Uterine Vascularization Research Articles

Detection of endometrial and subendometrial vasculature on the day of embryo transfer and prediction of pregnancy during fresh in vitro fertilization cycles

ObjectivesSuccessful implantation depends on interaction between a blastocyst and a receptive endometrium. Endometrial vasculature is important in the early endometrial response to blastocyst implantation, and vascular changes can affect uterine receptivity. This study aims to investigate whether vascular parameters measured using three-dimensional power Doppler ultrasound (3D PD-US) could predict pregnancy following fresh in vitro fertilization and embryo transfer (IVF–ET) using a gonadotropin releasing hormone (GnRH) agonist long protocol. Materials and methodsThis prospective observational study enrolled 236 nulliparous women who underwent a first IVF–ET using a GnRH long protocol with stimulation by recombinant FSH (rFSH) from May 2009 to April 2012. After excluding two cases of tubal pregnancy, 234 women were in either a pregnant group (n = 113) or a nonpregnant group (n = 121). Color Doppler ultrasound and 3D PD-US examinations were performed on the day of embryo transfer. Main outcomes were pulsatility index (PI), resistance index (RI), systolic/diastolic ratio (S/D) of the uterine artery, vascularization index (VI), flow index (FI), and vascularization flow index (VFI) of the endometrium and subendometrial region. Measurements were analyzed relative to IVF–ET outcome (pregnant vs. nonpregnant). ResultsNo significant differences were observed in patient age, infertility duration, body mass index (BMI), basal FSH levels, number of retrieved oocytes or good quality embryos, or endometrial thickness or volume between the two groups. The pregnant group had higher endometrial VI, FI, and VFI scores than the nonpregnant group (p = 0.001, p = 0.000, p = 0.021, respectively). By contrast, neither subendometrial region VI, FI, and VFI scores (p = 0.770, p = 0.252, p = 0.451), nor uterine artery PI, RI, or S/D scores (p = 0.256, p = 0.527, p = 0.365) differed between groups. Cut-off values of endometrial VI, FI, and VFI scores were 0.95, 12.94, and 0.15 for pregnancy achievement. ConclusionThree dimensional PD-US was a useful and effective method for assessing endometrial blood flow in IVF cycles. Good endometrial blood flow on the day of embryo transfer might be associated with high pregnancy success with a GnRH long protocol, because this is indicative of endometrial receptivity in fresh IVF cycles.

Fertility and uterine hemodynamic in cows after artificial insemination with semen assessed by fluorescent probes

Fluorescent probes (propidium iodide, Hoechst 33342, fluorescein isothiocyanate–conjugated Pisum sativum agglutinin, and 5,5′,6,6′-tetrachloro-1,1′,3,3′-tetraethylbenzimidazolcarbocyanine iodide) were used to simultaneously evaluate the integrity of plasma and acrosomal membranes as well as mitochondrial membrane function in cryopreserved bovine semen and to verify its influence on fertility and postinsemination uterine vascularization. One hundred eighty-two Nellore cows were distributed for artificial insemination (AI) using semen batches separated according to the cell percentage presenting intact plasma membrane, intact acrosome, and high mitochondrial function (IPIAH): group G (44.5% IPIAH, n = 68), group M (23.0% IPIAH, n = 56), and group R (8.5% IPIAH, n = 58). The uterine hemodynamic was evaluated by Doppler sonogram in three periods: 30 hours before AI, 4 and 24 hours after AI were considered the resistance index and the uterine vascularization score. The pregnancy rate of group G (64.7%) was greater (P > 0.05) compared with group R (36.2%), but both did not differ from group M (50.0%). There was no effect (P > 0.05) of semen quality on uterine vascularization. Greater vascularization was noticed 4 hours after AI than 30 hours before and 24 hours after AI. Semen evaluation using fluorescent probes contributes to predicting fertilizing potential of semen. The use of semen with less percentage of IPIAH sperm does not alter uterine hemodynamic in cows.

Artificial insemination causes uterine hemodynamic alterations in suckled beef cows subjected to an ovulation synchronization program

The objective of the present study was to verify the uterine hemodynamic of suckled beef cows after a timed artificial insemination (TAI) by Doppler ultrasound. Eighteen cows were randomly assigned in one of two groups – non-AI (CG, n=9) and AI group (AIG, n=9). Ultrasound evaluations were performed in five spectral mode moments (30h before AI, 4, 24, 48, and 168h after AI) to evaluate the resistance index (RI) of the uterine artery and in four Doppler color mode moments (4, 24, 48 and 168h after AI) to evaluate the percentage of the uterine horns vascularization. The animals showed similar vascularization in the beginning of the experiment. The data were first evaluated according to the side where ovulation occurred and no effects were observed. Vascularization was assessed in each group at each time. No differences were observed in any of the time points. Time effect was observed in both groups and behavior was similar for the groups. Highest values of RI were observed 48h after AI, followed by the 168h and values obtained 24h after AI. The lowest values of RI were noted 4h after AI, followed by the observation 30h before AI. Regarding the effect of time to EV, time effect was not observed in either group. Since there was no interaction group×time, data were analyzed for each group, regardless of the time and for each time, regardless of the group. The RI values were lower for AIG when compared to the CG; however, no differences were observed between the groups as far as uterine vascularization scores. Four hours after AI, the RI values were lower when compared to 24, 48 and 168h following AI, showing no difference in relation to 30h before AI. Thirty hours before AI, the RI values were lower when compared to 48 and 168h after AI, no different than the values observed 24h after AI. The highest RI value appeared 48h after AI, where this value was not statistically different from the one found 168h after AI. On the other hand, there was no difference between the vascularization scores regarding the evaluation periods (p>0.05). Artificial insemination of female bovines reduce uterine artery RI, but does not change the uterine vascular score. Moreover, changes in the uterine hemodynamics in cows are related to the period of evaluation.

Measurement of endometrial and uterine vascularity by transvaginal ultrasonography in predicting pregnancy outcome during frozen-thawed embryo transfer cycles.

An appropriate endometrial condition and vascular supply are usually considered essential for implantation of an embryo. This study was performed to assess the role of endometrial and uterine vascularity status measurement in predicting pregnancy outcome during frozen-thawed embryo transfer cycles. A total of 70 infertile women were recruited with controlled ovarian stimulation followed by oocyte retrieval. After in vitro fertilization or intracytoplasmic sperm injection, embryos were cultured to blastocysts and blastocysts with good quality were selected for cryopreservation. After endometrial preparation, vitrified blastocysts were thawed and assisted hatching by zona dissection was performed. On the day of embryo transfer, endometrial thickness (EMT), resistance index (RI) and pulsatility index (PI) of sub-endometrial artery (SEA) and uterine artery (UA) were obtained by transvaginal sonography. The women were divided into the pregnant and non-pregnant groups, and these variables were compared between the two groups. Patients' general demographic characteristics were not statistically different between the pregnant and non-pregnant groups. The overall implantation rate, clinical pregnancy rate, and ongoing pregnancy rate were 31.1%, 41.4% and 28.6%, respectively. Twenty-nine patients who conceived had average EMT, RI of SEA, PI of SEA, RI of UA, and PI of UA values of 9.15 mm, 0.91, 2.42, 0.95, and 3.37, respectively. Forty-one patients who did not conceive had average EMT, RI of SEA, PI of SEA, RI of UA, and PI of UA values of 9.31 mm, 1.01, 2.56, 0.94, and 3.00, respectively. In the two groups, none of the variables was statistically different (P > 0.05). EMT and blood flow index of endometrium and uterus measured by transvaginal sonography are not an effective predictor of pregnancy outcome in frozen-thawed embryo transfer cycles.

Maternal and Fetal Outcomes in Placenta Accreta After Institution of Team-Managed Care

Placenta accreta significantly contributes to maternal morbidity and mortality. We evaluated whether planned delivery and experienced, team-managed surgical intervention results in improved outcomes. We also examined whether risk factors differed for accreta, increta, and percreta and evaluated whether excess lower segment uterine vascularity correlates with disease severity. We retrospectively analyzed patients before versus after institution of a management protocol. Of the 58 044 deliveries over 10 years, there were 67 women whose pregnancies were histopathologically confirmed as placenta accreta, increta, or percreta (1/866). Clinical outcome measures were estimated blood loss (EBL), packed red blood cells (pRBCs) transfused, maternal and fetal complications, intensive care unit admission, and length of stay. There were no maternal or infant deaths. In the managed cohort, EBL was reduced by 48% (P < .001), intraoperative pRBCs transfused by 40% (P < .01), total transfused pRBCs per case by 50% (P < .01), and surgical intensive care unit admissions by >50% (P < .01). Assessment of maternal risk factors by diagnosis revealed marked differences between accreta versus increta and percreta. Clinically assessed excess vascularity of the lower uterine segment correlated with disease severity. The incidence of neonatal complications was similar in both cohorts. Targeted delivery at 34 weeks and team-managed diagnosis, treatment, and care of patients with placenta accreta were associated with improved maternal, but not neonatal outcomes.

Accuracy of ultrasonography and magnetic resonance imaging in the diagnosis of placenta accreta.

PurposeTo evaluate the accuracy of ultrasonography and magnetic resonance imaging (MRI) in the diagnosis of placenta accreta and to define the most relevant specific ultrasound and MRI features that may predict placental invasion.Material and MethodsThis study was approved by the institutional review board of the French College of Obstetricians and Gynecologists. We retrospectively reviewed the medical records of all patients referred for suspected placenta accreta to two university hospitals from 01/2001 to 05/2012. Our study population included 42 pregnant women who had been investigated by both ultrasonography and MRI. Ultrasound images and MRI were blindly reassessed for each case by 2 raters in order to score features that predict abnormal placental invasion.ResultsSensitivity in the diagnosis of placenta accreta was 100% with ultrasound and 76.9% for MRI (P = 0.03). Specificity was 37.5% with ultrasonography and 50% for MRI (P = 0.6). The features of greatest sensitivity on ultrasonography were intraplacental lacunae and loss of the normal retroplacental clear space. Increased vascularization in the uterine serosa-bladder wall interface and vascularization perpendicular to the uterine wall had the best positive predictive value (92%). At MRI, uterine bulging had the best positive predictive value (85%) and its combination with the presence of dark intraplacental bands on T2-weighted images improved the predictive value to 90%.ConclusionUltrasound imaging is the mainstay of screening for placenta accreta. MRI appears to be complementary to ultrasonography, especially when there are few ultrasound signs.

Differentiating Between Septate and Bicornuate Uterus: Bi-dimensional and 3-Dimensional power Doppler Findings

Study ObjectiveTo assess if any difference could be found in uterine vascularization between septate and bicornuate uterus. DesignPilot study (Canadian Task Force classification II-2). SettingUniversity hospital infertility clinic. PatientsOne hundred nine women with complete duplication of the uterine cavity. All had already received the final diagnosis of the type of uterine malformation, either septate uterus or bicornuate uterus, via diagnostic hysteroscopy and laparoscopy. Another group of 10 patients with uterine anomalies and affected by ovarian mass were also evaluated via intravenous contrast medium–enhanced ultrasound examination. InterventionsPatients were evaluated using 2-dimensional and 3-dimensional power Doppler imaging of the uterus. Measurements and Main ResultsSeventy-three patients with septate uterus, with or without cervical and vaginal duplication, and 36 patients with bicornuate uterus were selected for inclusion in the study. Irregular vascular networks were detected between the 2 hemicavities in the patients with septate uterus. All bicornuate uteri showed a peculiar vascular network between the 2 hemicavities: the main recognizable vessels formed a network depicting the Greek letter γ at the level of the uterine midline. Detection of the γ sign can be used to differentiate septate from bicornuate uterus. This finding was also confirmed in patients who underwent intravenous contrast medium–enhanced ultrasound examination. Conclusionspower Doppler provides a new and uninvasive tool for differentiation of septate from bicornuate uterus.

Treatment with eCG Decreases the Vascular Density and Increases the Glandular Density of the Bovine Uterus

The uterus plays an essential role in mammalian reproduction and is a target of several hormonal protocols used to improve fertility in cattle. Many studies highlighted the importance of eCG treatment following fixed-time artificial insemination in improving follicular growth, ovulation and pregnancy rates in cattle. Moreover, eCG has been implicated in angiogenesis, leading to important changes in uterine blood flow and vascularisation. However, there is still a lack of information regarding the specific alterations induced by eCG upon glandular and vascular characteristics of bovine uterus. To investigate the influence of eCG on: uterine thickness and area; uterine artery diameter and area; uterine vascular and gland density; and the expression of the VEGFA-system, the uteri of crossbred beef cows were collected. All cows were submitted to follicular wave emergence synchronization. On day four of protocol, cows submitted to superovulation (n=6) received 2000IU eCG, on day eight, after expected follicular deviation, cows submitted to stimulatory treatment (n=5) received 400IU eCG. Control cows (n=5) did not receive eCG. On day five po cows were subjected to ultrassonographic evaluation and slaughtered for uterine tissue sampling on day six po. Uterine vessels and glands were quantified by the counting point stereological method. The VEGFA-system was localized in different cellular types, showing no qualitative or quantitative differences in the site of expression or the intensity of the positive signal among the groups. Vascular density was decreased in the endometrium of stimulated and myometrium of superovulated cows compared with the control ones, which showed higher vascular density in the myometrium and endometrium of the ipsilateral uterine horn. The uterine gland density was higher in superovulated compared with stimulated and control cows. Thus, we can infer that stimulatory or superovulatory treatments with eCG influence the vascular density in the endometrium and myometrium in cattle.

Increased serum levels of inflammatory mediators and low frequency of regulatory T cells in the peripheral blood of preeclamptic Mexican women.

Regulatory T cells (Tregs; CD4+CD25highFoxp3+) are critical in maintaining immune tolerance during pregnancy and uterine vascularization. In this study, we show that, in Mexican women with different preeclamptic severity levels, the number of Tregs and the subset of CD4+CD25highFoxp3+ are decreased compared with those of normotensive pregnant women (NP). Moreover, a systemic inflammatory state is a pivotal feature in the pathogenesis of this disorder and could be related to hypertension and endothelial dysfunction. Likewise, we observed elevated levels of IL-6, TNF-α, and IL-8 in the serum of severe preeclamptic patients (SPE); no differences were found in the IL-1β and IL-10 levels compared with those of NP patients. An analysis of chemokines in the preeclamptic serum samples showed high levels of CXCL10, CCL2, and CXCL9. Our findings suggest that the preeclamptic state is linked with systemic inflammation and reduced numbers of Tregs.

Emerging role of Color Doppler in Infertility Management: A Public Health perspective

Color Doppler is emerging as a valuable diagnostic imaging modality in the field of reproductive medicine, primarily infertility. Reproductive disorders, including infertility and spontaneous abortions/miscarriages, have emerged as major public health problem(s) worldwide. Color Doppler energy imaging is a high throughput technology based on the total integral of energy frequency spectrum. We extracted the most relevant articles (comprehensive reviews and original research articles) for inclusion in our review by performing a comprehensive literature search using the Pubmed (last accessed on 2015 April 28) scientific database. Color Doppler is a high-throughput, sophisticated imaging technique for the assessment of uterine anomalies, intrauterine pathology, tubal patency, polycystic ovaries, ovarian follicular monitoring, endometrial receptivity, failed and/or ectopic pregnancy, male infertility, and uterine, endometrial, and ovarian vascularity. Assessments of the uteroovarian pulsatility indices (PIs), resistance indices (RIs), and endometrial color signals are important determinants of in vitro fertilization (IVF) cycles and pregnancy rates. With our clinical/scientific research experience in the field of reproductive medicine, we strongly believe that an overall public health model needs to be designed in managing infertility patients; therefore, major issues such as cost-effectiveness and technical artifacts should be addressed so as to achieve an accurate clinical diagnosis, successful IVF outcome/pregnancy, and overall patient satisfaction in a clinical research setting. Simple, safe, efficient, and affordable diagnostic modalities should be incorporated at infertility clinics coupled with well-designed patient counseling sessions and community-based public health awareness campaigns conducted so as to reduce the morbidity and mortality rates associated with reproductive disorders.

Different bleeding patterns with the use of levonorgestrel intrauterine system: are they associated with changes in uterine artery blood flow?

Objective. Evaluate if different bleeding patterns associated with the use of the levonorgestrel intrauterine system (LNG-IUS) are associated with different uterine and endometrial vascularization patterns, as evidenced by ultrasound power Doppler analysis. Methodology. A longitudinal study, with each subject acting as its own control was conducted between January 2010 and December 2012. Healthy volunteers with a history of heavy but cyclic and regular menstrual cycles were enrolled in the study. Ultrasonographic examination was performed before and after six months of LNG-IUS placement: uterine volume, endometrial thickness, and subendometrial and myometrial Doppler blood flow patterns have been evaluated. Results. A total of 32 women were enrolled out of 186 initially screened. At six months of follow-up, all subjects showed a reduction in menstrual blood loss; for analysis, they were retrospectively divided into 3 groups: normal cycling women (Group I), amenorrheic women (Group II), and women with prolonged bleedings (Group III). Intergroup analysis documented a statistically significant difference in endometrial thickness among the three groups; in addition, mean pulsatility index (PI) and resistance index (RI) in the spiral arteries were significantly lower in Group I and Group III compared to Group II. This difference persisted also when comparing—within subjects of Group III—mean PI and RI mean values before and after insertion. Conclusions. The LNG-IUS not only altered endometrial thickness, but—in women with prolonged bleedings—also significantly changed uterine artery blood flow. Further studies are needed to confirm these results and enable gynecologists to properly counsel women, improving initial continuation rates.

Effect of hCG application in three different moments of the estrous cycle on ovarian and uterine vascularization and serum progesterone concentration

The mare is a seasonal breeder and in most situations a monovulatory individual. Therefore, a limited number of cycles per season makes a high pregnancy rate per cycle a very important goal to be achieved, in mares carrying their own or recipient mares. The use of drugs during diestrus in order to improve conception rates in inseminated and recipient mares has been the focus of several research groups. Some studies using hCG found promising results regarding pregnancy rates and recipient uterine characteristics on the day of transfer (Fleury et al., Revista Brasileira de Reproducao Animal, 2007 Belo Horizonte, v.31, n.1, p.27-31whereas others have detected a negative effect, showing a decrease on pregnancy rate when hCG was used [McCue et al., J Eq Vet Sci 2012;32:415]. In addition, hCG has been shown to have an effect on uterine vascularization in swine [Ziecik et al., Endocrinology 1986;119:1159–63], rats [Hermsteiner et al., Eur J Physiol 1999;439:186–4] and humans [Janiaux et al., Human Reproduction 1992;7:1467– 73]. The objectives of the present study were to evaluate the effect of hCG administration on luteal and uterine vascularization and serum progesterone concentration. Treatment groups were: G1: (control) no hCG application; G2: 2500 IU of hCG to induce ovulation when a follicle greater than 35 mm and uterine edema were detected; G3: 2500 IU hCG on day 0; G4: 2500 IU hCG on day 5 post ovulation. Twelve mares were randomly assigned to each

Acquired uterine arteriovenous malformation developing in retained products of conception: A diagnostic dilemma

Abnormal uterine bleeding in the postabortal period requires meticulous diagnostic work-up to decide proper management. Imaging modalities including Doppler sonography and magnetic resonance imaging in concert with clinical and laboratory findings are useful to narrow the differential diagnoses but are not definitive. Presence of increased uterine vascularity and arteriovenous shunting is non-specific and can be detected in a variety of conditions including retained trophoblastic tissue, gestational trophoblastic disease, arteriovenous malformation (AVM), placental polyp and vascular neoplasm. We present here a case of a multiparous woman with unexplained postabortal bleeding posing a diagnostic challenge. Excluding the possibility of AVM before attempting dilatation and curettage in such a clinical scenario is crucial to prevent catastrophic bleeding.

Diet-induced obesity may affect the uterine immune environment in early–mid pregnancy, reducing NK-cell activity and potentially compromising uterine vascularization

To investigate the effect of obesity in early-mid pregnancy on crucial pregnancy hormones and the uterine immune environment. Obesity impacts reproductive ability, adversely affecting conception and leading to complications in pregnancy. Obesity is often regarded as a stress state and an immune disease, both of which may contribute to pregnancy failure. We previously demonstrated that stress in early pregnancy greatly alters progesterone secretion. As progesterone is an immunomodulator, altered progesterone secretion may adversely modify the maternal immune system. In the current study, we test the hypothesis that obesity during pregnancy adversely alters the uterine immune environment. An obese mouse model was created by feeding C57/BL6 mice on a high-fat (HF)/sugar diet for 12 weeks before pregnancy. Control mice were fed on lower-fat/sugar chow. Mice were mated, and on day 7.5 of pregnancy plasma progesterone and prolactin were measured by immunoassay. Cells from the uterus-draining inguinal lymph nodes were collected for analysis of the uterine immune response by flow cytometry. Diet-induced obesity increased the secretion of progesterone and altered a number of uterine natural killer (NK)- and T-cell responses. These included a marked reduction in the percentage of leucocyte-derived NK cells and reduced expression of interferon-γ (IFN-γ) in the NK cells compared with control mice. Maternal obesity, induced by an HF diet, may lead to a reduction in the expression of IFN-γ in NK cells. NK-cell-derived IFN-γ is reported to be involved in supporting uterine spiral artery remodelling. Thus, obesity in early pregnancy may compromise vascularization by reducing the expression of IFN-γ-positive NK cells. Furthermore, the expression of uterine CD8(+) cells was reduced in the HF diet-fed mice, suggesting obesity may adversely alter the maternal immune adaptation that is essential for effective pregnancy.

Measurment of endometrial and uterine vascularity by transvaginal ultrasonography in predicting pregnancy outcome during frozen-thawed embryo transfer cycles

An appropriate endometrial condition and vascular supply are usually known as essential for implantation of embryo. This study was performed to assess the role of endometrial and uterine vascularity status measurement in predicting pregnancy outcome during frozen-thawed embryo transfer (FET) cycles.

Novel insights into the regulation of uterine vascular tone by sphingosine 1-phosphate

s / Placenta 34 (2013) A1–A99 A3 stem cells in action. Vasculogenesis and angiogenesis of the fetal vasculature in the human placenta from mesenchymal stem cells and the sequential expression of endothelial adhesion molecules during vasculogenesis is a classic example of direct incorporation of stem cells in a growing vascular system. Modulation of the endothelial barrier and junctional phenotype with gestational age and altered maternal and placental milieu reflect paracrine repair and regeneration by vascular stem cells. Indeed, the phenotypic plasticity of the placental endothelial cells suggests their close proximity to the stem cell in the differentiation time line. This phenotypic plasticity has been successfully used by cell culture experimentalists for barrier studies. Moreover, de-differentiation of placental/umbilical cord derived endothelial cells in culture to a more mesenchymal/pericytic phenotype suggests that differentiation processes are not unidirectional. Recent studies of gene expression profiles of placental fetal endothelium combined with functional studies reporting an immature phenotype in the diabetic milieu further strengthen the stem cell but one nature and provide examples of endothelial de-differentiation in vivo. The phenotypic plasticity of fetal endothelial cells is advantageous to the fetus. It allows increased angiogenesis and permeability during gestation to sustain fetal growth; VEGF studies demonstrate this vividly. However, this very plasticity may then leave the fetus vulnerable to maternal diseases; the induced immature barrier phenotype or the accelerated aging upon sustained oxidative stress will lead to placental inefficiency and fetal morbidity. Fetal endothelial cells are not alone, other cell types in the placenta also show examples of plasticity and indeed trans-differentiation evidenced by differentiation of trophoblast cells during modulating of spiral arteries and expression of endothelial markers such as eNOS and caveolin-1. http://dx.doi.org/10.1016/j.placenta.2013.06.012 PL2.3. NOVEL INSIGHTS INTO THE REGULATION OF UTERINE VASCULAR TONE BY SPHINGOSINE 1-PHOSPHATE

Erratum to: Three-dimensional power Doppler study of changes in uterine vascularity after absorbable cervical tourniquet during open myomectomy

Erratum to: Three-dimensional power Doppler study of changes in uterine vascularity after absorbable cervical tourniquet during open myomectomy

Gonadotropin-releasing hormone agonist and depot medroxyprogesterone acetate following uterine artery embolization in the management of uterine arteriovenous malformation

A young woman presenting with recurrent episodes of uterine bleeding due to an extensive uterine arteriovenous malformation was treated with two sessions of uterine artery embolization. Further bleeding was managed with a combination of gonadotropin-releasing hormone and depot medroxyprogesterone acetate. The patient remains asymptomatic with a significant decrease in uterine and pelvic vascularity at one year follow-up. These drugs may decrease the need for repeat embolization.

In vivo MRI assessment of placental and foetal oxygenation changes in a rat model of growth restriction using blood oxygen level-dependent (BOLD) magnetic resonance imaging

To evaluate whether changes in BOLD signal intensities following hyperoxygenation are related to intrauterine growth restriction (IUGR) in a rat model. IUGR was induced in pregnant rats by ligating the left vascular uterine pedicle at day 16 of gestation. BOLD MR imaging using a balanced steady-state free-precession (balanced-SSFP) sequence on a 1.5-T system was performed on day 19. Signal intensities (SI) before and after maternal hyperoxygenation were compared in the maternal liver and in control and growth-restricted foetoplacental units (FPUs). Maternal hyperoxygenation resulted in a significant increase in SI in all regions of interest (P < 0.05) in the 18 rats. In the control group, the SI (mean ± SD) increased by 21 % ± 15 in placentas (n = 74) and 13 % ± 8.5 in foetuses (n = 53). In the IUGR group, the increase was significantly lower: 6.5 % ± 4 in placentas (n = 36) and 7 %± 5.5 in foetuses (n = 34) (P < 0.05). BOLD MRI allows non-invasive assessment of the foetoplacental response to maternal hyperoxygenation in the rat and demonstrates its alteration in an IUGR model. This imaging method may provide a useful adjunct for the early diagnosis, evaluation, and management of human IUGR. • Intra-uterine growth restriction is an important cause of perinatal morbidity and mortality. • Blood oxygen level-dependent MRI non-invasively assesses foetoplacental response to maternal hyperoxygenation. • In the rat, foetoplacental response to maternal hyperoxygenation is altered in IUGR. • Functional MRI may help to assess human IUGR.

Characterization of Local Algerian Population of Rabbit: Factors Influencing Fetal and Placental Development

The objective of our work was to study the effect of parity the parity of the does, the intra uterine position and vascularization of the fetuses and their number per horn on, available uterine space and placentae development in the rabbit at two stages (nulliparous and primiparous). To this aim, twenty rabbit does of locally Algerian population were distributed in two groups of 10 each (nulliparous and primiparous). The does were mated and slaughtered on 24th day of gestation. In the group of fetuses receiving poor blood supply (? 4 blood vessels), the individual weight and the crown-rump were lower (- 24.4 and - 12.6% respectively; p < 0.05) compared to those with higher number of blood vessels (? 5). The intra uterine position affects significantly the individual weight of maternal placenta and the heavier one was located in the oviduct. Significant interaction between parity and the number of blood vessels was recorded for the individual weight of fetal placenta (p < 0.05). Available uterine space was lower in the primiparous, in the middle position and in the class of fetuses with lower blood supply. In primiparous, the horns with 5 or 6 fetuses presented a better vascularization than those with the same number in nulliparous (+25%). The fetal weight and crown-rump decreased when the number of fetus per horn increased (p<0.05). A significant interaction was recorded between the parity and the number of fetus per horn for the weight of maternal placenta (+ 15% and + 30% respectively in the horn within 3 or 5 fetuses in nulliparous; p < 0.05). Available uterine space was greater in nulliparous compared to the primiparous and decreased when the number of fetus per horn increased. These results suggest that available uterine space and fetal development at 24th of pregnancy are affected respectively by parity of the rabbit and the vascularization of the implantation site.