Pregnancy Weeks: Your Complete Week-by-Week Guide

Welcome to the complete pregnancy weeks guide: 40 weeks from the first day of your last menstrual period to your due date. Whether you are tracking pregnancy by week to follow your baby's growth, or looking to calculate pregnancy by week to find your current week, every week is explained here in detail: your baby's size and fruit comparison, organ development, changes in your body, practical tips, and the answer to the most common question for that week.

Many mothers ask about pregnancy weeks by month: in short, one calendar month equals about 4 weeks and a third, and a full pregnancy is 40 weeks, or 9 calendar months. If you are wondering how many weeks are in a month during pregnancy, the table below shows the weeks of pregnancy by month exactly. To find your current week automatically, try the pregnancy weeks and months calculator on the home page; enter the first day of your last period and you will instantly know your week, trimester, and month.

The Three Pregnancy Trimesters at a Glance

Trimester	Weeks	Months	Highlights
First	1 - 13	Month 1 - 3	Major organs form; nausea and fatigue; end of the highest miscarriage-risk period
Second	14 - 27	Month 4 - 6	Nausea fades; first baby kicks; gender reveal; anatomy scan
Third	28 - 40	Month 7 - 9	Rapid growth and weight gain; preparing for birth; hospital bag

Pregnancy Months by Week: How Many Weeks in a Month?

Pregnancy Month	Pregnancy Weeks	Trimester
Month 1	Weeks 1 - 4	First
Month 2	Weeks 5 - 8	First
Month 3	Weeks 9 - 13	First
Month 4	Weeks 14 - 17	Second
Month 5	Weeks 18 - 21	Second
Month 6	Weeks 22 - 26	Second
Month 7	Weeks 27 - 30	Third
Month 8	Weeks 31 - 35	Third
Month 9	Weeks 36 - 40	Third

Note: the baby lengths and weights shown on the week pages are approximate averages; every baby is different, and that is normal as long as your doctor is reassured about the growth.

Jump Straight to Your Week

First day of your last period

Pregnancy Weeks: Your Complete Week-by-Week Guide

The Three Pregnancy Trimesters at a Glance

Pregnancy Months by Week: How Many Weeks in a Month?

Tools That Complete Your Week-by-Week Tracking

Jump Straight to Your Week

All 40 Weeks of Pregnancy

Week 1

Week 2

Week 3

Week 4

Week 5

Week 6

Week 7

Week 8

Week 9

Week 10

Week 11

Week 12

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

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

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