Implantation bleeding is considered to be a sign of early pregnancy. It is estimated that 1 in 4 pregnant women will experience implantation bleeding. It can also be accompanied by mild implantation pain.
If you’re not expecting to be pregnant, it could pass you by without you noticing. You might even mistake it for early spotting ahead of your next period. But if you’re trying to get pregnant, it’s natural that you might be more alert to the signs that something feels different. It is also natural to worry about whether something is wrong, or if it’s just normal. To put your mind at ease right from the beginning: implantation bleeding is totally normal. Only a quarter of pregnant women experience implantation bleeding, so if you don’t notice anything, there’s nothing to worry about either. Implantation bleeding is a phenomenon that doesn’t always occur, and it doesn’t mean there are any problems with your pregnancy. Here’s a helpful guide that tells you all you need to know about implantation bleeding.
What is implantation bleeding?
You may think of the moment of conception as the moment when the sperm meets the egg. Once they merge to become a single cell, life begins. However, it’s also helpful to view pregnancy as a process, rather than a single event.
The process begins when the egg is fertilised. This normally happens as the egg makes its way along the fallopian tube. The egg is fertilised when it joins with the sperm, and the process of cell division begins. Once fertilised, it will rapidly divide to become an embryo called a blastocyst. It is at this stage that the embryo reaches the uterus to start the implantation process. In total, this process takes between six to ten days once fertilisation has taken place.
Upon reaching the womb, the embryo is a sticky mass of cells that’s ready to attach itself to the lining of the uterus. Before implantation, the uterus will have already prepared itself for the embryo by getting thicker. This area of the female body is irrigated by a complex system of arteries, veins, and blood vessels needed to sustain an embryo and promote its healthy development. When implantation takes place, it is possible for some small blood vessels to capture the embryo and be broken as it settles into the womb lining. This is what sometimes leads to some blood loss and consequent spotting, known as an implantation bleed. This normally happens between ten to 14 days after conception.
How does implantation bleeding occur?
Non-pregnant women have roughly 100ml of blood circulating the uterine artery per minute. During early pregnancy, this rises to 120ml per minute. In these early stages, the uterus is well supplied by blood vessels and is therefore more prone to bleed. When the embryo sticks to the inner lining of the uterus, it can cause the veins and arteries of the endometrium to break, which causes an implantation bleed. This is very normal.
Implantation bleeding doesn’t occur because anything is wrong, or because the interaction between the endometrium and the embryo is ‘violent’. The embryo must be perfectly connected with the endometrial tissue to ensure the exchange of nutrients in the delicate gestation process that occurs in the following months. In order to do this, the bundle of cells that make up the embryo break the superficial capillaries of the endometrium with the intention of forming some new ones. The new capillaries will join the embryo and serve to feed the developing foetus through the future placenta.
The blood lost in this complex process is what we identify as implantation bleeding, and for this reason it is slightly different from menstrual blood. Since the endometrial tissue is full of blood vessels, bleeding can also occur for other equally natural reasons.
What colour is the blood?
Implantation bleeding occurs between seven to ten days after fertilisation. This time normally coincides with your menstrual cycle when your next period is expected. Implantation bleeding is identifiable by its lighter colour and thinner texture. The colour is less intense and not as dark as menstrual blood. Although it’s not uncommon to experience bright red or pink implantation bleeding, it will still be lighter in colour than blood during menstruation.
Implantation bleeding does not follow a fixed pattern. It can occur in one pregnancy and not in others, interchangeably. Spotting may also occur coinciding during the luteal phase, which is due to a hormonal issue and is not directly related to implantation, although it can be confused with it.
Losses due to embryonic implantation can last from one to three days, and are identified by the intensity of bleeding which is less than that which occurs with normal menstruation, although this can vary greatly among women but generally speaking it’s easy to observe the difference.
How is implantation bleeding different from a period?
Implantation bleeding is normally noticeable as a small amount of spotting or light bleeding that happens around 10 to 14 days after conception. It is light, stops by itself and does not require any treatment. Because of the timing, it is easy to confuse it with the onset of your next period, but there are some key differences. Let’s have a look at them:
- A normal period usually lasts between three to seven days, with the first couple of days usually being a flow of bright red blood.
- Implantation bleeding generally only lasts no longer than 24 to 48 hours. It is either brown, pinkish or black.
- Although it can sometimes extend beyond two days, it is light and intermittent and does not follow the more regular pattern of menstruation.
Intensity of bleeding
- Period bleeding is heavy at the beginning and lightens up towards the end.
- Implantation bleeding tends to be very light or consist only of light spots of blood, and it should not be heavy.
- As implantation bleeding has the consistency of light spotting, it should not stain in the same way as menstrual blood.
Amount of cramping
- For those who normally experience period cramping, it often occurs before the bleeding starts and lasts for two to three days. During this time, it can be quite severe.
- If any cramping occurs during the implantation of an embryo, it is usually mild.
It’s important to understand that these signs are not always indicative of a pregnancy, because they can have many other physical and hormonal causes. For this reason, they’re not infallible indicators to differentiate menstruation from implantation bleeding. Equally, one in every four pregnant women experience implantation bleeding or implantation pain, so it is only a sign of pregnancy in a minority of cases. There are also more common signs of early pregnancy which are both easier to recognise and easier to read:
- Breast tenderness: Breasts can feel tender as early as a week or two after conception. The circulation of extra oestrogen and progesterone makes the breast glands start to grow and they retain extra fluid, making them feel full, sore or unusually sensitive. Your nipples may also look darker, although this change is not noticeable until about week 10 of pregnancy.
- Fatigue: Tiredness is a normal response to all the hormonal changes happening within your body. The extra progesterone triggers a rise in basal body temperature and your heart starts to pump faster to deliver extra oxygen to the uterus, which can be exhausting!
- Morning sickness: Morning sickness affects the majority of pregnant women at around six weeks. For some, subtler feelings of nausea (which feels like mild travel sickness) can start after only two weeks.
- Frequently needing the loo: The need to urinate more often will increase as the pregnancy progresses, but it can also be a sign of early pregnancy. The extra blood flow to the kidneys starts early on, causing increased urine production.
Does implantation bleeding put the pregnancy at risk?
No. There is no evidence that relates implantation bleeding with a problematic pregnancy, such as an ectopic pregnancy.
Implantation bleeding is not connected to miscarriage or another danger to the baby. It’s true that gestational problems, especially those related to miscarriage, may be associated with bleeding. With implantation bleeding, as with menstrual bleeding, it’s noticeably more intense, usually painful and can come with other identifiable symptoms.
Ectopic pregnancies and miscarriages can also occur without any bleeding.
What should I do if bleeding occurs?
Although there is no reason to take special measures, it’s always advisable to consult your doctor or gynaecologist if you are in doubt or worried. They will be able to assess whether the bleeding is associated with embryo implantation. Your clinician should help you understand how implantation bleeding is a natural part of pregnancy and give you guidelines to help you proceed in the best way possible.
In most cases, bleeding after implantation normally causes no more than slight discomfort so it does not usually require any additional attention.
Does implantation bleeding happen with IVF?
Yes, implantation bleeding can occur after IVF. If you have a fertility treatment such as IVF, all the signs of early pregnancy are exactly the same. Whether the egg meets the sperm in the fallopian tube or in the laboratory, it still takes the same amount of time for the embryo to implant. If this does happen, the likelihood of implantation bleeding is still around 25%. All of the other signs of early pregnancy remain the same, too.
Is implantation cramping normal in early pregnancy?
Even though only 25% of women experience implantation cramping, it is a perfectly normal part of pregnancy like implantation bleeding. Here’s how you can recognise implantation pain as opposed to menstrual cramps:
- When? If you do have some implantation cramping, it occurs between 10 and 14 days after ovulation, which is usually around two to seven days before your next period is due. This is why it’s so easily confused with menstrual cramps.
- What does it feel like? Implantation cramps feel quite similar to menstrual cramps, but they are milder in intensity. Some women say that it feels like a sensation of light pulling, pricking or tingling.
- Where? The cramping or tingling feeling is in the lower abdomen and lower back. Sometimes it is only felt on one side of the body.
- How long? The duration can vary between individuals. It could be just a few isolated twinges or occasionally it could last between one and three days.
Getting in touch with us at IVI
If you do have any questions or concerns about your fertility, and would like to know more about assisted fertility treatments such as IUI, IVF or egg donation, do not hesitate to get in touch with us. You can even take a virtual visit by reserving a place at our free Virtual Open Evening. We’d love to hear from you.