Recurrent Miscarriage - Professor T.C.Li

What Is Recurrent Miscarriage?

Generally, recurrent miscarriage refers to three or more pregnancy losses and occurs in approximately 1% of women.

In about half of these cases a cause can be identified. However, in the remaining cases, even when a cause cannot be identified, there is good evidence to suggest that the care and support provided by a specialist clinic increases the chances of the next pregnancy being successful.

Causes Of Recurrent Miscarriage

Current medical literature suggests that causes are identified in approximately half of all cases of recurrent pregnancy loss. There are a number of well recognised causes and a number of possible causes.

Abnormal clotting of the blood
There are several disorders of blood clotting which are associated with recurrent miscarriage. These disorders result in the blood being particularly 'sticky', which may make the small vessels in the developing placenta prone to blockage by small clots, leading to a miscarriage.

The clotting disorders associated with recurrent miscarriage include antiphospholipid syndrome (APS), lupus anticoagulant syndrome, anti-thrombin III deficiency and protein C or S resistance. It is still unclear as to what extent Factor V Leiden contributes to recurrent pregnancy loss.

Structural abnormalities of the womb
A structural abnormality of the womb occurs in 15% of women with a history of recurrent pregnancy loss. The abnormalities include a septum (a division or partition in the womb), adhesions (scar tissue) within the cavity of the womb and large fibroids.

Genetic problems
In about 4% of cases, recurrent miscarriage may result from a chromosome abnormality in either the mother or the father.

Many sporadic miscarriages are caused by chance chromosome abnormalities in the baby. This is more common as maternal age increases, particularly over the age of 37 years. However, these faults are not very likely to recur.

Hormonal Problems
If you have irregular periods, this could be due to a condition called Polycystic Ovary Syndrome (PCOS). From our experience this condition is found in about 10% of women with recurrent miscarriage, but it is not yet clear whether this condition is a cause of recurrent pregnancy loss. However, our recent research has shown that if a woman also has raised male hormones (seen in about two-thirds of women with PCOS), then this is linked with an increased risk of a further miscarriage.

Some women with recurrent miscarriage have low levels of a hormone called progesterone. Although this is an essential hormone to maintain pregnancy, it is not yet clear whether low levels of this hormone are linked with recurrent miscarriage and further research in this area is continuing.

The thyroid gland is responsible for regulating the metabolic rate of the body and if this is not functioning sufficiently, can be a cause of miscarriage.

Weakness of the Cervix
Weakness of the cervix is commonly associated with pregnancy loss in the second trimester (14-28 weeks) but not in the first trimester (up to 13 weeks) of pregnancy. Typically this occurs as a sudden leakage of fluid, followed by a miscarriage.

Infections
Infections such as bacterial vaginosis (BV) may be a cause of later pregnancy loss and premature labour. However, infections do not appear to play a significant role in miscarriages in the first trimester (up to 13 weeks).

Natural Killer (NK) Cells
There is currently a great deal of interest into the possible link between elevated numbers of Natural Killer (NK) cells and recurrent miscarriage. NK cells are specific cells of the immune system which are present within the womb and, in elevated numbers, may be involved in attack of the developing baby.

Smoking, Drinking and Caffeine
Smoking and drinking can both increase the risk of a miscarriage and so it is important to discontinue these activities during pregnancy. There is evidence to suggest that reducing caffeine intake to 1-2 cups per day is also beneficial.

Unexplained Recurrent Miscarriage
In approximately 50% of women with recurrent pregnancy loss, no cause is found despite thorough investigation.

Treatment Of Recurrent Miscarriage

Following a thorough investigation, if a diagnosis is made then a number of treatment options exist. In addition, you will be offered regular appointments and ultrasound scans to carefully monitor your next pregnancy.

Abnormal clotting of the blood
If a diagnosis of antiphospholipid syndrome (APS) is made, then treatment involves low-dose aspirin and an injection of heparin daily throughout pregnancy and until 6 weeks after the baby is born. This is an extremely effective treatment current evidence suggests that with a diagnosis of APS there is an 80% chance of miscarriage without treatment, but an 80% chance of a live birth with treatment. You will be advised to contact the clinic as soon as you know you are next pregnant so treatment can begin.

If a different clotting disorder is detected then you will be referred to a specialist in blood clotting disorders, although the treatment is likely to be similar.

Structural abnormalities of the womb
If a structural abnormality of the womb is diagnosed, such as a septum (a division or partition in the womb), adhesions (scar tissue) within the cavity of the womb or large fibroids, then the condition can be treated surgically.

Genetic problems
If a chromosome abnormality is detected in either the mother or the father then genetic counselling will be offered.

Hormonal Problems
If a diagnosis of PCOS is made and this is associated with elevated levels of male hormones, then several possible treatment options will be discussed. Although there is currently no well-defined treatment for this condition, this is one of the active areas of our research and therefore possible treatments will be offered within the context of clinical research. Possible options include weight loss (if this is appropriate), the use of a drug called metformin and a surgical procedure known as laparoscopic ovarian drilling.

If low levels of progesterone are detected, then it is not yet clear whether this is linked with recurrent miscarriage and whether any treatment is necessary. Possible treatment options include the use of a drug called clomiphene citrate.

If the thyroid gland is found to be under-functioning, then treatment with thyroxine will resolve the problem.

Weakness of the Cervix
If a diagnosis of cervical weakness is made then a cervical suture may be inserted under general anaesthetic to strengthen the cervix.

Natural Killer (NK) Cells
If raised levels of NK cells are detected then this may be a cause of recurrent miscarriage. There have been several possible treatment options suggested within the medical literature, but since this work is only preliminary, these options will be offered within the context of clinical research.

One option involves the steroid drug prednisolone. A trial will first be offered to see if this is an effective method of lowering the number of NK cells. If this proves effective, then prednisolone will be offered during pregnancy.

An alternative option involves a recently reported technique known as the "endometrial scratch". This involves making a number of small scratches on the lining of the womb, via the cervix, which has been suggested as a possible method to lower the number of NK cells.

Unexplained Recurrent Miscarriage
Finally, if all tests come back normal, then there is good evidence to suggest that the care and support provided by a specialist clinic increases the chances of the next pregnancy being successful. At Sheffield, you will be given a direct telephone number that you can call as soon as you are pregnant. We will then arrange for regular appointments and ultrasound scans to monitor your pregnancy.

A recently reported technique known as the "endometrial scratch" (see above) has been shown to be effective in increasing the rate of success of a subsequent pregnancy and can be discussed as a possible treatment option in unexplained recurrent miscarriage within the context of clinical research.

Useful Links and Sources of Support

If you are feeling low after a miscarriage it sometimes helps to talk to other people who have had a similar experience. Why not contact someone from your nearest Miscarriage Support Group? The Miscarriage Association can give you details of your local group.

Website: http://www.miscarriageassociation.org.uk

Email: info@miscarriageassociation.org.uk

Helpline: 01924 200799 (Mon-Fri, 9am - 4pm)

Address:
   The Miscarriage Association
   C/o Clayton Hospital
   Northgate
   Wakefield
   West Yorkshire
   WF1 3JS

For a list of my publications on Recurrent Miscarriage, please click here