Kuchuluka kwa chiberekero, chomwe chimatchedwanso kuchuluka kwa kuchulukana kwa chonde, ndilo mlingo wolondola kwambiri wa kubala kwa chigawo mu dziko kapena dziko. Icho chimaimira pafupifupi chiwerengero cha amayi omwe angaberekepo mwa mkazi aliyense wa msinkhu wobereka, mosasamala kanthu za zinthu zakunja ndi zakufa. Kuchuluka kwa chiberekero kumasonyeza kusinthika kwa chiwerengero cha anthu.
Njira yothandizira kubereka
Kuti awerengere kuchuluka kwa chiberekero, chiwerengero cha ana obadwa panthaŵi inayake chiyenera kugawidwa ndi chiwerengero cha akazi a zaka zapakati pa 15-49 (zaka za kubala) ndi kuchulukitsidwa ndi 1000. Chiwerengero cha kubereka chiwerengedwa mu ppm (‰).
Ndi anthu ochepa kwambiri omwe amatha kufa m'malo mwa mibadwo, chiŵerengero chonse cha kubala chiyenera kukhala pamtunda wa 2.33. Ngati chiwerengero cha chonde chiposa 2.4 - ichi ndi chonde chokwanira, osakwana 2.15 - otsika. Chiwerengero cha ana 2 mwa amayi ndi chiwerengero cha kubereka. Chiŵerengero chokwanira chikuwonetsa mavuto omwe angathe kuthandizira makolo omwe akugwirizana ndi momwe angaphunzitsire ndi kuwathandiza ana awo. Kubeleka pang'ono kumathandiza kuti ukalambe wa anthu ndi kuchepetsa chiwerengero chake.
Chiberekero ndi mayiko a dziko lapansi
Makhalidwe a chiwerengero cha kubereka kwathunthu pa dziko lathu lapansi ali mu njira yachuma. Mwamwayi, zodziwika kuti chikhalidwechi chidzapitirira, pakatha zaka 30 zotsatira. Mwachitsanzo, kubereka ku Russia kwafika pa chiwerengero cha 1.4 pakuganizira anthu okhala ku Caucasus, mwachizoloŵezi kwambiri "chokwanira". Ndipo chiwerengero chomwecho ku Ukraine chakhala kale 1.28. Ngakhale pansi pa chiwerengero cha kubala kwa anthu a ku Belarus ndi 1,26 peresenti yokha.
Chiŵerengero chonse cha kubereka
Kawirikawiri, kuchepa kwa chiberekero kumawonekera padziko lonse lapansi. Ambiri mwa machitidwe amenewa amachitika m'mayiko okhudzana ndi mafakitale a kumadzulo kwa Ulaya, omwe amadziwika ndi kuchepa kwa chiwerengero cha anthu.
Pakati pa 1960-2010, chiŵerengero chonse cha kubala padziko lonse chinagwera kuchokera ku 4,95 mpaka 2.5648 kubadwa kwa amayi. M'mayiko otukuka kwambiri, kubala kotereku kunalembedwa kale m'ma 1960, ndipo pofika chaka cha 2000 chidafika 1.57. Tsopano chiwerengero chochepa kwambiri chobereka chonde m'dziko la Singapore (0.78), ndi chapamwamba kwambiri ku Niger (7.16).