Vhiki makumi maviri nemanomwe yehutachiwana inguva yekuchinja pakati pechipiri neyechitatu mitatu yekudzivirira. Nenguva ino nhengo dzose nezvirongwa zvemucheche zviri kutoshanda nesimba uye zvinoramba zvichikura kusvikira mwedzi 9.
Panguva iyoyo, mwana wacho atova mumwedzi wayo wechinomwe wekuvandudza uye anokwanisa zvachose. Mhedziso huru yenguva iyi inoshaya thermoregulation (mwana haasati achakwanisa kuchengeta kutonhora kwemuviri kana akaberekwa panguva ino). Mumapapu, inongoratidzwa chete yei-surfactant (chinhu chinoputika mapapu kubva mukati uye kuparadzira) chinotanga - ndiko kuti, mapapu emwana anoderera nokufema, iyo yakazara nekumira kwayo pasina mishonga yakakwana yezvokurapa.
Pamasvondo makumi maviri nemaviri, embryo, iyo inenge yatonzi "fetus" panguva ino, iri kutama kufamba, kunyange kufema, pasinei nokuti mapapu ayo akazadzwa neamniotic fluid uye haabatanidzi mumashandisi emagetsi. Izvi zvakakosha pakufambisa kwemapfupa ekufema emucheche. Iyo fetus inotanga kuvhura maziso, inobwinyisa, inotonha kufamba nemiromo, dzimwe nguva kunyange inonyatsomwisa mumwe.
Pakuvamba kwechitatu chechitatu, vakadzi vane pamuviri vari kutanga kutanga kuwedzera kuwanda, asi ichi chiratidzo chokutora kwakanaka kwepamuviri. Munguva iyi, zvinhu zvakakosha pakugadzirwa kwecheche mumwedzi miviri inotevera uye munguva yekupedzisira yekuchengetwa zviri kuchengetwa. Kazhinji uremu hunowanikwa pakuberekwa hunokurumidza kupera mushure mokuberekwa.
Mavhiki 27 ekuzvitakura - fetal muhomwe
Pamasvondo makumi maviri nemaviri, uremu hwomukomana huri pedo ne1-1.5 kg, zvichienderana nebumbiro revabereki. Panguva imwecheteyo, fetus iri yakaonda zvikuru uye yakareba murefu, sezvo huwandu hwemucheche huri mwedzi 8-9 yekuita gestation, i.e. pamusoro pemasvondo gumi anotevera. Uyewo, mwana anowedzera mukureba - panguva iyo urefu hwacho huri 30-35 cm, uye nenguva yekuzvarwa ichawedzera kusvika 50-55 cm.