Implantation bleeding

Implantation refers to when the fertilised egg attaches itself to the wall of the womb, and it occurs around the same time your period would’ve been due. Some women experience implantation bleeding around 8 weeks into their pregnancy, and it tends to show up as spotting/ light bleeding that you’ll likely become aware of after wiping when you use the toilet. “During the first trimester, many women will experience some sort of bleeding”, explains Abbas Kanani, pharmacist at Chemist Click. “This is caused by implantation, when the fertilised egg implants itself into the womb. This type of bleeding can last for a few days and is often mistaken for a light period. Other common causes can include infection, as the flora inside the vagina changes. This is not life threatening to the mother or baby and your doctor will advise whether antibiotics are required. Your immune system may even be able to clear the infection without treatment.”

Blood clot around the sac

Another potential reason why women may discover blood during their pregnancy is due to blood clotting around the sac. This manifests as a mass of blood situated between the placenta and the uterus walls, and although it’s not quite understood why it happens, it can be alarming for pregnant women although it doesn’t signal an impending miscarriage. Michelle Swer, consultant gynaecologist at London Gynaecology says, “Blood clots around the sac are often seen on a scan and does not usually affect the pregnancy but can lead to bleeding until the sac resolves. The bleeding usually turns brown in colour in keeping with old blood. She continues, “It is important that any bleeding especially as a first occurrence, or if you have a known underlying placental complication, is investigated to ensure it is not something more serious and that there is no need for further investigations or management.”

Cervical changes

When we become pregnant our body goes through so many changes, one of which is changes to our cervix that becomes softer and has a richer blood supply. This, as a subsequence, can often lead to bleeding. “During pregnancy, your body experiences changes, including changes to the cervix, where more blood vessels grow” says Abbas Kanani. “This can cause the cervix to bleed more easily during pregnancy.”

Early pregnancy problems

Sadly, bleeding during pregnancy can also be an indicator of an impending miscarriage, and this will occur in 1 in 4 women. “Bleeding with pain is associated with miscarriage”, says Michelle Swer. “This can be identified on a scan or women may need more than one scan to confirm the diagnosis. It is also important to rule out an ectopic pregnancy which is when the pregnancy implants outside the womb. As you can see there are a number of reasons for bleeding in pregnancy but the one that causes the greatest anxiety is the risk of miscarriage and rightly so. The ordeal women go through when bleeding due to a miscarriage varies so much hence it has been difficult to make sure that all accounts are taken into consideration. However, I feel it is important that each presentation is acknowledged, and women should be aware of each end of the spectrum so they can know when to seek advice in a timely fashion.”

Causes of bleeding in late pregnancy (24 weeks onwards)

Bleeding is rare during the 2nd trimester, but during the 3rd, there are three conditions that are uncommon but are still worth noting so that women are aware of them. Michelle Swer, consultant gynaecologist at London Gynaecology, outlines them.

Low lying placenta.
This is when the placenta lies low in the womb close or lying over the cervix. This will be identified on scan usually at 20 weeks and women will have a repeat scan to identify where the placenta is closer to delivery. Any bleeding in a woman diagnosed with a low-lying placenta should be seen by a doctor to ensure there is no risk of delivery which would not be suitable naturally.

Placenta Accreta Spectrum.
This occurs when the placenta attaches deep through the muscle wall and does not easily detach. This is also identified on a scan and urgent review is needed if there is bleeding in women diagnosed with this presentation.

Abruption of the placenta.
This is when the placenta comes away from the womb and is a serious and acute condition. There is often pain and bleeding and women should seek urgent medical advice.