Mu mimba yabwinobwino, mphamvu ya mtima imawonjezeka ndipo mphamvu ya mtima imachepa pamene msinkhu wa mimba ukuwonjezeka. Anthu ambiri amakhulupirira kuti mphamvu ya mtima imayamba kukwera pa masabata 8 mpaka 10 a mimba, ndipo imafika pachimake pa masabata 32 mpaka 34 a mimba, zomwe ndi 30% mpaka 45% kuposa zomwe sizili ndi mimba, ndipo zimasunga mulingo uwu mpaka kubadwa. Kuchepa kwa mphamvu ya mtima kumachepetsa kuthamanga kwa magazi, ndipo kuthamanga kwa magazi kwa diastolic kumachepa kwambiri, ndipo kusiyana kwa kuthamanga kwa mtima kumakula. Kuyambira masabata 6 mpaka 10 a mimba, kuchuluka kwa magazi kwa amayi apakati kumawonjezeka ndi kukula kwa msinkhu wa mimba, ndipo kumawonjezeka ndi pafupifupi 40% kumapeto kwa mimba, koma kuwonjezeka kwa mphamvu ya plasma kumaposa kwambiri kuchuluka kwa maselo ofiira a magazi, plasma imawonjezeka ndi 40% mpaka 50%, ndipo maselo ofiira a magazi amawonjezeka ndi 10% mpaka 15%. Chifukwa chake, mu mimba yabwinobwino, magazi amachepetsedwa, kumawonekera ngati kuchepa kwa kukhuthala kwa magazi, kuchepa kwa hematocrit, komanso kuchuluka kwa erythrocyte sedimentation rate [1].

Zinthu zolimbitsa magazi Ⅱ, Ⅴ, VII, Ⅷ, IX, ndi Ⅹ zonse zimawonjezeka panthawi ya mimba, ndipo zimatha kufika nthawi 1.5 mpaka 2.0 kuposa nthawi yachibadwa pakati pa mimba ndi kumapeto kwa mimba, ndipo ntchito za zinthu zolimbitsa magazi Ⅺ ndi  zimachepa. Fibrinopeptide A, fibrinopeptide B, thrombinogen, platelet factor Ⅳ ndi fibrinogen zimawonjezeka kwambiri, pomwe antithrombin Ⅲ ndi protein C ndi protein S zimachepa. Pa nthawi ya mimba, nthawi ya prothrombin ndi nthawi yoyambitsa prothrombin yochepa imafupikitsidwa, ndipo kuchuluka kwa fibrinogen m'magazi kumawonjezeka kwambiri, komwe kumatha kuwonjezeka kufika pa 4-6 g/L mu trimester yachitatu, yomwe ndi yokwera pafupifupi 50% kuposa nthawi yomwe si yapakati. Kuphatikiza apo, plasminogen idawonjezeka, nthawi yosungunuka ya euglobulin idakulitsidwa, ndipo kusintha kwa coagulation-anticoagulation kunapangitsa thupi kukhala lolimba kwambiri, zomwe zinali zothandiza pakuchotsa magazi m'thupi pambuyo pa kusokonekera kwa placenta panthawi yobereka. Kuphatikiza apo, zinthu zina zomwe zimapangitsa kuti magazi azigaya magazi ambiri panthawi ya mimba ndi monga kuchuluka kwa cholesterol yonse, ma phospholipid ndi ma triacylglycerols m'magazi, androgen ndi progesterone zomwe zimatulutsidwa ndi placenta zimachepetsa mphamvu ya zoletsa zina zogaya magazi, placenta, uterine decidua ndi ma embryos. Kupezeka kwa zinthu za thromboplastin, ndi zina zotero, kungapangitse magazi kukhala mu mkhalidwe wogaya magazi kwambiri, ndipo kusinthaku kumawonjezeka ndi kukula kwa msinkhu wa mimba. Kugaya magazi pang'ono ndi njira yotetezera thupi, yomwe ndi yothandiza kusunga fibrin mu mitsempha yamagazi, khoma la uterine ndi placental villi, kumathandiza kusunga umphumphu wa placenta ndikupanga thrombus chifukwa chochotsa, ndikuthandizira hemostasis mwachangu panthawi yobereka komanso pambuyo pake. , ndi njira yofunika kwambiri yopewera kutuluka magazi pambuyo pobereka. Nthawi yomweyo yogaya magazi, ntchito yachiwiri ya fibrinolytic imayambanso kuchotsa thrombus mu mitsempha ya uterine spiral ndi venous sinuses ndikufulumizitsa kukonzanso ndi kukonzanso endometrium [2].

Komabe, mkhalidwe wothira magazi ambiri ungayambitsenso mavuto ambiri obereka. M'zaka zaposachedwapa, kafukufuku wapeza kuti amayi ambiri apakati amakhala ndi vuto la thrombosis. Matendawa a thromboembolism mwa amayi apakati chifukwa cha zolakwika za majini kapena zinthu zomwe zimawayika pachiwopsezo monga mapuloteni oletsa magazi kuundana, zinthu zolimbitsa thupi, ndi mapuloteni a fibrinolytic amatchedwa thrombosis. (thrombophilia), yomwe imadziwikanso kuti prothrombotic state. Mkhalidwe wothira magazi umenewu sumayambitsa matenda otsekeka magazi, koma ukhoza kubweretsa zotsatira zoyipa za mimba chifukwa cha kusalingana kwa njira zotsekeka magazi-zoletsa magazi kuundana kapena ntchito ya fibrinolytic, microthrombosis ya mitsempha yozungulira ya uterine kapena villus, zomwe zimapangitsa kuti placental perfusion isagwire bwino ntchito kapena ngakhale infarction, monga Preeclampsia, placental abruption, placental infarction, disseminated intravascular coagulation (DIC), kuletsa kukula kwa mwana wosabadwayo kukula, kutayika kwa mimba mobwerezabwereza, kubereka mwana wakufa komanso kubadwa msanga, ndi zina zotero, kungayambitse imfa ya amayi ndi ana obadwa kumene pazochitika zoopsa.