Magnetic resonance imaging of the supra-cervical fetal membrane detects an increased risk of prelabor rupture of membranes.

Objective: In 10% of term deliveries and 40% of preterm deliveries, the fetal membrane (FM) ruptures before labor. However, the ability to predict these cases of premature rupture of membranes (PROM) and preterm premature rupture of membranes (PPROM) is very limited. In this paper, our objective was to determine whether a prediction method based on T2 weighted magnetic resonance imaging (MRI) of the supra-cervical FM could predict PROM and PPROM. Methods: This prospective cohort study enrolled 77 women between the 28th and 37th weeks of gestation. Two indicators of fetal membrane defects, including prolapsed depth >5 mm and signal abnormalities, are investigated for our prediction. Fisher's exact test was used to determine whether prolapsed depth >5 mm and/or signal abnormalities were associated with PROM and PPROM. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were calculated for prolapsed depth >5 mm, signal abnormalities, and the combination of prolapsed depth >5 mm and signal abnormalities. Result: Among 12 women with PROM (5 preterm and 7 term, prior to labor onset), 9 had membrane prolapse >5 mm and 5 had FM signal abnormalities. Among 65 women with rupture of membranes at term, 2 had membrane prolapse >5 mm and 1 had signal abnormalities. By Fisher's exact test both indicators, membrane prolapse >5 mm and signal abnormalities, were associated with PROM (P<0.001, P<0.001) and PPROM (P=0.001, P<0.001). Additionally, membrane prolapse >5 mm, signal abnormalities, and the combination of the two indicators all demonstrated high specificity for predicting PROM (96.9%, 98.5%, and 100%, respectively) and PPROM (90.3%, 97.2%, and 100%, respectively). Conclusion: MRI can distinguish the supra-cervical fetal membrane in vivo and may be able to identify women at high risk of PPROM.

Managing Reproduction Emergencies in the Field: Part 2: Parturient and Periparturient Conditions.

Selected conditions affecting broodmares are discussed, including arterial rupture, dystocia, foal support with ex utero intrapartum treatment, uterine prolapse, postpartum colic, the metritis/sepsis/systemic inflammatory response syndrome complex, and retained fetal membranes. Postpartum colic beyond third-stage labor contractions should prompt comprehensive evaluation for direct injuries to the reproductive tract or indirect injury of the intestinal tract. Mares with perforation or rupture of the uterus are typically recognized 1 to 3 days after foaling, with depression, fever, and leukopenia; laminitis and progression to founder can be fulminant. The same concerns are relevant in mares with retention of fetal membranes.

Intermembrane distances at the feto-maternal interface in epitheliochorial placentation.

INTRODUCTION: In an epitheliochorial placenta, the apical membranes of trophoblast cells and of uterine epithelial cells are in contact to each other (feto-maternal contact). In addition, there are also folds in which the trophoblast membrane is in contact with itself (feto-fetal contact) and areas where apical uterine epithelial membrane is in contact with itself (materno-maternal contact). METHODS: We use transmission electron microscopy of placental samples from pigs. (n = 3), cows (n = 2), sheep (n = 2), goat (n = 2) and roe deer (n = 1) to study the intermembrane distance in these three contact types. RESULTS: The measured intermembrane distances vary between 8 and 25 nm. One common feature is that the distance at feto-fetal contact sites is about 6-10 nm wider than at materno-maternal sites and feto-maternal sites show intermediate values. DISCUSSION: This finding suggests that the membrane distance at feto-maternal contact sites is determined by heterophilic binding of larger fetal to smaller maternal binding molecules. Homophilic binding of smaller maternal or larger fetal molecules lead to the smaller or wider intermembrane distances at materno-maternal or feto-fetal contact sites respectively. The observation that this similar pattern of membrane distances is present in pigs and in ruminants suggest that an evolutionary mechanism is involved in determining the intermembrane distance in epitheliochorial placentas.

Hyperechoic amniotic membranes in patients with preterm premature rupture of membranes (p-PROM) and pregnancy outcome.

OBJECTIVES: The early identification of women with preterm premature rupture of membranes (p-PROM) who are at higher risk of imminent delivery remains challenging. The aim of our study was to evaluate if an increased echogenicity of the amniotic membranes may represent a sonographic marker of impending delivery in women with p-PROM. METHODS: This was a prospective study including women with singleton pregnancies and diagnosis of p-PROM between 22 and 37 gestational weeks. A sonographic examination was performed within 24 h from the hospital admission and the appearance of the amniotic membranes close to the internal os was specifically evaluated. The membranes were defined as hyperechoic when their echogenicity was similar to that of the fetal bones or normoechoic in the other cases. The primary aim of the study was to compare the admission to spontaneous onset of labor interval and the pregnancy outcome between the cases of p-PROM with and without hyperechoic membranes. RESULTS: Overall, 45 women fulfilled the inclusion criteria with similar characteristics at admission. In women with hyperechoic membranes, the admission to spontaneous onset of labor interval was significantly shorter (11.5 [5.3-25.0] vs. 3.0 [1.5-9.0] p=0.04) compared to women with normo-echoic membranes. At binomial logistic regression after adjustment for GA at hospital admission, the presence of hyperechoic membranes was found as the only independent predictor of spontaneous onset of labor ≤72 h (aOR: 6.1; 95% CI: 1.0-36.9). CONCLUSIONS: The presence of hyperechoic membranes is associated with a 6-fold higher incidence of spontaneous onset of labor within 72 h independently from the gestational age at p-PROM.

Spontaneous septostomy in a monochorionic-diamniotic twin gestation.

Monochorionic twin gestations are associated with a greater incidence of neonatal morbidity and mortality when compared with their dichorionic counterparts. In turn, monochorionic-monoamniotic (MCMA) gestations carry greater risks compared with monochorionic-diamniotic (MCDA) gestations. While the true incidence of spontaneous septostomy of the dividing membranes (SSDM) in MCDA twins is unknown, SSDM has been demonstrated to be associated with increased morbidity and mortality, due to functional transition from a MCDA gestation to a MCMA gestation. We report a case of SSDM in a mid-trimester MCDA gestation, review the literature, and describe how to identify and manage this complication.

Fast In Vitro Procedure to Identify Extraembryonic Differentiation Defect of Mouse Embryonic Stem Cells.

Mouse embryonic stem cells (mESCs) are a powerful model to study early mouse development. These blastocyst-derived cells can maintain pluripotency and differentiate into the three embryonic germ layers and an extraembryonic layer, the extraembryonic endoderm (ExEn), which shares similar molecular markers to the definitive endoderm. Here, we present a fast procedure to identify a differentiation defect of mESCs toward ExEn in vitro through the molecular and cellular characterization of embryoid bodies, followed by direct differentiation of mESCs into ExEn. For complete details on the use and execution of this protocol, please refer to Ngondo et al. (2018).

Outcomes of prenatally diagnosed spontaneous chorioamniotic membrane separation in singleton pregnancies: A systematic review of case series and case reports.

OBJECTIVES: To provide an overview of perinatal outcomes in prenatally diagnosed spontaneous chorioamniotic separation (sCAS). METHODS: A systematic search of the literature was performed from inception to July 2019, including PubMed, Ovid MEDLINE, and Ovid EMBASE. All studies reporting prenatally diagnosed sCAS after 16 weeks' gestation in singleton pregnancies were eligible. Two independent reviewers used standardized forms for data abstraction. RESULTS: Of 408 screened abstracts, 17 studies reporting 118 cases of sCAS were included. Among 113 cases with delivery outcomes, preterm birth (PTB) occurred in 60 (53.1%, 95% confidence interval [CI] 43.9-62.3%). Intrauterine fetal demise (IUFD) occurred in seven (6.2%, 95% CI 1.8-10.6%) cases, with four due to cord strangulation. Spontaneous abortion occurred in one (0.88%, 95% CI -0.84-2.6%) case. Among 104 cases with postnatal follow-up, there were six (5.8%, 95% CI 1.3-10.3%) neonatal deaths and one (0.96%, 95% CI -0.91-2.8%) infant death. Perinatal mortality (IUFD and neonatal deaths) was 11.0% (95% CI 5.4-16.7%). CONCLUSIONS: sCAS may be associated with increased risk of PTB, however, the available data are largely case reports and series. Antepartum surveillance after viability can be considered due to risk of cord accidents. Prospective study is necessary to understand the clinical implications of sCAS.

Three-dimensional ultrasonographic features of diamniotic conjoined twins with body stalk anomaly.

BACKGROUND: Since conjoined twins were thought to be monoamniotic in the past, diamniotic conjoined twins would be improbable theoretically. Body stalk anomaly is a severe defect of the body wall, which is rare among twins. Body stalk anomaly in monochorionic diamniotic conjoined twins has never been reported prenatally so far as we know. CASE PRESENTATION: Here we present an extremely rare case of concordant body stalk anomaly in monochorionic diamniotic conjoined twins. Ultrasonography at 9 + 5 weeks revealed one chorionic and two amniotic cavities, close apposition of abdomen, limited movement, and common umbilical vessels. Follow-up ultrasonography at 11 + 6 weeks and 13 + 2 weeks showed close apposition of the lower abdominal region with cystic structures and a small bowel-like mass between the two fetuses. Three-dimensional ultrasonography assisted in observing the entire appearance of both twins in earlier first trimester, including amnioticity, conjoined region and umbilical vessels. We attribute this diamniotic conjoined twin in our case to the fusion theory. A single yolk sac was observed, challenging the idea that yolk sac number predicts amnionicity. Identification of single yolk sac and its allantois may form a common body stalk during this fusion, leading to concordant body stalk anomaly in monochorionic diamniotic twins. CONCLUSIONS: Our case may provide important insights into both ultrasonographic features and embryogenesis of this extremely rare anomaly.

Fetal Membranes, Not a Mere Appendage of the Placenta, but a Critical Part of the Fetal-Maternal Interface Controlling Parturition.

Fetal membranes (FMs) play a role in pregnancy maintenance and promoting parturition at term. The FMs are not just part of the placenta, structurally or functionally. Although attached to the placenta, the amnion has a separate embryologic origin, and the chorion deviates from the placenta by the first month of pregnancy. Other than immune protection, these FM functions are not those of the placenta. FM dysfunction is associated with and may cause adverse pregnancy outcomes. Ongoing research may identify biomarkers for pending preterm premature rupture of the FMs as well as therapeutic agents, to prevent it and resulting preterm birth.

Inter-foetus Membrane Segmentation for TTTS Using Adversarial Networks.

Twin-to-Twin Transfusion Syndrome is commonly treated with minimally invasive laser surgery in fetoscopy. The inter-foetal membrane is used as a reference to find abnormal anastomoses. Membrane identification is a challenging task due to small field of view of the camera, presence of amniotic liquid, foetus movement, illumination changes and noise. This paper aims at providing automatic and fast membrane segmentation in fetoscopic images. We implemented an adversarial network consisting of two Fully-Convolutional Neural Networks. The former (the segmentor) is a segmentation network inspired by U-Net and integrated with residual blocks, whereas the latter acts as critic and is made only of the encoding path of the segmentor. A dataset of 900 images acquired in 6 surgical cases was collected and labelled to validate the proposed approach. The adversarial networks achieved a median Dice similarity coefficient of 91.91% with Inter-Quartile Range (IQR) of 4.63%, overcoming approaches based on U-Net (82.98%-IQR: 14.41%) and U-Net with residual blocks (86.13%-IQR: 13.63%). Results proved that the proposed architecture could be a valuable and robust solution to assist surgeons in providing membrane identification while performing fetoscopic surgery.

Sonographic characteristics of the placenta, uterine wall, and placentomes during pregnancy in cows.

OBJECTIVE: In human medicine, contrary to bovine medicine, close monitoring of risk pregnancies is an integral part of obstetrics. A prerequisite for this is the knowledge of the normal findings during pregnancy. MATERIAL AND METHODS: For this purpose serial transrectal sonographic examination of the placentomes, uterine wall, and fetal membranes were carried out in 24 healthy (mean age 8.1 ± 3.7 years, Brown Swiss [n = 21], Red Holstein [n = 2], Simmental [n = 1]) cows from week 6 to 43 of gestation. An 8-MHz linear transducer was used to assess the thickness and appearance of the endometrium and myometrium, the height and width of placentomes, the thickness of the uterine wall including the adjacent chorion laeve (combined thickness of uterus and placenta, CTUP), and the echogenicity of the fetal fluids. The uterine wall and the placentomes were measured in 4 different zones of both uterine sides including a zone near the cervix, at the corpus near to the bifurcation, at the middle, and near the tip of the uterine horn. RESULTS: Placentome height and width were closely correlated with gestational age (height: r = 0.78; width: r = 0.83; both p < 0.0001). Placentome size increased progressively in all uterine zones until week 27, after which time their growth slowed until week 31 and then plateaued until parturition. Placentomes in the fetus-bearing horn were larger than in the non-fetus-bearing horn (p < 0.01) and were significantly smaller (height and width) near the tip of the horn than in the other 3 zones (p < 0.001 to < 0.01). The mean thickness of endometrium and myometrium, myometrium at the base of the placentome, and the mean CTUP did not change significantly during gestation. The echogenicity of the allantoic fluid did not change, but the amniotic fluid became more echogenic during gestation (p < 0.0001). CONCLUSION AND CLINICAL RELEVANCE: Sonographic examination of placentomes and amniotic fluid are a promising diagnostic tool for the estimation of the duration of bovine pregnancies and for diagnosing possible complications.

Raman microspectroscopy differentiates perinatal pathogens on ex vivo infected human fetal membrane tissues.

Streptococcus agalactiae, also known as Group B Streptococcus (GBS), is a major cause of chorioamnionitis and neonatal sepsis. This study evaluates Raman spectroscopy (RS) to identify spectral characteristics of infection and differentiate GBS from Escherichia coli and Staphylococcus aureus during ex vivo infection of human fetal membrane tissues. Unique spectral features were identified from colonies grown on agar and infected fetal membrane tissues. Multinomial logistic regression analysis accurately identified GBS infected tissues with 100.0% sensitivity and 88.9% specificity. Together, these findings support further investigation into the use of RS as an emerging microbiologic diagnostic tool and intrapartum screening test for GBS carriage.

Endoscopy, histology and electron microscopy analysis of foetal membranes in pregnant South American plains vizcacha reveal unusual excrescences on the yolk sac.

The South American hystricognathe Lagostomus maximus is a fossorial rodent whose females show unique reproductive characteristics. They have a 155-day long gestation, show massive polyovulation and a selective process of embryonic resorption in the first half of gestation. In order to explore and perform an in-situ characterization of the reproductive tract, we visualized internal structures through ultrasonography and video-endoscopy in pregnant and non-pregnant females. We describe the finding of protruding structures that lie on the yolk sac and their histological and ultrastructural characterization. The placenta was covered with whitish, small pearl-shaped structures. These structures were also seen on the extra-embryonic space, being the amnion and the umbilical cord free of them. Pearl-shaped structures were composed with loose connective tissue, lacked blood vessels, and showed collagen fibers organized in a spiral form. They were anchored by pedicles to the villous surface of the extraembryonic membrane. We discuss the biological and evolutionary meaning of the pearl-shaped structures that relate L. maximus to the African origin of the South American hystricognathe fauna.

Diagnosis of umbilical cord entanglement in a monochorionic diamniotic twin pregnancy with spontaneous septostomy of the dividing membranes using dual-gate Doppler imaging.

Umbilical cord entanglement is the leading cause of fetal mortality in monoamniotic twin pregnancies and a pseudo monoamniotic environment. Published methods for detecting this complication include color Doppler and pulsed Doppler sonography; however, no method provides an absolute diagnosis. In this case, we report the diagnosis of umbilical cord entanglement using dual-gate Doppler imaging. A 35-year-old woman was referred to our hospital at 28 weeks of gestation for prenatal management because of diagnosis of a monochorionic diamniotic twin pregnancy with spontaneous septostomy of the dividing membranes. Each fetus displayed normal fetal growth without obvious discordance and anatomical abnormalities. However, the dividing membrane was not detected, and an entangled cord was suspected. Dual-gate Doppler examination was carried out. Two regions of interest were considered at different areas of the umbilical arteries, and when each Doppler image showed two different heart rates at the same time, we considered this to be evidence of umbilical cord entanglement. Cesarean section was performed at 32 weeks of gestation and twins were delivered. The delivered umbilical cords had sixfold entanglement. In this case, dual-gate Doppler seems to have been more accurate than conventional single-gate Doppler for the diagnosis of cord entanglement because we confirmed two different heart rates at the same time with dual-gate Doppler.

Redefining 3Dimensional placental membrane microarchitecture using multiphoton microscopy and optical clearing.

INTRODUCTION: Remodeling of human placental membranes (amniochorionic or fetalmembrane) throughout gestation, a necessity to accommodate increasing uterine volume, involves continuous alterations (replacement of cells and remodeling of extracellular matrix). Methodologic limitations have obscured microscopic determination of cellular and layer-level alterations. This study used a combination of advanced imaging by multiphoton autofluorescence microscopy (MPAM) and second harmonic generation (SHG) microscopy along with tissue optical clearing to characterize the 3Dimensional multilayer organization of placental membranes. METHODS: Placental membranes biopsies (6 mm) collected from term, not-in-labor cesarean deliveries (n = 7) were fixed in 10% formalin (native) or treated with 2,2'-thiodiethanol to render them transparent for deeper imaging. Native and cleared tissues were imaged using MPAM (cellular autofluorescence) and SHG (fibrillar collagen). Depth z-stacks captured the amnion epithelium, underlying matrix layers, and in the cleared biopsies, the decidua layer. RESULTS: MPAM and SHG revealed fetal membrane epithelial topography and collagen organization in multiple matrix layers. Term amnion layers showed epithelial shedding and gaps. Optical clearing provided full-depth imaging with improved visualization of collagen structure, mesenchymal cells in extracellular matrix layers, and decidua morphology. Layer thicknesses measured by imaging corroborated with histology. Mosaic tiling of MPAM/SHG image stacks allowed large area visualization of entire biopsies. CONCLUSION: MPAM-SHG microscopy allowed for study of this multi-layered tissue and revealed shedding, gap formation, and other structural changes. This approach could be used to study structural changes associated with membranes as well as other uterine tissues to better understand events in normal and abnormal parturition.

Fetal membrane imaging and the prediction of preterm birth: a systematic review, current issues, and future directions.

BACKGROUND: Preterm premature rupture of membranes (PPROM) is the largest identifiable cause of preterm birth. There is currently no good screening test for PPROM in low-risk asymptomatic patients. Our goal was to identify how imaging methods can be utilized for examining the risks for PPROM in asymptomatic patients. METHODS: This paper is a systematic review of the literature on fetal membrane thickness and its use for the prediction of PPROM. Four key studies are identified and reviewed; two in vitro studies and two in vivo ultrasound studies each using differing methodologies. Additionally reviewed is a study using Optical Coherence Tomography, an emerging technique using near-infrared technology to produce high-resolution images. RESULTS: There is currently insufficient data to determine the association between fetal membrane thickness and PPROM by ultrasound. CONCLUSIONS: Fetal membrane thickness could have relevant clinical ramifications for the prediction of PPROM. Suggested improvements in study methodology and design will lead to progress in this area of research, as well as the use of newer technologies. Larger sample sizes, histological comparison, uniform methodologies for data collection, longitudinal study design and expanding data analysis beyond fetal membrane thickness to other properties would expand our knowledge in this field. In addition, transvaginal ultrasound should be utilized to improve resolution, as well as emerging methodologies such as MRI fusion imaging using ultrasound and Shear Wave Elastography.

In-vivo stretch of term human fetal membranes.

INTRODUCTION: Fetal membranes (FM) usually fail prior to delivery during term labor, but occasionally fail at preterm gestation, precipitating preterm birth. To understand the FM biomechanical properties underlying these events, study of the baseline in-vivo stretch experienced by the FM is required. This study's objective was to utilize high resolution MRI imaging to determine in-vivo FM stretch. METHODS: Eight pregnant women (38.4 ± 0.4wks) underwent abdominal-pelvic MRI prior to (2.88 ± 0.83d) caesarean delivery. Software was utilized to determine the total FM in-vivo surface area (SA) and that of its components: placental disc and reflected FM. At delivery, the SA of the disc and FM in the relaxed state were measured. In-vivo (stretched) to delivered SA ratios were calculated. FM fragments were then biaxially stretched to determine the force required to re-stretch the FM back to in-vivo SA. RESULTS: Total FM SA, in-vivo vs delivered, was 2135.51 ± 108.47 cm(2) vs 842.59 ± 35.86 cm(2); reflected FM was 1778.42 ± 107.39 cm(2) vs 545.41 ± 22.90 cm(2), and disc was 357.10 ± 28.08 cm(2) vs 297.18 ± 22.14 cm(2). The ratio (in-vivo to in-vitro SA) of reflected FM was 3.26 ± 0.11 and disc was 1.22 ± 0.10. Reflected FM re-stretched to in-vivo SA generated a tension of 72.26 N/m, corresponding to approximate pressure of 15.4 mmHg. FM rupture occurred at 295.08 ± 31.73 N/m corresponding to approximate pressure of 34 mmHg. Physiological SA was 70% of that at rupture. DISCUSSION: FM are significantly distended in-vivo. FM collagen fibers were rapidly recruited once loaded and functioned near the failure state during in-vitro testing, suggesting that, in-vivo, minimal additional (beyond physiological) stretch may facilitate rapid, catastrophic failure.