Week 14 begins the second trimester — for most women the easiest stretch of the pregnancy. Nausea has usually lifted, energy is returning, and the uterus is not yet large enough to get in the way of anything.
Your baby is about 14 cm and 40 grams — peach-sized. If that length looks like a sudden leap, it is: the way it is measured changed this week.
The short answer: from week 14 the fetus is measured crown to heel rather than crown to rump, which is why the number nearly doubles overnight — the baby did not double. The thyroid starts producing its own hormones and the spleen begins making red blood cells. For you, brain fog lifts and energy returns, though a blocked nose (pregnancy rhinitis) often arrives.
Your baby this week
Facial muscles are being trained. The fetus can now squint, frown and grimace, and many begin sucking a thumb — these are reflexes rather than expressions of feeling, but the machinery for expression is being wired.
The body becomes covered in lanugo, a very fine downy hair that holds the protective vernix against the skin. Most of it sheds before birth.
Two organs come online this week. The thyroid starts producing its own hormones, having relied entirely on yours until now — which is why maternal thyroid function matters most in the first trimester. The spleen begins helping produce red blood cells.
Your body this week
The mental cloudiness of the first trimester usually lifts around now, and with it the worst of the exhaustion. Many women describe this as the point where they feel like themselves again.
The trade-off is often pregnancy rhinitis — a persistently blocked or runny nose caused by oestrogen swelling the nasal membranes, made worse by the increased blood volume. It is not an infection and not an allergy. Saline rinses, a humidifier at night and sleeping slightly propped up all help; decongestant sprays are generally avoided in pregnancy, so ask before using one.
Increased blood flow to the pelvis means many women notice a return of libido. Sex is safe in an uncomplicated pregnancy at any stage, unless your doctor has advised otherwise because of bleeding, a low-lying placenta or a risk of preterm labour.
Tests and appointments
Nothing routine falls at 14 weeks, but this is the last week of the nuchal translucency window. If the combined test has not happened, ask now about the quadruple blood test, which is offered between 15 and 20 weeks.
This is also the ideal week to start or restart exercise. Your centre of gravity is beginning to shift, and the back muscles that will carry the load later are best strengthened before they are under strain. Our safe exercise guide covers what is appropriate at each stage.
✅ Worth doing this week
- Start prenatal yoga or swimming if your doctor has not advised against it — this is the easiest trimester to build the habit
- Watch your posture now, before the centre of gravity shifts further; it prevents back pain later rather than treating it
- Use saline rinses for a blocked nose rather than decongestant sprays
- Confirm the screening result if the combined test was done, and ask about the quad test if it was not
- Do not be alarmed by the length figure — the measurement basis changed this week
When to call your doctor
Call the same day if: you have bleeding, severe or one-sided abdominal pain, a severe headache with visual disturbance or sudden swelling of the face and hands, fainting, a temperature above 38°C, burning on passing urine, or fluid leaking from the vagina. Nosebleeds are common in pregnancy and usually harmless, but one that will not stop after 20 minutes of pressure needs attention.
FAQ — 14 weeks pregnant
Why did the length jump from 7.5 cm to 14 cm in one week?
Because the measurement changed, not the baby. Up to week 13 the fetus is measured crown to rump, because the legs are curled and cannot be measured reliably. From week 14 the standard becomes crown to heel. It is the same convention every clinic and reference chart uses — but it is almost never explained, and it looks alarming when the number nearly doubles overnight.
Why do I have a blocked nose in pregnancy?
It is called pregnancy rhinitis and it affects a substantial minority of pregnant women. Oestrogen causes the mucous membranes lining the nose to swell, and the increased blood volume adds to the congestion. It is not an allergy or an infection, it can last the whole pregnancy, and it resolves within a couple of weeks of birth. Saline rinses and a humidifier help; decongestant sprays are not usually recommended in pregnancy.
Is it safe to exercise in the second trimester?
For most women, yes, and this is usually the easiest trimester for it. Prenatal yoga, swimming, walking and stationary cycling are all well suited. Swimming is particularly good because the water takes the weight off your joints. Avoid contact sports, anything with a fall risk, and lying flat on your back for long periods after mid-pregnancy. Ask your doctor first if you have bleeding, a low-lying placenta, or a history of preterm birth.
Will my energy come back now?
Usually. The second trimester is often called the easiest for a reason — hCG has fallen, nausea has largely lifted, and the "brain fog" and crushing tiredness of the first weeks tend to ease. The uterus is not yet big enough to interfere with sleep or breathing. If you are going to feel well at any point in the pregnancy, this is generally when.
Week 14 at a glance
Week 14 starts the second trimester. Your baby is about 14 cm crown to heel and 40 grams — and the length appears to jump because the measurement changed from crown-to-rump this week, not because the baby grew that fast. Facial muscles are training, lanugo covers the skin, the thyroid begins producing its own hormones and the spleen starts making red blood cells. For you, brain fog and exhaustion usually lift, libido often returns, and a blocked nose from pregnancy rhinitis often arrives. It is the best week of the pregnancy to start exercising and to fix your posture before the load increases.
Inside Baby Novum: weight and activity are tracked together, with gain plotted against the WHO corridor for your pre-pregnancy BMI — which matters from here, because the second trimester is when most of the gain happens.