A recent study conducted by Redcliffe Labs in India has revealed a significant link between chromosomal abnormalities and recurrent miscarriages. The research found that infertile couples experiencing repeated miscarriages exhibited a notably higher frequency of chromosomal polymorphisms (CPM), reaching up to 33.7%. Traditionally, chromosome polymorphisms have been considered normal variations with little practical significance. However, this study is the first to identify a much higher prevalence—approximately 33.7%—of these polymorphisms among couples facing recurrent pregnancy loss and infertility. As a result, CPM has been identified as a major contributing factor to repeated miscarriages.
Chromosomal polymorphism refers to the innate differences in chromosome number and structure among a population. Chromosome segment inversions, translocations, deletions and duplications are examples of these changes. Even though these polymorphisms are frequently benign and do not directly affect health, they may influence genetic processes during reproduction. They may contribute to disorders like recurrent miscarriages, congenital defects and other reproductive difficulties by causing genetic imbalances in the progeny.
Changes brought about by cell division and spontaneous genetic recombination are the causes of CPMs.
• Meiotic errors: Chromosomes recombine during the development of eggs and sperm. Inaccuracies in this procedure may cause segments to be moved or changed, giving rise to polymorphisms.
• Chromosome mutations: If either parent carries these mutations, then CPMs can be inherited from them. Many CPMs are benign and don’t harm people, but depending on how they pair together during fertilisation, they may cause complications in the progeny.
• Mutations: Chromosome structural alterations can result from random mutations that happen in DNA.
Link between Chromosomal Polymorphism and Recurrent Pregnancy Loss
CPMs can interfere with normal chromosomal activity during reproduction, which can result in genetic imbalances in the developing embryo. This may result in various difficulties with reproduction:
• Miscarriages: CPMs can result in the development of embryos with chromosomal abnormalities, which frequently cause early pregnancy loss. Significant genetic imbalances usually result in non-viable embryos.
• Impaired implantation: One of the main causes of miscarriage is the existence of CPMs, which can obstruct the embryo’s proper implantation in the uterus.
• Genetic imbalances: CPMs can result in genetic imbalances that can lead to congenital abnormalities or disorders that are incompatible with life, even if a pregnancy goes on.
Identification and treatment diagnosis
Genetic testing is frequently recommended for couples experiencing recurrent pregnancy loss in order to detect any chromosomal abnormalities, including CPMs. These polymorphisms can be found using karyotyping techniques or more advanced approaches like array comparative genomic hybridisation (aCGH) and next-generation sequencing.
Management
Genetic counselling is essential if CPMs are found. Counsellors can assist couples in considering their reproductive options and comprehending the consequences of their findings. Preimplantation genetic diagnosis (PGD), one of the assisted reproductive technology (ART) methods, may be suggested to choose embryos free of major genetic abnormalities.
The author, Dr. Shikha Tandon, is a Consultant, at Birla Fertility & IVF, Gorakhpur.
