A miscarriage is a pregnancy that ends on its own within the first 20 weeks of gestation. Most miscarriages go unrecog­nised because they occur before a woman’s next expected period.

Miscarriage affects 1 in every 4 women. Having a miscarriage can be traumatic and many women experience grief over their loss. It may provide some comfort to know that it is natural and very common.

Some miscarriage statistics:

  • One in every 4 women have a miscarriage
  • 70% of fertilized eggs die before they are 6 days old
  • 99% of miscarriages occur in the first 12 to 14 weeks of pregnancy (1st trimester)
  • In all, 82% of conceptions do not result in the birth of a live baby
  • 75% of women who have had three or four miscarriages will go on to have a successful pregnancy.

What is miscarriage?

undefinedMiscarriage is a pregnancy that ends spontaneously before 20 weeks or when the baby's weight is under 400 grams and the baby dies. Sometimes a doctor or nurse may refer to your miscarriage as a spontaneous abortion. Abortion is the common medical name for all pregnancies that end before 20 weeks.

Bleeding during pregnancy doesn't always lead to miscarriage

Vaginal bleeding during pregnancy may be the first sign of miscarriage. However, about 20% of women have vaginal bleeding during the first 12 weeks of pregnancy and less than half of them miscarry. If you have any bleeding during pregnancy, talk to your lead maternity carer (LMC).

What should I do if I think I am miscarrying?

  • Ring your LMC and describe your symptoms.
  • Ask your partner, a friend or relative to stay with you, preferably someone with a driver's licence and car who can take you to the doctor or hospital if needed.
  • Place a hot water bottle on your stomach to relieve pain. Take paracetamol or aspirin for bad pain.
  • Soak up the blood with sanitary pads or towels. Lie down if you are bleeding very heavily.
  • Pack an overnight bag for hospital, just in case you need it later.
  • Save everything you pass in a bowl or bucket (rather than sitting on the toilet) to be seen by the doctor or tested to see why your miscarriage happened. If there was a small foetus, you can save it for burial. In some cases there is not a foetus or it is simply too small to find.

In an emergency: If you are alone and things are happening fast, dial 111 and ask for an ambulance. Never drive yourself to hospital if you are having a miscarriage.

Types of miscarriage

Very early miscarriage

Up to 50% of all miscarriages are thought to occur soon after implantation. Without the use of an ultra sensitive pregnancy test, you may not even have been aware that you were pregnant.

  • If a home pregnancy kit showed faintly positive, it was not a false pregnancy test, it was evidence that conception had taken place.
  • When your period does arrive it can be put down to a late one and is usually heavier than normal.

Missed miscarriage

A pregnancy where no embryo ever developed after fertilization and implantation. The non-viable fetus which will not have a heartbeat is usually discovered early in the pregnancy through a routine scan.

Threatening miscarriage

May be experienced for days or even weeks before you lose the baby. At this stage you could experience any of the following:

  • light bleeding
  • pain similar to period pain
  • you may no longer feel pregnant and the tender breasts and nausea associated with pregnancy may disappear.

If you have any of these symptoms, talk to your doctor. Bleeding episodes during early pregnancy can be frightening but are quite common. In about half of these cases the symptoms settle down and the pregnancy continues as normal.  These situations only lead to a miscarriage in 20% of cases.

Inevitable miscarriage

Here, the cervix opens, the placenta comes away from the uterine wall and passes out of the vagina. The most common signs are:

  • bleeding becomes heavy
  • pain is like bad period pain or birth contractions
  • faintness and nausea
  • you pass pieces of placenta which look like blood clots or pieces of raw liver
  • you may see the foetus
  • if your miscarriage is due to an incompetent cervix and you are more than four months' pregnant, the foetus may be alive.

The earlier you are in the pregnancy, the more likely that your body will complete the miscarriage on its own. Once the uterus is empty the cervix closes, the pain stops and the bleeding slows down and should stop by seven days.

Incomplete miscarriage

This occurs when some placenta remains inside the uterus after a miscarriage. Most miscarriages occurring between 6 and 12 weeks are incomplete. Treatment for incomplete miscarriage may include:  

  • waiting to see if the remaining placenta is expelled during your next period (this needs to be closely monitored*)
  • ultrasound scans to check for remaining tissues
  • tablets to promote complete passing of any remaining tissue
  • dilation and curettage (D&C) procedure to remove remaining placental tissues (this requires a general anaesthetic).

When to seek medical advice

Tell your LMC immediately if you experience fever and chills, pain or there is an odour – you may have an infection which requires hospital treatment. If not treated, an incomplete miscarriage can make you very ill and may also have an effect on future pregnancies.

What can my doctor do if I'm pregnant and bleeding?

If you are pregnant and experiencing light vaginal bleeding, your healthcare provider will probably organise an ultrasound to help assess whether your pregnancy is healthy. An ultrasound can help determine whether:

  • there is a fetal heartbeat
  • the amniotic sac that surrounds the fetus is normal
  • the pregnancy is ectopic (occurring outside the uterus, such as in one of the fallopian tubes)
  • you may have spontaneously aborted one fetus in a twins or triplets pregnancy.

Unfortunately, your healthcare provider cannot stop you from miscarrying. The main goal of treatment during or after a miscarriage is to prevent hemorrhaging (heavy bleeding) and/or infection.

  • The earlier you are in the pregnancy, the more likely that your body will expel all the fetal tissue by itself and will not require further medical procedures.
  • When the body does not expel all the tissue it is called an incomplete miscarriage.

Why does miscarriage occur?

Miscarriage is usually a natural process. The chain of events from conception through early gestation is complex. Most miscarriages occur because something went wrong during or soon after conception. There are thought to be many reasons which cause this, including:

  • the fertilised egg may implant in the wrong place
  • in many cases the part of the pregnancy that grows into the baby fails to develop
  • something may be wrong with the placenta
  • the mother's immune system may reject the placenta
  • the mother may be sick, badly injured or under too much stress
  • she may have a deformed uterus, a weak cervix or an intrauterine contraceptive device (IUCD) inside the uterus
  • exposure to environmental chemical pollution, cigarette smoke, alcohol and recreational drugs.

What are the chances of having a miscarriage?

For women in their childbearing years, the chances of having a miscarriage can range from 10-25%. Risk factors include:

  • Health: The risk of miscarriage is lower in healthy women, where the average risk is about 15-20%.
  • Maternal age: An increase in maternal age affects the chances of miscarriage:
    • women under the age of 35 yrs old have about a 15% chance of miscarriage
    • women who are 35-45 yrs old have a 20-35% chance of miscarriage
    • women over the age of 45 can have up to a 50% chance of miscarriage.
  • Previous miscarriage: A woman who has had a previous miscarriage has a 25% chance of having another (only a slightly elevated risk than for someone who has not had a previous miscarriage).

What if I keep having miscarriages?

If a woman experiences three consecutive miscarriages, the miscarriages are considered recurring. A woman suffering recurring miscarriages may undergo medical tests to try and discover any underlying conditions that may be causing her to miscarry.

Learn more

Miscarriage: causes, risks, signs, symptoms Southern Cross Healthcare Group NZ, 2014