6 weeks pregnant

How big is your baby at 6 weeks?

About the size and shape of a pea — around 6 mm (0.24 in) long, head to bottom — roughly triple last week's length. The NHS notes some people think it resembles a tadpole at this stage, because of the little tail that disappears over the coming weeks.

A note on the numbers: in the first trimester babies are measured crown to rump — head to bottom, not head to heel, because the legs are curled. Weight is not reliably estimated this early, so any site quoting grams or ounces before about 14 weeks is guessing.

What's developing this week

The arms and legs are starting to form as limb buds. There are tiny dents where the ears will be, a bump where the heart is and another where the head will be, and the whole embryo is covered with a thin layer of transparent skin. The liver, brain and musculoskeletal system are all developing.

Can you see a heartbeat at 6 weeks?

Sometimes. The NHS says the heartbeat can occasionally be picked up on a transvaginal ultrasound at 6 weeks, but that you are unlikely to be offered one unless you have had IVF or there is a clinical reason. If you do have an early scan and no heartbeat is seen, that is often about dating rather than outcome — being three or four days earlier than you thought is enough to explain it, and a repeat scan a week later is standard.

What you might feel

Week 6 is when many people stop suspecting they are pregnant and start feeling it. Nausea is the headline, and despite the name the NHS points out morning sickness can happen at any time of day or night. Things that help some people: a snack by the bed, six small meals rather than three, ginger in any form, ice cubes, acupressure wristbands. None work for everyone, and the fact that they do not work for you is not a failure of effort.

Alongside it: exhaustion that sleep does not fix, a metallic taste, sore breasts, mood swings, headaches, food aversions, a sense of smell that has become a liability, frequent urination, discharge, cramping and bloating. If you cannot keep food down, tell your midwife or doctor — severe pregnancy sickness is a recognised condition with real treatment.

Is 6 weeks pregnant 1 month or 2 months?

Week 6 is in month 2, its second week.

There is no official weeks-to-months map. A calendar month averages about 4.3 weeks, not 4, so 40 weeks is a little over nine months — and two apps can disagree about which month you are in. The most widely used mapping:

• Month 1 — weeks 1 to 4
• Month 2 — weeks 5 to 8
• Month 3 — weeks 9 to 13
• Month 4 — weeks 14 to 17
• Month 5 — weeks 18 to 22
• Month 6 — weeks 23 to 27
• Month 7 — weeks 28 to 31
• Month 8 — weeks 32 to 35
• Month 9 — weeks 36 to 40

Your maternity team will not use months. Everything is booked by week and day — "11 weeks and 3 days" — because a few days change what is offered.

Miscarriage risk at 6 weeks

Week 6 sits on the first real milestone. Tommy's cites research showing that once a pregnancy gets past 6 to 7 weeks and has a heartbeat, miscarriage risk drops to around 10 per cent.

A study of over 300 women with a history of recurrent miscarriage found that seeing a heartbeat at 6 weeks gave a 78 per cent chance of the pregnancy continuing, rising to 98 per cent at 8 weeks and 99.4 per cent at 10 weeks.

One caveat almost never stated: those heartbeat figures come from a study of over 300 women with a history of recurrent miscarriage, so their baseline risk was higher than average. For most people the equivalent numbers would be at least as reassuring.

The catch, as Tommy's points out, is that most people are not scanned until around 11 or 12 weeks, so most pass this milestone without knowing it.

You will find week-by-week miscarriage percentage tables all over the internet. Tommy's, which funds the UK's national miscarriage research centre, says openly that beyond the well-evidenced drop after 12 weeks, reliable week-by-week risk research does not really exist. We give you what is evidenced instead.

The most common cause of early miscarriage is a chromosomal problem that happens by chance. Not lifting something, not a glass of wine before you knew, not stress or exercise. Tommy's states it directly: miscarriages very rarely happen because of something you did or did not do.

Is it safe to fly at 6 weeks pregnant?

Yes, in a straightforward pregnancy. The RCOG is unambiguous: occasional air travel is not harmful in an uncomplicated pregnancy. There is no evidence that cabin pressure or humidity harm you or the baby, and no evidence that flying causes miscarriage, early labour or your waters to break.

The honest issue at 6 weeks is not safety, it is misery. The RCOG specifically notes that motion sickness on a flight can make pregnancy sickness worse, and week 6 is often peak nausea. The RCOG also notes most obstetric emergencies fall in the first and third trimesters, and advises that if you have an increased chance of miscarriage or ectopic pregnancy you ask for a reassurance scan before you fly. From 6 to 7 weeks a scan can usually confirm the pregnancy is in the right place.

The risk that is real: blood clots

Pregnancy raises deep vein thrombosis (DVT) risk from the earliest weeks. ACOG puts it plainly: any travel of four hours or more — car, train, bus or plane — doubles DVT risk, and pregnancy adds to that. Under four hours the RCOG says you are unlikely to need special measures. Over four hours:

• Loose clothing, comfortable shoes, an aisle seat, regular walks about the cabin
• In-seat exercises roughly every 30 minutes
• Water steadily; cut down on caffeine
• Graduated compression stockings — not ordinary flight socks, and sized for you by a midwife or doctor

With other clot risk factors you may be advised to have heparin injections around the flight.

Practical points

• No airline restricts travel this early — cut-offs sit around 36 to 37 weeks for one baby, 32 for twins.
• Check what maternity and emergency care exists at your destination.
• Tell your insurer you are pregnant; cover should include pregnancy-related care.
• Some travel vaccines and anti-malarial tablets are unsuitable in pregnancy; travel to Zika areas is not recommended.

ACOG names 14 to 28 weeks as the best time to travel. That is guidance about comfort and access to care, not a prohibition on flying now.

When to call your midwife or doctor

Early pregnancy is full of sensations that turn out to be nothing. These are the ones worth a phone call.

Get emergency help now

Call your local emergency number (999 in the UK and Ireland, 911 in the US and Canada, 000 in Australia, 111 in New Zealand) or go to an emergency department if you have bleeding with any of the following, which the NHS lists as needing immediate assessment:

• Severe abdominal pain you cannot concentrate through
• Pain in the tip of your shoulder
• Feeling sick, faint or dizzy, or losing consciousness
• Heavy bleeding that soaks through a pad quickly

Sudden sharp abdominal pain with dizziness, faintness or looking very pale can indicate a ruptured ectopic pregnancy, needing same-day surgery. Around 1 in every 90 UK pregnancies is ectopic, and the NHS notes symptoms usually appear between weeks 4 and 12 — where you are now.

Call your midwife, early pregnancy unit or health line today

• Light bleeding or spotting, with mild or no pain
• One-sided pain low in your abdomen or pelvis
• Brown, watery discharge that is new for you
• Pain when you pee or open your bowels
• You cannot keep food or fluid down for 24 hours, your urine is very dark or absent for 8 hours, you feel severely weak or faint, or you are vomiting blood or losing weight — the NHS triggers for pregnancy-sickness help, which is treatable

You do not need a booking appointment first, and you do not need to be certain something is wrong.