1(st) trimester miscarriage: four decades of study

Area of Science:

• Reproductive Biology
• Genetics
• Obstetrics

Background:

• Miscarriage is a common human occurrence, necessitating a deeper understanding of pregnancy failure.
• Early research relied on cytogenetic methods and tissue culture, with advancements in laboratory tools improving results.
• Maternal age was identified as a factor in trisomy, with high rates of cytogenetic abnormalities in first-trimester miscarriages.

Purpose of the Study:

• To review published research on pregnancy failure and the evolution of diagnostic tools.
• To clarify definitions, range of losses, and scientific methods used to understand miscarriage.
• To discuss the advantages and limitations of various cytogenetic and molecular genetic techniques.

Main Methods:

• Classical/conventional cytogenetics and tissue culture were early methods.
• Newer molecular genetic techniques include Fluorescent In Situ Hybridisation (FISH), Comparative Genomic Hybridisation (CGH), array-based CGH, Single Nucleotide Polymorphism (SNP) detection, quantitative Polymerase Chain Reaction (qPCR), and quantitative fluorescent PCR (QF-PCR).
• These methods allow for sample examination without tissue culture and can be site-specific or whole genome.

Main Results:

• Cytogenetic methods revealed unbalanced chromosomal karyotypes as a significant cause of pregnancy failure.
• First-trimester miscarriages show high rates of cytogenetic abnormalities, decreasing in later losses.
• Newer molecular methods offer advantages over conventional cytogenetics, though each has limitations.

Conclusions:

• A combined approach using both conventional and molecular genetic methods is optimal for elucidating the cause of miscarriage in almost all cases.
• Advancements in genetic technologies have significantly improved the understanding of pregnancy failure.
• Continued research and application of these tools are crucial for clinical settings.