How best to assess the gestational age if any of the following sonological parameters are supplied to you?? Sono- embryology chart –How helpful is this chart when FGR is so rampant nowadays for various life style disorders, smoking, diff drug intake, addiction including minimal rest, stress?? Unless initial USG report is known to us(dating USG) e are put in difficulty to establish AFD, LFD or S FD or FGR !!! The following chart is the time table !!!

Date                         Event

Day 14                    Ovulation                  Collapse of Follicle ,Free                                                                                                          Fluid                                      Day15                  Fertilization                  corpus luteum Secretory                                                                         endometrium     Day 18           Morula stage                    Decidualization of                                                                    Endometrium Day22-23      Blastocyst                       Implantation window Day 23         Primary Yolk sac             Implantation site Day26-28   Extra Embryonic            implantation site recognition Day27-28 Secondly Yolk sac Day28    Syncytiotrphoblast                And sometimes seen Chorionic cavity Week 5 Gastrulation                           Visualization of Gestational                                                                 Sac and secondary. Yolk sac 29/30 31/42      Neuralisation                         Growth of sac 34/44       Sometimes                            Embryo  fetal cardiac                                                                          Activity                                                               Embryo visualization                                                              Crown rump length Cardiac activity Week6-12                Cardiovascular                                  System 6 Weeks                    Unidirectional                  Cardiac activity                                  Blood flow 8 Weeks                  Heart/                                  Seen by TVS  10 Weeks                Peripheral vascular               Visualized                                   System