You may think that bleeding or spotting is the last thing you want to see when you're trying to conceive – but in fact this light spotting could be implantation bleeding, which is one of the early signs that you are pregnant. About 25% of women will experience implantation bleeding as an early pregnancy indicator.
Light bleeding or spotting in your wet watery pregnancy discharge doesn't confirm that you are pregnant, but some women do experience it just after they've conceived.
So, just what does this bleeding mean, why does it happen and how long does this implantation bleed last?
What is implantation bleeding?
"Bleeding in early pregnancy, known as early pregnancy implantation bleeding or implantation spotting, can be a sign that you are pregnant.
The 'bleed' happens in some women when the embryo lodges itself into the side of the uterus, 'implanting' and causing some light spotting in some women, says Lesley Gilchrist.
How long does implantation bleeding last?
Implantation bleeding usually lasts around 1-2 days, but can last anything from a few hours to spotting on and off for many days, and be extremely light, and stay light. It tends to occur a few days before your period would be due. A study of 151 pregnant women who experienced implantation bleeding found that most episodes of bleeding occurred at least 5 days after implantation.
As with everything, everyone is different – some women may find that the implantation bleeding lasts as long as their normal period, some won't see any spotting at all.
When does implantation bleeding occur?
If you do get implantation bleeding, it commonly happens around the three weeks pregnant or four weeks pregnant mark.
Implantation spotting can also confuse the dates your midwife may give you for your estimated birth date, based on the first day of your last menstrual period. When you do see your midwife they will ask you when your last menstrual period was and also if it was ‘lighter’ than normal. From this, they can deduce whether or not this was an implantation bleed and ‘date’ your pregnancy as 4 weeks earlier.
This is important when it comes to timing your 12 week or ‘dating’ scan; too late and you may miss the window for some of the screening tests that are offered, says Lesley Gilchrist.
However, it can be difficult to tell the difference between implantation bleeding and your period. Dr Sameer Kumar, MBBS., MS ., FMAS, says that there are many reasons for mid-cycle spotting, but one of the most common is ovulation: "The most common cause of mid-cycle spotting is ovulation bleed which is physiological in most women," he adds.
What is implantation?
Once your egg has been fertilised it then has to travel through your fallopian tube, into your womb and burrow into the lining of your womb, or ‘implant’. This stage, when it attaches to the lining, usually takes around seven days from fertilisation, says Lesley Gilchrist.
The rule of thumb is that ovulation occurs around two weeks after the first day of your last period, and fertilisation around 24-36 hours after ovulation. To confuse things a little more, sperm can survive for up to seven days, so the day that you had intercourse may not be the date you conceived. Sperm can easily wait up to a week in your fallopian tube for the egg, which in contrast will usually only live for 24-36 hours.
Because of this, it can be tricky to calculate a due date for your baby. Tracking your menstrual cycle carefully can make things a lot easier.
What does implantation bleeding look like?
The blood is usually brown or pink and is quite light, usually contained in a panty liner, rather than a sanitary pad.
Implantation bleeding colour is different from the darker red blood associated with menstrual bleeding, however, many women begin their period with this type of blood loss and if they’re not expecting to be pregnant may mistake it for a regular period.
Implantation bleeding colour is different from the darker red blood associated with menstrual bleeding or ovulation spotting, however, many women begin their period with this type of blood loss and if they’re not expecting to be pregnant may mistake it for a regular period, says Lesley Gilchrist.
Most women with implantation bleeding will feel that their period was early, very light and use words such as ‘spotting’.
This ‘spotting’ may continue for 2-4 days in some women, and for those not expecting to be pregnant may simply mistake this for a ‘light’ period and think nothing else of it, until they miss their next period.
Ingefleur, a fertility homeopath and YouTube content creator, has a great video explaining what implantation bleeding can look like. She says implantation bleeding can be "any colour of the rainbow...watery pink, red, brownish, cervical mucus that is blood streaked or little red dots."
Is implantation bleeding a sign of miscarriage?
Implantation bleeding is not a sign that there is anything wrong with the pregnancy and there are no links to implantation bleeding and miscarriage.
Implantation bleeding is not a sign that there is anything wrong with the pregnancy and there are no links to implantation bleeding and early symptoms of miscarriage.
If you do think that you may have had a lighter than normal menstrual period it’s probably a good idea to take a pregnancy test one week later, says Lesley Gilchrist.
Not only will this confirm your pregnancy, it also lessens the chances of your midwife incorrectly calculating the date for your first scan and therefore limiting your access to certain screening tests that can be done", says Lesley Gilchrist.
Also according to Dr Deborah Lee, Dr Fox Online Pharmacy: "implantation bleed is a light episode of vaginal bleeding that can occur at fertilisation. Around 1 in 4 women experience an implantation bleed. It is normal and nothing to worry about.
It’s causes?
The egg and sperm fertilise inside the fallopian tube, and it takes 5 days for the developing blastocyst (ball of cells) to be propelled along the tube and into the uterine cavity. Here it attaches to the uterine wall to form the placenta. The bleeding is thought to occur from the physical process of burrowing into the endometrium and in due course, the myometrium (the muscular wall of the uterus), says Dr Deborah Lee.
A woman usually ovulates around day 14 (in a 28-day cycle), and fertilisation, if it happens, takes place soon after. Implantation then occurs around day 19. This means the most common time to see the bleeding will be around day 19 or after – in the latter half of the cycle. It can occur around the time of the missed period.
The blastocyst produces the hormone B-HCG which is what is detected by a pregnancy test. But, as the implantation bleed is so early, levels of B-HCG may still be very low and a pregnancy test at this time may be negative, Dr Deborah Lee.
Symptoms?
A woman may notice a light pink or brownish vaginal loss. This will only last 24-48 hours and will only need a light pad. It shouldn’t be soaking through a towel. Any heavy red bleeding is too heavy to be an implantation bleed. It should also be more or less painless.
As the bleeding is part of early pregnancy there may be other early pregnancy symptoms such as tiredness, sore breasts, nausea, bloating or headache, Dr Deborah Lee.
Women can also bleed vaginally from infections such as chlamydia, or gonorrhoea. If you have been at risk of an STI, or are 25 or under and have never been tested, it's highly advisable to go to the Sexual Health Clinic. Both of these are treatable with antibiotics.
When to see a doctor?
An implantation bleed is common and normal and there is no reason to contact your GP. However, other conditions can cause bleeding in early pregnancy which do need medical attention. These include a miscarriage or an ectopic pregnancy, says Dr Deborah Lee.
If you think you could be pregnant and have heavy bleeding, and/or abdominal or pelvic pain, you should get medical help without delay. Contact your GP or go to A&E. They are likely to refer you to the nearest Early Pregnancy Unit (EPU), but you do need a GP referral – they do not offer a walk-in service.", says Dr Deborah Lee.
Meet the experts:
Lesley Gilchrist, BSc Midwifery Studies, MSc Clinical Research Methods, has been a midwife since 2003, and has extensive experience as a labour ward co-ordinator and as a community midwife.
Dr Deborah Lee, of Dr Fox Online Pharmacy, has worked for many years in the NHS, mostly as Lead Clinician within an integrated Community Sexual Health Service, and now works as a health and medical writer, with an emphasis on women's health, including medical content for Dr Fox pharmacy. She has published several books and remains passionate about all aspects of medicine and sexual health. After completing her Medical Degree at University of Southampton Medical School in 1986, Dr Lee trained as a GP and after a number of years specialised in Sexual & Reproductive Health (S&RH).
