Repetitive pregnancy loss or “habitual abortion” in medical literature, is a condition in which there are at least two consequent spontaneous miscarriages during the first 3 months of pregnancy.
Approximately, 2% of couples have this problem. The diagnosis and treatment of this condition is one of the hardest subjects for reproductive medicine.
Miscarriage (abortion) is the most common complication of pregnancy. Actually, sometimes women may experience miscarriages accompanying menstrual bleeding without even noticing that they have been pregnant; “missed miscarriage”. Thus, not every fertilization results in a healthy pregnancy.
Sometimes there is fertilization, however, the fertilized material doesn’t implant (attach) inside the womb and it is discharged during menstrual bleeding. This condition can only be noticed by pregnancy tests. We call it “chemical pregnancy”.
Causes of Recurrent Miscarriages
- Structural malfunctions of the uterus and cervix insufficiency
- Hormonal (endocrine) conditions
- Infections
- Chromosome disorders
- Autoimmune diseases
- Environmental and other factors
1. Structural malfunctions of the uterus and cervix insufficiency
Cervix insufficiency is a condition in which the cervix effaces and dilates without any pain, especially between the 4th and 6th months of pregnancy, and with the tearing of pregnancy sacs the fetus (baby) is discharged, eventually. Its treatment is usually surgical. At the end of the third month, the cervix may be sewn closed (cervical cerclage) (McDonald and Shirodkar operations). Structural problems of the uterus may include uterine myoma, intrauterine adhesions, uterine septum (partition in the uterine cavity), uterus didelphys (aka double uterus) and other malfunctions. The frequency rate of these conditions regarding repetitive pregnancy loss is 10-15%. These conditions are responsible for making the area in which the fetus will be placed unfit by changing and making the uterine cavity smaller or by affecting the vein system in the area negatively. Surgical corrective operations on these conditions reduce the rate of miscarriages.
2. Hormonal (endocrine) conditions for repetitive pregnancy loss
Three types of conditions are, commonly, thought of as the causes of repetitive pregnancy loss; these are:
- Diabetes
- Thyroid gland diseases
- Corpus luteal insufficiency, which is a menstruation problem.
Diabetes under control is known not to increase the risk of miscarriages. That is, if the blood glucose levels of a pregnant diabetic patient are kept successfully under control, the risk of a miscarriage will not increase.
There is insufficient scientific evidence regarding the relation between thyroid diseases and loss of pregnancies. That’s why, it is stated that it is not imperative to investigate thyroid hormones in recurrent pregnancy loss cases.
Problems regarding menstruation are usually observed in relation to “ovulation” (producing eggs) issues. Specifically, malfunctions leading to insufficiency of the “progesterone” hormone, which is necessary for the continuity of the pregnancy, are thought to, probably, be causes of recurrent miscarriages.
It may be helpful to share some information regarding “common physiology” to better understand how problems related to menstruation may cause miscarriages.
When the egg (oocyte) is produced and released, the formation left in the ovaries is called “Corpus Luteum” or sometimes called as “yellow body” due to its color. Its duty is to produce the hormone progesterone to maintain pregnancy after fertilization. Progesterone, on the other hand, prevents the rejection and the discharge of the fertilized material.
The duration of secretion of progesterone hormone is about the duration of corpus luteum, about 14 days, in cases when there is no pregnancy, however, when there is a pregnancy it can last up to 3 months and then leaves the duty to the placenta.
When corpus luteum degenerates faster than it should and dissolves before leaving its duty to the placenta in spite of pregnancy, the condition is called “Corpus Luteum insufficiency” and the pregnancy ends with a miscarriage.
The diagnosis for corpus luteum insufficiency can be reached by a biopsy of intrauterine tissue (endometrial biopsy).
Treatment for corpus luteum insufficiency is to overcome the lack of progesterone by additional substitutive hormone medication in the initial stages of the condition. This treatment is usually continued during the first three months of pregnancy.
3. Infections
Viral and bacterial infections are thought to cause miscarriages.
Listeria monocytogenes, types of toxoplasma, mycoplasma hominis and ureaplasma urealyticum are the most common micro-organisms of this sort. However, although it is known that they can cause single miscarriages, it is not totally proven that they lead to recurrent miscarriages.
4. Chromosome disorders
Chromosome disorders of the mother/father have been found on 5% of couples suffering from repetitive pregnancy loss.
This rate is interestingly higher than the general average. Genetic problems of which the parents are carriers and which do not lead to any diseases, can manifest themselves during pregnancy and lead to miscarriages.
In order to anticipate the possibility of repetitive pregnancy loss, genetic examination on the couples can be helpful. Findings constitute a base for genetic counselling.
Chromosome analysis of the miscarriage material is, also, helpful in investigating the failure of a treatment.
5. Autoimmune diseases
In the 1980s, researchers stated that formations manifesting themselves by stimulation of a factor called antiphospholipid antibody, which is produced due to a malfunction in the body and which affects the organization of the immune system but which could not be defined clearly might have been one reason for recurrent miscarriages. Positive links have been observed regarding these formations and fetus deaths.
The effective functioning mechanism of these formations is that they cause vein deformations which lead to lack of blood of the placenta.
In order for such patients to be able to have babies, steroid treatment, low dose aspirin treatment or a treatment with a substance called heparin, an anticoagulant (to prevent clotting), may be necessary.
6. Environmental and other factors
Loss of pregnancy increases by older age. The rate of pregnancy decreases dramatically in women older than 35 years old, compared to younger ones. The risk of a miscarriage reaches almost 50% for women older than 40. Women should be made aware of such risks.
Research done in Scandinavian countries has shown that working does not increase the risk of miscarriages for women. However, at work, they should make sure not to be exposed to chemicals which might put their pregnancy under threat.
Smoking and alcohol consumption increase the risk of miscarriage. There are no decisive data regarding the effects of passive smoking.
Since it is difficult to study them, it is not certain whether psychological factors cause recurrent miscarriages or not.
Observations regarding repetitive pregnancy loss patients
The risk of miscarriage increases with the increase in the number of miscarriages. After 4 consecutive miscarriages, the risk of repetitive loss increases up to 50%.
When caring for patients suffering from recurrent miscarriages, the most important approach is to be knowledgeable and to provide support.
Patients should be informed about the fact that even if there is no diagnosed reason, the risk of loss will increase with age and that they may be under the risk of complications such as premature labor and ectopic pregnancy.
It is also helpful to state that it is difficult to give damage to a healthy pregnancy, and, that activities such as sexual intercourse and exercise which may increase uterine cramps will not damage the pregnancy.
Generally, laboratory procedures should be started after the third miscarriage for women under the age of 35, and, the second one for older women. This will reduce laboratory work and medical expenses to a certain degree.
However, some couples would prefer to wait for a long time while others may wish to start the procedure right after the first miscarriage.
Couples, having experienced miscarriage(s), need extensive support from a specialist for the first three months after their full evaluation has been done and after they have managed to get pregnant.
A recently discussed condition called “Thrombophilia” reduces blood flow to the placenta due to blood coagulation (clotting) and thus the baby inside the womb is lost. When this condition is noticed, medication to prevent blood coagulation and a “low methionine diet” are suggested.
Families, experiencing repetitive pregnancy loss should know that this is not their fate. With faith and patience, necessary precautions should be taken in cooperation with the specialist. It shouldn’t be forgotten that, after treatment regarding the causes, success rates can be very high (90%).
Then again, the risk of miscarriage decreases to 3-5% with the ultrasound detection of heart beat on the 8th week of pregnancy.
