Kwabasetyhini abakhulelweyo abaqhelekileyo, xa bekhula ngexesha lokukhulelwa, umlinganiselo wentliziyo uyanda kwaye ukumelana nomzimba uyancipha. Ngokuqhelekileyo kukholelwa ukuba umlinganiselo wentliziyo uqala ukwanda kwiiveki ezisi-8 ukuya kwezili-10 zokukhulelwa kwaye ufikelela kwincopho kwiiveki ezingama-32 ukuya kwezingama-34 zokukhulelwa, ukunyuka kwe-30% ukuya kuma-45% xa kuthelekiswa nokungakhulelwa, kwaye kugcina eli nqanaba de kube kuzelwe. Ukwehla kokumelana nomzimba ongaphakathi kunciphisa uxinzelelo lwemithambo yegazi, kwaye uxinzelelo lwegazi lwe-diastolic luyancipha kakhulu, kwaye umahluko woxinzelelo lwe-pulse uyanda. Ukusuka kwiiveki ezi-6 ukuya kwezili-10 zokukhulelwa, umthamo wegazi wabasetyhini abakhulelweyo uyanda ngokunyuka kweminyaka yokukhulelwa, kwaye unyuka malunga nama-40% ekupheleni kokukhulelwa, kodwa ukwanda komthamo we-plasma kudlula kakhulu inani leeseli ezibomvu zegazi, i-plasma inyuka ngama-40% ukuya kuma-50%, kwaye iiseli ezibomvu zegazi zinyuka nge-10% ukuya kwi-15%. Ke ngoko, kukukhulelwa okuqhelekileyo, igazi liyancitshiswa, libonakala njengokuncipha kwe-viscosity yegazi, ukwehla kwe-hematocrit, kunye nokwanda kwesantya se-erythrocyte sedimentation.

Izinto ezibangela ukujiya kwegazi Ⅱ, Ⅴ, VII, Ⅷ, IX, kunye Ⅹ zonke ziyanda ngexesha lokukhulelwa, kwaye zinokufikelela kwi-1.5 ukuya kwi-2.0 amaxesha aqhelekileyo phakathi kokukhulelwa kunye nokugqibela, kwaye imisebenzi yezinto ezibangela ukujiya Ⅺ kunye  iyancipha. I-Fibrinopeptide A, i-fibrinopeptide B, i-thrombinogen, i-platelet factor Ⅳ kunye ne-fibrinogen zanda kakhulu, ngelixa i-antithrombin Ⅲ kunye neproteni C kunye neproteni S zehla. Ngexesha lokukhulelwa, ixesha le-prothrombin kunye nexesha le-prothrombin elisebenzayo elingasebenziyo liyafinyezwa, kwaye umxholo we-plasma fibrinogen uyanda kakhulu, onokunyuka uye kwi-4-6 g/L kwi-trimester yesithathu, engaphezulu ngama-50% kunaleyo kwixesha elingakhulelwanga. Ukongeza, i-plasminogen yanda, ixesha lokuchithwa kwe-euglobulin landiswa, kwaye utshintsho lwe-coagulation-anticoagulation lwenze umzimba ube kwimeko yokujiya kakhulu, eyayiluncedo kwi-hemostasis esebenzayo emva kokuphazamiseka kwe-placenta ngexesha lokubeletha. Ukongeza, ezinye izinto ezibangela ukubola kakhulu ngexesha lokukhulelwa ziquka ukunyuka kwe-cholesterol iyonke, ii-phospholipids kunye nee-triacylglycerols egazini, i-androgen kunye ne-progesterone ekhutshwa yi-placenta inciphisa impembelelo yezinye izithinteli zokubola kwegazi, i-placenta, i-uterine decidua kunye nee-embryos. Ubukho bezinto ezibangela i-thromboplastin, njl.njl., bunokukhuthaza igazi ukuba libe kwimeko yokubola kakhulu, kwaye olu tshintsho luba mandundu xa ixesha lokukhulelwa lisanda. Ukubola kancinci kancinci yindlela yokukhusela umzimba, eluncedo ekugcineni i-fibrin ifakwa kwimithambo yegazi, udonga lwesibeleko kunye ne-placental villi, inceda ukugcina ukuthembeka kwe-placenta kunye nokwenza i-thrombus ngenxa yokukrazula, kwaye iququzelele i-hemostasis ekhawulezayo ngexesha nasemva kokubeleka. , yindlela ebalulekileyo yokuthintela ukopha emva kokubeletha. Ngexesha elifanayo lokubola, umsebenzi wesibini we-fibrinolytic uqalisa nokucoca i-thrombus kwimithambo yegazi ye-uterine kunye ne-venous sinuses kwaye ukhawulezise ukuvuselelwa nokulungiswa kwe-endometrium.