this week sits between the two.

The third trimester is nearly here, and the signs of preterm labour are worth knowing now. SOGC advises going to the hospital for regular contractions before 37 weeks that don't go away when you change your activity.

Your Baby at 27 Weeks: Development & Growth

At 27 weeks pregnant, your baby's nervous system is continuing to mature and fat is beginning to build under the skin, according to Mayo Clinic. Mayo Clinic gives no measurement this week; it places the baby at about 230 millimetres and 820 grams at week 26, and about 250 millimetres and 1,000 grams at week 28.

The headline this week is maturation, not a milestone you can point to on a scan. Mayo Clinic explains that "at 27 weeks... your baby's nervous system is continuing to mature." The wiring is getting more sophisticated, quietly.

Fat is the other change. Mayo Clinic notes that "your baby also is gaining fat, which helps the skin look smoother," and adds that "this fat gain will continue into the third trimester." The thin, wrinkled look of earlier weeks is starting to fill in.

How big is your baby? Mayo Clinic gives no figure at 27 weeks, so the honest answer is a bracket. Mayo Clinic puts the baby at "9 inches (230 millimeters) long from crown to rump" weighing "nearly 2 pounds (820 grams)" at week 26, and "nearly 10 inches (250 millimeters)" weighing "about 2 1/4 pounds (1,000 grams)" at week 28. Week 27 falls between them.

Just after now, the reflexes sharpen. Mayo Clinic notes that by week 28 "your baby's eyelids can partially open" and the central nervous system "can trigger breathing movements, which can be seen on an ultrasound." The practice for life outside is well underway.

Your Body at 27 Weeks: Symptoms & Changes

At 27 weeks pregnant, many of the common discomforts of pregnancy can still come and go, and a growing bump brings its own aches. SOGC lists tender breasts, constipation, backaches, headaches, mood swings and leg cramps among the usual symptoms. Movement is often stronger and more patterned now. Every pregnancy is different.

Your body is carrying real weight now, and it shows. SOGC explains that weight gain "isn't just the baby" — "your placenta, increased blood volume, larger breasts, and fat stores to support breastfeeding, also contribute." A heavier, rounder middle is your body doing exactly what this stage asks.

The everyday symptoms haven't necessarily left. SOGC lists tender or swollen breasts, "constipation, gas or bloating," "backaches and headaches," mood swings and leg cramps among the common discomforts. Any of these can still be part of your week, and SOGC is clear that "every pregnant woman is different."

Movement is the reassuring throughline. By this stage most mothers feel a clear rhythm — SOGC notes that "by 24 weeks, almost all women will feel their baby's movements in a predictable way," and that a baby's patterns, while they "vary," "tend to be consistent for any one baby, in any one pregnancy." Getting to know that pattern matters now.

Mood deserves honest attention, too. SOGC notes that mood swings "are not usually severe," but adds a firm caveat: "depression or disruptive mood swings are not normal and it is important to seek help for these more serious concerns." That is a reason to reach out, not to wait.

What to Do at 27 Weeks Pregnant

NUTRITION AT 27 WEEKS PREGNANT

Get ready for the third-trimester calorie step-up. SOGC states: "In the third trimester, you need about 450 extra calories" — more than the second trimester’s 340 — and notes this "generally equates to 2 or 3 additionally servings from any of Canada’s Food Guide’s food groups." Think an apple and yogurt, or toast and a cup of milk. Quality first, always.
Stay on top of iron. SOGC advises increasing "your daily iron intake to 27mg daily during the final six+ months of pregnancy to support an increase in red blood cells and fetal tissues," and notes that, "like most women, you may need a good supplement to meet this need." The third trimester is when this matters most.
Mind your choline. SOGC notes that "choline intake above 450mg a day is linked to improved fetal stress responses and a reduced risk of neural tube defects," and adds that "this vitamin may not be found in your prenatal daily vitamin" — so it is worth checking your label.

WHAT SUPPLEMENTS TO TAKE AT 27 WEEKS PREGNANT

Keep taking 400mcg of folic acid daily. The Public Health Agency of Canada states that "a daily multivitamin with 400 mcg (0.4 mg) of folic acid is recommended for anyone who could become pregnant," and advises: "Continue taking folic acid throughout your pregnancy and while breastfeeding."
Don’t raise your folic acid dose on your own. The Public Health Agency of Canada advises: "You should not increase your dose of folic acid beyond 1 mg per day without talking to your health care provider." A higher dose is a conversation, not a decision for the supplement aisle.
Ask about vitamin D. SOGC notes that "taking a vitamin D supplement of 2000IU in the last six months of pregnancy will enhance the vitamin D content of your breast milk towards meeting the daily needs of your breastfeeding infant." Worth raising at your next visit.

LIFESTYLE TIPS AT 27 WEEKS PREGNANT

Keep moving — aim for at least 150 minutes a week. SOGC advises that "pregnant women should accumulate at least 150 minutes of moderate intensity physical activity each week," spread across "at least 3 days a week, and up to 7 days a week." Walking, swimming and stationary cycling are good options as your bump grows.
Build in pelvic floor exercises. SOGC notes that "pelvic floor muscle training (e.g., Kegel exercises) can be performed every day to reduce the risk of urinary incontinence." Easy to fold into a daily routine, and useful now.
Keep caffeine to 300mg a day. Health Canada recommends a maximum daily caffeine intake of 300 mg for people who are pregnant. For reference, Health Canada puts one 8oz (237ml) cup of brewed coffee at about 135mg — so roughly two cups is the ceiling, and that total includes tea, cola and chocolate.
Learn your baby’s movement pattern. SOGC notes that "your perception of your baby’s movements is one of the strongest indicators of your baby’s wellbeing," and that it "is a good idea to be aware if any changes in your baby’s usual activity level, especially in the third trimester." Noticing the rhythm now makes any change easier to spot later.

When to Contact Your Doctor or Midwife

Most of week 27 is steady progress, not alarm. But a handful of symptoms should always be checked — and near the third trimester, the signs of early labour are the ones worth knowing cold. Contact your doctor, midwife or other health care provider if you experience:

Signs of preterm labour. SOGC advises contacting your health care provider right away for any of these: backache that comes and goes, regular contractions less than 10 minutes apart, cramping in your lower abdomen, fluid leaking from your vagina, pressure in your pelvis or vagina, or vaginal bleeding. SOGC is direct about the urgency: it is very important to go to the hospital if you have regular contractions at any time before 37 weeks that don't go away when you change your activity, and warns that staying home thinking this couldn't possibly be labour because it is too early is dangerous.
Any vaginal bleeding. SOGC advises: "It's important for you to take any vaginal bleeding seriously. Contact your health care provider as soon as you notice any bleeding." It adds that signs of a pregnancy loss include vaginal bleeding, the passage of clots and tissue, and cramping or pain in the lower pelvis or back, and that with signs of infection like fever or heavy bleeding, you should see your care provider right away. If bleeding is heavy or you feel very unwell, seek emergency medical care immediately.
Any concern about your baby's movements. SOGC advises that "if you ever have concerns regarding your baby's movement pattern, you should have the baby assessed as soon as possible," and that mothers should always trust their intuition. If you are counting and don't feel 6 movements in 2 hours, contact your health care provider as soon as possible.
Persistent low mood or disruptive mood swings. SOGC advises that "depression or disruptive mood swings are not normal and it is important to seek help for these more serious concerns."
Severe abdominal pain, a severe or persistent headache, or any symptom that frightens you. Sudden, severe pain warrants urgent assessment — seek emergency medical care immediately if it is intense or you feel faint. For anything that simply worries you, your health care provider is there for exactly that.

Questions fréquemment posées

How big is my baby at 27 weeks pregnant?

Mayo Clinic gives no measurement at 27 weeks, so the honest answer is a range. Mayo Clinic puts the baby at "9 inches (230 millimeters) long from crown to rump" weighing "nearly 2 pounds (820 grams)" at week 26, and "nearly 10 inches (250 millimeters)" weighing "about 2 1/4 pounds (1,000 grams)" at week 28. At 27 weeks your baby sits between those two figures — roughly 230 to 250 millimetres crown to rump, and about 820 grams to 1 kilogram.

Is 27 weeks the end of the second trimester?

Yes. Mayo Clinic states plainly that "this week marks the end of the second trimester." The third trimester begins at 28 weeks. According to Mayo Clinic, at 27 weeks "your baby’s nervous system is continuing to mature" and your baby "is gaining fat, which helps the skin look smoother," a process that "will continue into the third trimester."

How many extra calories do I need in the third trimester?

More than in the second. SOGC states: "In the third trimester, you need about 450 extra calories" — up from "about 340 extra calories per day" in the second trimester. SOGC notes this "generally equates to 2 or 3 additionally servings from any of Canada’s Food Guide’s food groups," such as "1 piece of toast and a cup of milk."

What are the signs of preterm labour at 27 weeks?

SOGC lists these signs and says to contact your health care provider right away: "backache that comes and goes," "regular contractions less than 10 minutes apart," "cramping in your lower abdomen," "fluid leaking from your vagina," "pressure in your pelvis or vagina," and "vaginal bleeding." SOGC stresses that it is "very important to go to the hospital if you have regular contractions at any time before 37 weeks that don’t go away when you change your activity," and that assuming it is "too early" to be labour "is dangerous."

How much caffeine is safe at 27 weeks pregnant?

Health Canada recommends a maximum daily caffeine intake of 300 mg for people who are pregnant. Health Canada puts one 8oz (237ml) cup of brewed coffee at about 135mg, so roughly two cups a day is the ceiling — and that total should include tea, cola and chocolate, which also contain caffeine.

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