FORTY WEEKS

ACT 01 · THE ORGAN

what is there before anything happens

The anatomy here is drawn to measured dimensions, not scanned. Unlike /heart and /mind, there was no open female anatomical scan to build it from: BodyParts3D's model is male. Every number — organ sizes, hormone levels, Carnegie stages, the growth curve — is real and sourced in the file behind this page.

where these numbers come from

Carnegie staging from O'Rahilly & Müller and the Kyoto Collection. Fetal growth from the INTERGROWTH-21st standards and Hadlock for weight. Cycle endocrinology from published reference ranges. Organ dimensions and the uterine changes of pregnancy from Gray's Anatomy (41st ed.) and Williams Obstetrics (26th ed.).

The geometry is built, not scanned. /heart and /mind are BodyParts3D, measured triangle for triangle; this could not be, because that model is male — it has a prostate and no uterus — and the open alternatives carry no licence or need a signed agreement. So every shape here is constructed from the measured dimensions and the whole scene is built in centimetres, which is why the fetus at week 20 is 25.6 cm against a ruler that is really 55 cm long. Drag to turn it, pinch or scroll to zoom.