Week 5 is when a great many women find out. A missed period has usually registered by now, and home tests are reliable at this point. Excitement and worry arriving together is ordinary, not a sign that anything is wrong.
Your body this week
There is still nothing to see. What there is, is tiredness — the kind the NHS describes as extreme, and the kind that is hard to explain to anyone who does not know yet.
Hormone levels are climbing steeply, and they are behind most of what you feel. Some women notice light bleeding around this time and assume it is a period arriving late. It can also be implantation bleeding, when the embryo attaches to the lining of the womb.
Worry is common enough to be worth naming. NHS guidance points out that around one in five women feel anxious or stressed during pregnancy, and it advises talking to a midwife or doctor rather than sitting with it. That is not a sign of coping badly. It is the most-reported feeling of the first trimester after tiredness.
What you may notice
The NHS lists tiredness, a metallic taste, sore breasts, nausea at any hour, mood swings, new food likes and dislikes, a sharper sense of smell, needing to pee more often, a milky white discharge, cramping like period pain, and light spotting.
Food cravings and aversions can start now. Both come from hormones changing how taste and smell work, and neither predicts anything about the pregnancy.
Two things do not belong on a wait-and-see list: heavy bleeding, and pain that is severe or concentrated on one side. Both need to be assessed today.
Your baby this week
Around week 5, an embryo is roughly 2mm long — about the size of a sesame seed, as the NHS illustrates it. These are population figures, and no woman's own pregnancy has to match them.
This is the week the heart begins to form and beat, and the brain and spinal cord are taking shape rapidly. Blood vessels are appearing, and some of them will become the umbilical cord. The placenta is being built and will eventually take over from the yolk sac.
What care usually happens around now
Nothing is routinely scheduled. This is the week to make contact if you have not: the first booking appointment usually falls between weeks 8 and 12 in the UK, and services elsewhere run to different timetables.
If you take medication for an existing condition, guidance is to tell your prescriber that you are pregnant rather than stopping anything on your own. That single conversation is more useful this month than any other.
This week's tip
Book the midwife or GP appointment today rather than after the weekend. Waiting lists exist, the booking appointment takes about an hour, and every screening choice offered later has a window attached to it. Getting into the system early is the one thing this week that changes what is available to you in weeks 11 to 14.
When to see a doctor
Any bleeding should be reported, even if it settles. So should severe pain, one-sided pain, pain at the tip of the shoulder, or feeling faint. Early pregnancy changes covers what is ordinary this early, and pregnancy warning signs covers what is not.
Seek care now: Contact your local emergency services or go to your nearest emergency department if you have heavy bleeding, severe or one-sided tummy pain, pain in the tip of your shoulder, a severe headache with vision changes, sudden swelling of the face or hands, a fever, chest pain, trouble breathing, fainting, or a seizure. Femio cannot assess a pregnancy.
Frequently asked questions
I bled a little and I am still testing positive. What does that mean?
It needs to be assessed rather than interpreted at home. Light spotting is common and often harmless, and it can also be the first sign of something that needs care today. Contact a midwife, GP or early pregnancy unit.
Should the tiredness be this bad?
For many women it is, and it usually eases in the second trimester. Week 6 covers the nausea that often arrives next, and week 4 explains why the counting starts where it does. If tiredness is stopping you functioning, say so at your first appointment.