Pregnancy and birth can be great experiences and whether you are surprised by an unplanned pregnancy or something long planned, the week by week pregnancy changes that happen to women’s bodies can be major. When you first see the positive pregnancy test results, the immediate thing to do is make an appointment with an OB/GYN to find out how far along you are.

Pregnancy Week by Week


Week by week Pregnancy – First Trimester

The first trimester is the roughest for many women and the easiest for others. Morning sickness can be so severe for some mothers-to-be that smell or sight of food can induce vomiting.

Weeks 1 & 2 – As your body prepares for ovulation and fertilization, your pregnancy begins. Alcohol, medications, x-rays and other factors can cause miscarriage at this early state, and the mother would never have known there was a chance of pregnancy.
Week 3 – This is when fertilization of the egg occurs and the group of cells that will be your baby forms.
Week 4 – The embryo and placenta split into separate forms.
Week 5 – The heart and circulatory system begins to form and home pregnancy tests show positive at this point.
Week 6 – The baby’s face begins to take shape and you notice an increased need to urinate.
Week 7 – The baby’s brain is rapidly developing and mom’s breasts are becoming larger and more sensitive.
Week 8 – Actual movement begins, but mom may not feel it yet. Morning sickness can still be an issue.
Week 9 – As baby’s muscle forms, mom feels more tired and the need for sleep increases.
Week 10 – With mom’s hormones raging, extreme moodiness could set in. The little one inside is quite little, indeed- the size of a grape to be exact, and fingers and toes are becoming defined.
Week 11 – As the babe starts to look more human and less alien, mom begins to feel more normal, having less fatigue, less moodiness, and less morning sickness in most cases.
Week 12 -The baby doubles in size from week 11 to week 12.
Week 13 – Mom begins to notice her baby bump, but a lot is fluid, as the baby is only the size of a tennis ball.

Week by week Pregnancy – Second trimester

Week 14 – Hair now adorns the tiny head inside mom’s womb, and the babe even has eyebrows.
Week 15 – Skin changes can alter make up routines and a thick, dark line may appear down the center of your protruding belly. The little one is urinating inside its amniotic sac.
Weeks 16 & 17 – Movement in the belly is definitely noticeable by now and the increased blood in your body may cause sweating. Vaginal discharges could become heavier than normal.
Weeks 18 & 19 – Sleeping is more difficult, due to your bump. The babe has teeth buds forming and if it’s a girl, the ovaries contain primitive eggs.
Week 20 – Most women are able to find out what the sex is by this time.
Weeks 21 to 24 – You are definitely aware of baby’s sleep pattern, usually your movement throughout the day keeps her asleep until you lay down for the night. The baby is almost completely formed, including fingernails! Libido increases around this time.

Week by week Pregnancy – Third Trimester

Weeks 25 & 26 – Baby’s bones are hardening & veins are visible through the skin. Mom feels great during this time, maybe the best of the entire pregnancy.
Weeks 27 & 28 – The little one is 2-3 pounds, and mom begins to put on more weight very fast.
Week 29 – Breathing may become harder because the internal organs are crowded. It only gets worse until the baby comes.
Weeks 30 to 33 – The little one grows to four pounds and you can distinguish tiny knees from tiny elbows when they push on the tummy. Light sensitivity can occur, so when you go outside those kicks could increase.
Week 34 – Milk is forming in the breasts and your Braxton Hicks contractions begin to seem more like the real thing. The body is preparing for the shift into labor.
Week 35 – At almost 5 pounds, the baby has an excellent chance of surviving if born now. Mom is having more trouble than ever with sleeping.
Week 36 – At over 5 pounds, the baby would normally be fine if you went into labor now. Your doctor visits are now every week, instead of every other week.
Week 37 – This is considered “term” and so baby can come at any time now. She is practicing breathing by inhaling amniotic fluid into her lungs.
Weeks 38 to 40+ – The baby & mom put on weight in these last few weeks. A plan of action should be made for when labor starts. A bag should be packed for the hospital as you wait for the moment. You may go into labor with or without you water breaking. Sleeping may be very difficult, but rest is important so that when it’s time to push, mom won’t be too tired.

You may review this week by week pregnancy guide as often as you can during your maternity, as it provides information that will also help you monitor your pregnancy.