Incidence of recurrent pregnancy loss
Miscarriage is exceptionally common and may affect up to 50% of pregnancies. Somewhere in around 1 in 8 women who present for pregnancy care, will eventually miscarry. About 1 to 2% of women will suffer 2 to 3 miscarriages in a row. Miscarriage can happen for many reasons and many cannot be determined by blood tests. Having a miscarriage does not mean that a woman will have another miscarriage. It is important to remember that the vast majority of miscarriages are not due to any vitamin deficiency, excessive physical exercise, stress or other events that the patient has control over. About two thirds of women with recurrent pregnancy loss will eventually have a healthy pregnancy, often without any extra treatment. The chance of this is higher if you have already had a live birth.
If you have had two or more miscarriages, you should talk to your gynaecologist or fertility specialist. Often women decide to continuing trying to conceive naturally, but in some situations the doctor might suggest treatments and investigation to help to reduce your risk.
Possible causes and treatment
Problems confined to the uterus
This may include problems such as uterine fibroids, uterine septum (divided uterus) or an abnormal cervix. These can be treated surgically, either by hysteroscopic or laparoscopic (hey hole) surgery but in many cases this will not be necessary and often there is a considerable judgement call to be made as to whether or not this may be helpful. Many of these surgical procedures are relatively minor and will require only a day or two in hospital.
Clotting disorders and auto immune problems
Women with auto immune (antibodies that effect the body itself) or clotting problems (thrombophilia) may be treated with low dose aspirin and anti-clotting injections (heparin or enoxaparin). These medicines must be taken during pregnancy to lower the risk of miscarriage. Some of these treatments have side effects and so we need to be sure whether this treatment would be appropriate for you. It will be necessary to take these treatments for many weeks- possibly the whole pregnancy- and timing of cessation must be discussed with your gynaecologist or obstetrician.
Other medical problems
Recurrent pregnancy loss can also be related to medical problems such as diabetes, over active thyroid, underactive thyroid, or high levels of a protein called prolactin. There is also a slightly higher chance of miscarriage in a condition called polycystic ovarian syndrome. Note that many women have polycystic ovaries and only a subset of these will have polycystic ovarian syndrome. Treatment involves correcting the underlying abnormality.
There is no question that obesity/morbid obesity increases the chances of miscarriage. In some cases, patients will need to make substantial efforts to lose weight and defer trying for a pregnancy whilst this is taking place. General practitioner and dietician help is invaluable.
Some patients (very much the minority) have a specific area in their chromosomes or genetic material that predisposes them to miscarriage. Note that these conditions are generally “all or none”. Many of these people have children quite successfully. Unfortunately it is not possible to correct these genetic abnormalities, but often we can screen for them. In about 5% of couples with recurrent pregnancy loss, one parent has a rearrangement (translocation) of their chromosomes. Prospective parents can have a blood test (karyotype) to see if they have a translocation. If this is the case, then it will be necessary to see a geneticist/genetic counsellor, who will go into detail regarding the nature of the problem and its possible consequences.
Genetic problems are very hard to treat, but many of them can be now screened for in IVF created embryos prior to transfer.
In general whatever is healthy for the woman is also healthy for the pregnancy and healthy for the embryo. It is essential to stop smoking, stop illicit drug use, and limit or cease consumption of alcohol and caffeine. Excessive caffeine intake is probably more than five coffees per day, including caffeinated beverages such as tea or cola drinks. Being overweight is also linked to recurrent miscarriage and healthy weight loss under the supervision of a dietician might also help in future pregnancies.
There is no proof that stress and anxiety or mild depression causes recurrent pregnancy loss.
Because of the anxiety surrounding recurrent miscarriage a lot of treatments are trialed and given credibility before being adequately proven.
There is no proof that intravenous infusions of blood products such as immunoglobulins or medicine such as steroids, soybean oil infusions or sporadic doses of aspirin and Clexane decrease the risks of miscarriage. Many of these treatments may indeed be harmful.