Embryology is the medical specialty concerned with the study of the growth and development of the embryo and fetus throughout pregnancy, from fertilization of the ovum until birth.
The human embryonic period (first 8 weeks) is divided into 23 "Carnegie Stages", named after the Institute that began collecting and classifying embryos during the early 1900s. These stages are based on the external and/or internal morphological development of the embryo and are not directly dependent on either age or size. Criteria beyond morphological features include age in days, number of somites present, and embryonic length.
Embryonic development (0-8 weeks) is followed by fetal development (9-36 weeks, i.e. up to the time of delivery).
During the fetal development stage there is extensive growth in size and mass, together with ongoing differentiation of organ systems established in the embryonic period.
There are many controversial ethical issues concerning aspects of embryology. Some of these arise from the various wishes and religious opinions about research using human embryos held by medical practitioners, scientific researchers, politicians, and people who are or might want to seek treatments for medical conditions suffered by themselves or their loved ones and others. These considerations together with the scientific advances that result from such studies combine to keep embryology in the news for both scientific and political reasons.
- A medical specialist in the field of embryology is called an embryologist.
- The adjective used to refer to embryology is embryological, although that word is rarely used.
Links to other relevant areas on this website include:
- Glossary Section: General Medical Terms.