Ultrasonographic assessment of placental abnormalities

Placental lakes vs lacunae: spot the differences

Sonographic sonolucencies are anechoic areas surrounded by tissue of normal echogenicity, commonly found in the placental parenchyma during the second and third trimesters of pregnancy. The ultrasound appearance of lakes and lacunae derives from the low echogenicity of villous-free areas within the placental parenchyma, filled with maternal blood of varying velocities. In normal placentation, lakes usually start appearing as soon as maternal blood begins to flow freely within the intervillous space at the end of the first trimester, whereas, in accreta placentation, lacunae develop progressively during the second trimester. Larger lakes are found mainly in areas of lower villous density under the fetal plate or in the marginal areas, but can also be found in the center of a lobule above the entry of a spiral artery. Lakes of variable size, position and shape are of no clinical significance, except if they transform into echogenic cystic lesions, which have been associated with poor fetal growth and placental malperfusion. Lacunae are formed by the distortion of one or more placental lobules developing inside a uterine scar, resulting from high-volume, high-velocity flows from the radial/arcuate arteries, and are associated with a high probability of placenta accreta spectrum at birth. They often present with ultrasound signs of uterine remodeling following scarring. Lakes and lacunae can coexist within the same placenta and both will change in size and shape as pregnancy advances. Better understanding of the etiopathology of placental sonolucent spaces and associated morphological changes is necessary to identify patients at risk of subsequent complications during pregnancy and/or at delivery. © 2023 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Association of Pre-Pregnancy Obesity and COVID-19 with Poor Pregnancy Outcome

BACKGROUND AND OBJECTIVES

During the COVID-19 pandemic, a possible overlap of obesity and COVID-19 infection has raised concerns among patients and healthcare professionals about protecting pregnant women from developing a severe infection and unwanted pregnancy outcomes. The aim of this study was to evaluate the associations of body mass index with clinical, laboratory, and radiology diagnostic parameters as well as pregnancy complications and maternal outcomes in pregnant patients with COVID-19.

MATERIALS AND METHODS

Clinical status, laboratory, and radiology diagnostic parameters and pregnancy outcomes were analyzed for pregnant women hospitalized between March 2020 and November 2021 in one tertiary-level university clinic in Belgrade, Serbia, due to infection with SARS-CoV-2. Pregnant women were divided into the three sub-groups according to their pre-pregnancy body mass index. For testing the differences between groups, a two-sided p-value <0.05 (the Kruskal-Wallis and ANOVA tests) was considered statistically significant.

RESULTS

Out of 192 hospitalized pregnant women, obese pregnant women had extended hospitalizations, including ICU duration, and they were more likely to develop multi-organ failure, pulmonary embolism, and drug-resistant nosocomial infection. Higher maternal mortality rates, as well as poor pregnancy outcomes, were also more likely to occur in the obese group of pregnant women. Overweight and obese pregnant women were more likely to develop gestational hypertension, and they had a higher grade of placental maturity.

CONCLUSIONS

Obese pregnant women hospitalized due to COVID-19 infection were more likely to develop severe complications.

New insights into the etiopathology of placenta accreta spectrum

Placenta accreta has been described as a spectrum of abnormal attachment of villous tissue to the uterine wall, ranging from superficial attachment to the inner myometrium without interposing decidua to transmural invasion through the entire uterine wall and beyond. These descriptions have prevailed for more than 50 years and form the basis for the diagnosis and grading of accreta placentation. Accreta placentation is essentially the consequence of uterine remodeling after surgery, primarily after cesarean delivery. Large cesarean scar defects in the lower uterine segment are associated with failure of normal decidualization and loss of the subdecidual myometrium. These changes allow the placental anchoring villi to implant, and extravillous trophoblast cells to migrate, close to the serosal surface of the uterus. These microscopic features are central to the misconception that the accreta placental villous tissue is excessively invasive and have led to much confusion and heterogeneity in clinical data. Progressive recruitment of large arteries in the uterine wall, that is, helicine, arcuate, and/or radial arteries, results in high-velocity maternal blood entering the intervillous space from the first trimester of pregnancy and subsequent formation of placental lacunae. Recently, guided sampling of accreta areas at delivery has enabled accurate correlation of prenatal imaging data with intraoperative features and histopathologic findings. In more than 70% of samples, there were thick fibrinoid depositions between the tip of most anchoring villi and the underlying uterine wall and around all deeply implanted villi. The distortion of the uteroplacental interface by these dense depositions and the loss of the normal plane of separation are the main factors leading to abnormal placental attachment. These data challenged the classical concept that placenta accreta is simply owing to villous tissue sitting atop the superficial myometrium without interposed decidua. Moreover, there is no evidence in accreta placentation that the extravillous trophoblast is abnormally invasive or that villous tissue can cross the uterine serosa into the pelvis. It is the size of the scar defect, the amount of placental tissue developing inside the scar, and the residual myometrial thickness in the scar area that determine the distance between the placental basal plate and the uterine serosa and thus the risk of accreta placentation.

The role of noninvasive diagnostic imaging in monitoring pregnancy and detecting patients at risk for preterm birth: a review of quantitative approaches

Preterm birth (PTB) is the leading cause of neonatal morbidity and mortality worldwide. The ability to predict patients at risk for preterm birth remains a major health challenge. The currently available clinical diagnostics such as cervical length and fetal fibronectin may detect only up to 30% of patients who eventually experience a spontaneous preterm birth. This paper reviews ongoing efforts to improve the ability to conduct a risk assessment for preterm birth. In particular, this work focuses on quantitative methods of imaging using ultrasound-based techniques, magnetic resonance imaging, and optical imaging modalities. While ultrasound imaging is the major modality for preterm birth risk assessment, a summary of efforts to adopt other imaging modalities is also discussed to identify the technical and diagnostic limits associated with adopting them in clinical settings. We conclude the review by proposing a new approach using combined photoacoustic, ultrasound, and elastography as a potential means to better assess cervical tissue remodeling, and thus improve the detection of patients at-risk of PTB.

Value of ultrasound scoring system for assessing risk of pernicious placenta previa with accreta spectrum disorders and poor pregnancy outcomes

PURPOSE

To evaluate a system for assessing the risk of pernicious placenta previa (PPP) with placenta accreta spectrum (PAS) disorders and poor pregnancy outcomes.

METHODS

This prospective study focused on PPP women at ≥ 28 weeks' pregnancy. Transabdominal or transvaginal ultrasonography was used to assess PAS and poor pregnancy outcomes with a system involving uteroplacental demarcation, number and size of lacunae, bladder line, and placental basal and lacunae flow. Every item was assigned 0-2 points, and the sum yielded the final score. Diagnosis of PAS was based on surgery or pathology. One or more of postpartum hemorrhage (PPH) ≥ 1000 ml, hysterectomy, and organ invasion were regarded as a poor pregnancy outcome. Receiver operating characteristic (ROC) curves were generated.

RESULTS

Fifty-one PPP women were included, with 70.6% having PAS and 75.0% of PAS women having a poor pregnancy outcome. The incidence of PAS diagnosis was 36.4% for those with a score < 5 points, with 0% having a poor outcome; 76.5% for those with a score ≥ 5 to < 8 points, with 61.5% having a poor outcome; and 100% for those with a score ≥ 8 points, with 100% having a poor pregnancy outcome.

CONCLUSION

The system for predicting PPP with PAS and poor pregnancy outcomes was of high accuracy.

Case Series of Intrauterine Subamniotic Hemorrhage

We present here 9 cases of intrauterine subamniotic hemorrhage to describe the pathological sequence. The definite diagnosis of subamniotic hemorrhage was mainly made macroscopically with the presence of hemorrhage or hematoma wrapped in the membrane on the fetal surface by postnatal examining of the placenta. In 7 of them (78%), the presence of gradual subamniotic hemorrhage in the second trimester of pregnancy was suspected. In the cases, severe fetal growth restriction and preterm delivery were recognized in 2 (29%) and 4 cases (57%), respectively. In the other 2 cases (22%), acute anemia associated with acute subamniotic hemorrhage was clinically suspected. This may be the first report examining the clinical characteristics of acute or gradual intrauterine subamniotic hemorrhage. Both patterns of subamniotic hemorrhage seemed to be associated with the adverse perinatal outcomes.

MRI evaluation of the placenta from normal variants to abnormalities of implantation and malignancies

Even though the placenta has been known for millennia, it is still considered one of the most complex and least understood human organs. Imaging of the placenta is gaining attention due to its impact on fetal and maternal outcomes. MRI plays a vital role in evaluation of inconclusive cases by ultrasonography. It enables precise mapping of placental abnormalities for proper multidisciplinary planning and management. In this article we provide a comprehensive in-depth review of the role of antenatal MR in evaluating "The Placenta." We will describe the protocols and techniques used for MRI of the placenta, review anatomy of the placenta, describe MRI features of major placental abnormalities including those related to position, depth of implantation, hemorrhage, gestational trophoblastic neoplasia, and retained products of conception and discuss the added value of MRI in the management and preoperative planning of such abnormalities. Level of Evidence: 3 Technical Efficacy Stage: 5 J. Magn. Reson. Imaging 2019;50:1702-1717.

Pregnancy complications and adverse outcomes in placental chorioangioma: a retrospective cohort analysis

Objective: To measure the relative risk of pregnancy complications and adverse outcomes in women with placental chorioangioma, and postnatal developmental deficiencies in their offspring.Methods: We designed a retrospective cohort study using records from 140,387 pregnancies at our hospital between 1 January, 2008 and 1 July, 2017. Follow-up of children in the placental chorioangioma group was conducted by phone interview.Results: Placental chorioangioma was diagnosed in 56 patients (incidence = 0.04%). Fifty-one cases were detected during routine prenatal ultrasound. Placental chorioangioma patients were at increased risk for fetal loss or induced abortion (RR = 9.93, 95% CI [4.66, 21.20]), preterm birth (n = 13, RR = 2.45, 95% CI [1.52, 3.95]), birth by cesarean section (n = 45, RR = 1.62, 95% CI [1.42, 1.84]), and polyhydramnios (n = 9, RR = 9.98, 95% CI [5.48, 18.18]), but not fetal distress (n = 5, RR = 0.49, 95% CI [0.22, 1.15]) or preeclampsia (n = 5, RR = 1.61, 95% CI [0.70, 3.73]), although there was an increased risk for preeclampsia after controlling for preterm birth (n = 3, RR = 3.6, 95% CI [1.33, 9.74]). No developmental complications were reported in offspring.Conclusion: Placental chorioangioma increases the risk of fetal demise, pregnancy complications and adverse outcomes. In cases with mild complications or when early cesarean termination of pregnancy is feasible, the prognosis is excellent.

Pathophysiology of placental-derived fetal growth restriction

Placental-related fetal growth restriction arises primarily due to deficient remodeling of the uterine spiral arteries supplying the placenta during early pregnancy. The resultant malperfusion induces cell stress within the placental tissues, leading to selective suppression of protein synthesis and reduced cell proliferation. These effects are compounded in more severe cases by increased infarction and fibrin deposition. Consequently, there is a reduction in villous volume and surface area for maternal-fetal exchange. Extensive dysregulation of imprinted and nonimprinted gene expression occurs, affecting placental transport, endocrine, metabolic, and immune functions. Secondary changes involving dedifferentiation of smooth muscle cells surrounding the fetal arteries within placental stem villi correlate with absent or reversed end-diastolic umbilical artery blood flow, and with a reduction in birthweight. Many of the morphological changes, principally the intraplacental vascular lesions, can be imaged using ultrasound or magnetic resonance imaging scanning, enabling their development and progression to be followed in vivo. The changes are more severe in cases of growth restriction associated with preeclampsia compared to those with growth restriction alone, consistent with the greater degree of maternal vasculopathy reported in the former and more extensive macroscopic placental damage including infarcts, extensive fibrin deposition and microscopic villous developmental defects, atherosis of the spiral arteries, and noninfectious villitis. The higher level of stress may activate proinflammatory and apoptotic pathways within the syncytiotrophoblast, releasing factors that cause the maternal endothelial cell activation that distinguishes between the 2 conditions. Congenital anomalies of the umbilical cord and placental shape are the only placental-related conditions that are not associated with maldevelopment of the uteroplacental circulation, and their impact on fetal growth is limited.

Placenta accreta spectrum: pathophysiology and evidence-based anatomy for prenatal ultrasound imaging

Placenta accreta spectrum is a complex obstetric complication associated with high maternal morbidity. It is a relatively new disorder of placentation, and is the consequence of damage to the endometrium-myometrial interface of the uterine wall. When first described 80 years ago, it mainly occurred after manual removal of the placenta, uterine curettage, or endometritis. Superficial damage leads primarily to an abnormally adherent placenta, and is diagnosed as the complete or partial absence of the decidua on histology. Today, the main cause of placenta accreta spectrum is uterine surgery and, in particular, uterine scar secondary to cesarean delivery. In the absence of endometrial reepithelialization of the scar area the trophoblast and villous tissue can invade deeply within the myometrium, including its circulation, and reach the surrounding pelvic organs. The cellular changes in the trophoblast observed in placenta accreta spectrum are probably secondary to the unusual myometrial environment in which it develops, and not a primary defect of trophoblast biology leading to excessive invasion of the myometrium. Placenta accreta spectrum was separated by pathologists into 3 categories: placenta creta when the villi simply adhere to the myometrium, placenta increta when the villi invade the myometrium, and placenta percreta where the villi invade the full thickness of the myometrium. Several prenatal ultrasound signs of placenta accreta spectrum were reported over the last 35 years, principally the disappearance of the normal uteroplacental interface (clear zone), extreme thinning of the underlying myometrium, and vascular changes within the placenta (lacunae) and placental bed (hypervascularity). The pathophysiological basis of these signs is due to permanent damage of the uterine wall as far as the serosa, with placental tissue reaching the deep uterine circulation. Adherent and invasive placentation may coexist in the same placental bed and evolve with advancing gestation. This may explain why no single, or set combination of, ultrasound sign(s) was found to be specific for the depth of abnormal placentation, and accurate for the differential diagnosis between adherent and invasive placentation. Correlation of pathological and clinical findings with prenatal imaging is essential to improve screening, diagnosis, and management of placenta accreta spectrum, and standardized protocols need to be developed.

Prediction of morbidly adherent placenta using a scoring system

OBJECTIVE

To evaluate the accuracy of an ultrasound-based scoring system for diagnosing morbidly adherent placenta (MAP).

METHODS

This study included pregnant women referred to our ultrasound unit during 2013-2015 because of suspected MAP on a previous ultrasound examination or because they had at least one previous Cesarean delivery. All women were assessed using a scoring system based on the following: number and size of placental lacunae; obliteration of the demarcation between the uterus and placenta; placental location; color Doppler signals within placental lacunae; hypervascularity of the placenta-bladder and/or uteroplacental interface zone; and number of previous Cesarean deliveries. Each criterion was assigned 0, 1 or 2 points and the sum of points yielded the final score. Patients were classified into low, moderate or high probability for MAP based on the final score. The presence of MAP was determined by the surgeon at delivery and clinical descriptions were documented in the electronic patient file. Pathological diagnoses were available only in cases that underwent hysterectomy.

RESULTS

In total, 258 pregnant women were included in the study, of whom 23 (8.9%) were diagnosed with MAP. There was a statistically significant difference in the prevalence of MAP when women were grouped according to the scoring system, with 0.9%, 29.4% and 84.2% in the low, moderate and high probability groups, respectively (P < 0.0001). All sonographic criteria of the scoring system were significantly associated with MAP (P < 0.0001). Receiver-operating characteristics (ROC) curves for prediction of MAP using the number of placental lacunae and obliteration of the uteroplacental demarcation yielded an area under the ROC curve of 0.94 (95% CI, 0.86-1.00).

CONCLUSIONS

Our proposed scoring system is highly predictive of MAP in patients at risk. This allows an adequate multidisciplinary team approach for the planning and timing of delivery in such cases. Copyright © 2015 ISUOG. Published by John Wiley & Sons Ltd.

Placental tumor (chorioangioma) as a cause of polyhydramnios: a case report

Placental chorioangioma is the most common type of placental tumor. It is usually symptomless and may be associated with serious maternal and fetal complication when it reaches a large size. We presented a case of an angiomatous type of placental hemangioma diagnosed in the second trimester of pregnancy in a patient with polyhydramnios. A normal volume of amniotic fluid was successfully achieved by three amnioreductions with conservative management. The size of the placental tumor remained the same from the time of diagnosis to the end of pregnancy. A term labor was uncomplicated and a healthy newborn was delivered. Macroscopic and microscopic examination of the placenta confirmed the diagnosis. Despite the rarity of placental tumors, they should be considered as differential diagnosis in cases of polyhydramnios.

Prenatal diagnosis of a placental infarction hematoma associated with fetal growth restriction, preeclampsia and fetal death: clinicopathological correlation

The lesion termed 'placental infarction hematoma' is associated with fetal death and adverse perinatal outcome. Such a lesion has been associated with a high risk of fetal death and abruption placentae. The fetal and placental hemodynamic changes associated with placental infarction hematoma have not been reported. This paper describes a case of early and severe growth restriction with preeclampsia, and progressive deterioration of the fetal and placental Doppler parameters in the presence of a placental infarction hematoma.

An epidemiological study investigating the relationship between chorangioma and infantile hemangioma

OBJECTIVES

This study aimed to verify whether the infantile hemangioma (IH) incidence in children whose placentas showed a chorangioma is higher than in the general population, thus addressing the hypothesized relationship between chorangioma and IH.

METHODS

All chorangioma diagnoses by the 1st Service of Pathology, University of Padova in 2004-2010, based on the analysis of placentas sent by the Department of Gynecological Sciences and Human Reproduction (University of Padova), were identified. Demographic, anamnestic and clinical data were collected from the mothers and newborns; mothers and pediatricians were interviewed by telephone within 1 year after birth to verify if any IH appeared. The incidence rates of IH and other adverse events (IUGR, preterm delivery, cesarean section, stillbirth) were compared with national and regional data, when available, or with estimates from the scientific literature.

RESULTS

Thirty-eight chorangioma diagnoses were found. Of 33 infants born with a placenta affected by chorangioma, 18 infants had IH. The IH incidence recorded in our series (55%) was significantly higher than that recorded in national and regional surveys and in the scientific literature. Similar findings have been observed for the incidence of stillbirth, preterm birth and low birth weight incidence.

CONCLUSIONS

The IH incidence observed in our series appears to be significantly higher than that recorded among the general population, suggesting that an association between placental chorangioma and IH could exist which should be further verified in prospective studies.

Non-invasive prenatal testing for aneuploidy: current status and future prospects

Non-invasive prenatal testing (NIPT) for aneuploidy using cell-free DNA in maternal plasma is revolutionizing prenatal screening and diagnosis. We review NIPT in the context of established screening and invasive technologies, the range of cytogenetic abnormalities detectable, cost, counseling and ethical issues. Current NIPT approaches involve whole-genome sequencing, targeted sequencing and assessment of single nucleotide polymorphism (SNP) differences between mother and fetus. Clinical trials have demonstrated the efficacy of NIPT for Down and Edwards syndromes, and possibly Patau syndrome, in high-risk women. Universal NIPT is not cost-effective, but using NIPT contingently in women found at moderate or high risk by conventional screening is cost-effective. Positive NIPT results must be confirmed using invasive techniques. Established screening, fetal ultrasound and invasive procedures with microarray testing allow the detection of a broad range of additional abnormalities not yet detectable by NIPT. NIPT approaches that take advantage of SNP information potentially allow the identification of parent of origin for imbalances, triploidy, uniparental disomy and consanguinity, and separate evaluation of dizygotic twins. Fetal fraction enrichment, improved sequencing and selected analysis of the most informative sequences should result in tests for additional chromosomal abnormalities. Providing adequate prenatal counseling poses a substantial challenge given the broad range of prenatal testing options now available.

High-output cardiac failure in a fetus with thanatophoric dysplasia associated with large placental chorioangioma: case report

Placental chorioangioma is an angioma arising from chorionic tissue. Fetal thanatophoric dysplasia is a lethal skeletal dysplasia due to mutation of fibroblast growth factor receptor 3 gene. These two conditions are rare and their coexistence in a given fetus is even rarer. We present a case of a fetus with thanatophoric dysplasia having high-output cardiac failure due to a large placental chorioangioma.

A case of a huge placental lake; prenatal differential diagnosis and clinical management

Placental lakes are sonolucent or hypoechoic areas in images of the placenta, usually considered a physiological dilation of intervillous space with a rather good obstetrical outcome. However, diagnostic criteria for and the clinical significance of placental lakes are yet to be completely established, because of a wide variety of ultrasound findings, especially on color Doppler examination. We experienced a case of a huge placental lake, larger than the total placental area, located in an entire retroplacental space, concomitant with several penetrations of artery type blood flow. The antenatal differential diagnosis and course of clinical management are reported.

No correlation between ultrasound placental grading at 31-34 weeks of gestation and a surrogate estimate of organ function at term obtained by stereological analysis

We test the experimental hypothesis that early changes in the ultrasound appearance of the placenta reflect poor or reduced placental function. The sonographic (Grannum) grade of placental maturity was compared to placental function as expressed by the morphometric oxygen diffusive conductance of the villous membrane. Ultrasonography was used to assess the Grannum grade of 32 placentas at 31-34 weeks of gestation. Indications for the scans included a history of previous fetal abnormalities, previous fetal growth problems or suspicion of IUGR. Placentas were classified from grade 0 (most immature) to grade III (most mature). We did not exclude smokers or complicated pregnancies as we aimed to correlate the early appearance of mature placentas with placental function. After delivery, microscopical fields on formalin-fixed, trichrome-stained histological sections of each placenta were obtained by multistage systematic uniform random sampling. Using design-based stereological methods, the exchange surface areas of peripheral (terminal and intermediate) villi and their fetal capillaries and the arithmetic and harmonic mean thicknesses of the villous membrane (maternal surface of villous trophoblast to adluminal surface of vascular endothelium) were estimated. An index of the variability in thickness of this membrane, and an estimate of its oxygen diffusive conductance, were derived secondarily as were estimates of the mean diameters and total lengths of villi and fetal capillaries. Group comparisons were drawn using analysis of variance. We found no significant differences in placental volume or composition or in the dimensions or diffusive conductances of the villous membrane. Subsequent exclusion of smokers did not alter these main findings. Grannum grades at 31-34 weeks of gestation appear not to provide reliable predictors of the functional capacity of the term placenta as expressed by the surrogate measure, morphometric diffusive conductance.

Ultrasound of the placenta: a systematic approach. Part I: Imaging

Diagnostic ultrasound has been in use in clinical obstetrics for close to half-a-century. However, in the literature, examination of the placenta appears to be treated with less attention than the fetus or the pregnant uterus. This is somewhat unexpected, given the obvious major functions this organ performs during the entire pregnancy. Examination of the placenta plays a foremost role in the assessment of normal and abnormal pregnancies. A methodical sonographic evaluation of the placenta should include: location, visual estimation of the size (and, if appearing abnormal, measurement of thickness and/or volume), implantation, morphology, anatomy, as well as a search for anomalies, such as additional lobes and tumors. Additional assessment for multiple gestations consists of examining the intervening membranes (if present). The current review considers the various placental characteristics, as they can be evaluated by ultrasound, and the clinical significance of abnormalities of these features. Numerous and varied pathologies of the placenta can be detected by routine ultrasound. It is incumbent on the clinician performing obstetrical ultrasound to examine the placenta in details and in a methodical fashion because of the far reaching clinical significance and potentially avoidable severe consequences of many of these abnormalities.

Prenatal Diagnosis of a Large Subchorionic Placental Cyst with Intracystic Hematomas

A large intrauterine cyst containing a heterogenous mass was found by ultrasound in the placenta of a 35-year-old gravida 2 para 1 woman. The cyst, measuring 10.9 x 10.1 cm with a heterogenous mass shadow, was attached near the placental cord insertion site. The woman delivered a healthy female baby weighing 3,330 g by cesarean section without complication. A histopathological examination revealed that the lesion was a subchorionic cyst and contained an internal hematoma. Large subchorionic cysts are extremely rare, and secondary hemorrhage within the cyst has not been reported. In this article, we report the case of a woman with a large subchorionic cyst complicated by an intracystic hematoma and review its clinical significance.

A prospective study of ultrasound screening for molar pregnancies in missed miscarriages

OBJECTIVE

To examine the relationship between ultrasound and histological features in the screening for molar changes in missed miscarriage.

METHODS

A prospective cohort study was conducted on all missed miscarriages, with features suspicious of molar pregnancy, on transvaginal ultrasound and/or on histological examination over a 5-year period. All cases of molar pregnancy diagnosed histologically were examined and cross-referenced with cases diagnosed on ultrasound and with the supplementary report from the regional referral center. When available, maternal serum beta-human chorionic gonadotropin (hCG) levels were recorded.

RESULTS

Fifty-one cases of suspected molar pregnancy were referred to the regional center for further histological opinion and follow-up, and five cases were subsequently excluded from the final analysis because of the diagnosis of hydropic abortion (HA). In 33 cases a molar pregnancy was suspected at the initial scan. Of these, 26 (78.8%) were confirmed on histology, resulting in a 56% detection rate using ultrasound alone. In 15 cases hCG results were available, of which nine were greater than two multiples of the median.

CONCLUSIONS

The diagnosis of both complete (CHM) and partial (PHM) hydatidiform moles in first-trimester miscarriages is difficult. hCG is significantly higher in both CHM and PHM and, in conjunction with transvaginal ultrasound, could provide the screening test required to enable clinicians to counsel women more confidently towards non-surgical methods of management of their miscarriage, where histopathological examination is not available.

Magnetic resonance image findings of placental lake: report of two cases

Two cases with a large cystic mass within the placenta are reported. By ultrasonography, it was found that both women had a subchorionic hypoechoic lesion (11.0 x 4.8 x 4.0 cm and 6.6 x 3.7 x 2.2 cm, respectively) at 24 and 35 weeks of gestation, respectively. In both cases, turbulent blood flow generated by a pulsatile jet flow (pulse rate; 40 to 60 beats per minute) into the cystic lesion seen on real-time imaging and lesions being low intensity on T1-weighted and isointensity on T2-weighted magnetic resonance image suggested that they contained fresh maternal blood. In both cases, the sonolucency of the lesions did not change until cesarean deliveries of females, both of whom were small-for-gestational-age infants (1940 g at 37 weeks and 2195 g at 37 weeks, respectively). Biochemical analysis of the fluid in the cystic lesion sampled during the cesarean section in the latter case confirmed that the fluid had originated from the maternal blood. These lesions histologically corresponded to large avillous areas surrounded by normal villi. Thus, a huge placental lake was diagnosed in both cases.

Trophoblastic oxidative stress in relation to temporal and regional differences in maternal placental blood flow in normal and abnormal early pregnancies

Onset of the maternal-placental circulation was studied by Doppler ultrasonography in 65 pairs of age-matched normal and abnormal pregnancies. In normal pregnancies intervillous blood flow increased with gestational age, being detected in 9 of 25 cases at 8 to 9 weeks but in 18 of 20 at 12 to 13 weeks (P = 0.001). By contrast, in abnormal pregnancies flow was detected in nearly all cases (22 of 25) at 8 to 9 weeks (P < 0.001). In addition, regional differences were observed between the groups. Early flow was restricted to the peripheral regions of most normal placentas (P < 0.001), whereas in missed miscarriages it was most common in central regions or throughout the placenta (P < 0.05 and P < 0.001, respectively). Immunoreactivity for heat shock protein 70 and nitrotyrosine residues was greater in samples from peripheral than from central regions of normal placentas (P = 0.028 and P = 0.019, respectively), and from missed miscarriages compared to controls (P = 0.005 and P = 0.001, respectively). Our results indicate that oxidative damage to the trophoblast, induced by premature and widespread onset of the maternal placental circulation secondary to shallow trophoblast invasion, is a key factor in early pregnancy loss. High oxygen concentrations in the periphery of normal early placentas may similarly induce local regression of the villi, leading to formation of the chorion laeve.

Are placental lakes of any clinical significance?

The aim of this study was to determine prospectively whether an association exists between the finding of placental lakes at the 20 week scan and an increased risk of uteroplacental complications or a poor pregnancy outcome. We studied the placental appearances in 1,198 consecutive second trimester ultrasound scans performed for routine foetal abnormality screening at our institution. The placental thickness was measured at its widest diameter in the sagittal plane and the presence or absence of placental lakes was recorded. The birth weight in each case was plotted against the centile charts in use at the hospital and recorded. Specific outcome measures included foetal growth restriction (IUGR) with a birth weight below the 5th centile, pre-eclampsia, placental abruption, and perinatal deaths. Placental lakes were seen in 17.8 per cent of the scans. There was no significant association with either maternal socio-demographic factors or perinatal mortality (OR 0.94, 95 per cent CI 0.35-2.51). No association was seen with maternal cigarette smoking (OR 1.07, 95 per cent CI 0.75-1.52), a birth weight below the 5th centile (OR 0.68, 95 per cent CI 0.39-1.18), the development of pregnancy induced hypertension (OR 0.68, 95 per cent CI 0.35-1.32), severe pre-eclampsia (OR 0.72, 95 per cent CI 0.21-2.50), or placental abruption (OR 1.79, 95 per cent CI 0.46-6.99). A finding of placental lakes was six times more likely with a thick placenta >3 cm at 20 weeks gestation (OR 6.30, 95 per cent CI 4.39 to 9.05). A finding of placental lakes during the second trimester ultrasound scan does not appear to be associated with uteroplacental complications or an adverse pregnancy outcome. The lesions are more prevalent with increasing placental thickness.

Role of color Doppler imaging in diagnosing and managing pregnancies complicated by placental chorioangioma

PURPOSE

The purpose of this study was to evaluate the role of color Doppler imaging in the diagnosis and management of placental chorioangioma.

METHODS

The medical records, sonographic reports, and sonograms of all pregnant women who had placental masses diagnosed in our sonography unit during the years 1992 through 2000 and had been evaluated using both gray-scale and color Doppler sonography were included in this study. Subjective evaluation of the amount and distribution of intralesional vascularity by color Doppler imaging was made in all cases. Cases of chorioangioma of the placenta were compared with cases of placental hemorrhage or subchorionic hematoma. The outcomes of the pregnancies were also recorded.

RESULTS

Fifteen cases of placental masses were evaluated; 8 of them were identified as placental hemorrhage or subchorionic hematoma on the basis of the sonographic findings. The other 7 cases were identified prenatally as placental chorioangioma, at a mean menstrual age of 23 weeks and a mean maternal age of 29 years. The mean size of the tumor was 6.5 cm (range, 4-13 cm). All cases of chorioangioma showed either substantial internal vascularity or a large feeding vessel within the tumor. Three infants were delivered at term with favorable outcome; 2 of them demonstrated reduction of the intratumoral blood flow during follow-up. The other 4 cases were delivered at or before 32 weeks' menstrual age (1 intrauterine fetal death, 2 terminated pregnancies, and 1 normal infant). No case of placental hematoma demonstrated blood flow within the lesion or was associated with complications of the pregnancy.

CONCLUSIONS

Color Doppler imaging helps differentiate placental chorioangioma from other placental lesions and may be useful in the prenatal follow-up of chorioangioma.

Second trimester maternal serum analytes in triploid pregnancies: correlation with phenotype and sex chromosome complement

Second trimester maternal serum alpha-fetoprotein (MS-AFP), human chorionic gonadotrophin (hCG), unconjugated estiol (uE3), and inhibin-A (INH-A) levels were evaluated in pregnancies complicated by triploidy. In addition to seven new triploid pregnancies, the results for 67 published cases were reviewed. All cases appear to fall into two major groups. First, those identifiable as screen-positive for both Down syndrome and an open neural tube defect (ONTD) with elevated MS-AFP, grossly elevated hCG, low/normal uE3, and probably elevated INH-A. Pregnancies in the second group are identifiable as screen-positive for trisomy 18 with low/normal MS-AFP, and very low hCG, uE3 and INH-A. Triploid pregnancies with high maternal serum hCG nearly always show a placenta with partial mole (25/27 or 93%), a high frequency of ONTDs or ventral wall defects (VWDs) (8/28 or 29%) and have either an XXX or XXY karyotype (observed ratio 6:10, respectively). Low hCG is infrequently associated with a molar placenta (1/11 or 9%), does not appear to be associated with ONTDs or VWDs (0/29 or 0%), and shows an excess of XXX over XXY karyotypes (observed ratio 17:2). There were 16 cases with either a molar placenta, an ONTD or a VWD that received the MS-AFP and hCG tests. All 16 were screen-positive for an ONTD (MS-AFP> or =2 multiples of the median). In addition, all 31 cases that received MS-AFP, hCG, uE3 (and where available INH-A) were screen-positive for either Down syndrome or trisomy 18. The findings are discussed in the context of expected differences between digynic and diandric triploidy. It is suggested that the sex chromosome complement in triploidy is an important factor in determining risk for partial mole development and in utero survival.

Prenatal diagnosis of solid placental masses: the value of color flow imaging

OBJECTIVES

To determine the value of color flow imaging in the prenatal differentiation of solid placental masses protruding from the fetal surface of the placenta.

METHODS

Seven pregnancies in which a large solid mass was seen on the fetal surface of the placenta were prospectively studied. Color flow imaging was used to identify vessels within the mass and the prenatal ultrasound finding correlated with placental pathology.

RESULTS

Postpartum examination of the placenta revealed four cases of chorioangioma, two cases of subchorionic thrombohematoma and one case of subamniotic hematoma. Prenatal ultrasound using color flow imaging correctly identified all cases of placental chorioangioma by the demonstration of blood flow within the mass. Conversely, absence of blood flow signals was invariably documented in both cases of subchorionic thrombohematoma and in the single case of subamniotic hematoma. Among the four cases of chorioangioma, two developed complications requiring delivery. No complications were noted in cases of avascular placental masses in this series.

CONCLUSIONS

Color Doppler ultrasound plays an important role in the prenatal evaluation of solid placental masses. This technique allows the identification of those cases at increased risk of pregnancy complications which need close monitoring throughout gestation.

Maternal circulation in the first-trimester human placenta--myth or reality?

The classic theory of development of the uteroplacental and intervillous circulation determined that maternal blood enters the intervillous space in high-pressure streams from the early first trimester. This theory has recently been challenged and our hypothesis to be presented is that the intervillous circulation is not fully established until the end of the first trimester. Ex vivo studies of hysterectomy specimens have demonstrated that trophoblastic plugs obstruct blood flow into the intervillous space in early pregnancy and only at 12 to 13 weeks do these plugs become loose and allow for continuous maternal blood flow into the intervillous space. This concept is supported by many other experimental findings. In complicated early pregnancies the uteroplacental circulation demonstrates flow characteristics that are strikingly different from those of normal early pregnancies. In abnormal pregnancies increased flow within the intervillous space is demonstrated by color Doppler imaging. Our hypothesis supports other studies that have shown that the embryo favors an environment low in oxygen during early development and that oxygen levels in placental tissue are low in the early first trimester. The classic drawing of placental circulations is based on second- and third-trimester studies, and its applicability to the early first trimester should be revisited because we will show that new data support the hypothesis that the development of the early intervillous circulation is a progressive phenomenon.

Fetal and neonatal haemodilution associated with multiple placental chorioangioma: case report

A pregnancy with polyhydramnios and abnormal antepartum fetal heart rate pattern was found to have multiple placental haemangiomas. Multiple placental haemangiomas can give rise to fetal cardiac failure due to a hyperdynamic circulation or fetal anaemia either due to haemodilution or possibly destruction of blood cells in the chorioangioma. Whether fluid restriction with or without diuretics or blood transfusion is the correct form of treatment of neonatal cardiac failure in such a case is discussed.

Sonographic, stereological and Doppler flow velocimetric assessments of placental maturity

OBJECTIVE

To determine whether sonographic assessments of increasing placental maturity are associated with changes in the theoretical diffusing capacity of the organ and with changes in vascular resistance.

DESIGN

Placental maturity was assessed sonographically in 10 organs: five were classified as completely immature and five as completely mature. Doppler flow velocimetric recordings were obtained shortly before delivery performed by elective caesarean section. Placental biopsies taken immediately after delivery were analysed stereologically.

RESULTS

No differences were observed in either placental weight or volume, but the morphometric diffusing capacity of the villous membrane was 40% higher in the mature than in the immature placentas. Doppler indices did not alter with increasing placental maturity.

CONCLUSIONS

Normal term placentas differ significantly in their diffusion characteristics, even when organ weight and volume remain constant. Umbilical vascular resistance may be heavily influenced by the number of parallel circulatory units offered by the placental lobules.

Placental vascular malformation with mesenchymal hyperplasia and a localized chorioangioma. A rarity simulating partial mole

We here report a case of placental vascular malformation with mesenchymal hyperplasia of the villi and a localized chorioangioma. After an uneventful pregnancy our patient delivered a non-malformed live female infant. The placenta was grossly enlarged, and macroscopically it was characterized by strongly enlarged varicous chorionic vessels. On the maternal plate vesicle-like structures, giving the impression of partial mole, were seen. At microscopy level, areas of normal looking tissue alternated with areas of excessively enlarged villi, in which the ground substance contained large amounts of acid mucopolysaccharide, corresponding to "mesenchymal hyperplasia". Moreover, a localized chorioangioma was found. In none of the histological sections were cisterns, abnormal trophoblastic proliferation, stunted ramification or stromal trophoblastic inclusions observed. In week 15 maternal se-AFP was elevated to 3.03 multiples of the median. Genetic analyses revealed a normal female karyotype and biparental genomic contributions to 7 unlinked loci. Placental vascular malformation with mesenchymal hyperplasia is a differential diagnosis to partial mole which should be considered when vesicle like placental enlargement is observed along with a living fetus.

Absent umbilical artery diastolic flow in a fetus with a partial mole at 18 weeks' gestation

We present a case in which Doppler velocimetry of the umbilical artery in a fetus with a partial mole at 18 weeks' gestation revealed absent diastolic flow. To the best of our knowledge, this is the first report of Doppler velocimetry of the umbilical artery in this rare condition. Increased placental resistance in this abnormal placenta may explain this finding.

Transvaginal Color Doppler Ultrasonography in the Evaluation of Placental Circulation

Transvaginal color Doppler sonography has provided the capability to qualitatively evaluate blood flow in small branches of the uterine arteries, umbilical cord arteries, and intraplacental fetal arteries in early pregnancy. Accurate identification of these small vessels and analysis of their flow characteristics have improved our understanding of the physiology and pathophysiology of early pregnancy that alters the umbilicaluteroplacental circulations. Further development of this technique may help to predict fetal outcome in highrisk pregnancies and in pregnancies with complications, such as intrauterine growth retardation, preeclampsia, and trophoblastic invasion.