A miscarriage is the loss of a pregnancy that occurs during the first 23 weeks. Around three quarters of miscarriages happen during the first 12 weeks of pregnancy (the first trimester).
While a miscarriage does not usually seriously affect a woman’s physical health, it can have a significant emotional impact. Many couples experience feelings of loss and grief.
For most women, a miscarriage is a one-off event and they go on to have a successful pregnancy in the future.
It is thought that two thirds of early miscarriages are due to abnormal chromosomes in the baby.
Losing three or more pregnancies in a row (recurrent miscarriages) is uncommon and affects around 1 in 100 women. Even in cases of recurrent miscarriages, an estimated three quarters of women go on to have a successful pregnancy in the future.
The most common symptom is vaginal bleeding. The bleeding may come and go over several days and can vary from light spotting or brownish discharge, to heavy bleeding and bright red blood.
Light vaginal bleeding is common during the first 12 weeks of pregnancy, and therefore does not necessarily indicate a miscarriage. However, anyone with bleeding in the first 12 weeks of pregnancy should contact their local maternity services.
Other symptoms include:
• lower abdominal cramping and pain
• vaginal discharge
•noticing the absence of normal pregnancy symptoms e.g. breast tenderness or sickness
Emergency services should be contacted if a woman experiences:
•heavy vaginal bleeding (soaking more than one sanitary pad every hour)
•persistent and severe abdominal pain
•pain in the shoulder tip
•feeling very faint and light-headed, and possibly fainting
The above could be symptoms of an ectopic pregnancy which usually occurs between weeks 5-14 of the pregnancy. An ectopic pregnancy is a medical emergency.
If a miscarriage happens during the first trimester of pregnancy (the first 12 weeks), it is usually due to problems with the unborn baby.
If a miscarriage happens during the second trimester of pregnancy (between weeks 14 and 26), it is usually the result of an underlying health condition in the mother.
First trimester miscarriages
Chromosomes are blocks of DNA. They contain a detailed set of instructions that control a wide range of factors.
Sometimes, something can go wrong at conception and the foetus receives too many or not enough chromosomes. The reasons for this are often unclear, but it means that the baby will not develop normally, resulting in a miscarriage.
Up to two thirds of early miscarriages are associated with chromosome abnormalities.
The placenta links the mother’s blood supply to the baby. If there is a problem with the development of the placenta it can also lead to a miscarriage.
The age of the mother is one of the most important risk factors:
•Women under 30: 1 in 10 pregnancies will end in miscarriage.
•Women 35-39: up to 2 in 10 pregnancies will end in miscarriage.
•Women over 45: more than half of all pregnancies will end in miscarriage.
Other risks factors
•smoking during pregnancy
•drug misuse during pregnancy (particularly cocaine)
•drinking more than 200mg of caffeine a day: one mug of tea contains around 75mg of caffeine, and one mug of instant coffee contains around 100mg of caffeine
•drinking more than two units of alcohol a week: one unit is half a pint of bitter or ordinary strength lager, a small glass of wine or a 25ml measure of spirits
Second trimester miscarriages
There are several long-term health conditions that can increase the risk of having a miscarriage:
• poorly controlled diabetes
•severe high blood pressure
•lupus (where the immune system attacks healthy tissue)
•an overactive thyroid gland
•an underactive thyroid
Some infections may increase the risk of having a miscarriage:
•rubella (German measles)
•a bacterial infection of the vagina - bacterial vaginosis
• chlamydia, gonorrhoea and syphilis
•retinoids (used for eczema and acne)
•non-steroidal anti-inflammatory drugs
To be sure that a medicine is safe in pregnancy, always check with your doctor, midwife or pharmacist before taking it.
Antibodies are proteins that are produced by the immune system to fight infection.
Some women who have had three or more miscarriages in a row (recurrent miscarriages) have a higher than usual level of an antibody called antiphospholipid (aPL) in their blood. The aPL antibodies are known to cause blood clots. These blood clots can block the supply of blood to the foetus, which can cause a miscarriage. Having a high number of aPL antibodies in your blood is known as Hughes syndrome.
Abnormalities with the womb can also lead to second trimester miscarriages. Possible problems include:
•non-cancerous fibroid growths in the womb
•scarring on the surface of the womb
In some cases, the muscles of the neck of the womb are weaker than usual. This is known as cervical incompetence. This may be due to a previous injury to this area, or may be something the woman is born with.
The muscle weakness causes the cervix to open during pregnancy, leading to a miscarriage.
Prolactin is a hormone produced during pregnancy. Prolactin helps to prepare the breasts for breastfeeding. High levels of prolactin in the body may be linked to an increased risk of miscarriage.
Polycystic ovary syndrome
PCOS can lead to hormonal imbalances and is a leading cause of infertility. There is some evidence to suggest that it may also be linked to an increased risk of miscarriage in women who are still fertile. The exact role that PCOS plays in miscarriages is unclear.
An increased risk of miscarriage is NOT linked to:
•a mother experiencing stress or having depression
•having a shock or fright during pregnancy
•exercise during pregnancy (but discuss what type of exercise is suitable for you during pregnancy with your GP or midwife)
•lifting or straining during pregnancy
•working during pregnancy
•having sex during pregnancy
•blood tests to measure hormones associated with pregnancy, such as beta-human chorionic gonadotropin (hCG) and progesterone
•a transvaginal ultrasound scan: a small probe is inserted into the vagina to take a close-up image of the womb
•a pelvic examination
The test are done in order to determine if the pregnancy has ended in miscarriage. The tests will also tell if:
•There is still some foetal tissue left in your womb (an incomplete miscarriage).
•All the foetal tissue has been passed out of your womb (a complete miscarriage).
Sometimes a miscarriage is diagnosed during a routine scan. The scan may reveal that the baby has no heartbeat, or that the baby is too small for the date of the pregnancy. This is called a missed or delayed miscarriage
Treatment depends on whether the miscarriage has been complete or incomplete.
When there is no foetal tissue left in the womb no further medical treatment is required. Miscarriage can have a significant emotional effect counselling or support may be offered.
When there is tissue left in the womb this needs to be removed as there is a risk that it could become infected. This can be done by:
•using minor surgery to remove the tissue
•using medication to remove the tissue
•waiting for the tissue to pass naturally out of your womb (expectant management)
The doctor in charge of your care should discuss the benefits and risks of each option that should be considered when making the decision.
There are circumstances where immediate surgery is advised, including:
• continuous heavy bleeding
•infection of the remaining foetal tissue
•if medication or waiting for the tissue to pass out naturally have been unsuccessful
Surgery is usually performed under general anaesthetic and the tissue will be removed using a suction device. This type of surgery is known as evacuation of retained products of conception (ERPC).
This involves taking tablets that cause the cervix to open, allowing the tissue to pass out. There are two types of tablets:
•tablets that are swallowed
•tablets called pessaries that are inserted directly into the vagina, where they dissolve
The effects of the tablets usually begin within a few hours. Medication is successful in removing foetal tissue in around 9 out of 10 cases. However, if the medication is unsuccessful surgery will be required. The woman will experience symptoms like a heavy period - cramping and vaginal bleeding.
It can take time for the natural passage of the womb contents and bleeding can last up to 3 weeks.
For more than half of miscarriages, this method is unsuccessful in removing foetal tissue. In these cases medication or surgery will be required.
In some cases, if a cause of the miscarriage has been identified, it may be possible to have treatment to prevent this causing any more miscarriages.
Hughes syndrome, an autoimmune condition that causes blood clots. Research has shown that a combination of aspirin and heparin can improve pregnancy outcomes in women with Hughes syndrome.
A weakened cervix, also known as cervical incompetence, can be treated with an operation to put a small stitch of strong thread around the cervix to keep it closed. This is usually carried out after the first 12 weeks of pregnancy, and is removed around week 37.
A miscarriage can have a profound emotional impact, not only on the woman herself but also on her partner, friends and family.
Sometimes this is felt immediately whereas in other cases it can take several weeks.
The most common emotions that are felt are grief and bereavement.
•loss of appetite
•shock and numbness
•an overwhelming sense of sadness
Different people grieve in different ways. Some people find it comforting to talk about their feelings while others find the subject too painful to discuss.
Miscarriage can also cause feelings of anxiety or depression, and can lead to relationship problems.
Some women their partners may need further treatment and counselling. There are support groups that can provide or arrange counselling for people who have been affected by miscarriage.
The following organisations can also help:
•The Miscarriage Association is a charity that offers support to people who have lost a baby. They have a helpline 01924 200 799 (Monday to Friday, 9am to 4pm) and an email address email@example.com and can put you in touch with a support volunteer.
•Cruse Bereavement Care helps people understand their grief and cope with their loss. They have a helpline 0844 477 9400 (Monday to Friday, 9am to 5pm) and a network of local branches where you can find support.
One can't often prevent a miscarriage. However, there are ways to lower the risk:
•Do not smoke during pregnancy
•Do not drink alcohol during pregnancy.
•Do not use illegal drugs during pregnancy.
•Drink at least 1.2 litres (six to eight glasses) of fluids, such as water and fruit juice, every day.
•Eat a healthy, balanced diet with at least five portions of fruit and vegetables a day.