PLACENTA PREVIA

PLACENTA PREVIA

Perdarahan antepartum / Antepartum Haemorrhage (APH)

Bleeding from genital tract after the 28th week of pregnancy and before labour. Seems reasonable that 24 weeks should also form the new boundary between the definition of APH and bleeding of early pregnancy2 Perdarahan pada trimester terakhir dari kehamilan3 Perdarahan dari jalan lahir pada wanita hamil dengan usia kehamilan 20 minggu atau lebih4Plasenta previa / Placenta praevia / Placenta previa Placenta is located over or very near the internal os1 Placenta is partly or wholly implanted in the lower uterine segment2 Plasenta yang berimplantasi rendah sehingga menutupi sebagian atau seluruh ostium uteri internum3 Plasenta yang letaknya tidak normal sehingga menutupi sebagian atau seluruh ostium uteri internum4Degrees of placenta previa11. Total placenta previa: internal cervical ostium (ICO) covered completely

2. Partial placenta previa: ICO partially covered

3. Marginal placenta previa: the placenta is at the margin of ICO

4. Low-lying placenta: the placenta is implanted in the lower uterine segment, placenta edge actually is does not reach the ICO but is in close proxymity to it

Grading of placenta praevia21. Lateral (grade I): the placenta just encroaches on the lower uterine segment

2. Marginal (grade II): the placenta reaches the margin of cervical os

3. Complete (grade III): the placenta covers parts of the os

4. Complete (grade IV): the placenta covers the os when dilated

Klasifikasi31. Plasenta previa totalis: seluruh OUI tertutup plasenta

2. Plasenta previa lateralis: sebagian OUI tertutup plasenta

3. Plasenta previa marginalis: hanya pada pinggir OUI terdapat plasenta

Terdapat satu kelompok yang tidak dimasukkan ke dalam plasenta previa yaitu plasenta letak rendah

The degree of placenta previa will depend in large measure on the cervical dilatation at the time of examination1Penentuan macamnya plasenta previa bergantung pada besarnya pembukaan3Etiology1 Maternal age; at Parkland Hospital 1988-1999, 1 in 1500 for women 19 or less and for women over 35 it is 1 in 100

Multiparity; Babinszki and collaborators (1999) reported the incidence was increased 2.2 percent in women who were para 5 or greater

Prior cesarean delivery; Miller and associates (1996) cited a threefold increase in women with prior cesarean delivery

Smoking; Williams and collagues (1991b) found the relative risk to be increased twofold related to smoking

Risk factors2 Previous abortions; recent studies, however, have found a clear association with previous spontaneous or induced abortion (Annath et al 1997a, Macones et al 1997)

Ethnic origin; American women of Asian origin were 86% more likely to have placenta praevia than were White women, particularly primigravidae (Taylor et al 1995)

Hypertension; there is a reduced incidence of hypertension of pregnancy among women with placenta praevia (Annath et al 1997b)

Increased of the placenta area; such as twins and placenta membranacea

Etiologi3 Mioma uteri

Hipoksemia yang terjadi akibat karbon monoksida akan dikompensasi dengan hipertrofi plasenta. Hal ini terjadi terutama pada perokok berat (lebih dari 20 batang perhari)

Plasenta yang besar dan luas; seperti pada eritoblastosis, diabetes mellitus, dan kehamilan multipel

Manifestasi klinik / Clinical findingsGejala / Symptoms. The most characteristic event is painless hemorrhage, wich usually does not appear until near the end of the second trimester or after.1 The bleeding is usually unprovoked, although there is occasionally a history of coitus just beforehand.2 The most catasthropic cases of haemorrhage occur from ill-advised attemps at vaginal examination2 The formation of the lower uterine segment and the dilatation of the internal os result inevitably in tearing of placental attachments. The bleeding is augmented by the inability of the myometrial fibers of the lower uterine segment to contract and thereby constrict the torn vessels1Perdarahan bersifat berulang-ulang karena dengan majunya kehamamilan regangan dinding rahim dan tarikan serviks akan bertambah dan menimbulkan perdarahan baru.3 Setelah bulan ke-4 terjadi regangan dinding rahim karena isi rahim lebih cepat tumbuhnya dibanding dinding rahim, akibatnya istmus uteri tertarik menjadi bagian dinding korpus uteri yang disebut segmen bawah rahim. Jadi, dalam kehamilan tidak diperlukan his untuk menimbulkan perdarahan, namun sudah jelas his pembukaan menyebabkan perdarahan pada persalinan.3Tanda / Signs. The abdomen is soft with no tenderness. The presenting part is easily felt and the fetal heart rate should be normal. The low placenta displace the presenting part, with a high incidence of malpresentation. The condition should be suspected if there is an unstable lie even without any bleeding2Bagian terendah anak sangat tinggi karena plasenta terletak pada kutub bawah rahim sehingga tidak dapat mendekati pintu atas panggul dan panjang rahim berkurang hingga sering disertai kelainan letak3Such examination of the cervix is never permissible unless the women is in operating room with all the preparation for the immidiate cesarean delivery, because even the gentlest examination of this sort can cause torrential hemorrhage (double set up). Furthermore, such an examination should not be made unless delivery is planned.1 If there is a doubt about the cause of vaginal bleeding in admission, while digital vaginal examination is contraindicated, a speculum examination is often helpful before arranging a scan.2 Pada pemeriksaan in speculo plasenta previa, darah akan terlihat darah yang keluar dari ostium uteri eksternum3Dapat juga dilakukan perabaan fornises dengan hati-hati. Pemeriksaan ini hanya dapat dilakukan pada presentasi kepala karena pada letak sungsang bagian terendahnya lunak hingga sukar dibedakan dengan jaringan lunak plasenta. Pada presentasi kepala, jika tulang kepala dapat diraba dengan mudah, kemungkinan plasenta previa kecil. Sebaliknya, jika antara jari dan kepala teraba bantalan lunak, kemungkinan plasenta previa besar sekali3Ultrasonography (USG). According to Laing (1996), the average accuracy is about 96%, and rates as high as 98% have been obtained. False-positive results are often as result of bladder distention. Therefore, ultrasonic scans in apparently positive cases should be repeated after emptying the bladder1

Migrasi plasenta. Dengan bantuan USG, diagnosis plasenta previa/plasenta letak rendah sering kali sudah dapat ditegakkan sebelum kehamilan trimestes ke-tiga. Namun, dalam perkembangannya dapat terjadi migrasi plasenta (placental migration).3

The apparent movement of the low-lying placenta relative to the internal os probably results from inability to precisely define this relationship in a three-dimensional manner using two-dimensional sonography in early pregnancy. The difficulty is coupled with differential growth of lower and upper myometrial segments as pregnancy progress. Thus, the placentas that migrates most likely never had actual circumferential villus invasion that reached the internal cervical os in the first place1