7 weeks pregnant: development and how your due date is set
7 weeks pregnant is a stage at which, the NHS says, the embryo is around 10 mm long from head to bottom and the brain and spinal cord are taking shape at a fast pace (NHS, 2026). This page sets out what the NHS and ACOG say about week 7, including how the due date is worked out.
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Seek help now if you have any of these symptoms
Bleeding and cramping are common in early pregnancy and often do not mean miscarriage. The symptoms below, however, need to be assessed straight away.
- Soaking two or more sanitary pads per hour, or passing large clots
- Severe lower abdominal pain, especially on one side
- Pain at the tip of the shoulder
- Dizziness, fainting, or collapse
- Signs of shock — pale, clammy, rapid heartbeat, breathlessness
- Pain on opening bowels, or bladder or bowel changes
- Feeling very unwell, or feverish
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How the sources describe development around 7 weeks
- Size and shape, NHS
- The NHS week 7 page in its week-by-week guide (NHS, 2026) gives the embryo as around 10 mm long from head to bottom and compares it to a grape. It says the brain is growing faster than the rest of the body, so there is a large forehead, with small dimples where the nose and ears will be and eyelids beginning to grow and cover the eyes.
- Limbs and brain, NHS
- The NHS says the limb buds are starting to form cartilage that will make the bones of the arms and legs, that the arm buds are getting longer with flattened ends that will soon become tiny hands, and that the embryo is generating around 100 new brain cells every minute (NHS, 2026).
- Development, ACOG
- ACOG’s list for weeks 1 to 8 includes the muscles of the eyes, nose and mouth forming and webbed fingers and toes poking out from the developing hands and feet (ACOG, How Your Fetus Grows During Pregnancy, 2024).
Weeks are counted from the first day of the last menstrual period, so about two weeks of the count come before conception (ACOG, How Your Fetus Grows During Pregnancy, 2024). This page covers 7 weeks 0 days to 7 weeks 6 days.
A normal pregnancy lasts about 40 weeks from the first day of the last menstrual period, so at 7 weeks about 33 weeks remain to the estimated due date (ACOG, How Your Fetus Grows During Pregnancy, 2024). Your own due date depends on your last period or a scan, not on the week alone.
Your body at 7 weeks, as the NHS describes it
The NHS says there is more blood pumping around your body than there was 7 weeks ago and that, as pregnancy goes on, the volume increases by up to 50%, feeding the uterus with oxygen and nutrients. It says this can make you feel thirstier than usual, that your womb is about the size of a lemon while the baby is the size of a grape, and that in a first pregnancy you may not start looking pregnant until around week 12 (NHS, 2026).
The NHS also says not to ignore any strange symptoms, such as feeling itchy all over, and to talk to your midwife or doctor about aches and pains (NHS, 2026).
How your due date is set
The NHS points to its own due date calculator and says you will get a more accurate date from your doctor or midwife when you have a dating scan, usually at 8 to 14 weeks (NHS, 2026).
ACOG says the estimated due date is calculated from the first day of your last menstrual period, and that when that date is uncertain an ultrasound in the first trimester may be used to estimate it. The scan measures the crown–rump length, from the top of the head to the bottom of the area that will become the buttocks. ACOG adds that before 7 weeks the crown and rump cannot be seen, so the greatest length of the embryo is measured, and a formula then estimates the gestational age (ACOG, 2024).
The due date is an estimate: ACOG says only about 1 in 20 women give birth on their due dates (ACOG, 2024).
Work out which week you are in
The Pregnancy week calculator takes your last period, conception date, scan or IVF transfer and shows how many weeks and days pregnant you are today.
Sources
- NHS Best Start in Life. Week 7 of pregnancy (week-by-week guide to pregnancy). nhs.uk, 2026.
- American College of Obstetricians and Gynecologists. How Your Fetus Grows During Pregnancy (FAQ156). ACOG, 2024.
Frequently asked questions
When is my baby due if I am 7 weeks pregnant?
It depends on the first day of your last period or on a scan. The NHS says a dating scan, usually at 8 to 14 weeks, gives a more accurate date than a calculator (NHS, 2026). ACOG says the due date is worked out from the first day of the last menstrual period, and that an ultrasound may be used when that date is uncertain (ACOG, 2024).
How is a scan used to date a pregnancy at 7 weeks?
ACOG says the crown–rump length is measured, and that if you are less than 7 weeks pregnant the crown and rump cannot be seen, so the greatest length of the embryo is measured instead. A formula then estimates the gestational age (ACOG, 2024).