What is it?
The medical definition of miscarriage is the spontaneous loss of a pregnancy before 24
weeks’ gestation, when the foetus has a chance of survival outside the womb.
Why does it happen?
Sadly, miscarriage is the most common reason for gynaecological admissions into hospital in
The most sensitive studies suggest that with fertile couples pregnancy occurs in at least 60%
of natural cycles. The studies also suggest that as many as 50% of pregnancies miscarry
before implantation in the womb occurs. Early after implantation (before a pregnancy is
clinically recognised) pregnancy loss rate is around 30%. And even after a pregnancy is
clinically recognised as many as one quarter of pregnancies miscarry, usually during the first
The most risky time is between six and eight weeks from the last menstrual period.
Over half the babies who are miscarried during this period have a chromosomal abnormality.
This occurs when the crossover of genes from the sperm and the egg takes place at the time
of conception. Sometimes, some genetic information is lost and the pregnancy cannot
continue. This is known as a ‘chance event’ and has no known medical cause. Exactly which
information is lost determines when the miscarriage will happen. The point at which the
information is needed, and is not there, is the point at which the baby stops developing and
dies, and, usually, the miscarriage begins. This genetic information may be needed
immediately, or not for some weeks, and the pregnancy will carry on as normal until that time.
The miscarriage may not happen immediately, leading to what is called a ‘missed’
miscarriage which may not be picked up until some weeks later, following slight bleeding or
The second most common cause of miscarriage is the baby not implanting itself correctly in
the womb lining - another chance occurrence.
Other risk factors include the age of the mother: miscarriage risk rises as maternal age
increases. For women under 35 the clinical miscarriage rate is 6.4%, at 35-40 it is 14.7%, and
over 40 it is 23.1%.
Smoking, certain drugs (prescribed or illicit substances), multiple pregnancies such as twins
or triplets, poorly controlled conditions such as diabetes, and auto-immune disorders such as
Lupus may also increase the risk of miscarriage.
Types of miscarriage
Although ‘miscarriage’ is used as a general term, there are several different types. By feeling
the cervix (the neck of the womb), a doctor can often determine the type and stage of
Threatened miscarriage this is used to describe bleeding in early pregnancy, where the
cervix is found to be tightly closed. The pregnancy is most likely to continue.
Inevitable miscarriage this describes bleeding in early pregnancy where the cervix is found to
be open, suggesting that the pregnancy will be lost.
Incomplete miscarriage miscarriage has definitely started, but there is still some pregnancy
tissue left in the womb. The cervix is usually found to be open.
Complete miscarriage when the pregnancy has been lost, the womb is now empty and the
cervix has closed.
Missed miscarriage when the pregnancy stopped growing some weeks ago, but there was no
bleeding at this time. This type of miscarriage usually causes a slight, dark-brown blood loss
and the sudden end of normal pregnancy symptoms. It is sometimes called a blighted ovum.
Miscarriage later in pregnancy
Four-fifths of miscarriages occur in the first 12 weeks (first trimester) of pregnancy. Pregnancy
loss later than this is much less common, and the causes may be different to those described
above. They are more likely to be related to physical problems, for example with the structure
of the womb, the strength of the cervix holding the weight of the growing pregnancy, or
problems with the function of placenta. A medical specialist can provide specific advice.
The most common symptom is vaginal bleeding, which can range from light spotting to heavy.
The blood may contain clots or other tissue.
However, vaginal bleeding during a pregnancy does not always signal that a miscarriage has
taken place, particularly if it is light and only lasts a short time. Prolonged or heavy bleeding,
like a period or heavier, is more likely to signify a miscarriage.
There can often be cramping, with period-like pains, and back pain. The cramping sensations
can be rhythmic and very uncomfortable, similar to contractions during labour. There may be
a distinct loss of fluid, particularly if the pregnancy is more advanced. Some women find that
the usual symptoms of pregnancy, such as nausea, breast tenderness and fatigue, may stop
Any such symptoms should be reported immediately to a doctor, although once a miscarriage
has started very little can be done to prevent it.
If a miscarriage is complete then no further treatment is needed. When miscarriage occurs
under 10 weeks, it is more likely to complete by itself. The other types of miscarriage
frequently require treatment, though in some cases it is appropriate to see first if nature takes
its course. The decision on whether medical treatment is needed depends on the stage of
pregnancy, the amount of bleeding, any risk to health, and each woman's personal choice.
For missed miscarriage or when there is significant bleeding, treatment with drugs or surgery
may be needed to remove the remaining pregnancy tissue. Although bleeding may be more
prolonged afterwards, research suggests that avoiding an operation may halve the risk of an
infection. However, it is very important that the woman is monitored closely to ensure that all
the pregnancy tissue is expelled naturally, as a significant delay can occasionally result in
The medicine doctors prescribe is called misoprostol, and it makes the womb contract so that
the remainder of the pregnancy is expelled. It is normally prescribed for miscarriage under
seven weeks, or where there is a small amount of tissue remaining in the womb.
Surgical treatment involves going to theatre for a short operation under general anaesthetic,
taking about 5 minutes, to empty the womb. This is known as an evacuation of retained
products of conception (ERPOC). A soft plastic tube is passed through the cervix into the
womb and the pregnancy material is removed by suction. A similar but less common
procedure is a dilation and curettage (D&C), which involves the cervix being gently widened
to enable the pregnancy tissue to be removed by gently scraping away some of the lining of
Miscarriage is a very common event and many women experience two miscarriages, purely
by chance. Having more than one miscarriage can lead to anxieties that a normal pregnancy
will never occur. But even after two miscarriages it is statistically unlikely that there is any
underlying problem, and there should be every chance of a successful pregnancy in the
After three consecutive miscarriages it is advisable to undergo some tests to rule out a
specific cause. Possibilities include a hormonal disturbance, genetic problems, abnormalities
of the womb, or immune disorders such as ‘antiphospholipid syndrome’ (also called Hughes
The physical effects of a miscarriage tend to clear up quickly. Any bleeding should cease
within seven to 10 days, with the next period returning around six weeks later. Sometimes
infection can make the bleeding last longer or cause a discharge that is itchy, smelly or
greenish in colour. If this happens, a course of antibiotics can be prescribed to clear it up
The emotional effects of miscarriage can be greater. Grief is a normal reaction to miscarriage
and it is normal for it to be intense as that after any other bereavement. Many people describe
a feeling of numbness and emptiness following a miscarriage. Feelings of jealousy and
sometimes anger towards others are also common.
As with any bereavement, there is no ‘right’ way to deal with the emotional effects of
miscarriage. Some couples withdraw, feeling alone and isolated, others may wish to talk
about it and find comfort in sharing their experiences, perhaps at a support group. Men and
women often deal with miscarriage very differently and show their emotions in various ways.
Some couples will decide that they want to begin trying for another pregnancy right away,
while others may feel that this is too soon and need longer to recover. It is thought advisable
to wait for at least one normal menstrual cycle after the woman’s period returns before trying
again, though it is safe to have sex when the bleeding has settled and both partners feel
The Miscarriage Association provides support and information for those suffering the
effects of pregnancy loss, dealing with tens of thousands of telephone calls, letters and emails
each year. The MA also seeks to raise awareness of issues relating to pregnancy loss and
works with health professionals to raise standards of care in this area.
Helpline: 01924 200799
The Hughes Syndrome Foundation is dedicated to promoting awareness and funding
research into Hughes Syndrome, which is also known medically as the antiphospholipid
syndrome (APS). The main aims of the Hughes Syndrome Foundation are:
to support research into the condition
to offer understanding and support to sufferers of Hughes Syndrome
to offer information and education on Hughes Syndrome
to raise funds to provide information, education and research.
General enquiries: 020 7188 8217
This information sheet was written and edited in accordance with the Babyloss editorial policy.
Last reviewed: July 2009