Therapeutic amnioinfusion for chronic abruption-oligohydramnios sequence: A possible prevention of the infant respiratory disease

Chronic abruption-oligohydramnios sequence (CAOS) revisited: possible implication of premature rupture of membranes

AIM

The pathogenic mechanism of chronic abruption-oligohydramnios sequence (CAOS) remains unknown, and there are no objective standards for diagnosis on imaging or using pathological evidence. We aimed to reconsider and clarify the true pathology of CAOS by integrating clinical, magnetic resonance imaging (MRI) and histopathological findings of the placenta.

MATERIAL AND METHODS

This is a case series of patients with CAOS managed at our hospital between 2010 and 2020. The clinical data of the patients, including MRI findings and placental pathology, were reviewed retrospectively.

RESULTS

A total of 18 patients were eligible. Preterm birth occurred in 17 (94%) cases; the median gestational age at delivery was 25. Three neonates (17%) died within two years, and 10 neonates (56%) developed chronic lung disease. MRI was performed in 13 cases and clearly showed intrauterine hematoma and hemorrhagic amniotic fluid. Pathologically, in all cases, retroplacental hematoma was not detected, and fetal membranes were extremely fragile and ragged. Shedding and necrosis of the amniotic epithelium was a characteristic finding, which was confirmed in 17 cases (94%). Diffuse chorionic hemosiderosis (DCH) was detected in all cases.

CONCLUSIONS

The fundamental cause of CAOS is repeated intrauterine hemorrhage and subsequent subchorionic hematoma, which induces hemorrhagic amniotic fluid and DCH. Consequently, these factors result in the necrosis and weakening of the amnion. Therefore, the true pathology of CAOS is believed to be premature rupture of membranes rather than chronic abruption.

Histological distribution pattern of hemosiderin deposition on the chorionic plate and fetal membrane of diffuse chorioamniotic hemosiderosis related to chronic abruption oligohydramnios sequence

INTRODUCTION

Chronic abruption oligohydramnios sequence (CAOS) is histologically characterized by diffuse chorioamniotic hemosiderosis (DCH). However, the criteria for the histological evaluation of the extent of CAOS-related hemosiderin deposition (HD) of the membranes and the difference in HD between the chorionic plate (CP) and fetal membrane (FM) are not well studied. This case control study compared the degree and distribution pattern of HD on CP and FM to present the histological features of DCH and the criteria for histological evaluation.

METHODS

From the medical records of Kyoto University Hospital (2010-2019), we selected 20 CAOS cases that were clinically diagnosed by Elliot's criteria. Twenty non-CAOS cases matched to the CAOS group by gestational age were selected as controls. We compared the clinical data and pathological features in the two groups. We performed iron staining in all the cases and analyzed HD in CP and FM according to the histological score (H-Score: 0-12), which was determined as the density (0-3) multiplied by the extent of staining (0-4).

RESULTS

HD was found in 100% (20/20) of CAOS and 15% (3/20) of control cases. In both the FM and CP, CAOS cases showed a significantly higher HS than control cases (CAOS, HS = 4-12; Control, HS = 0-1, p < 0.0001). Three CAOS patients presented HD alone in the CP. The HS of the CP was significantly higher than that of the FM (p = 0.0003).

DISCUSSION

CAOS presented DCH with HS ≥ 4. This study showed that the CP might be more suitable for evaluating DCH than the FM.

Amniotic epithelial cells damage by oxidative stress in cases of diffuse chorioamniotic hemosiderosis

The amniotic membrane plays an important role in the physiological maintenance and protection of the embryo. Indeed, dysfunction of the amniotic membrane is thought to have an adverse effect on the continuation of pregnancy. In this report, we examined the pathological changes in the amniotic epithelium in three cases of diffuse chorioamniotic hemosiderosis (DCH) and investigated the cause of necrosis of the amniotic epithelial cells and its relationship with oligohydramnios. Diffuse chorioamniotic hemosiderosis was confirmed in all three cases. More extensive amniotic epithelial necrosis led to more severe hemosiderosis. Immunostaining for 8-hydroxy-2'-deoxyguanosine, a marker of oxidative stress, was positive in the amniotic epithelial cells. We speculate that oxidative DNA damage of the amniotic epithelium occurs by decomposition products of blood cells in cases accompanying subchorionic hematomas and pathological DCH. Furthermore, disorder of the amniotic epithelium may disrupt the balance of the amniotic fluid volume and cause oligohydramnios.

MRI findings of chronic abruption-oligohydramnios sequence (CAOS): report of three cases

Chronic abruption-oligohydramnios sequence (CAOS), characterized by chronic vaginal hemorrhage and oligohydramnios, is a rare clinical condition of pregnancy. Because CAOS is associated with preterm delivery and lung injury to the infant, it is a major clinical concern. This report describes three CAOS cases which presented characteristic MRI findings reflecting CAOS pathological mechanisms and pathological findings. First, in all cases, the placenta detached from the uterus at the peripheral portion of the placenta because of placental marginal hematoma. Because the cause of CAOS is presumed to be chronic peripheral separation of the placenta developing from bleeding from the peripheral vein of the placenta, the MRI finding corresponds to the CAOS pathophysiology. Second, the placental marginal hematoma spread extensively along the decidua. This MRI finding can explain the vaginal hemorrhage of CAOS patients. Finally, the amniotic fluid of all patients showed high signal intensity on T1-weighted images, suggesting that amniotic fluid contains blood-derived products. In CAOS patients, chronic venous bleeding engenders the release of blood-derived products into the amniotic cavity. The aspiration of these products might be a cause of lung injury to the fetus. We presented these MRI findings with radiologic-pathologic correlation.

Symptoms of an intrauterine hematoma associated with pregnancy complications: a systematic review

OBJECTIVE

To evaluate the predictive value of the symptoms of an intrauterine hematoma (IUH) for adverse pregnancy outcomes.

METHODS

A literature review was performed with the search terms, including intrauterine/subchorionic/retroplacental/subplacental hematoma/hemorrhage/bleeding/collection/fluid, covering the period from January, 1981 to January, 2014. We just focused on the pregnancy outcomes associated with different symptoms of an IUH.

RESULTS

It is generally agreed that a retroplacental, posterior or subchorionic in the fundus of uterus, and/or persistent IUH is associated with adverse outcomes in the ongoing pregnancy. However, the prognosis value of both volume and gestational age at diagnosis of IUH still remains controversial. Some researchers argue that a large IUH is associated with an increased risk of adverse events during pregnancy while others refuted. It is believed by some that the earlier an IUH was detected, the higher the risk for adverse outcomes would be, while no or weak association were reported by other studies. The prognostic value of the simultaneous presence of vaginal bleeding on pregnancy outcome is also controversial.

CONCLUSIONS

Both the position relative to the placenta or uterus and duration of IUH have strong predictive value on the prognosis in the ongoing pregnancy. However, the prognostic values of the IUH volume, gestational age at diagnosis and the simultaneous presence of vaginal bleeding remain controversial up to now. Moreover, most of previous reports are small, uncontrolled studies with incomplete information. Prospective, large sample, cohorts studies which take all detailed symptoms of an IUH into consideration are needed when we evaluate its clinical significance in the prognosis of pregnancy.