NAČINI PLACENTACIJE U LJUDI I NJIHOV UTJECAJ NA ISHOD TRUDNOĆE. (Croatian)

TYPES OF PLACENTATION IN HUMANS AND THEIR INFLUENCE ON THE PREGNANCY OUTCOME. (English)

Possible mechanisms of placental development in twins which can in humans can be dyzygotic and monozygotic. Special emphasis is given to the possible complications ow twin pregnancies with regard to the type of placentation. In twin pregnancies with two placentas (biamniotic bichorionic, either separate or fused), the complications are basically the same as in singleton pregnancies, with increased incidence of velamentous insertion of one or both umbilical cords, and increased incidence of single umbilical artery, usually in only one twin. In monozygous twins whose placenta is monoamniotic monochorionic, the main complication is intrauterine death of twins, that usually occurs in the second trimester and is caused by umbilical cords twisting or knots. In monozygous twins that share one chorionic plate, but have two separate amniotic cavities, the greatest danger is the development of feto-fetal transfusion syndrome (twin twin transfusion syndrome-TTS). This syndrome develops because of blood vessel anastomoses between the twins. Pathological and histopathological examination of twin placenta is described, as well as the methodology of assessement of blood vessel anastomoses. Pathological fi ndings in case of intrauterine death of one or both twins with TTTS are also described. The most bizarre complication of biamniotic monochorionic pregnancy is the development of twin reversed arterial perfusion (TRAP). The proposed ways of its development and morphological fi ndings are also described. [ABSTRACT FROM AUTHOR]

Prikazani su mogući načini nastanka blizanačke trudnoće, kao i načini na koje dolazi do razvoja posteljice u ljudi u dva oblika blizanačke trudnoće: dvojajčane i jednojajčane. Posebni naglasak je stavljen na komplikacije blizanačkih trudnoća do kojih dolazi zbog načina placentacije. Kod blizanačkih trudnoća kod kojih se razvijaju dvije korionske ploče i dvije amnijske šupljine (odvojene ili srasle) komplikacije su uglavnom jednake kao u jednoplodnih trudnoća uz povećanu učestalost velamentozne insercije jedne ili obaju pupkovina, kao i razvoja samo jedne pupčane arterije, običnu u samo jednog blizanca. Kod jednojajčanih blizanaca sa samo jednom korionskom pločom i jednom zajedničkom amnijskom šupljinom najteža komplikacija je intrauterina smrt blizanaca do koje najčešće dolazi u drugom tromjesečju trudnoće uslijed komplikacija vezanih za zaplitanje pupkovina. Jednojačani blizanci čija je posteljica građena od zajedničke korionske ploče i dvije amnijske šupljine u posebnoj su opasnosti od razvoja sindroma feto-fetalne transfuzije (eng. twin twin transfusion syndrome -TTTS) uslijed postojanja krvožilnih anastomoza. Opisan je način patološke makroskopske i patohistološke analize blizanačkih posteljica, način dokazivanja krvnožilnih anastomoza, kao i obdukcijski nalazi u slučajevima intrauterine smrti jednog ili oba blizanca. Opisana je i komplikacija blizanačke trudnoća koja se naziva eng. twin reversed arterial perfusion - TRAP, pretpostavljeni način njezina nastanka i morfološki nalaz u blizanca u kojega se ta patološka promjena razvila. [ABSTRACT FROM AUTHOR]

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