How much weight should I gain in pregnancy?

For a normal BMI, about 11.5 to 16 kg total is typical, but your ideal range depends on your pre-pregnancy weight. Your doctor will guide you.

Is it safe to exercise during pregnancy?

Yes, for most people. ACOG recommends about 150 minutes of moderate activity weekly, such as walking, prenatal yoga or swimming, unless your doctor advises otherwise.

What are the warning signs I should never ignore?

Heavy bleeding, severe abdominal pain, severe headache with vision changes, high fever, reduced baby movements, fluid leaking, or painful/burning urination — contact your doctor or go to hospital immediately.

Home › Blog › Week-by-Week Pregnancy Guide

Pregnancy · Doctor-reviewed

Week-by-Week Pregnancy Guide: The Complete 40-Week Handbook

✍️ Baby Circle Medical Team🩺 Reviewed by an OB-GYN🗓️ Updated Jul 2026⏱️ ~12 min read

👩‍⚕️

Medically reviewed by

Baby Circle Medical Board

Reviewed on 12 July 2026

Pregnancy lasts about 40 weeks, counted from the first day of your last period, and unfolds across three trimesters. This handbook walks you through every single week — how big your baby is, what's developing, how your body feels, which tests matter, and the warning signs to never ignore — in one calm, trustworthy place.

Key takeaways

40 weeks, 3 trimesters: weeks 1–12 (early growth), 13–27 (the "golden" middle), 28–40 (final growth & birth prep).
Full-term is 37–42 weeks; your due date is the 40-week mark. A first-trimester scan dates it most accurately.
First heartbeat ~6 weeks; first movements ~16–22 weeks; anatomy scan ~18–20 weeks.
Every pregnancy is different — use this as a map, not a rulebook, and follow your doctor's advice.

📊 Suggested infographic — "The 40-Week Journey at a Glance" (place directly under the intro). AI prompt: "Clean, warm pastel medical infographic timeline of 40 weeks of pregnancy split into 3 colour-coded trimesters, with baby-size fruit icons and key milestones, soft purple/green/blue palette, flat vector style." Alt text: "Timeline infographic of the 40 weeks of pregnancy divided into three trimesters with baby size and milestones." Caption: Your whole pregnancy on one timeline — bookmark this page and check back each week.

How pregnancy is measured (and your due date)

Doctors count pregnancy in weeks from the first day of your last menstrual period (LMP) — which means you're considered "2 weeks pregnant" around conception. A full-term baby arrives between 37 and 42 weeks; 40 weeks is your estimated due date (EDD). An ultrasound in the first trimester is the most accurate way to date your pregnancy. (Sources: ACOG, NHS.)

💡 Quick tip: EDD ≈ first day of last period + 280 days. Only about 1 in 20 babies actually arrive on the exact due date — a week either side is completely normal.

The three trimesters at a glance

1st Trimester · Weeks 1–12All major organs form. Symptoms: nausea, fatigue, tender breasts. First scan & booking bloods.

2nd Trimester · Weeks 13–27Energy returns, bump shows, first kicks, anatomy scan. Often the most comfortable phase.

3rd Trimester · Weeks 28–40Rapid growth & brain development. Back ache, Braxton-Hicks, birth prep, hospital bag.

Week-by-week: all 40 weeks

Sizes are approximate (babies grow at their own pace). "Size" uses the familiar fruit/veg comparison; length & weight are typical averages.

Week	Baby size	Length / weight*	What's developing	Your body
1–3	Poppy seed	<2 mm	Fertilisation & implantation; the blueprint is set.	You may not know yet; a missed period is the first clue.
4	Poppy seed	~2 mm	Neural tube (brain & spine) begins forming.	Positive test! Start folic acid if not already.
5	Sesame seed	~3 mm	Heart starts to beat; major systems begin.	Fatigue, tender breasts, nausea may begin.
6	Lentil	~5 mm	Heartbeat visible on scan; limb buds appear.	Morning sickness, frequent urination.
7	Blueberry	~1 cm	Brain growing fast; hands & feet forming.	Nausea peak for many; food aversions.
8	Kidney bean	~1.6 cm	Fingers, toes, all organs taking shape.	First prenatal (booking) visit & bloods.
9	Grape	~2.3 cm	Now a fetus; tiny movements (unfelt).	Mood swings, bloating, tiredness.
10	Kumquat	~3 cm	Vital organs functioning; nails forming.	Heartbeat may be heard on Doppler.
11	Fig	~4 cm	Bones hardening; can hiccup.	Nausea may start to ease.
12	Lime	~5.4 cm	Reflexes develop; NT scan window.	Lower miscarriage risk after this point; bump may show.
13	Pea pod	~7.4 cm	Fingerprints form; vocal cords develop.	Welcome to the 2nd trimester — energy returns.
14	Peach	~8.7 cm	Can squint, frown, grasp.	Appetite improves; "glow" begins.
15	Apple	~10 cm	Sensing light; forming taste buds.	Possible round-ligament twinges.
16	Avocado	~11.6 cm	Facial muscles, tiny movements.	Some feel first flutters (quickening).
17	Pear	~13 cm	Fat stores begin; skeleton to cartilage.	Bump growing; skin changes.
18	Bell pepper	~14.2 cm	Ears in position; can hear sounds.	Anatomy scan window opens.
19	Mango	~15.3 cm	Vernix (protective coating) forms.	Leg cramps, dizziness possible.
20	Banana	~25.6 cm†	Halfway! Anatomy scan; swallowing.	Feeling movements more clearly.
21	Carrot	~26.7 cm	Rapid growth; eyebrows appear.	Bigger appetite; visible kicks.
22	Papaya	~27.8 cm	Sense of touch developing.	Stretch marks may appear.
23	Grapefruit	~28.9 cm	Hearing your voice & heartbeat.	Swollen ankles; talk/sing to baby.
24	Corn cob	~30 cm	Viability milestone; lungs developing.	Glucose screening (24–28 wks).
25	Cauliflower	~34.6 cm	Gaining fat; hair colour forming.	Backache, haemorrhoids possible.
26	Lettuce	~35.6 cm	Eyes open; responds to sound.	Braxton-Hicks may begin.
27	Cauliflower	~36.6 cm	Sleep-wake cycles; hiccups.	End of 2nd trimester.
28	Eggplant	~37.6 cm	Brain surface folding; dreams (REM).	3rd trimester; count kicks daily.
29	Butternut squash	~38.6 cm	Muscles & lungs maturing.	Shortness of breath, heartburn.
30	Cabbage	~39.9 cm	Eyesight developing; bone marrow.	Fatigue returns; nesting urge.
31	Coconut	~41.1 cm	Rapid brain & nerve growth.	Leaky breasts (colostrum) possible.
32	Jicama	~42.4 cm	Practising breathing; toenails.	Antenatal visits become frequent.
33	Pineapple	~43.7 cm	Immune system strengthening.	Trouble sleeping; pelvic pressure.
34	Cantaloupe	~45 cm	Lungs nearly ready; fat plumping.	Pack your hospital bag.
35	Honeydew melon	~46.2 cm	Kidneys mature; liver working.	Baby may "drop"; more waddling.
36	Romaine lettuce	~47.4 cm	Usually head-down now.	Weekly checks begin; birth-plan talk.
37	Winter melon	~48.6 cm	Early term; practising sucking.	Watch for labour signs.
38	Leek	~49.8 cm	Firm grasp; organs ready.	Nesting, Braxton-Hicks stronger.
39	Mini watermelon	~50.7 cm	Full term; building fat.	Rest, hydrate, watch for labour.
40	Small pumpkin	~51.2 cm / ~3.4 kg	Ready to meet you! 🎉	Due date — but 41–42 wks can be normal.

*Averages; your baby may differ. †From ~week 20 length is measured head-to-heel (crown-heel) instead of crown-rump, so the number jumps. Sources: NHS, ACOG, IAP.

Explore each week in detail:
First trimester (weeks 4–12)
Week 4 Week 5 Week 6 Week 7 Week 8 Week 9 Week 10 Week 11 Week 12
Second trimester (weeks 13–27)
Week 13 Week 14 Week 15 Week 16 Week 17 Week 18 Week 19 Week 20 Week 21 Week 22 Week 23 Week 24 Week 25 Week 26 Week 27
Third trimester (weeks 28–40)
Week 28 Week 29 Week 30 Week 31 Week 32 Week 33 Week 34 Week 35 Week 36 Week 37 Week 38 Week 39 Week 40

🍎 Suggested visual — "Baby size by fruit, every week" carousel/interactive. AI prompt: "Cute flat-vector grid of fruits and vegetables from poppy seed to pumpkin representing baby size week by week, soft pastel background, consistent icon style." Alt text: "Fruit and vegetable size comparisons for baby from week 4 to week 40." Caption: From poppy seed to pumpkin — a fun way to picture your growing baby.

Key tests & scans timeline

When	Test / scan	Why it matters
6–9 wks	Booking visit + bloods (Hb, blood group, TSH, infections)	Baseline health, dating
11–13+6 wks	NT scan + dual marker (optional)	Screens for chromosomal conditions
18–20 wks	Anatomy (TIFFA) scan	Checks baby's structure & growth
24–28 wks	Glucose challenge (GTT)	Screens for gestational diabetes
28 wks	Anti-D (if Rh-negative)	Prevents Rh complications
28–40 wks	Growth scans, BP, urine, kick counts	Monitors baby & you

⚠️ India note: Under the PCPNDT Act, revealing the baby's sex before birth is illegal. Reputable clinics will never disclose it.

Eating well: do's & don'ts

✅ Do enjoy

Folic acid + iron + calcium (as prescribed)
Dal, eggs, paneer, chicken, fish (low-mercury)
Colourful fruits & veg, whole grains
Milk/curd, nuts, seeds; plenty of water
Small, frequent meals for nausea/heartburn

🚫 Do avoid

Raw/undercooked meat, eggs & fish
Unpasteurised milk & soft cheeses
High-mercury fish; excess caffeine (>200 mg/day)
Alcohol & smoking — completely
Large amounts of raw papaya/pineapple

Guidance aligned with WHO, CDC & IAP. Always personalise with your doctor.

Myths vs facts

Myth: "Eating for two means double the food." Fact: You need only ~300–450 extra calories/day in later trimesters — quality over quantity.

Myth: "The shape of your bump reveals the baby's sex." Fact: Bump shape reflects your body & baby's position, not sex.

Myth: "Exercise is dangerous in pregnancy." Fact: Moderate activity is recommended for most and helps mood, sleep & labour.

Myth: "You can't fly or travel." Fact: Travel is usually fine until ~36 weeks; check with your doctor first.

🚨 Warning signs — call your doctor or go to hospital now

Heavy bleeding or fluid leaking from the vagina
Severe or persistent abdominal pain or cramping
Severe headache, blurred vision or sudden swelling (possible pre-eclampsia)
High fever (>38°C) or chills
Reduced or no baby movements after 28 weeks
Painful or burning urination; persistent vomiting

Trimester checklist

1st trimester

Start folic acid & prenatal vitamins
Book first antenatal visit & bloods
Confirm due date with a dating scan
Stop alcohol/smoking; review medicines

2nd trimester

Anatomy scan (18–20 wks)
Glucose test (24–28 wks)
Start gentle exercise/prenatal yoga
Plan finances & maternity leave

3rd trimester

Count kicks daily
Pack hospital bag by ~34 wks
Finalise birth plan & hospital
Learn labour signs & breathing

Any time

Stay hydrated & rest well
Attend every antenatal visit
Ask questions — no question is silly
Look after your mental health too

🌳 Suggested visual — "When will labour start?" simple decision tree. AI prompt: "Minimal flowchart decision tree for recognising early labour signs (contractions, water breaking, show), soft purple flat vector, mobile-friendly." Alt text: "Decision tree showing early signs of labour and when to go to hospital." Caption: Not sure if it's labour? This quick guide helps — but when in doubt, call your doctor.

You don't have to do this alone 💜

Join The Circle — Baby Circle's private, doctor-supported community for every stage of pregnancy. Ask questions, track your journey, and connect with parents due the same month as you.

Explore The Circle Find the perfect baby name

Frequently asked questions

How many weeks is a full-term pregnancy?

A full-term pregnancy is 39–40 weeks and 6 days, counted from the first day of your last period. From 37 weeks it's considered "term"; 40 weeks is your standard due date.

How is my due date calculated?

Usually 40 weeks (280 days) from the first day of your last period, or confirmed by a first-trimester dating ultrasound — the most accurate method.

When can I hear my baby's heartbeat?

A heartbeat is often visible on ultrasound at ~6 weeks and heard on a Doppler at ~10–12 weeks.

When will I feel my baby move?

First flutters (quickening) usually happen between 16 and 22 weeks — often earlier in a second pregnancy.

When can I find out the baby's sex?

Anatomy typically shows at the 18–20 week scan. In India, sex determination before birth is illegal under the PCPNDT Act.

Which foods must I avoid?

Raw/undercooked meat, fish & eggs; unpasteurised dairy; high-mercury fish; excess caffeine; alcohol; and large amounts of raw papaya/pineapple. Ask your doctor if unsure.

How much weight should I gain?

For a normal BMI, roughly 11.5–16 kg total — but your ideal range depends on your starting weight. Your doctor will guide you.

Is exercise safe during pregnancy?

Yes, for most people. ACOG suggests about 150 minutes of moderate activity weekly (walking, prenatal yoga, swimming) unless advised otherwise.

Is morning sickness normal, and when does it end?

Very normal — it often peaks around weeks 7–9 and eases by weeks 12–16. Severe, persistent vomiting (hyperemesis) needs medical care.

How many antenatal check-ups do I need?

WHO recommends at least 8 antenatal contacts across pregnancy; your doctor may advise more based on your needs.

Is it safe to travel or fly?

Usually fine until ~36 weeks for low-risk pregnancies. Stay hydrated, move your legs, and check with your doctor first.

Can I sleep on my back?

From the second half of pregnancy, sleeping on your side (preferably left) is recommended for better blood flow.

What is gestational diabetes?

High blood sugar that develops in pregnancy, screened around 24–28 weeks. It's usually managed with diet, activity and monitoring.

Are Braxton-Hicks contractions labour?

No — they're irregular "practice" contractions. Regular, intensifying contractions that get closer together may mean real labour.

When should I go to the hospital in labour?

Common guidance is the 5-1-1 rule: contractions every 5 minutes, lasting 1 minute, for 1 hour — or immediately if your water breaks, there's bleeding, or reduced movements.

How can I look after my mental health?

Rest, talk openly, lean on your partner and community, and tell your doctor if you feel persistently low or anxious. Perinatal mental health matters as much as physical health.

Keep exploring

👶 27,000+ Baby Names 💜 The Circle Community 🌱 Growing Up Guide 📖 More Baby Circle guides

References & sources

World Health Organization (WHO). WHO recommendations on antenatal care for a positive pregnancy experience. who.int
ACOG. Your Pregnancy and Childbirth. acog.org
NHS. Week-by-week guide to pregnancy. nhs.uk
CDC. During Pregnancy. cdc.gov
UNICEF. Maternal and newborn health. unicef.org
Indian Academy of Pediatrics (IAP). iapindia.org

Medical disclaimer: This article is for general education and is not a substitute for professional medical advice, diagnosis or treatment. Always consult your obstetrician or a qualified healthcare provider about your pregnancy. If you have any warning signs, seek care immediately. Reviewed by the Baby Circle Medical Team; last updated July 2026.