Recurrent Pregnancy Loss

* Miscarriage is the commonest complication of pregnancy. Approximately one in five of all pregnancies end in a miscarriage and one in four of women who become pregnant will experience at least one miscarriage.

Women who have had a miscarriage may be divided into two groups:

* Those who have suffered a single, sporadic miscarriage
* Those who repeatedly miscarry
* Recurrent miscarriage is usually defined as the loss of three or more consecutive pregnancies, and fortunately only 1% of couples fall into this group.
* If we include women who have experienced two miscarriages in the definition of recurrent miscarriage, the scale of the problem increases considerably and 3% to 5% of couples will be affected by this problem.
* The difference between sporadic and recurrent miscarriage is important. It helps us to predict the chance of a successful pregnancy in the future, and the likelihood of there being a recurring cause for the loss of the pregnancy. A woman who has suffered a single sporadic miscarriage has an 80% chance and a woman with three consecutive miscarriages a 60% chance of her next pregnancy being successful.

What Causes Recurrent Miscarriage?

* There is no single cause for recurrent miscarriages.
* Pregnancies miscarry at different times and there are different ways in which a miscarriage may occur.
* Briefly, the causes can be divided into several groups - genetic, hormonal, thrombophilic (blood clotting problems), anatomical (or structural), infective, and other causes.
* Many cases of recurrent miscarriage will remain unexplained even after detailed investigations have been performed. Importantly, the prognosis for a future successful pregnancy in the unexplained group is usually as it is for couples in whom a recognised cause is identified.

Genetic causes

* The most common cause for a single miscarriage is a chromosomal abnormality of the fetus.
* The chromosomes carry the genetic information and the fetus inherits one half of its chromosomes from the mother and one half from the father.
* Chromosomal problems in either partner, causing little or no problem to the individual, but making it more difficult to achieve a successful pregnancy.
* Errors in the transmission and the division of the chromosomes can occur and lead to the fetus having either too many or too few chromosomes. In many of these cases, the chromosome content is incompatible with life and the pregnancy miscarries. It is important to stress that these errors occur randomly and are rarely a cause of recurrent miscarriage.
* In a small percentage of couples, between 3 and 5%, one partner possesses abnormal chromosomes which they repeatedly pass on to the fetus. The most common condition is when the chromosomes, although being of the correct number, are arranged differently. This is called a balanced or reciprocal translocation and is a recognized cause of recurrent miscarriages.

Hormonal Conditions

*It has long been thought that a hormonal (endocrine) abnormality underlies many cases of recurrent miscarriage. Many theories have been suggested, but none has attracted wide acceptance.
*Low levels of progesterone hormone are frequently found in women whose pregnancies are miscarrying. There are contradictory views on the relation between progesterone and miscarriage. Some consider that the low progesterone levels in early pregnancy reflect the fact that the pregnancy has not implanted successfully in the womb lining, rather than because the developing placenta is not producing enough progesterone to maintain the pregnancy. While others, consider that the low level of progesterone (as the case in luteal phase defects) results in miscarriage.
* A pelvic ultrasound scan shows that many women with recurrent miscarriage have polycystic ovaries (PCO). This is a common condition, found in 25% of all women, in which there are multiple small cysts within the ovary. These cysts are not dangerous and cannot be removed as they are within the ovary. Polycystic ovaries can sometimes be associated with a number of hormonal imbalances such as increased production of LH and testosterone. Hyperinsulinemia, associated with PCO, may be a contributing factor in the higher rate of miscarriage. Elevated levels of insulin interfere with the normal balance between factors promoting blood clotting and those promoting breakdown of the clots. Increases in plasminogen activator inhibitor activity (PAI-Fx) associated with high insulin levels may result in increased blood clotting at the interface between the uterine lining (endometrium) and the placenta. This could lead to placental insufficiency and miscarriage.

Thrombophilic / Blood Clotting Disorders

The importance of blood clotting disorders in causing recurrent miscarriage has now been firmly established.
* Whilst it has been known for a considerable time that a woman's blood has increased tendency for clot formation in pregnancy, it has only recently been established that this process is more pronounced in some women compared with others. If blood clots occur in the blood vessels of the placenta the blood flow to the baby is decreased and this can lead to either miscarriage or, if the pregnancy proceeds, to the birth of a baby that is smaller than supposed to be.
* Women with increased levels of antiphospholipid antibodies, the two most important of which are the lupus anticoagulant and the anticardiolipin antibodies, are at increased risk of blood to clot. That would lead in 90% of the cases to recurrent miscarriage. Studies have shown that using blood thinning agents treat the problem very successfully.
* There also other blood disorders, some of which are inherited, are related to the balance between factors that promote clot formation and those who dissolve clots. These conditions cause recurrent miscarriage similar to antiphospholipid syndrome.
* pregnancy can aggravate (often previously unnoticed) autoimmune disorders (meaning that the body fights itself). Indeed, this type of disorder may first reveal itself in a woman through pregnancy problems such as repeated miscarriages.

Infection and Recurrent Miscarriage

* The role of vaginal infections in the causation of recurrent miscarriage is a new field. Infection may well play a role in causing late pregnancy losses (14 weeks gestation) in a small number of women but it is unlikely to be important in causing early miscarriages, and usually single miscarriage rather than repeated pregnancy loss.

Structural abnormalities of the uterus and cervical Incompetence

* These might lead to repeated miscarriage during the second half of pregnancy. There are different anomalies that could happen during the formation of the uterus that are linked to recurrent miscarriage. The most accurate way of diagnosis is by direct vision using hysteroscopy. That would assess the condition as well as the feasibility of surgical correction such as uterine septum.
* Cervical incompetence is often mentioned as being a cause of miscarriage. It only affects pregnancies that have progressed beyond 14 weeks gestation. It is most commonly diagnosed on the history of there being a painless miscarriage and the insertion of a cervical stitch is often recommended. There is no reliable method to diagnose cervical incompetence and in practice it is an over-diagnosed condition.

General

* There is some evidence that women who smoke are at increased risk of miscarriage and that this risk is related to the number of cigarettes smoked. Similarly, women with an excessive alcohol intake are thought to be more prone to have a higher rate of miscarriage.
* Recent research shows that there is no association between the use of video display units (VDUs) and miscarriage.
* It is also well recognised that in many couples no reason may be identified for their recurrent miscarriages. Yet even in these couples there is a good chance eventually of a successful pregnancy.
* We try to address all the possible causes of your repeated pregnancy losses, investigate them, and then treat you appropriately. As there is no single cause, there is no single treatment that will prevent all miscarriages. We hope to offer you the most effective treatment for your particular problem(s).
* Remember! When you are pregnant you should contact the clinic as soon as possible for an immediate appointment early in the pregnancy. We will see you frequently in the early stages to monitor you and the pregnancy closely.