Week 12 closes the first trimester for most women, and it usually brings the scan. For a lot of people it is also the week they start telling other people, which is a social convention rather than a medical one. Symptoms often begin to ease from around here.
Your body this week
The placenta is probably feeding the pregnancy by now, having taken over from the yolk sac, and hormone levels settle somewhat once that has happened. That is the reason sickness commonly eases in the weeks after this one.
Your waist is thickening and your breasts are larger. As the sickness fades, appetite often returns, and with it the worry about whether you are eating enough or too much.
The bump question is worth answering directly. The NHS lists what determines how big a stomach looks: hormones, pre-pregnancy weight, how many babies you have had before, and the strength of your muscles. It is a poor guide to anything, and comparing bumps with someone else at the same week tells you nothing.
What you may notice
An aching stomach, nausea, mood swings, a metallic taste, sore breasts, indigestion and heartburn, headaches, dizziness, new likes and dislikes, a sharper sense of smell, a white milky discharge, light spotting, cramping, darker patches on the face, greasier skin, thicker hair, and bloating.
Spotting still means a call, not a wait. So does any bleeding, at any stage.
Your baby this week
Around week 12, the NHS gives a measurement of 5.4cm from head to bottom — about the size of a plum. That is a population average, and a scan measuring above or below it is a matter for the sonographer rather than a verdict.
Internal organs and muscles have grown, and a heartbeat can be picked up on an ultrasound scan. The skeleton is hardening from tissue into bone. Sex organs have formed, although most scans cannot tell the sex this early.
What care usually happens around now
The dating scan usually happens between 11 and 14 weeks in England, at the same visit as screening for Down's syndrome, Edwards' syndrome and Patau's syndrome. The scan works out how far along the pregnancy is, checks how many babies there are, and looks at the physical development the scan can see at this stage.
ACOG describes ultrasound in similar terms — a picture built with sound waves, used to assess growth and dating. The timing and the exact bundle of tests differ between countries, so a UK schedule is an illustration and not a rule.
This week's tip
Ask for a printed scan photograph and ask what the measurements were. Not for the fridge — for your notes. Knowing the date the scan gave, and what it moved your due date to, saves an entire conversation at every appointment for the next six months.
When to see a doctor
Any bleeding, severe pain, a fever, or a headache with vision changes needs same-day contact. Pregnancy basics covers the shape of the whole pregnancy, and pregnancy warning signs covers what not to wait on.
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
Is 12 weeks the safe point to tell people?
There is no medical line at 12 weeks. Many people wait until after the first scan because that is when they feel ready, and telling people earlier is equally reasonable — particularly if you would want support should anything go wrong.
My bump is much smaller than my friend's. Should I worry?
Bump size at the same week varies enormously and depends on things that have nothing to do with the pregnancy. Week 13 starts the second trimester, and week 11 covers the screening choices. Your midwife measures growth properly from around 24 weeks.