Recurrent miscarriage is a common problem. You are not the only woman facing it. Statistics show that 70% of women are unable to complete their pregnancy. Out of these, 15-20% women face multiple miscarriages before 20 weeks. According to official figures, the RPL i.e. recurrent miscarriage rate in India is 7.4%, which is quite high. Its causes are still being researched. One such new research is shedding light on the role of chromosomal polymorphism in the causes of miscarriage.

However, it is reassuring to know that there are international and national recommendations based on scientific studies to diagnose and treat the causes of recurrent pregnancy loss or RPL.

Causes of recurrent pregnancy loss

Causes responsible for recurrent miscarriage include antiphospholipid syndrome, endocrine or metabolic disorders, uterine problems, and genetic causes of chromosomal abnormalities. According to these guidelines, only half of patients receive current treatment. In contrast, doctors do not always know the cause of RPL and in about half of the cases, the cause remains unknown.

swapping of chromosome segments

Parental karyotype is recommended worldwide to detect balanced translocations (swapping of chromosome segments). It is considered the gold-standard for diagnosis, evaluation, and treatment in couples experiencing recurrent miscarriages.

How the investigation is done

In addition to testing for chromosomal abnormalities, evidence has emerged in the past few years that variations in the short arm and nuclear organization (NOR) regions of chromosomes, known as chromosomal polymorphisms or chromosomal polymorphisms (CPMs), may be associated with recurrent miscarriages, unexplained infertility, and other fertility problems.

In chromosomal polymorphisms, genetic elements are arranged differently than in a normal person. This type of arrangement is usually found in couples suffering from infertility.

See More: IVF Treatment in India

Is chromosome polymorphism also a cause of pregnancy loss?

In several studies conducted on RPL patients, the incidence of chromosomal polymorphisms has been reported to be high. That is, 8% to 15% of couples have been found to have malformation and miscarriage problems. The actual impact of chromosomal polymorphisms or common variants on genetics in humans remains a matter of controversy.

It is still considered a common, normal karyotype. In fact, no phenotypic and functional impact has been found associated with it. However, in the last few years, various scientific studies have found that chromatin variation can affect centromere functioning. It can affect the segregation of chromosomes through microtubule binding via the kinetochore. This can lead to mispairing between sister chromatids.

What could be the problem

Chromosome biorientation may also cause problems in pairing of homologous chromosomes and hence cell division during gametogenesis. It is also believed that the heterochromatin region of the chromosome plays an important role in spindle attachment, chromosome movement and joining of sister chromatids.

There is also a great dilemma regarding the treatment of couples classified in the idiopathic category suffering from RPL. Counselling of such patients is complex and challenging for gynecologists. Moreover, even after routine investigations of RPL, no abnormality is found in the chromosomes.

This new study on chromosome abnormalities is important

The current study, led by Dr Ashish Faujdar, Head of Cytogenetics at Radcliffe Labs, looked at pre-existing, genetic causes through a single-center case-control study. The study focused on patients who underwent conventional cytogenetics culture techniques to detect chromosomal abnormalities. The study group comprised 1400 people. Of these, 700 were couples who were diagnosed with recurrent miscarriage.

Presence of chromosome polymorphisms tested

For the first time, a study has reported the prevalence of chromosomal polymorphisms, which is about 33.7%. This is much higher than previous studies conducted on recurrent miscarriage and primary infertility in young couples in the subcontinent.

Chromosomal polymorphisms were found to be more prevalent than in previous studies. Polymorphisms associated with the D/G chromosome set were significantly higher in the study group of patients than in the control group.

This study can become the basis for a case study

This study presents the prevalence of chromosomal polymorphisms and should be interpreted with caution until more concrete evidence is available. Until then, patients should be counseled on a case-by-case basis. In the future, CPM may play an important role in the diagnosis and management of the ambiguous RPL group.

Overall, common variants in patients with recurrent miscarriages should be interpreted very carefully as they may play an important role in diagnosis and treatment. Also, until more concrete evidence is available, treatment should be done on a case-by-case basis.

Both treatment and counseling are necessary

Dr. Ashish Faujdar says, "Till then, clinicians can help by counselling couples of patients with unexplained RPL and providing timely treatment to plan future pregnancies. Further case-control follow-up studies need to be conducted with men and women with polymorphisms through assisted reproductive technologies.

He adds, Periimplantation genetic screening for aneuploidy screening (PGS-A) should be conducted to know the real impact of CPM on embryo development. Along with this, blastocyst rate, clinical pregnancy rate after aneuploidy rate, early miscarriage and live birth rate are the criteria for further investigation of chromosomal polymorphisms in the 21st century.