Fetal development begins right after conception, and each week brings exciting changes. Here’s your pregnancy week-by-week guide to help you understand what’s happening inside your belly over the next 40 weeks.
First Trimester
- Week 1
Oddly enough, you’re not technically pregnant yet. This is the first day of your last period, which is used to estimate your due date. - Week 2
Ovulation typically occurs around day 14. If sperm meets egg, fertilisation happens and your pregnancy journey begins. - Week 3
The fertilised egg, now called a zygote, travels from the fallopian tube to the uterus while dividing into a cluster of cells known as a blastocyst. - Week 4
The blastocyst implants in the uterine lining and starts forming the embryo and placenta. Your baby is about the size of a grain of rice. - Week 5
Your embryo grows rapidly, forming the umbilical cord and neural tube, which will become the brain and spine. Hormones kick in, bringing nausea, spotting, or cravings. - Week 6
Now 4 to 7mm long, your baby starts developing facial features. You might feel fatigued, nauseous, or notice breast tenderness. - Week 7
At 1cm, your baby’s arms and legs begin to take shape. You might go up a bra size, even if your bump isn’t visible yet. - Week 8
Facial features refine and bone structures start forming—knees, elbows, and wrists begin to develop. - Week 9
Your baby is almost an inch long and moving, though you won’t feel it yet. A heartbeat might be detectable on ultrasound. - Week 10
The embryo officially becomes a fetus, measuring about 3cm. Organs and bones continue to develop. - Week 11
About the size of a ping pong ball. Fingers and toes are no longer webbed, and tiny tooth buds and hair follicles form. - Week 12
The digestive system starts working and kidneys begin producing urine. Your baby can hear and respond to sound. - Week 13
Your baby is about 7cm and the placenta is fully developed. A small bump might be visible now
Second Trimester
- Week 14
Morning sickness fades and your baby can now make facial expressions. - Week 15
Your baby senses light and practices breathing. Stuffy nose? Pregnancy hormones are to blame. - Week 16
Growth spurt alert! Despite being avocado-sized, your baby will double in size soon. - Week 17
Baby is gaining fat and your milk glands are prepping for breastfeeding. - Week 18
Genitals are visible on a scan, and you might catch baby hiccups on screen. - Week 19
Now the size of a tomato, your baby develops skin pigmentation. - Week 20
Halfway there! Your baby swallows more amniotic fluid and produces meconium. - Week 21
Kicks get stronger. Baby can now taste flavors from your diet. - Week 22
Facial features like lips and eyelids are well-defined. Baby looks more human. - Week 23
Breathing motions begin. You might hear the heartbeat with a stethoscope. - Week 24
Your baby weighs 600g and is about a foot long. Your uterus is the size of a soccer ball. - Week 25
Peach fuzz grows. You might notice thicker hair too. - Week 26
Baby recognises voices and responds with kicks. Talk or sing often for bonding.
Third Trimester
- Week 27
Baby now sleeps and wakes regularly, and loves sucking fingers. - Week 28
Eyelashes appear and baby can blink and sense light. - Week 29
Brain activity peaks. Movement is more frequent and responsive. - Week 30
Baby looks more proportional. You may feel first trimester symptoms return. - Week 31
Practising life skills like breathing and sucking. Braxton Hicks contractions might begin. - Week 32
Baby plumps up. Some mothers may start leaking colostrum. - Week 33
Weighing around 2kg, baby is running out of space in the womb. Bones harden and the immune system develops. - Week 34
At 46cm long, baby is almost ready. If born now, she’ll likely need short-term NICU care. - Week 35
Brain growth continues. Most of the physical development is almost complete. - Week 36
Baby drops into the pelvis. Breathing gets easier as pressure on your lungs decreases. - Week 37
Nipples may protrude more, making it easier for baby to latch after birth. - Week 38
Weighing about 3kg and 50cm long, baby is nearly ready to meet you. - Week 39
Your baby is full term and preparing for labour. If water breaks early, call your doctor. - Week 40
You made it! Baby is now about 3.5kg. Swaddling can help soothe her post-birth. - Weeks 41–42
Still no baby? That’s normal. About 30% of pregnancies go beyond 40 weeks. Doctors may suggest inducing labour or a c-section depending on baby’s size.
Final Thoughts
Use this pregnancy week-by-week guide to stay informed and excited about each little milestone. Always consult your doctor for specific medical advice during your pregnancy.
