Implantation bleeding

Some women have never heard of implantation bleeding and instead, interpret it as a light period or old blood loss. In fact, implantation bleeding is relatively common up to 30%of pregnant women will experience some degree of bleeding in their pregnancy, often, this is due to an implantation bleed.

In the earliest days of conception, the blastocyst or ball of cells which is soon to become an embryo and eventually becomes the baby, needs to nestle down into the uterine wall to grow. The blastocyst has already been growing since it left the fallopian tube and now has to find the ideal spot in uterus to bed down for the next nine months.

There can be a minor disruption to the lining of the uterus because it is so full of blood and nourishment for the blastocyst. This often causes light . Sometimes this is obvious and can be seen on underwear, or it may be only slight. Some women only become aware they are bleeding when they have been to the toilet and see blood on the toilet paper after wiping.

Blood loss during an implantation bleed tends to be light, or described as spotting. It is mostly pinkish and watery in appearance, though it may also be a brighter red or even brown colour. After lying down or first thing in the morning, the blood may be more of a brownish colour. This is because it may have been sitting in the cervix or vagina for a few hours.

It is also common to have some mild uterine cramping during an implantation bleed. Not to the same degree as period pain but a vague, heavy, dull feeling in the pelvis. Often, rest is recommended and beneficial. It's also useful to avoid doing anything too strenuous. Resting won t prevent the implantation bleeding from occurring, but it may help you feel you're doing something positive by not exerting yourself.

When does implantation bleeding happen?

It normally occurs at around the same time as the period is due, around 6-12 days after ovulation. Which is why implantation bleeding can be both confusing and disappointing. Confusing because it can be interpreted as a light period and a sign of not being pregnant and disappointing for the same reasons. Women who are keen to conceive can become very upset at the sight of any blood loss and interpret this as a negative sign.

An implantation bleed occurs even before the pregnancy has been confirmed. Human Chorionic Gonadotrophin hormone (hCG) is the pregnancy hormone which is detected in the mother's urine. This is not produced until after the embryo has embedded in the uterus and there has been some very early development of the placenta. This is why an implantation bleed frequently occurs so early, even for the most perceptive of couples to know with any certainty that they have conceived.

One of the symptoms of pregnancy can be having vaginal bleeding which is considered lighter than normal. An implantation bleed can certainly be mistaken for a period. Many times it's only with the benefit of hindsight that a woman reflects back on what she thought was an early period, but in fact, was really an implantation bleed.

How long does implantation bleeding last?

Generally implantation bleeding only lasts for a day or so - normally, between 24-48 hours. It tends to settle quickly and is not like a normal period which can last up to a week or more.

What can I do to prevent implantation bleeding from happening?

Nothing really. Unless you have pain as well, or the bleeding is continuous and heavy, there really is nothing which you can do. If you have already had your pregnancy confirmed and it has been longer than two weeks since fertilisation, then an implantation bleed is unlikely.

An implantation bleed is not necessarily a bad thing. It can be a sign that fertilisation has occurred and the pregnancy is progressing as it needs to. But of course, when it happens you won t know you're pregnant, it's too early to say.

Some women believe that breast tenderness, nausea and early pregnancy symptoms are also present at around the time they experience implantation bleeding. But this is unlikely. It is too early for the hormones which cause these symptoms to have been released by the placenta.

Written and reviewed by Jane Barry, midwife and child health nurse on 12/01/20