Every visible mark on the page needs translating: the main fields, the registrar's stamp, any marginal annotations, late-registration endorsements, legitimation or adoption notes, and the back of the document if anything is printed or stamped there. A translation that covers only the main fields is the most common rejection cause for this document type.
Birth certificates are issued in dozens of formats around the world, and most of them carry more text than people assume. The main printed fields — name, date, place, parents — are the obvious part. The less obvious parts are the ones that get skipped.
Marginal annotations are notes added by the issuing registrar after the original issue. A name change, a court-ordered correction, a parent's death recorded against the child's record. They sit in the margins as small handwritten or stamped text. UKVI reads them as part of the document; a translation that ignores them is partial.
Late-registration stamps appear on births registered weeks, months or years after the event. These are common in Pakistan (NADRA late registration), India (rural late entries), and across much of West Africa. The stamp confirms when the registration actually happened, which UKVI sometimes cross-references against other documents in the file.
Legitimation endorsements appear on certificates where the parents married after the birth. These rewrite the child's status under the issuing country's law and have to appear on the translation, because they affect whether the child counts as a 'child of the marriage' under UK family-visa rules.
The back of the document matters too. Some Pakistani NADRA certificates carry verification stamps and serial numbers on the reverse. Some Indian state certificates print the issuing authority block on the back. A scan that omits the reverse is a half-document, and a translation of a half-document is a half-translation.