Chromosomal deletions are generally defined as the loss of chromosomal segments, which can occur at any position on any chromosome and can be classified into two categories, terminal and intermediate deletions, depending on the position of the lost segment. There are many causes of chromosome deletions, including thermal radiation, viral infection, effects of physicochemical factors, errors in transfer factors or recombinases, etc., which can lead to mutations or abnormal genetic conditions. In general, if a gene deletion is homologous to a chromosome, it may cause a pseudodominant expression, i.e., a recessive appearance of another normal chromosome. If deletions occur on both chromosomes, they can lead to the death of the organism. Catcalling syndrome, a common clinical condition, is a chromosomal deletion caused by the deletion of the short arm on the fifth chromosome in humans. The affected child exhibits symptoms such as crying like a cat, low birth weight, growth retardation, microcephaly, feeding difficulties, and generally has a relatively short life span after birth. Another common disorder is caused by deletion of the eleventh chromosome pair, which manifests as kidney disease, mental retardation, and the absence of iris in the eyes. In addition, a few patients have partial deletion of the Y chromosome, causing male infertility. During pregnancy, women should stay away from radiation and other harmful and toxic environments, pay attention to regular maternity checkups, and need to start intervention and treatment as early as possible once fetal abnormalities are detected.