FOETAL DEVELOPMENT FROM 3RD LUNAR MONTH ONWARDS
| Age (Weeks) | CR Length (mm)* | Foot Length (mm)* | Foetal Weight (gm)+ | Main External characteristics | |
| Menstrual | Fertilization | ||||
| 11 | 09 | 50 | 07 | 08 | Eyes closing or closed. Head more rounded. External genitalia still not distinguishable as male or female. Intestines are in the umbilical cord. |
| 12 | 10 | 61 | 09 | 14 | Intestine in abdomen. Early finger nail development. |
| 14 | 12 | 87 | 14 | 45 | Sex distinguishable externally well defined neck. |
| 16 | 14 | 120 | 20 | 110 | Head erect. Lower limbs well developed. |
| 18 | 16 | 140 | 27 | 200 | Ears stand out from head. |
| 20 | 18 | 160 | 33 | 320 | Vernix caseosa present. Early toenail development. |
| 22 | 20 | 190 | 39 | 460 | Head and body hair (lanugo) visible. |
| 24 | 22 | 210 | 45 | 630 | Skin wrinkled and red. |
| 26 | 24 | 230 | 50 | 820 | Fingernails present. Lean body. |
| 28 | 26 | 250 | 55 | 1000 | Eyes partially open. Eyelashes present. |
| 30 | 28 | 270 | 59 | 1300 | Eyes open. Good head of hair. Skin slightly wrinkled. |
| 32 | 30 | 280 | 63 | 1700 | Toe nails present. Body filling out. Testes descending. |
| 34 | 32 | 300 | 68 | 2100 | Fingernails reach fingertips. Skin pink and smooth. |
| 38 | 36 | 340 | 79 | 2900 | Body usually plump. Lanugo hair almost absent. Toenails reach toe tips. |
| 40 | 38 | 360 | 83 | 3400 | Prominent chest, breasts protrude. Testes in scrotum or palpable in inguinal canals. Fingernails extend beyond fingertips. |
* These measurements are averages and so may not apply to specific cases : dimensional variations increase with age.
+ These weights refer to foetus that have been fixed for about two weeks in 10% formalin. Fresh specimens usually weigh about 5% less.
