Counselling for recurring Miscarriage
A non - progressive pregnancy is always a difficult thing psychologically. A huge disapointment after the initial good news of a positive pregnancy test. But if miscarriages keep recurring, then it is even harder both psychologically and physically. For this reason, the CRG has a support program for women who have had three or more repeat miscarriages.
What is a miscarriage?
Miscarriage is a biological phenomena, whereby a foetus no longer continues to develop and is expelled from the uterus after a few days or weeks, accompanied by cramps and blood loss.
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Genetic card of a miscarriage showing a double copy of every set of chromosomes. |
For the purposes of definition, it refers to a foetus with a weight of 500g or less. Miscarriage is considered to be a natural selection process, because the cause is generally due to a genetic or development fault in the foetus, or an incorrect implantation in the uterus. In rare cases, it can be due to specific abnormalities in the woman: haematological (blood or immune system), hormonal (uncontrolled diabetes or thyroid gland imbalances), or anatomical (malformation of the uterus).
How great is the risk?
Approximately 15% of all pregnancies end in miscarriage. 80% occur during the first 12 weeks of pregnancy. The further a pregnancy progresses, the smaller the chance of miscarriage. After twelve weeks, the chance is only about 1%.
The risk is clearly linked to the woman's age. A 20 year old woman has a 12% risk, while a woman over 40 has a 26% risk of having a miscarriage. This is logical (see
the woman's age) because the quality of a woman's eggs diminishes with age and the chance of genetic abnormalities increases. Furthermore, the uterus becomes less receptive, the older it is. It is generally accepted, that the risk of miscarriage due to genetic abnormalities begins to increase from the age of 30 and the risk of miscarriage of a normal, healthy embryo due to faulty implantation begins to increase from the age of 37.
What is meant by 'recurring miscarriage'?
Recurring miscarriage is by definition, the occurrence of three miscarriages one after the other, without there being a normal pregnancy in between. The risk of another miscarriage after the first is 17%, after two, 25% and after three, 30-45%. According to statistics, repeat miscarriage occurs in 0.3% of all women, or 1 in 100 worldwide.
Possible causes of recurring miscarriage
Mostly, a reason for the repeat occurrence of miscarriage cannot be found. In 60% of cases, the following pregnancy is normal. In patients who have already had a previous normal pregnancy and delivery, this will be 70%. In a minority of cases, a cause for the miscarriages can be identified.
Genetic factors
In couples affected by the phenomena, 2.6% appear to have some sort of genetic abnormality evident. This is higher than in the general population, where the figure is around 0.5%.
In single miscarriages, the cause is usually a dividing fault in chromosomal material, whereby 75% of repeated cases illustrate an incorrect chromosomal component in either the man or the woman.
The chance that after repeat miscarriage, the following pregnancy will progress normally, is around 50%. Couples from whom one of the partners is a carrier of a specific genetic abnormality will be advised to have an amniocentesis test or placental test carried out. In some cases, it may be advised to have IVF treatment combined with genetic analysis of the embryos (see
pre-implantation genetic diagnosis).
environmental factors
Smoking, alcohol, heavy intake of caffeine, (see
lifestyle), and exposure to anaesthetic gases, tetrachloroethyleen (used in dry cleaners) and isotretinoine (medication for acne) are associated with repeated miscarriage.
No connection with other external factors can be shown. There are no studies illustrating the effects of bedrest, physical exertion, gym activity, or violence. But obviously every case must be examined and analysed individually.
Hormonal factorsMild, or well controlled hormonal abnormalities have not been shown to lead to miscarriage. However, badly treated hormonal problems on the other hand - such as diabetes, serious thyroidal problems, or too high a prolactine level in the blood - do increase the risks. Also, low progesterone levels in the period following the implantation of the embryo is another possible cause. (See in
preparation for a potential pregnancy).
Anatomical abnormalities
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A septum in the uterus can cause repeat miscarriages. |
In 10-15% of women who have had repetitive miscarriage, an abnormality in the uterus is found. In nearly all cases, this is a septum (a division in the cavity). This defect is present from birth which leads to the embryo being unable to develop properly. In the general population, 2-4% of women have abnormalities of the uterus. See
medical image forming techniques for the various investigative techniques regarding gynaecological abnormalities.
infectious and immunological causes
There is little hard evidence that infections can cause recurrent miscarriages. However, examinations are always performed for the presence of infection.
On the other hand, abnormalities in the immune system, although rare, can lead to miscarriages. In most cases, this is due to an excess in antibodies, against the body's own tissues and cells. This is known as an Auto-immune condition.
In principle, repeat miscarriage can also be caused by allo-immunity: a defensive reaction to foreign tissues. A foetus which consists of 50% material from the man is not rejected in a normal pregnancy. However, in allo-immunity, a defensive reaction takes place and can lead to miscarriage.
Strangely enough, if the genetic tissue is too similar between the man and the woman, for example in incestual relationships, a miscarriage can follow.
Possible examinations
in repeated miscarriage, a number of investigations can be performed, to identify the cause.
Options regarding support and treatment
The following treatments can be applied:
- avoidance of risk factors such as alcohol consumption and smoking;
- treatment of hormonal conditions. This is advantageous for your general wellbeing and to increase the chance of a normal pregnancy;
- if there is an abnormality in the uterus, this can be corrected surgically (see therapeutic hysteroscopy). This will greatly increase the chance of a normal pregnancy occurring;
- if there is an infection present, this should be treated with medication;
- certain blood abnormalities can be treated with medication;
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PGD|PGS: one cell is removed from an eight cell embryo for genetic analysis. |
- if one of the partners has a genetic abnormality and it is opted for medically assisted conception treatment (ICSI) a genetic diagnosis of the embryos can be performed, in order to replace only normal embryos at transfer (see pre-implantation genetic diagnosis or PGD);
- in patients where neither partner has any genetic abnormality, a chromosomal analysis of the embryos can be performed (pre implantation genetic screening or PGS). This establishes whether there are any divisional faults, i.e. if the number of chromosomes are normal. Here too, selection of only healthy embryos is possible for replacement in the uterus.
The treatment is only useful if there are sufficient embryos available for testing, if the patient is younger than 37 and for diagnostic reasons. Your doctor at the CRG will inform you as to whether the performance of this technique will be beneficial in your case.