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Trimester 1 · Week 6 of 40

Week 6 of pregnancy: First Heartbeat

Cardiac activity may show on a scan from about 6 weeks. When an early scan helps, why a first look can be inconclusive, and ways to cope with nausea.

Last updated 28 September 2026

What's happening this week?

The neural tube closes, limb buds appear and the looping heart tube may now show as a flicker on a transvaginal scan. For many people this is also the week nausea arrives, often with a new sensitivity to smells. It is worth working out what helps you eat and drink on bad days, and knowing when sickness has gone beyond what is normal. If you are offered an early scan, it can confirm where the pregnancy is and how many embryos there are; if you are not, that is usually fine too.

Baby's development

The neural tube, which began forming last week, closes over the first days of week 6: first the upper end that will become the brain, then the lower end. Small swellings called arm buds appear on the sides of the embryo, followed a little later by leg buds. Shallow pits mark where the ears will develop, and small outpouchings called optic vesicles are the first step towards the eyes.

Inside, the liver begins to develop and an early circulation starts moving blood. The connection between the embryo and the yolk sac forms, part of what will become the umbilical cord.

The heart is still a tube that is looping and folding, not the four-chambered heart it will become. On a transvaginal scan its movement shows as a flicker, which sonographers call embryonic cardiac activity. It is often visible from about 6 weeks, at a rate of roughly 100 to 120 beats a minute, rising over the following weeks.

Not seeing cardiac activity at exactly 6 weeks is not, by itself, a sign of a problem, especially when dates are uncertain. Scan specialists use clear measurement thresholds before drawing any conclusions, so an early scan that is inconclusive is usually followed by another after a short interval.

Your baby's size

About the size of a lentil

2-6 mm

0.8 in · Length

< 1 g

Weight

Week 6

Gestational age

Embryos at 6 weeks usually measure about 2 to 6 mm from head to bottom. This crown–rump length is the measurement used on scans until about 20 weeks. A few days' difference in when you ovulated changes the figure a lot at this stage, which is why early measurements can move your due date.

Your body this week

Nausea and vomiting affect about three in four pregnant women. It often starts around week 6, can happen at any time of day despite the name morning sickness, and tends to peak around 9 weeks before easing for most people by 13 to 14 weeks. A heightened sense of smell, food aversions and a metallic taste often come with it.

Tiredness is often marked from now until about 12 weeks. Your breasts may keep feeling full and sore, and progesterone contributes to bloating and constipation. Some people also feel light-headed if they go too long without eating, another reason to keep snacks close by.

Feeling unwell for weeks can wear you down, and it is common to feel low, irritable or guilty about not coping as usual. Accepting help with cooking and housework, and telling your employer if symptoms affect your work, can make this stretch easier. Severe sickness is a medical condition that deserves treatment, not a sign of weakness.

Symptoms you may notice

Every pregnancy is different - you may have some, all or none of these.

Nausea and vomiting: Often starts around now and peaks at about 9 weeks. Many people find small, frequent snacks and sipping fluids between meals easier than large meals. Not keeping fluids down for about 24 hours needs same-day care.
Strong sense of smell: Cooking smells, perfume, smoke or petrol can set off nausea. Keeping windows open and letting someone else cook strong-smelling dishes, where possible, may help.
Food aversions: Foods you used to enjoy may suddenly seem unbearable. It is fine to eat what you can manage for now; for most people appetite improves once nausea eases.
Tiredness: Common between about 6 and 12 weeks. Early nights and short naps help where you can fit them in.
Bloating and constipation: Progesterone plays a part. Fluids, fruit and whole grains help, and gentle walking may too.

Medical care and tests

Early pregnancy (viability) scan
Commonly offered
About 6 to 9 weeks
In Indian private care a transvaginal scan between 6 and 9 weeks is common. It can confirm that the pregnancy is in the womb, look for cardiac activity, count embryos and help date the pregnancy. It is not needed in every pregnancy: in the UK the first routine scan is the dating scan at about 11 to 14 weeks. In India, a Form F is filled in by law for every pregnancy scan. If you have bleeding or pain, a scan becomes more clearly useful whatever your stage.
Treatment for severe sickness
Only if needed
When vomiting stops fluids staying down
About 1 to 3 in 100 pregnant women develop hyperemesis gravidarum, severe vomiting that leads to dehydration and weight loss. Anti-sickness medicines that are safe in pregnancy and, if needed, fluids through a drip are available. Asking early means you do not have to struggle on.

Scan practice varies a great deal between hospitals and countries. If you are not offered a scan now and have no pain or bleeding, that is normal.

Nutrition this week

Eat little and often. Many people find an empty stomach makes nausea worse, so a plain rusk, khakhra or a few crackers before getting out of bed may help.
Choose foods that are easy to face: plain rice, curd rice, idli, poha, khichdi, bananas or chilled fruit. Cold foods tend to smell less than hot, spicy or fried dishes.
Sip fluids through the day. Small amounts of water, nimbu pani or coconut water may stay down better than a large glass.
Fresh ginger (adrak) in food or tea may ease mild nausea. The evidence is limited, so keep to food amounts and avoid high-dose ginger capsules unless your doctor agrees.
If you can manage only a few foods for now, that is okay for a short time. Keep taking folic acid, and tell your doctor if the tablet itself makes you sick.

Movement and exercise

On better days, a gentle walk, ideally in fresh air, may help you feel better. On bad days it is fine to rest.
Try not to exercise on an empty stomach; a small snack beforehand may help prevent dizziness.
Drink water during activity, particularly in hot weather, because vomiting can leave you short of fluids. Stop if you feel faint.
Prenatal yoga with slow, steady breathing is fine if you feel up to it; skip poses that press on your tummy or leave you dizzy.

Things to keep in mind

Note the foods, smells and times of day that make you feel worst; patterns can help you plan around them.
After vomiting, rinse your mouth with water and wait before brushing, to protect your teeth.
If nausea affects your work, it may help to tell a manager early, even before you share the news widely.
Home Doppler devices cannot pick up anything this early, and they are not recommended for reassurance at any stage of pregnancy.

When to contact your doctor

Call your doctor or midwife the same day if you have

You cannot keep food or fluids down for about 24 hours.
Your urine is dark or you are passing very little.
You feel dizzy when you stand up, or are losing weight because of vomiting.
Any vaginal bleeding or spotting.
Stinging or burning as you pass urine.

Get emergency care now if you have

Vomiting with confusion, fainting or blood in the vomit.
One-sided tummy pain with dizziness, fainting or pain in the shoulder tip.
Heavy bleeding or passing clots.
Severe tummy pain.

In India, call 108 for an ambulance, 102 for free transport for pregnant women in many states, or 112 for any emergency - or go straight to your nearest hospital with a maternity unit.

If something feels wrong, trust that feeling and call - you never need to wait for your next appointment.

Questions to ask your doctor

Do I need an early scan, and what can it show at this stage?
What can I take if my nausea gets worse?
What happens if the scan does not show cardiac activity yet?
Can I change when I take folic acid if it makes me feel sick?

Week 6 checklist

Keep plain snacks by the bed and in your bag
Carry a water bottle and sip often
Note foods and smells that trigger nausea
Check your urine colour each day
Ask about an early scan if you have pain or bleeding

Frequently asked questions

Can you see a heartbeat at 6 weeks?

Often, but not always. On a transvaginal scan, the flicker of the early heart is often visible from about 6 weeks. If your dates are even a few days off, it may simply be too early. Not seeing it at this stage is not by itself a sign of a problem, and a repeat scan is usually suggested. Hand-held Doppler devices cannot pick it up until around 10 to 12 weeks.

When is morning sickness a problem?

Nausea on its own, even with some vomiting, is common. It becomes a concern if you cannot keep fluids down for about 24 hours, your urine becomes dark or scanty, you feel dizzy on standing, or you are losing weight. These can be signs of hyperemesis gravidarum, which needs medical treatment. Contact your doctor the same day; safe medicines and fluids are available.

Why do smells make me feel sick?

A heightened sense of smell is a common early pregnancy change and often goes hand in hand with nausea. Cooking smells, perfume, smoke and petrol are frequent triggers. Keeping rooms ventilated, staying out of the kitchen while strong dishes cook, and choosing cold foods may help. For most people it eases along with the nausea.

This page is general information, not a diagnosis or a substitute for care from your own doctor or midwife. Pregnancies differ, and timings here are typical ranges rather than deadlines. Read our medical disclaimer and editorial policy.