Normal and abnormal development of human embryos: First report of the analysis of 1,213 intact embryos

Abstract

This survey of the development of a large number of virtually unselected human embryos from healthy women allowed us to establish more reliable standards of normal development with respect to crown-rump length, body weight, and external form than those usually cited. Remarkable variation was noted with regard to the relation between clinical age and these attributes and thus it is concluded that crown-rump length and body weight are more reliable indicators of the general state of development than clinically established age.Dead embryos occurred with a significantly greater frequency in women with a history of genital bleeding during pregnancy than in those without. Externally m dformed embryos were found with increasing frequency with advancing developmental stage, with the maximum figure of 3.92% at horizons 19-23. Malformations observed included external defects such as exencephaly, cyclopia, myeloschisis, cleft lip, and several limb malformations. It is of considerable interest that the incidence of most of these defects was far higher than that observed in newborn infants.

Embryonic Liver Morphology and Morphometry by Magnetic Resonance Microscopic Imaging

“…Approximately 44,000 human embryos, comprising the ''Kyoto collection,'' are historical specimens collected and stored at the Congenital Anomaly Research Center of Kyoto University (Nishimura et al, 1968;Nishimura, 1975;Shiota, 1991;Yamada et al, 2004). In most cases, pregnancy was terminated during the first trimester of pregnancy for socioeconomic reasons under the Maternity Protection Law of Japan.…”

A genetic and epidemiologic study of polydactyly in human embryos in Japan

“…20 items. Further details of the collection and the characteristics of the embryonic population have been described elsewhere by Nishimura et al (1968) and Matsunaga and Shiota (1977).…”

Introduction – Developmental Overview of the Human Embryo

“…Since the attending obstetricians were not involved in examining the aborted materials, the collection of embryos was not biased by their outcome (e.g., normal or abnormal, live or dead), thus, the embryo collection is considered representative of the total intrauterine population in Japan (Nishimura, 1974(Nishimura, , 1975. Using this representative embryo population, it was reported that the incidence of malformations in embryos wer e m o r e f r e q u e n t t h a n t h a t i n i n f a n t s (Nishimura et al, 1968), and that embryos with severe malformations were prone to spontaneous abortion at high rates (Shiota, 1991). Of these embryonic malformations, holoprosencephaly (HPE) was observed at a high frequency in the Kyoto Collection.…”

“…It is also important to point out that Streeter's human series included pathological specimens obtained from spontaneous abortion or ectopic implantation. In the present chapter, the CG models ranging from CS1 to CS11 were based on Carnegie criteria (O'Rahilly and Müller, 1987), while CS13 to CS23 were based on Kyoto Collection samples (Nishimura et al, 1968.…”