Pregnancy is such a wonderful time of life. Whether you’re a Mum/Dad to be, an expectant Grandparent or just interested in pregnancy then this week by week guide to pregnancy is for you! We’ve detailed highlights of each week of pregnancy into this guide, we hope you really enjoy reading through each week and enjoy the miracle of pregnancy.
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Month 1 – Weeks 1 to 4
Month 1 is all about establishing the pregnancy. It’s a time of preparation for both the Mother and Baby.
- Week 1 – Massive changes in your body, time to prepare just in case you’re pregnant!
- Nutrition supplements – Now is the time to take supplements like Folic Acid
- Rapid growth – The rate of growth is faster in week one than at any other stage
- Sex decided – The sex of your baby is already decided, even at this early stage
- Week 2 – Rapid changes again, time to plan and prepare for a healthy pregnancy
- Healthy living – Stock up on fruit and vegetables, quit smoking if you can!
- Hormones – Your body is producing all the hormones needed for the pregnancy
- Major organs – All the major organs are already beginning to form
- Week 3 – Growth & travel, baby now a Blatocyst – there is much power in this bundle
- Ball of cells – Baby to be is a ball of unrecognisable cells but growing constantly
- Implantation – The Blatocyst travels from the fallopian tube to the uterus
- PMS symptoms – Normal symptoms like sore boobs and cramps may arise
- Week 4 – Development is at pace, take a pregnancy test, you may begin to feel pregnant
- Development – Brains, central nervous / circulatory systems & heart all develop
- Measurements – The size of a sesame seed, length is 0.13cm, weight is 0.11g
- Pregnancy Test – Taking a pregnancy test now will confirm you are pregnant
Week 4 is the time to take a pregnancy test if you suspect you are pregnant
Month 2 – Weeks 5 to 8
In month 2 Baby will develop significantly (e.g. limbs and organs), due to hormonal changes Mom is likely to experience morning sickness and other pregnancy symptoms.
- Week 5 – Into month 2 you will experience pregnancy symptoms, baby is growing rapidly
- Heartbeat – It may be possible to view a heartbeat in scans for the first time
- Limbs – In week 5 limbs will start to develop for the first time
- Tadpole – Your baby will currently look like a very small tadpole at this stage
- Week 6 – All babies vital organs are in place, watch your health and diet at this stage
- Cleavage – Your cleavage size will have noticeably grown in readiness for baby
- Diet – Change your diet to aid morning sickness & also for a healthy pregnancy
- Hormonal – Hormones will be “kicking in”, exhaustion & morning sickness follow
- Week 7 – Avoid illnesses wherever possible at this key time, baby brain rapidly develops
- Avoid illnesses – Be sensible avoid illnesses, particularly rubella and parvovirus
- Brain development – Baby brain develops, 100+ brain cells a minute created
- Embryo – Your baby is still an embryo but will rapidly transform into a little person
- Week 8 – Lips, eyelids, nose, fingers/toes visible on foetus, morning sickness continues
- Foetus – At week 8 your baby is officially called a foetus!
- Measurements – The size of a raspberry, length is 1.5cm, weight is 1g
- Webbed fingers and toes – All fingers and toes are developed, but are webbed
Month 3 – Weeks 9 to 13
During month 3, Baby is developing rapidly and will start to become active, exercise and activity is important for Mom at a time where sickness reduces and hunger increases.
- Week 9 – Baby has definite human features, heartbeat audible, fatigue usually an issue
- Heartbeat audible – An ultrasound in week 9 should detect the baby heartbeat
- Jelly baby – Your baby resembles a jelly baby! and is continuing to grow rapidly
- Loo trips – Trips to the loo will increase at this stage, this is completely normal
- Week 10 – Baby features rapidly develop, heart formed, Mother’s tummy starts to show
- Hair – The foetus will have a fuzzy hair covering their body
- Heart – The heart is fully formed & beats 2-3 times faster than Mother’s heart rate
- Nails – The foetus will be developing nails. Fingers & toes are no longer webbed
- Week 11 – Babies features develop more (e.g. facial), sickness eases & hunger rises
- Hunger – Mom often becomes hungry and needs to eat more to feed baby!
- Straightening – Babies torso straightens, creating more human-like appearance
- Wriggling – Baby will wriggle a lot and even do somersaults inside the womb!
- Week 12 – Baby is moving a lot, time for a first scan, the first trimester ends
- Dating scan – Many Mothers have their first scan during week 12
- First trimester end – Well done, the end of the first trimester has been reached!
- Measurements – The size of a lime, length is 5.8cm, weight is 14.4g
- Week 13 – Second trimester begins, baby gets active, development of kidneys & lungs
- Baby functions – Baby has some party tricks – burping, swallowing, yawning, etc.
- Exercise – Exercise is a great idea now, try swimming, dancing, yoga, etc.
- Kidneys and lungs – The kidneys are functional, baby breathes for the first time
Month 4 – Weeks 14 to 17
Baby is adding lots of functions this month, (e.g. fingerprints, sexual organs, limb mobility, etc.) Mothers may experience new pregnancy symptoms such as dental issues and blocked noses, food cravings may develop as well as an insatiable appetite.
- Week 14 – Sexual organs in place, fingerprints visible, pregnancy gathers momentum
- Fingerprints – Babies own unique fingerprints are all in place and unique to them
- Nasal blockages – Mothers may have blocked noses due to extra blood supply
- Sperm & Eggs – Baby boys have sperm production ability, girls have ovaries
- Week 15 – Food cravings, babies recognise voices & flavours, dental care may arise
- Dental – Mouth changes in pregnancy, bleeds & gum inflammation may arise
- Food cravings – It’s around now that food cravings (e.g. coal, sweets) may set in
- Linea Nigra – Dark outline around the “baby bump” may develop in some women
- Week 16 – Baby continues to form, as limbs and joints are developed baby gets mobile
- Eyes working – Babies eyes are working now, as well as other muscles too
- Limbs & joints – All limbs and joints are fully formed, baby actively uses them!
- Measurements – The size of an avocado, length is 11.9cm, weight is 103.8g
- Week 17 – Baby is growing at pace & practising for birth, gaining more function everyday
- Wriggling – Although week 21 is more common, some Mothers feel wriggles now
- Growing appetite – Queasy days are over, most Mothers can’t eat enough now
- Sucking and swallowing – Baby is practising sucking and swallowing even now
Month 5 – Weeks 18 to 21
Month 5 sees the 20-week scan as the baby continues to develop and “pile on” weight. Mothers are likely to experience “aches and pains” due to the growing size of baby who is very active during this month.
- Week 18 – Baby is very active with lots of room / mobility, babies sex identifiable in scan
- 50% – There is a 50% survival rate if baby is born premature during week 18
- Baby very active – Baby is kicking and very active at this stage
- Sex identifiable – Most scans are in week 20, but babies sex could be known now
- Week 19 – Hair on baby scalp grows, baby piles on weight, Mother may have heartburn
- Heartburn/indigestion – Mother may begin to experience heartburn & indigestion
- Piling on weight – Baby starts to pile on weight “big style” from now onwards
- Vernix Caseosa – Baby covered in this fluid protecting skin from amniotic fluid
- Week 20 – 20-week scan is exciting, Mother may ache more, and baby continues to grow!
- 20 week scans – Many Mothers have a 20-week scan and find out Babies sex!
- Aches & pains – Mothers may have aches due to abdominal stretching
- Measurements – The size of a pomegranate, length is 26cm, weight is 303.1g
- Week 21 – Babies taste buds are developing, time to book ante natal classes
- Ante Natal classes – It’s a good time to book/start to attend ante natal classes
- Baby tastes – Baby will be able to taste foods via amniotic fluid
- Movement – In first pregnancies, movement is often felt first during week 21
Month 6 – Weeks 22 to 26
In month 6, Baby is really piling on the weight this month and developing the senses they will need for the outside world. Mothers will experience new symptoms such as ankle swelling and stretch marks but all these challenges will be worth it in the end!
- Week 22 – Baby senses grow (e.g. sound & light), Mother may struggle with ankles/feet
- Ankles and feet – At this stage ankles and feet may begin to become swollen
- Light / dark recognition – Babies sense light, even though it’s dark in the womb
- Voice recognition – Babies are known to respond to voices at week 22
- Week 23 – Baby gains weight rapidly from now on, Mothers may suffer back discomfort
- Back ache – For many Mothers back ache may set in from around week 23
- Rapid weight gain – Baby gains weight rapidly, doubling weight in next 4 weeks
- Stretch marks – From now on stretch marks will become more prominent
- Week 24 – Baby has a high chance of survival if born now, babies lung maturing steadily
- Measurements – The size of a coconut, length is 30.5cm, weight is 630.5g
- Pregnant belly button – Many pregnant Mother’s belly button pops out from now
- Viable – If born now a baby is considered viable with a high chance of survival
- Week 25 – Baby is preparing to breathe air, babies enjoy sounds outside the womb
- Enjoy Mothers voice – Babies enjoy Mothers voice, speak and read to Baby!
- Haemorrhoids & constipation – From now on especially rectal issues may occur
- Lungs & nostrils – This week nostrils open / lungs mature in readiness to breathe
- Week 26 – Breathing practice is all-important to baby, the second trimester now ends
- Baby opens eyes – For the first time baby opens eyes from around week 26
- Breathing – Baby get ready for life out of the womb by practicing breathing air
- Second trimester end – Well done, the end of the second trimester has been reached!
Month 7 – Weeks 27 to 30
Month 7 sees the third trimester; baby continues to add weight and is practising for life outside of the womb. For Mothers it’s important to keep fit and take rest wherever possible practising breathing and attending ante natal classes is important too.
- Week 27 – The third trimester begins, Mothers needs to ensure they keep fit & healthy
- Breathing exercises – “Mom to be” should practise breathing exercises for birth
- Hiccups – Expect to experience baby hiccups especially from now, this is normal
- Keep fit – Mothers will get hungry but should balance food intake with exercise
- Week 28 – Baby continues to gain weight, babies heartbeat is especially strong now
- Baby heartbeat – Partner may hear baby heartbeat by placing ear on belly
- Measurements – The size of an aubergine, length is 38.1cm, weight is 1038.7g
- Rapid weight gains continue – Every week now, baby gains weight rapidly
- Week 29 – Babies will shed downy hair, Mothers can count babies kicks easily this week
- Counting baby’s kicks – It is fun to count babies kicks which are now all too clear!
- Downy hair loss – Baby sheds downy hair loss around week 29
- Rest – It’s important for “Mom to be” to get as much rest as she can
- Week 30 – Baby is preparing for life out of the womb, Mother needs to plan for the birth
- Amniotic fluid levels – The levels of amniotic fluids will reduce over coming weeks
- Baby brain growth – Babies brain grows which is needed for life out of the womb
- Bone marrow – Baby starts making their own red blood cells via bone marrow
Month 8 – Weeks 31 to 34
Month 8 and baby is readying for delivery, babies bones will be hardening and Baby will be developing a layer of fat ready for outside the womb. It’s an important time for Mothers to rest and take exercise whilst also planning for the delivery.
- Week 31 – Mothers can expect Braxton Hicks contractions now, baby prepares for birth
- Baby brain senses – Baby is working overtime to develop his five senses for birth
- Braxton Hicks – Expect Braxton Hicks contractions from around week 31
- Heartburn – Heartbeat/indigestion can occur now, seek medical advice if an issue
- Week 32 – Baby gets into birth position anytime now and also adds weight rapidly
- Positioning – There’s little room, baby will take delivery position in weeks 32-38
- Measurements – The size of an pineapple, length is 43.3cm, weight is 1728.2g
- Opaque skin – Baby skin is now opaque and not transparent as it once was
- Week 33 – Mom needs to rest, babies bones will harden & immune systems will develop
- Bones hardening – Babies bones will begin to harden in readiness for birth
- Immune system – Baby is developing an immune system from Mom’s antibodies
- Rest & exercise – Mother should get as much rest & light exercise as possible
- Week 34 – Baby is readying for birth, lungs are mature and baby continues to add weight
- Developed lungs – Most babies born in week 34 will have fully developed lungs
- Fingernails & toenails – Finger and toe nails will be completely ready
- Slowdown myth – Babies appear to be slower, it’s due to a lack of room to move!
Month 9 – Weeks 35 to 40
Month 9, it’s not long to go now until your bundle of joy arrives! Baby is fully formed and readying for birth. Mothers need to prepare for birth and as in month 8 take as much rest as possible.
- Week 35 – Baby is fully formed & birth-ready, Mother should ensure birth plans are clear
- Fully formed – Baby is fully formed by now and just gaining weight at this stage
- Premature? – A week 35 baby is premature but would fare well out of the womb
- Soft skull – Baby will be born with a soft skull to aid the birthing process
- Week 36 – Baby is likely to be engaged by now, Mother/Baby are readying for delivery
- Baby drops – When baby “drops” both eating and breathing will become easier
- Circulation & Immunity – Blood flow / immunity systems are ready for birth
- Engaged position – Most babies are now in the engaged position, ready for birth
- Week 37 – A baby is now full-term, baby may still have a little lanugo hair, and birth is near!
- Breast milk – Breast milk antibodies will help develop the immunity system further
- Full-term – A baby at week 37 is considered full-term and can be born anytime
- Measurements – The size of a butternut squash, length 49.5cm, weight 8g
- Week 38 – 40 – Patience is the word! Mom should rest and prepare, Baby is ready
- Cervix – The Cervix will dilate up to 10 centimetres at the time of delivery
- Perineal Massage – Consider a self-applied perineal massage to ready for birth
- Rest – “Mom to be” can’t get enough rest ahead of the big day ahead
Well there we are, we’ve now finished our week by week guide to the 40 weeks of pregnancy. For further reading you may like to visit the following link. We hope very much that you’ve enjoy reading this guide as much as we did writing it. We wish you all the very best with a safe pregnancy and delivery.