Can you get your period and still be pregnant?

Why you can't have your period while pregnant

To answer this question in more detail we’ll need to dive into the biology of reproductive health. A period – otherwise known as menstruation – is when blood and tissue from your uterus leave your body through your vagina[1]. This typically happens once every month, although the length of the menstrual cycle varies from person to person.

During the follicular phase of each menstrual cycle, the levels of the hormone estrogen gradually rise, and the lining of the uterus, known as the endometrium, starts to thicken in preparation for a potential pregnancy. An egg is then released from an ovary, in a process known as ovulation. Once the egg leaves the ovary, it travels down one of the fallopian tubes. If the egg joins together with sperm, this is known as fertilisation, which is a key step towards pregnancy[2].

If you become pregnant, the pregnancy hormone human chorionic gonadotropin (hCG) will be produced in your body. This triggers your body to produce more of the hormone progesterone which thickens your uterine lining and supports pregnancy[3]. This interups the usual pattern of the menstrual cycle, when the uterine lining is shed. Hence why you don’t get periods when you’re pregnant.

However, if the egg isn’t fertilized by a sperm cell, the egg is reabsorbed into the body, oestrogen and progesterone levels fall, and the lining of the womb comes away, leaving the body as a period[4].

Is spotting normal during pregnancy?

While you won’t get a period during pregnancy, you may experience some spotting, a type of bleeding from the vagina that is typically much lighter than normal menstrual bleeding.

Spotting is common during early pregnancy, particularly during the first 12 weeks, and it happens in around 50% of pregnancies[5]. It often happens during this early phase of pregnancy as the developing embryo plants itself into the wall of the womb – sometimes known as implantation bleeding, which often happens around the same time that your period would be due[6]. It can also be caused by hormonal changes to your cervix. It doesn’t last as long as a period, though, usually lasting only one or two days[5].

Although spotting during early pregnancy is common, and usually very normal, it’s still a good idea to speak to your healthcare provider to rule out any other causes of bleeding.

Signs of period vs pregnancy

If you’re wondering whether your bleeding is related to conception or menstruation, here are some things to look out for that you can use to differentiate between signs of period vs pregnancy. Keep in mind that nothing replaces a conversation with your healthcare professional, so always talk to your doctor in the first instance if you have questions or concerns.

While pregnancy has its own set of distinct signs, there are some symptoms that overlap with those of premenstrual syndrome and the onset of a period, such as tiredness, lack of libido, and sore breasts. While the wait can be frustrating, the best way to tell whether or not you are pregnant is to take a pregnancy test on the first day of your missed period.

Other causes of bleeding

There are some other causes of bleeding and spotting during pregnancy, some of which are harmless, and others which are a sign of something more serious. That’s why it’s always important to speak to your doctor or midwife about any bleeding, at any stage of your pregnancy.

During the first trimester

As well as spotting caused by implantation bleeding, some other causes of bleeding during the early stages of pregnancy include:

Cervical changes

Pregnancy hormones can cause some changes to the cervix, which may cause bleeding. You may experience bleeding after sex due to these changes, for example[6].

Infection

Bleeding may sometimes be caused by an infection. In most cases, this can be cleared up with antibiotics, which are safe to take when you’re pregnant[9].

Threatened miscarriage

Threatened miscarriage happens when there’s bleeding during the first 24 weeks of pregnancy, with no dilation of the cervix – but the pregnancy continues as normal. This is a fairly common occurrence, happening in around 20% of pregnancies[10].

Subchorionic haematoma

A subchorionic haematoma (SCH) is when there’s bleeding or a build-up of blood in the womb, around the embryonic sac that the fetus is developing in. It’s the most common cause of bleeding in early pregnancy[11].

If you have a subchorionic haematoma, you won’t usually experience any pain, although you may have some cramping. Most people who have a SCH go on to have a healthy pregnancy with no issues, although it can sometimes cause complications – so again, it’s important to speak to your healthcare provider to find out what it means for you.

Miscarriage

Bleeding in early pregnancy could also be a sign of miscarriage. Pregnancy loss is most prevalent in early pregnancy, and while it’s not often talked about it’s relatively common. It’s estimated that 10%-20% of known pregnancies end in miscarriage[12]. 

The main symptom of miscarriage is vaginal bleeding, and you may also experience cramping and pain in your lower abdomen. Other symptoms include discharge of fluid or tissue from your vagina, and no longer experiencing the symptoms of pregnancy, like feeling sick or breast tenderness[13].

It’s important to seek medical advice if you experience bleeding, especially if it’s accompanied by pain or cramping – but it’s also important to remember that many people have light bleeding during early pregnancy, and it’s not necessarily a sign of miscarriage.

Ectopic pregnancy

An ectopic pregnancy happens when a fertilized egg cell implants outside of the womb – meaning an ectopic pregnancy isn’t a viable one. Ectopic pregnancies don’t always cause symptoms, but if you do have symptoms, they’ll most commonly happen between weeks four and twelve of your pregnancy.

They may include:

• Vaginal bleeding or brown discharge
• Abdominal pain, usually low down and on one side
• Pain in the tip of your shoulder
• Pain when going to the bathroom[14]

These can all be symptoms of other things, too – but it’s important to get medical advice if you have any of these symptoms, ectopic pregnancies are extremely rare, but are serious and should be treated as a medical emergency.

Molar pregnancy

A molar pregnancy is when there’s a genetic issue with the fertilized egg. This means that the fetus and placenta don’t develop the way they should. A molar pregnancy isn’t viable. It’s rare, affecting about 1 in 600 pregnancies[15].

The symptoms of a molar pregnancy may include vaginal bleeding or dark discharge in early pregnancy, a swollen tummy, bad morning sickness and signs of an infection[15].

Second and third trimesters

Later in your pregnancy, bleeding may be caused by:

Having sex

Having sex when you’re pregnant is perfectly safe (unless you’ve been told to avoid it by your doctor). However, it can cause bleeding – although this is usually just light spotting[16].

Vaginal examinations

If you have any internal vaginal examinations, you may experience some bleeding afterwards. Again, this is typically spotting rather than bleeding[16].

Late miscarriage

The timeline for how late miscarriage is defined can vary, but typically a late misscarriage is one that happens any time after 13 weeks and before 20 weeks of pregnancy. The most common symptoms of a miscarriage during the second trimester are:

• Vaginal bleeding
• A gush or trickle of clear liquid from the vagina
• Pain in your stomach or abdomen, such as cramping pains
• Your baby’s movements slow down, change or stop[17].

If you experience any of these symptoms, contact your midwife or maternity unit straight away.

Placenta praevia

As your pregnancy progresses, your womb expands, which can affect the position of your placenta. If the cervix is completely covered by the placenta, it’s known as placenta praevia, while if the placenta is less than 2cm from the cervix, it’s known as low-lying placenta. It happens in around 1 in every 200 births[18].

It can cause heavy bleeding, which is usually bright red and happens during the last three months of pregnancy. It may put you and your baby at risk, meaning it’s very important to contact your doctor, midwife, or maternity unit if this happens. You may be given extra scans, asked to come into hospital during the later stages of pregnancy for monitoring, and it’s likely that your baby will need to be born by caesarean section[19].

Placental abruption

A placental abruption is a condition where the placenta starts to come away from the wall of your womb before your baby is born. It can happen any time after 20 weeks of pregnancy, most commonly happening later in the third trimester, between 28 to 40 weeks[20].

Most people with placental abruption will have vaginal bleeding – but not everyone. Other symptoms include abdominal pain, lower back pain and contractions[21].

It can lead to complications, including affecting your baby’s growth, premature birth and stillbirth. It’s important to remember that this condition only affects around 1% of pregnancies[21], but it’s always advised to seek medical advice if you experience any bleeding during pregnancy.

Vasa praevia

This is when the baby's blood vessels run through the free placental membranes (which are thin, unprotected parts of the amniotic sac where the placenta does not directly attach). This is most dangerous when they are also near the cervix, as it is when a vasa praevia is most likely to rupture.

It’s a very rare condition, thought to affect between 1 in 1200 and 1 in 5000 pregnancies[22] – but it can be very serious. Because the baby’s blood vessels aren’t protected, they can tear during labor or when your waters break – which can mean the baby loses a dangerous amount of blood.

Not everyone with vasa praevia will experience symptoms, but some may have vaginal bleeding. You may be diagnosed with it before you go into labor, or you may also be diagnosed with it during early labor if you have any bleeding, if an internal examination reveals vasa praevia, or if your baby is in distress when your waters break[23]. 

There’s no way to prevent vasa praevia, but it’s better for your baby if it’s diagnosed early – which is why it’s so crucial to speak to your doctor or midwife if you experience any bleeding, at any point during your pregnancy.

A bloody show

A ‘show’ or a ‘bloody show’ is when the mucus plug that’s been in your cervix during pregnancy comes away. This signals that the cervix is getting ready for labor to begin. It looks different for everyone, and the blood could be red, pink or brown. For some people, it may have a jelly, stringy texture while for others, it may be more mucus-like and streaked with blood. And for some people, the mucus plug will come out all at once, while for others it may happen more gradually[24].

There’s no set amount of time between the bloody show and labor beginning. Some people go into labor very quickly after, while it can take a few days. Either way, it clearly signals that labor will happen relatively soon – and while it can look alarming, it’s completely normal and nothing to worry about.

What to do if you're bleeding or spotting during pregnancy

Some spotting or bleeding during pregnancy is perfectly normal, particularly in early pregnancy. On the other hand, it can be a sign of something more serious. That’s why it’s important to speak to your doctor or midwife about any spotting or bleeding when you’re pregnant. They’ll be able to investigate the potential causes. It can be worrying to experience spotting or bleeding when you’re pregnant, but your healthcare provider will be able to provide reassurance and the right care for your needs.

Plan pregnancy with Natural Cycles

Natural Cycles is an FDA Cleared app that can help you understand your cycle better, making sure you know what normal looks like for you, and aid you on your journey to planning a family. You can easily track your menstrual cycle and log symptoms like spotting, discharge, and more. Our temperature-based algorithm is able to predict your most fertile days and ovulation window so you are always aware of what's happening in your body.