Recurrent pregnancy loss can affect the mother-to-be both physically and emotionally. But science is trying its best to improve the effectiveness of treatments for habitual abortion

Recurrent Pregnancy Loss (RPL) (Recurrent abortion; Habitual abortion) is typically defined as three or more consecutive pregnancy losses that occur usually before 20 weeks of gestation.  Although approximately 25 per cent of all pregnancies result in miscarriage, less than 5 per cent will experience two consecutive miscarriages and only 1 per cent will experience three or more.

The causes for RPL could be divided into two major categories : Foetal and Maternal

Foetal causes : include the genetic composition of the foetus.  It is uncommon to find an inherited genetic cause for recurrent miscarriages.  A chromosome analysis performed from the parents’ blood identifies an inherited genetic cause in less than 5 per cent of couples.

In contrast to this many early miscarriages are due to the de-novo (by chance) occurrence of a chromosomal abnormality in the embryo.  In fact, 60 per cent or more of early miscarriages may be caused by a random chromosomal abnormality, usually a missing or duplicated chromosome.

Maternal causes :  include abnormalities in the “environment” in which the foetus develops.
Age : The chance of miscarriages increases as a woman ages.  After the age of 40 years, more than one-third of all pregnancies end in miscarriage.  Most of the embryos have an abnormal number of chromosomes.
Uterine abnormalities : Distortion of the uterine cavity is considered to cause about 10 – 15 per cent of recurrent miscarriages.  The most common abnormality is a uterine septum i.e., a partition of the uterine cavity.  The diagnosis can be made by x-rays or ultrasound scan of the uterus.

The other congenital abnormalities include a double uterus, and a uterus in which only one side has formed.  Scar tissue in the uterine cavity (Ashermann’s syndrome), large uterine fibroids and polyps could result in pregnancy loss. In the second trimester, a weak cervix can become a recurrent problem.  Most of these conditions can be surgically treated.

Immunological causes

These are poorly understood and the theories proposed by authorities in this field appear to be constantly evolving. Two major categories of immunologic causes of RPL are : Autoimmune, in which the woman’s immune system attacks her own organs and tissues and Allo immune, in which the immune system attacks tissues considered foreign. Two main treatment options are : Leucocyte immunisation with paternal or donor blood cells, or  Immunoglobulin treatment with IV injections – which is very expensive.

This should be conducted only in research settings, as their benefits are largely unproven.

Metabolic abnormalities

Poorly controlled diabetes increases the rate of miscarriage.  Women with diabetes improve pregnancy outcome if blood sugars are controlled before conception. Women who have insulin resistance, such as obese women and women with polycystic ovaries also have higher rates of miscarriages.

Hormonal abnormalites

The second half of the menstrual cycle i.e the time from ovulation up to the next period is called the Luteal phase. This phase is characterised by high circulating levels of a hormone called Progesterone in the blood.  Progesterone, which is produced by the ovary after release of an egg (ovulation), is necessary for a healthy pregnancy. Inadequate levels of progesterone, often called as Luteal phase deficiency may cause repeated miscarriages.