Pregnancy can be a confusing time. Usually, and for most women, the first sign that they are pregnant is when they miss a period. This also means that most women don’t expect to have any bleeding when they are pregnant. Best of all for some, they don’t experience period pain, let alone bleeding. If they do bleed, they worry.
What is a period?
What is a period? A period is when women bleed from their vaginas – usually once a month. This is the body’s natural way of getting rid of the lining of the womb an egg is not fertilised and a baby is conceived.1,2
This means that once an egg is fertilised, a woman is pregnant, and if she bleeds, she’s not menstruating.
That’s a long way of saying that no, you can’t be pregnant and still have a period.
What can cause bleeding during pregnancy?
Very early in your pregnancy, you could experience some light bleeding or spotting. This is not unusual and can sometimes be confused with a light period. Usually, though, this bleeding is when the embryo that will become your baby, attaches itself to your womb. Bleeding, if it happens, can occur between one to two weeks after conceiving and only in about 25% of the population.3
Also, early in pregnancy, your cervix – the neck of the womb – changes and with these changes, there may also be a little bleeding or light spotting.
In both these instances, i.e., implantation bleeding and cervical changes, there is usually no reason for concern.
When bleeding in pregnancy is a worry
Reasons why you could bleed if you’re pregnant, vary. Instinctively, women know that if they bleed heavily and they’re having a baby, there could be something very wrong.
Usually, heavy bleeding is a sign that you should get medical help.
Causes of bleeding during the first three months of pregnancy
We’ve already mentioned two reasons why you might bleed when you’re pregnant, which are not caused for concern. There are, however, four other possible reasons – all of which are reasons to get quick medical help. The first is an infection, and the second, a possible miscarriage. If treated properly, there are no other complications from an infection and the miscarriage is stopped, most women go on to have normal pregnancies and healthy babies.
Bleeding, especially heavy bleeding is a sign that something is wrong like when the embryo implants itself outside the womb; this is known as an ectopic pregnancy. Ectopic pregnancies are quite rare and develop between the 4th and 12th weeks of pregnancy.4 An even more rare cause of vaginal bleeding in pregnancy is if a fertilised egg doesn’t properly develop into a separate embryo with a placenta. This is known as a molar pregnancy. The baby will not survive and the pregnancy either ends in a miscarriage or must be terminated.5
Causes of bleeding during the last six months of pregnancy
The most obvious cause of bleeding during the last six months of pregnancy is if your baby is miscarrying and/or you go into premature labour. If you go into labour before your 37th week and your cervix begins to open and will probably be some bleeding and you should get to the hospital or clinic so that you can stop your baby from arriving early. In rare cases, the placenta (also known as the afterbirth) can either separate itself too early from the womb (placental abruption) or moves so that it covers the opening of the cervix (placenta previa). Although both these conditions are rare, they can result in very heavy bleeding and both need urgent and proper medical treatment.6,7
Summary: pregnancy and bleeding don’t go together
Although we have noted that sometimes, pregnant women can experience a little spotting (light bleeding), this happens quite early in the pregnancy and is not a period. So, if you experience consistent and/or heavy bleeding, especially with pain, you should get medical help as soon as possible.
Disclaimer: The information on this site should not be used as a substitute for professional medical care or advice. Contact a health care provider if you have questions about your health.
- The Johns Hopkins University Menstrual Cycle: An Overview [Online] Available from <https://www.hopkinsmedicine.org/health/wellness-and-prevention/menstrual-cycle-an-overview> 29/06/2022
- Periods and fertility in the menstrual cycle – Periods National Health Service, UK [Online] Available from <https://www.nhs.uk/conditions/periods/fertility-in-the-menstrual-cycle/> 29/06/2022
- Bradley, S & Mariz, F (reviewer). 2022. What Is Implantation Bleeding? Healthline Media [Online] Available from <https://www.healthline.com/health/pregnancy/implantation-bleeding> 19/10/2022
- National Health Service, UK, 2022 Ectopic pregnancy NHS [Online] Available from <https://www.nhs.uk/conditions/ectopic-pregnancy/> 19/10/2022
- National Health Service, UK, 2022 Molar pregnancy NHS [Online] Available from <https://www.nhs.uk/conditions/molar-pregnancy/> 19/10/2022
- Nall, R. & Wilson, D R. (Reviewer). 2018. What Is Placental Abruption? Healthline Media [Online] Available from <https://www.healthline.com/health/pregnancy/complications-placental-abruption> 19/10/2022
- Johnson, S & Mariz, F, (Reviewer). 2021. What is placenta previa? Healthline Media [Online] Available from <https://www.healthline.com/health/placenta-previa> 19/10/2022