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PubMed2005

Coping with placenta praevia and accreta in a DGH setting and words of caution.

The incidence of placenta praevia and accreta has been increasing with rising caesarean section rates. We highlight the increasing incidence of severe post-partum haemorrhage due to placenta accreta. Four cases occurred within 3 years (2002--2004) in a small District General Hospital (DGH) with a delivery rate of 1,800 per year. All of the cases had previous caesarean sections and three had an associated anterior low-lying placenta. These patients were diagnosed to have placenta accreta in the third stage of labour, as the placenta was completely adherent and was difficult to remove. However, two of them had a provisional diagnosis made of placenta accreta and prophylactic measures had been taken in the form of counselling and consent for possible hysterectomy. Patients were counselled regarding this condition, and the possible need for hysterectomy was discussed. Two of them had to be managed by post-partum hysterectomy and the other two were treated conservatively. The purpose of writing these case reports is to warn others of the need for vigilance, particularly in keeping their primary caesarean section rates down and being prepared for long-term complications.

Adult↗

PubMed1992

Placental compressibility: implications for indirect diagnosis of posterior placenta previa.

A number of problems beset the indirect diagnosis of posterior placenta previa using transabdominal ultrasound. We add a new potential complicating factor. In 128 pregnancies at or beyond 30 weeks' gestation, measurements were taken from the fetal skull to the maternal sacrum before and after compression. Up to 69% compressibility of the placenta was found in vivo and in vitro. Modified fetal skull to maternal sacrum measurement criteria were devised from the results. Placenta previa is highly unlikely if the measurement from the fetal skull to maternal sacrum is less than 10 mm before compression or less than 7 mm after compression. Placenta previa is probable if the measurement is greater than 20 mm before compression or greater than 15 mm after compression. In 40% of the cases, posterior placenta previa could not be excluded. We conclude that placental compressibility is an additional confounding problem for indirect ultrasound assessment of posterior placenta previa and that indirect assessment should be attempted only if maneuvers to image the lower uterine segment directly are unsuccessful.

Female↗

PubMed1985

The placenta as a site of cytomegalovirus infection in guinea pigs.

The development of cytomegalovirus (CMV) infection in the placenta was studied in Hartley guinea pigs inoculated at midgestation, and its role in determining the outcome of fetal CMV infection was assessed. A hematogenous spread of CMV from the mother to the placenta occurred early during the course of the infection. However, the virus remained present in placental tissues long after CMV had been cleared from maternal blood (i.e., 3 and 4 weeks postinoculation). At that time, the virus was able to replicate in placental tissues in the presence of specific maternal antibodies. Viral nucleocapsids were seen within nuclei of trophoblastic cells, and virions were present surrounding infected cells. In addition, typical CMV-induced histopathological lesions bearing CMV antigens were consistently localized at the transitional zone between the capillarized labyrinth and the noncapillarized interlobium. Whenever CMV infection of the fetus occurred, virus was isolated from the associated placenta. Among placental-fetal units with CMV-infected placentas, only 27% of the fetuses were found to be infected. In addition, there was a delay in the establishment of the infection in the fetus in relation to the placenta, although frequencies of virus isolation in placental and fetal tissues peaked at 3 weeks after CMV inoculation. These results suggest that during primary CMV infection of pregnant guinea pigs, the placenta not only serves as a reservoir for CMV but also acts to limit transmission of the virus to the fetus.

Animals↗

PubMed1997

Normal placenta: gadolinium-enhanced dynamic MR imaging.

PURPOSE: To establish the appearance of the normal placenta on dynamic, gadolinium-enhanced magnetic resonance (MR) images. MATERIALS AND METHODS: Eleven patients underwent MR imaging for suspected uterine (four patients) or placental (seven patients) abnormalities (but not placental insufficiency or intrauterine growth retardation). Unenhanced or gadolinium-enhanced, T1-weighted, fat suppressed, spoiled gradient-recalled-echo MR images and T2-weighted, half-Fourier, single-shot, spin-echo-train MR images were obtained. Two investigators retrospectively evaluated the images to determine the rate, pattern, and degree of placental contrast material enhancement with myometrial enhancement as a reference. RESULTS: The diagnoses were normal placenta (six patients), abnormal placental position (four patients), and subchorionic hematoma (one patient). The placenta rapidly and intensely enhanced on images acquired immediately after contrast material administration and preceded substantial enhancement of the myometrium. Immediately postcontrast images showed closely packed 2-3-cm lobules of placental enhancement in third-trimester pregnancies and heterogeneous placental enhancement in second-trimester pregnancies. In all cases, placental enhancement became more homogeneous over time. The placenta could be readily distinguished from the myometrium. All neonates were healthy with no evidence of intrauterine growth retardation. CONCLUSION: Normal placental enhancement is intense on immediately postcontrast images and precedes substantial myometrial enhancement. Third-trimester placentas exhibit a lobular pattern of enhancement, while second-trimester placentas exhibit heterogeneous enhancement.

Adult↗

PubMed2005

Increased prevalence of fetal thrombi in monochorionic-twin placentas.

OBJECTIVE: Fetal vessel thrombosis has been related to pregnancy complications and adverse neonatal outcomes in singleton pregnancies, but the clinical and pathologic characteristics of fetal thrombosis in twin pregnancy are still ill defined. METHODS: To clarify the characteristics of fetal thrombosis in twins, we reviewed the histology slides and medical records of live-born infants of twin pregnancies involving the live birth of at least 1 fetus (monochorionic: 389 cases; dichorionic: 780 cases) and singleton pregnancies (1162 cases). RESULTS: The incidence of fetal thrombosis in monochorionic-twin pregnancies was significantly higher than that of dichorionic-twin and singleton pregnancies (5.1% vs 3.0% and 2.8%, respectively). The incidence of velamentous umbilical cord insertion in monochorionic- and dichorionic-twin placentas was also higher than in singleton placentas (12% and 7% vs 2%, respectively). Fetal thrombosis in twin placentas was associated with intrauterine growth restriction. In monochorionic twins, fetal thrombosis was associated with co-twin fetal death, but in dichorionic twins no correlation was identified. Microscopically, fetal vessel thrombosis in twin placentas was associated with vascular cushions (fibrous hyperplasia of fetal vessel), as is the case occasionally in singletons. CONCLUSIONS: The incidence of fetal vessel thrombosis in monochorionic placentas was higher than that seen in dichorionic-twin placentas and singleton gestations. Fetal vessel thrombosis in twin pregnancies showed a correlation with intrauterine growth restriction, peripheral cord insertions, and major vascular cushions.

Female↗

PubMed2002

Decreased neutrophil function as a cause of retained placenta in dairy cattle.

It is unclear why some cows fail to expel the placenta following calving. One theory suggests the fetal placenta must be recognized as "foreign" tissue and rejected by the immune system after parturition to cause expulsion of the placenta. We hypothesized that impaired neutrophil function causes retained placenta (RP). We examined the ability of neutrophils to recognize fetal cotyledon tissue as assessed by a chemotaxis assay, which utilized a placental homogenate obtained from a spontaneously expelled placenta as the chemoattractant. Neutrophil killing ability was also estimated by determining myeloperoxidase activity in isolated neutrophils. Blood samples were obtained from 142 periparturient dairy cattle in two herds. Twenty cattle developed RP (14.1%). Neutrophils isolated from blood of cows with RP had significantly lower neutrophil function in both assays before calving, and this impaired function lasted for 1 to 2 wk after parturition. The addition of antibody directed against interleukin-8 (IL-8) to the cotyledon preparation used as a chemoattractant inhibited chemotaxis by 41%, suggesting that one of the chemoattractants present in the cotyledon at parturition is IL-8. At calving, plasma IL-8 concentration was lower in RP cows (51 +/- 12 pg/ml) than in cows expelling the placenta normally (134 +/- 11 pg/ml). From these data, we suggest that neutrophil function is a determining factor for the development of RP in dairy cattle. Also, depressed production of IL-8 may be a factor affecting neutrophil function in cows developing RP.

Animals↗

PubMed1999

Placenta percreta: report of a case.

Placenta accreta, increta, or percreta are rare but potentially lethal obstetric emergencies. Removal of abnormal growth of the placenta into the uterine wall is difficult or impossible and results in massive blood loss. Hysterectomy may be necessary to save the mother's life. The common predisposing factors in development of placenta percreta are repeat cesarean and placenta previa. The diagnosis of placenta percreta may remain undiagnosed until delivery. The case presented describes a scenario involving placenta percreta with bladder involvement in which the diagnosis was known in advance. The article describes the preoperative preparation, intraoperative events, and postoperative status of this particular case.

Adult↗

PubMed1992

Placenta accreta/percreta/increta: a cause of elevated maternal serum alpha-fetoprotein.

OBJECTIVE: To investigate the relationship between elevated maternal serum alpha-fetoprotein (MSAFP) and abnormal placental adherence (placenta accreta/percreta/increta). METHODS: We reviewed the MSAFP levels of 11 women who had cesarean hysterectomies because of placenta accreta/percreta/increta. The control group consisted of 14 women who delivered by cesarean because of placenta previa but who had no abnormal placental adherence. RESULTS: Five of the 11 women with placenta accreta/percreta/increta had elevated MSAFP, whereas all 14 controls had normal levels. CONCLUSION: These results indicate a significant association between elevated MSAFP and placenta accreta/percreta/increta (P = .017). Patients with an unexplained elevation of MSAFP as well as placenta previa may be at increased risk for abnormal placental adherence.

Female↗

PubMed1989

[Pathologic analysis of the placenta in preterm deliveries].

The results of pathological analysis of 198 placentae from preterm deliveries of 28-37 week pregnancy in year 1985-1988 were presented Grossly there were: placenta previa and low implantation 2.91%, bipartate placenta and rupture of marginal sinus 0.97%, large placenta 2.91%, short cord 4.85%, velamentous insertion of cord 3.88, etc; all significantly different from those from term deliveries statistically. Microscopic, 165 placentae showed: infection of membranes and umbilical vessels in 19 (11.52%), of which 11 cases were with premature rupture of membranes or cervical interventions and 8 could be regarded as the cause of preterm delivery. Among 72 PIH cases, 65 (90.28%) had arteriopathy of decidual capsularis. Notably 18 cases (25%) of PIH were not diagnosed as such clinically until the discovery of arteriopathy of decidual capsularis microscopically and upon reviewing the case history. Combining with placental examinations, it is possible to tell the cause of preterm delivery whether in placenta, amniotic fluid or umbilical cord. In 20 PIH cases (27.78% of total PIH) with premature rupture of membranes, whether the decidual arteriopathy makes it liable to have membranes ruptured needs further study.

Decidua↗

PubMed1978

Circumvallate placenta and intrauterine growth retardation.

A study has been made of a prospectively selected material of circumvallate placentae; the latter being defined as an elevated edge of more than 50% of the circumference. The material consists of 447 placentae from liveborn singleton infants, where 287 were from exemplary pregnancies, and 160 from births with a gestational age (GA) of less than 266 days and/or a birth weight of less than 2750 g. The material was prospectively randomized. It was divided into clinical groups according to the GA and under-weight. Nineteen circumvallate placentae were found. Among these were more multigravidae and more with pre-gestational menstrual irregularity than expected. The number of antepartum haemorrhages was as expected. There were more premature infants, premature under-weight infants and under-weight infants than expected. Nine of the 20 premature under-weight infants in the material had circumvallate placenta. In relation to a previously published basic material, it was found that the birth weight, and placental content of RNA and DNA were significantly reduced. It is concluded that placentae with more than 50% circumvallation are associated with prematurity and under-weight, as well as a placenta with fewer cells than normal. The genesis of the anomaly is discussed.

Birth Weight↗

PubMed1986

Pathology of the placenta.

The placenta has a considerable functional reserve capacity, easily repairs ischaemic damage, is able to compensate for toxic injury and does not appear to age. Most of the macroscopically visible abnormalities of the placenta are of no functional significance, the major exception to this general banality being the uncommon large haemangioma which can cause complications in the mother, fetus and neonate. Most of the histological abnormalities seen in the placental villi represent a reaction to alterations in either maternal or fetal blood flow through the placenta, but a failure of adequate maturation of the villous tree may impair the functional efficiency of the placenta, as may defective trophoblastic differentiation. Infections of the placenta are important but do not influence placental function, whilst there is currently no firm evidence that the placenta ever suffers immune-mediated damage. Intrinsic placental 'insufficiency' is extremely rare and it is becoming increasingly clear that this clinical syndrome is usually due to a restricted supply of maternal oxygen and nutrients as a result of inadequate transformation of the spiral arteries into uteroplacental vessels. This failure of placentation represents an abnormality of the relationship between fetal and maternal tissues at a relatively early stage of pregnancy, and it is only by gaining a better understanding of this relationship that the problems posed by such conditions as pre-eclampsia and idiopathic intrauterine growth retardation will be answered.

Female↗

PubMed1995

[The location of the placenta in pregnant women with one or more past cesarean sections].

We examined 282 pregnant women who have had one or more previous cesarean sections. The localization of placenta was done with ultrasound after 32 weeks of gestation. The control group consists of 1560 pregnant women without previous operative births. Placenta praevia is found in 3.9% in patients with previous cesarean sections and in 0.45% in the control group. The bleeding in the group of placenta praevia after previous operative births is observed in 44.4% against 28.5% when the placenta praevia is in intact uterus. A significant dependence was found between the number of sections and the risk of placenta praevia and bleedings in the following pregnancy. Placenta praevia shows preference to the anterior uterine wall in 67% in scared uterus and in 33% in intact uterus. A very poor is the combination of febrile postoperative period with endometritis and very short interval to the next pregnancy. These conclusions are important for the prognosis and management of such pregnancies.

Adult↗

PubMed1998

A microscopical study of wound repair in the human placenta.

In order to fulfill its many functions as the selective interface between maternal and fetal circulations it is imperative that the human placenta remains intact and in good operational order. That damage of some sort occurs during its short but extremely active life seems inevitable given the dynamic environment in which the placenta exists, and evidence has accumulated that disruption is indeed a regular event. The implications of such damage, one could speculate, may impact on functions such as transport and hormone secretion as well as mutual protection against attack by maternal and fetal immune systems. Consequently, it would seem a theoretical necessity for discontinuities in the placenta surface to be repaired as soon as possible. We have used a combination of ex vivo observation, in vitro modelling, immunohistochemistry and correlative microscopy to provide evidence for a wound response in the placenta and to begin dissecting the detail of how this may operate. Evidence for small lesions caused by fusion and subsequent tearing of the syncytiotrophoblast in vivo, as well as plugging of such wounds by underlying cells is shown. We also identify a putative role for migratory cytotrophoblasts in the healing of larger scale injuries and demonstrate that certain molecules, common to wound repair in other tissues, appear to be involved in placenta repair also. Taken together these results clearly show that the human placenta is capable of a degree of self-maintenance by activating what appears to be an endogenous wound healing mechanism.

Chorionic Villi↗

PubMed2000

Manual removal of placenta at caesarean section.

BACKGROUND: Although manual removal of the placenta is commonly carried out, opinions differ about the best technique for delivery of the placenta at caesarean section. OBJECTIVES: The objective of this review was to assess the effects of manual removal of the placenta at caesarean section. SEARCH STRATEGY: We searched the Cochrane Pregnancy and Childbirth Group trials register. SELECTION CRITERIA: Randomised and quasi-randomised trials comparing manual removal of placenta to spontaneous separation and controlled cord traction for delivery in pregnant women undergoing elective or emergency caesarean section. DATA COLLECTION AND ANALYSIS: Trial quality assessment and data extraction were done by one reviewer. MAIN RESULTS: Three trials involving 224 women were included. The trials were of reasonable quality. Manual removal of the placenta was associated with a clinically important and statistically significant increase in maternal blood loss (weighted mean difference 436.35, 95% confidence interval 347.82 to 524.90). Manual removal was also associated with increased post-partum endometritis (odds ratio 5.44, 95% confidence interval 1.25 to 23.75) and a statistically non-significant trend towards an increase in feto maternal haemorrhage (odds ratio 2.19, 95% confidence interval 0.69 to 6.93). REVIEWER'S CONCLUSIONS: The evidence suggests that manual removal of the placenta at caesarean section may do more harm than good, by increasing maternal blood loss and increasing the risk of infection.

Cesarean Section↗

PubMed2003

Over-expression and secretion of angiogenin in intrauterine growth retardation placenta.

Human angiogenin is a potent inducer of neovascularization. There is a strong evidence to suggest that it might be involved in morphological and angiogenic changes in the placenta, that are necessary for a successful fetal outcome during pregnancy. However, its precise role in the pathogenesis of abnormal pregnancies is yet unknown. Intrauterine growth retardation (IUGR), an abnormal pregnancy is not a specific disease entity per se, but rather a manifestation of many possible fetal and maternal disorders. In this study, we demonstrated, for the first time, that placental explants in vitro secrete significantly elevated levels of angiogenin in placental tissues from patients with IUGR. We also observed enhanced mRNA expression in placenta from these patients. In addition, using the immunohistochemical methods, we observed identical staining of angiogenin to villous syncytiotrophobalst and fetal endothelial cells in both IUGR and normal placenta. Functionally active placental explants were used to detect immunoreactive angiogenin in conditioned media of all the samples from IUGR placenta and normal term group. The mean levels of angiogenin secreted by IUGR placenta were 1.4-, 1.6-, and 1.3-fold higher (P < 0.01) than normal term samples at 24, 48, and 72 hr of culture, respectively. Expression profiles of angiogenin from term and IUGR cases are in agreement with its mRNA levels and immunoblot analysis. In conclusion, the significant elevated levels of angiogenin in IUGR placenta may provide a molecular mechanism for the abnormal placental development.

Female↗

PubMed1995

Nonoverlapping expression of Cx43 and Cx26 in the mouse placenta and decidua: a pattern of gap junction gene expression differing from that in the rat.

We characterized the expression of two gap junction genes (Cx26 and Cx43) in the mouse decidua and placenta. In the decidua, in situ hybridization analysis and immunostaining studies revealed a high level of Cx43 expression. In contrast, Cx26 expression was not detected. Analysis of the placenta revealed that both Cx43 and Cx26 transcripts are expressed, but in nonoverlapping cell populations. Cx26 transcripts were observed only in the labyrinthine trophoblast layer of the placenta, a tissue of ectoplacental cone derivation. In contrast, no Cx43 transcripts were found in the placenta proper, but only in the maternally derived decidual cap covering the placenta. These results, in conjunction with previous observations in the mouse and rat, indicate that there may be species-specific differences in the pattern of Cx43/Cx26 expression in the placenta and decidua.

Animals↗

PubMed1976

An ultrahistochemical study of the distribution of acid and alkaline phosphatases in placentae from normal and complicated pregnancies.

The subcellular localisation of acid and alkaline phosphatase has been studied in the trophoblast of placentae from both normal and complicated pregnancies. In placentae from uncomplicated pregnancies the number of trophoblastic acid-phosphatase-containing organelles decreases progressively as gestation proceeds whilst alkaline-phosphatase activity, although abundant at term, could not be demonstrated during the early stages of pregnancy. The acid-phosphatase-containing organelles are of two types; one is a small round body which is probably a lysosome whilst the other is a multivesicular body. The alkaline phosphatase is distributed mainly on the syncytial microvilli and plasma-membrane. It is suggested that the marked lysosomal activity during early pregnancy is related to the architectural refashioning of the placenta during this period and that there are two phosphatase-linked transfer systems in the trophoblast, one dependent upon acid-phosphatase-containing multivesicular bodies and being utilised during early pregnancy and the other reliant upon alkaline phosphatase and dominating during the second half of gestation. In placentae from prolonged pregnancies there is a further decrease in trophoblastic acid phosphatase and, usually, a continuing increase in alkaline-phosphatase activity. In placentae from babies of low birth weight this trend is sometimes reversed and alkaline-phosphatase activity either disappears or its reaction product diffuses throughout the syncytium; this is usually accompanied by a marked increase in the number of acid-phosphatase-containing multivesicular bodies. Placentae from women with pre-eclampsia show no loss of alkaline-phosphatase activity but are characterised by an increased number of lysosomal bodies.

Acid Phosphatase↗

PubMed2007

Deep-hidden anastomoses in monochorionic twin placentae are harmless.

OBJECTIVES: Our objective was to identify the clinical consequences of deep-hidden anastomoses that occur underneath the placental surface. METHODS: Twelve placentae that underwent intrauterine laser ablation of placental anastomoses for twin-twin transfusion syndrome (TTTS) and 14 non-TTTS controls were investigated for deep-hidden anastomoses. Additionally, we investigated the inter-twin haemoglobin differences as an indicator for fetofetal transfusion. Placentae were divided into four groups: TTTS placentae without residual chorionic-plate anastomoses without deep-hidden anastomoses (group 1) and with deep-hidden anastomoses (group 2), and non-TTTS placentae with chorionic-plate anastomoses without deep-hidden anastomoses (group 3) and with deep-hidden anastomoses (group 4). RESULTS: Deep-hidden anastomoses were identified in 58% (7/12) of the TTTS placentae after laser surgery and in 64% (9/14) of the non-TTTS placentae. Groups 1 and 2 had equal inter-twin haemoglobin differences: medians 1.4 and 1.2 gr/dL, respectively (p = 0.48). In group 3, the median inter-twin haemoglobin difference without deep-hidden anastomoses was 2.6 gr/dL (group 3) and with deep-hidden anastomoses (group 4) it was 5.1 gr/dL (p = 0.26). CONCLUSION: Both comparisons imply that deep-hidden anastomoses did not cause any additional increase in Hb difference. In conclusion, haematological and additional hemodynamical analysis show that deep-hidden anastomoses are likely to occur without any clinical consequences.

Female↗