Introduction

Welcome

Somewhere in the next 280 days, a single cell will become a person who can breathe, cry, grip your finger and know your voice. This book walks beside you for every one of those days.

You do not need to read it all, and you do not need to read it in order. Most people open it each morning or each evening, read the day they are on, and glance ahead when something is coming up. Some read a week at a time. Partners often read along. All of that works.

What you will find here is steady, practical company: what your baby is doing today, what your body is doing and why, what is normal, what is worth a phone call, and small things you can do that actually help. What you will not find is pressure to do pregnancy perfectly. There is no such thing.

How to use this book

The book has three parts around its centre.

Before you begin covers the basics worth knowing on day one: the habits that matter most, the care you can expect, and the signs that always deserve a call.

The daily entries run from day 1 to day 280, grouped into three trimesters. Every week opens with an overview of your baby's size and development, your body, and the week's focus. Every day then has one topic and ends with a small thing to try, or a note for your partner. After day 280 come the chapters on going past your due date, labour and birth, the first days with your baby, and the fourth trimester. At the very end you will find a quick reference of warning signs and a glossary.

Find today's entry by working out how many days pregnant you are (next section). If you find out you are pregnant at day 30 or day 60, start there; the earlier entries will still be waiting if you want them.

How pregnancy is counted

Pregnancy is counted from the first day of your last menstrual period, not from the day you conceived. That day is day 1. Conception usually happens about two weeks later, around day 14 or 15, so for the first two weeks of "pregnancy" you are not actually pregnant yet. It sounds odd, but almost everyone knows the date of their last period and almost no one knows the moment of conception, so this is the convention used everywhere.

Your due date is 280 days (40 weeks) after the first day of your last period. A quick way to find it: take that first day, add one year, subtract three months, and add seven days. A period that started on 1 January points to a due date of 8 October. (The rule can be a day or two off, because months differ in length; a pregnancy wheel or app counts the exact 280 days.)

Ages in pregnancy are written in completed weeks and days. On day 1 you are 0 weeks 0 days; on day 45 you are 6 weeks 2 days; on day 280 you are 39 weeks 6 days, and the next day is your due date at 40 weeks 0 days. Every entry in this book carries both numbers, so you can match it to whatever your care provider says.

If your cycles are long, short or irregular, or you conceived through fertility treatment, your dates may be set differently. An early ultrasound (usually between 8 and 14 weeks) measures your baby and is the most accurate way to date a pregnancy. If your scan moves your due date, follow the new date in this book too.

Keep in mind that a due date is an estimate. Only about one baby in twenty arrives on the exact day. A birth anywhere from 37 to 42 weeks is considered term.

Figure 1. Your pregnancy at a glance: the three trimesters and when common tests and milestones usually happen.

Sizes, numbers and averages

Each week gives your baby's approximate length and weight. Until week 20 the length is measured from the crown of the head to the bottom (crown to rump), because the legs are curled up; from week 21 it is measured from head to heel. These are averages. Healthy babies come in a wide range of sizes, and your scans and measurements are what matter for your baby.

Figure 2. Your baby's average weight week by week. Healthy babies vary widely around this line.

A note on medical advice

This book follows current mainstream guidance from international health and obstetric bodies, written in plain language. It is not a substitute for your own midwife, doctor or care provider, who knows your history and can examine you. Recommendations differ a little between countries and change over time; when this book and your care provider differ, follow your care provider.

Whenever an entry includes a line that begins Call your care provider if or Get help right away if, take it seriously. You are never wasting anyone's time by calling about a worry in pregnancy.