The percentage of live births to mothers aged under 20 has fallen every year since 2004, while the percentage of live births to older mothers has increased slightly over the same period.
Mae canran y genedigaethau byw ymhlith mamau dan 20 oed wedi gostwng bob blwyddyn ers 2004, tra mae canran y genedigaethau byw ymhlith mamau hŷn wedi cynyddu rhywfaint dros yr un cyfnod.