Early Human DevelopmentHILL, MARK ANTHONY PhDClinical Obstetrics & Gynecology: March 2007 - Volume 50 - Issue 1 - pp 2-9 doi: 10.1097/GRF.0b013e31802f119d First Trimester Pregnancy Complications Abstract Author Information Human development in the first 8 weeks is potentially one of the most exciting areas of biologic research. Beyond historic staging of fixed human embryos, it is also one of the least understood. In contrast, detailed information exists for the embryonic period of several other species, from which human development information is extrapolated. This period is also the most sensitive to system abnormalities generated by teratogens. This review combines the human embryo Carnegie stages, available online at UNSW Embryology (http://embryology.med.unsw.edu.au), with teratogen-sensitive information. Integrating this data with current molecular, imaging, and online tools will provide insights to this period. School of Medical Sciences, The University of New South Wales, Sydney, Australia Correspondence: Dr Mark Anthony Hill, PhD, Cell Biology Laboratory, School of Medical Sciences, The University of New South Wales, Sydney NSW 2052, Australia. E-mail: email@example.com © 2007 Lippincott Williams & Wilkins, Inc.