14 weeks pregnant: the placenta and the second trimester
14 weeks pregnant is a stage at which, the NHS says, the baby is around 8.5 cm long from head to bottom, about the size of a kiwi fruit, with a head that is getting rounder and more in proportion (NHS, 2026). This page sets out what the NHS and ACOG say about week 14 and the placenta.
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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 14 weeks
- Size and shape, NHS
- The NHS week 14 page in its week-by-week guide (NHS, 2026) gives the baby as around 8.5 cm long from head to bottom and compares it to a kiwi fruit. It says the head is getting rounder and more in proportion with the rest of the body.
- Movement and fluid, NHS
- The NHS says the baby is kicking around but that you probably will not feel it yet, and that your midwife might be able to hear the heartbeat using a handheld monitor placed on your tummy. It says the baby swallows small amounts of amniotic fluid, which pass into the stomach, and that the kidneys then pass the fluid back out as urine (NHS, 2026).
- Development, ACOG
- ACOG’s list for weeks 13 to 16 includes bones hardening, toenails forming, a defined neck and developed lower limbs, and lungs beginning to form tissue that will allow them to exchange oxygen and carbon dioxide after birth (ACOG, How Your Fetus Grows During Pregnancy, 2024). It does not date these to a single week.
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 14 weeks 0 days to 14 weeks 6 days.
A normal pregnancy lasts about 40 weeks from the first day of the last menstrual period, so at 14 weeks about 26 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.
What the placenta does
The NHS says the placenta is full of blood and pumps out nutrients, oxygen and hormones while removing waste products such as carbon dioxide. It says the placenta is firmly attached to your womb and links up with the baby through the umbilical cord, and that your blood and the baby’s come into close contact in the placenta but do not mix (NHS, 2026).
ACOG describes the placenta as a life-support system: oxygen, nutrients and hormones pass across it to the fetus, and waste products from the fetus pass back across it for removal (ACOG, 2024).
Your body at 14 weeks, as the NHS describes it
The NHS says you may feel less tired and sick now and that your appetite may return with your energy levels. It says you may notice yellow stains in your bra, which is probably colostrum, the first milk you will produce, and it asks you to ask your doctor or midwife to look if you are worried about any changes (NHS, 2026).
Where the second trimester starts
The NHS week-by-week guide treats week 14 as part of the second trimester, which it starts at week 13 (NHS, 2026). ACOG defines the second trimester as 14 weeks and 0 days to 27 weeks and 6 days, so week 14 is its first week (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 14 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
How big is the baby at 14 weeks pregnant?
The NHS says around 8.5 cm long from head to bottom, about the size of a kiwi fruit (NHS, 2026).
What does the placenta do?
ACOG says oxygen, nutrients and hormones pass across the placenta to the fetus and waste products pass back for removal (ACOG, 2024). The NHS adds that your blood and the baby’s blood come into close contact in the placenta but do not mix (NHS, 2026).