Even in the healthiest couples, miscarriages can still happen. The chances of a spontaneous miscarriage depends to a large extent on the woman’s age, in fact the probability of spontaneous miscarriage in a woman of 20 is approximately 13%, whereas for a woman of 45 years old the risk is higher than 50%.
This type of miscarriage, which is confirmed clinically by hormone analysis and ultrasound, is the most common complication of pregnancy, and happens in about 15% of pregnancies.
What is repeated miscarriage?
Repeated spontaneous miscarriage, recurring miscarriage or repeated pregnancy loss is defined as the spontaneous loss of two or more pregnancies.
It has been calculated that between 1 and 2% of couples experience recurring miscarriages.
The most common symptom causing danger of miscarriage is vaginal bleeding, which may or may not be accompanied by severe stomach pains; however, a quarter of pregnant women experience small amounts of blood loss during the early stages of pregnancy, and about 50% of these carry the pregnancy to full term.
What are the risk factors associated with Repeated Miscarriage?
There are some factors which we need to investigate, which have been associated with Repeated Miscarriage, and which can guide us when it comes to finding a solution to this problem. These are:
- Chromosomal anomalies: the earlier the miscarriage happens, the greater the chance that it is due to a chromosomal irregularity. Around 60% of repeated miscarriages are caused by genetic factors. It can be the case that one partner (or both) in the couple has some sort of anomaly in their chromosome set, or it can be the ova or the spermatozoa which have a chromosomal anomaly.
When it is the case that one partner is the carrier of a chromosomal anomaly, it is normal for doctors to propose a cycle of IVF with pre-implantation genetic diagnosis (PGD IVF). This treatment enables those embryos which are not affected to be selected and transferred to the uterus. However it is also possible, depending on the type of anomaly in question, for doctors to suggest that a couple undergoes IVF treatment using either donor semen or donor eggs (or both).
- Coagulation factors: these are foetal losses caused by anomalies in coagulation factors, which are due especially to antithrombin deficiencies in the blood, causing clots to form in vascular tissue, which prevent the correct development of the placental bed. When this happens, the patient is usually given heparin or drugs such as aspirin, which are very strictly controlled, throughout the pregnancy.
- Anatomical irregularities of the uterus: malformations of the body of the uterus. These can involve either the cervix or the main uterine body, whether from part of this organ being missing or because there is some sort of structure inside it which may prevent the normal implantation of an embryo, for example a uterine septum (the presence of a wall which divides the uterus into two compartments). In order to diagnose these anomalies, tests must be carried out such as a hysteroscopy, or Nuclear Magnetic Resonance, or even a high resolution or 3-D ultrasound, which help to identify the most appropriate treatment.
- Endocrine factors: the most common endocrine pathologies are normally luteal phase insufficiency, polycystic ovarian syndrome, elevated levels of the hormone prolactin, diabetes, and serious thyroid problems. Treatment is case-specific and is based on correcting hormone levels by administering drugs which regulate (or which supply, in cases of a total or relative deficit) the relevant hormones.
- Infection factors: these are usually localised and can affect the embryo or foetus, the tissue of the placenta or the endometrium (endometritis). Serological tests performed on the blood and cultures of the affected organs can identify which agent is responsible for the infection, and consequently which is the best antibiotic.
- Immune factors: for as yet unknown reasons, antibodies sometimes form in the woman’s blood, which cause the embryo to die. These can be due to an autoimmune response (relating to the biology of the woman’s own body) or alloimmune (rejection of the foetus’s antigenic make-up arising from the woman’s partner).
- Environmental factors: there is also an increased risk of losing a pregnancy due to excessive consumption of coffee or alcohol, smoking, obesity, exposure to anaesthetic gases and tetrachloroethylene (a colourless, heavy, non-flammable liquid, which is normally used as a solvent in cleaning textiles and metals).
In spite of all the measures available to us today, studies have concluded that in around 50% of cases of repeated miscarriage the cause is undiagnosed. Even so, the prognosis in terms of reproduction is generally good as 50 – 70% of patients manage to go on to have a baby.