Myxedema

✍ 1st week of gestation : fertilization and implantation , beginning of embryonic period.
✍ 2nd week of gestation : endoderm and ectoderm appear ( bilaminar embryo ).
✍ 3rd week of gestation : first missed menstrual period, mesoderm appears (trilaminar embryo), somites begin to form.
✍ 4th week of gestation : neural folds fuse, folding of embryo into human like shape, arm and leg buds appear , crown-rump length is 4 to 5 mm .
✍ 5th week of gestation : lens placodes,primitive mouth,digital rays on hands.
✍ 6th week of gestation : primitive nose , philtrum ,primary palate , crown-rump length 21 – 23mm
✍ 7th week of gestation : eyelids begin
✍ 8th week of gestation : ovaries and testes distinguishable
✍ 9th week of gestation : fetal period begins, crown-rump length is 5 cms, weight is 9 grams .
✍ 10th week of gestation : external genitalia distinguishable
✍ 20th week of gestation : usual lower limit of viability ,weight is 460 grams , length is 19cms
✍ 28th week of gestation : eyes open , fetus turns head down , weight is 1000 grams
✍ 38th week of gestation : term.