MuFrance, zuva rinotarisirwa rekusununguka rinotarisirwa zvakarongeka mwedzi mipfumbamwe mushure mezuva rinotarisirwa rekutanga kwepamuviri, kureva mavhiki makumi mana nerimwe (masvondo eamenorrhea, kureva mavhiki asina nguva) (41). Semuenzaniso, kana zuva rekupedzisira nguva iri March 1, kutanga kwepamuviri kunofungidzirwa, munyaya yenguva dzose ovulatory cycles, March 10; iyo DPA saka yakaiswa muna Zvita 24 (Kurume 24 + 24 mwedzi). Kuti uite kuverenga uku, gynecologist kana nyamukuta anoshandisa "pregnancy disc".

Nekudaro, iri rinongori zuva rekufungidzira iro zvinhu zvakasiyana zvinogona kukanganisa:

• nguva yekutenderera: iyi nzira yekuverenga inoshanda kune yakajairwa kutenderera kwemazuva makumi maviri nemasere
• zuva rekuvhiya iro rinogona kusiyanisa, kunyangwe pakutenderera, kana kubva kutenderera kuenda kune imwe
• nguva yekupona kwezai nembeu, izvo zvinogona kukanganisa zuva rekusangana

Chimwe chishandiso chichaita kuti zvikwanise kusimbisa kana kugadzirisa iyi yekutanga theoretical date: yekutanga nhumbu ultrasound yakaitwa pa12 WA uyezve inonzi "kufambidzana ultrasound". Munguva iyi ultrasound, chiremba achaverenga nhamba ye fetus, tarisa simba rayo uye kuita biometry (kutora zviyero) izvo zvichaita kuti zvikwanise kufungidzira zera remimba uye naizvozvo inotarisirwa zuva rekusununguka. Ichayerwa:

• iyo cranio-caudal kureba kana LCC, iyo inoenderana nemusoro-kumagaro kureba kweembryo
• iyo biparietal diameter kana Bip, kureva dhayamita redehenya

Aya maitiro maviri anofananidzwa nereferensi macurves uye anobvumira kufambidzana kwepamuviri uye fungidziro yezera remudumbu kusvika mukati memazuva matatu. Iyi ultrasound inoonekwa seyakanakisa nzira yekufambidzana pamuviri (3).

Kunyange kana iyo ultrasound inogona kuvimbika zera rekuzvitakura, kuchine imwe data inogona kukanganisa zuva rekusununguka: nguva yekuzvitakura pachayo. Zvisinei, iyiwo fungidziro; uyezve, munyika dzakawanda, nguva yekubata pamuviri haina kuverengerwa pamwedzi 9 asi vhiki yapfuura, kureva 40 mavhiki. (3) Zvichienderana nemaitiro ekuverenga, genetic factor uye mamwe maitiro aamai, nguva yekubata pamuviri inosiyana pakati pe280 ne290 mazuva kubva pazuva rekutanga rekupedzisira nguva (kwenguva yemazuva makumi maviri nemasere). Nguva yekuzvitakura saka inosiyana pakati pe28 + 40 uye 0 + 41 mavhiki (3). Ongororo ichangoburwa (4) yakatoratidza kuti avhareji yenguva kubva pakuzvara kusvika pakuzvara yaive mazuva 5 (kureva mavhiki makumi matatu nemasere nemazuva maviri) nekusiyana kwakasimba (kusvika kumasvondo mashanu) zvichienderana naamai.