Source:http://linkedlifedata.com/resource/umls/id/C0008922
MSH: The earliest developmental stage of a fertilized ovum (ZYGOTE) during which there are several mitotic divisions within the ZONA PELLUCIDA. Each cleavage or segmentation yields two BLASTOMERES of about half size of the parent cell. This cleavage stage generally covers the period up to 16-cell MORULA.,CSP: the first stage of embryogenesis; cleavage of fertilized ovum, leading to formation of the embryo.