Gestational loss and growth restriction by angiogenic defects in placental growth factor transgenic mice.

OBJECTIVE: Angiogenesis is an important biological process during development, reproduction, and in immune responses. Placental growth factor (PlGF) is a member of vascular endothelial growth factor that is critical for angiogenesis and vasculogenesis. We generated transgenic mice overexpressing PlGF in specifically T cells using the human CD2-promoter to investigate the effects of PlGF overexpression. APPROACH AND RESULTS: Transgenic mice were difficult to obtain owing to high lethality; for this reason, we investigated why gestational loss occurred in these transgenic mice. Here, we report that placenta detachment and inhibition of angiogenesis occurred in PlGF transgenic mice during the gestational period. Moreover, even when transgenic mice were born, their growth was restricted. CONCLUSIONS: Conclusively, PlGF overexpression prevents angiogenesis by inhibiting Braf, extracellular signal-regulated kinase activation, and downregulation of HIF-1α in the mouse placenta. Furthermore, it affected regulatory T cells, which are important for maintenance of pregnancy.

Comparison of reproductive outcome, including the pattern of loss, between couples with chromosomal abnormalities and those with unexplained repeated miscarriages.

AIM: Chromosomal abnormalities are an important cause of repeated miscarriage. Several studies have discussed the association between chromosomal abnormalities and repeated miscarriage. This study attempts to describe the pattern of miscarriage in this group of women and the eventual pregnancy outcome of couples with chromosomal abnormalities compared with couples with unexplained repeated pregnancy loss. MATERIAL AND METHODS: This was a retrospective study involving 795 couples with repeated miscarriages. RESULTS: Out of 795 couples, 28 (3.52%) were found to have a chromosomal abnormality (carrier group). Over half (65.5%) of the chromosomal abnormalities were balanced reciprocal translocations. After referral, this carrier group had a total of 159 pregnancies, leading to 36 live births (22.6%) among 18 couples. The after referral miscarriage rate in the chromosomal anomaly group (55.6%) was significantly (P < 0.01) higher than that in the unexplained recurrent miscarriage group (28.1%). In couples with chromosomal anomaly, the miscarriages were more likely to occur between 6 and 12 weeks' gestation. CONCLUSIONS: The encouraging cumulative live birth rate of 64.3% for couples with chromosomal anomaly and repeated miscarriage suggests that further attempts at natural conception are a viable option.

Perinatal death of triplet pregnancies by chorionicity.

OBJECTIVE: The purpose of this study was to evaluate the perinatal risk of death by chorionicity at >22 weeks of gestation of triplet pregnancies. STUDY DESIGN: In a retrospective cohort study, the perinatal data were collected from triplet pregnancies in Japanese perinatal care centers between 1999 and 2009. We included maternal characteristics and examined the following factors: prenatal interventions, pregnancy outcome, and neonatal outcome. The association between fetal or neonatal death of triplets and chorionicity was evaluated by logistic regression analysis. RESULTS: After the exclusion of 253 cases, the study group comprised 701 cases: 507 trichorionic triamniotic (TT) triplet pregnancies, 144 diamniotic triamniotic (DT) triplet pregnancies, and 50 monochorionic triamniotic (MT) triplet pregnancies. The mortality rate (fetal death at >22 weeks of gestation; neonatal death) in triplets was 2.6% and included 2.1% of TT triplet pregnancies, 3.2% of DT triplet pregnancies, and 5.3% of MT triplet pregnancies. No significant risk of death was identified in DT triplet pregnancies; however, MT triplet pregnancies had a 2.6-fold greater risk (adjusted odds ratio, 2.60; 95% confidence interval, 1.17-5.76; P = .019) compared with TT triplet pregnancies. Prophylactic cervical cerclage did not reduce the perinatal mortality rate at >22 weeks of gestation in triplets. CONCLUSION: The risk of death for MT triplet pregnancies is significantly higher than that of TT triplet pregnancies; however, the risk of death for DT triplet pregnancies is not.

Aldosterone deficiency adversely affects pregnancy outcome in mice.

Circulating aldosterone levels are increased in human pregnancy. Inadequately low aldosterone levels as present in preeclampsia, a life-threatening disease for both mother and child, are discussed to be involved in its pathogenesis or severity. Moreover, inactivating polymorphisms in the aldosterone synthase gene have been detected in preeclamptic women. Here, we used aldosterone synthase-deficient (AS(-/-)) mice to test whether the absence of aldosterone is sufficient to impair pregnancy or even to cause preeclampsia. AS(-/-) and AS(+/+) females were mated with AS(+/+) and AS(-/-) males, respectively, always generating AS(+/-) offspring. With maternal aldosterone deficiency in AS(-/-) mice, systolic blood pressure was low before and further reduced during pregnancy with no increase in proteinuria. Yet, AS(-/-) had smaller litters due to loss of fetuses as indicated by a high number of necrotic placentas with massive lymphocyte infiltrations at gestational day 18. Surviving fetuses and their placentas from AS(-/-) females were smaller. High-salt diet before and during pregnancy increased systolic blood pressure only before pregnancy in both genotypes and abolished the difference in blood pressure during late pregnancy. Litter size from AS(-/-) was slightly improved and the differences in placental and fetal weights between AS(+/+) and AS(-/-) mothers disappeared. Overall, an increased placental efficiency was observed in both groups paralleled by a normalization of elevated HIF1α levels in the AS(-/-) placentas. Our results demonstrate that aldosterone deficiency has profound adverse effects on placental function. High dietary salt intake improved placental function. In this animal model, aldosterone deficiency did not cause preeclampsia.

Adverse fetal and neonatal outcomes associated with a life-long high fat diet: role of altered development of the placental vasculature.

Maternal obesity results in a number of obstetrical and fetal complications with both immediate and long-term consequences. The increased prevalence of obesity has resulted in increasing numbers of women of reproductive age in this high-risk group. Since many of these obese women have been subjected to hypercaloric diets from early childhood we have developed a rodent model of life-long maternal obesity to more clearly understand the mechanisms that contribute to adverse pregnancy outcomes in obese women. Female Sprague Dawley rats were fed a control diet (CON--16% of calories from fat) or high fat diet (HF--45% of calories from fat) from 3 to 19 weeks of age. Prior to pregnancy HF-fed dams exhibited significant increases in body fat, serum leptin and triglycerides. A subset of dams was sacrificed at gestational day 15 to evaluate fetal and placental development. The remaining animals were allowed to deliver normally. HF-fed dams exhibited a more than 3-fold increase in fetal death and decreased neonatal survival. These outcomes were associated with altered vascular development in the placenta, as well as increased hypoxia in the labyrinth. We propose that the altered placental vasculature may result in reduced oxygenation of the fetal tissues contributing to premature demise and poor neonatal survival.

Neuropathology of the area postrema in sudden intrauterine and infant death syndromes related to tobacco smoke exposure.

The area postrema is a densely vascularized small protuberance at the inferoposterior limit of the fourth ventricle, outside of the blood-brain barrier. This structure, besides to induce emetic reflex in the presence of noxious chemical stimulation, has a multifunctional integrative capacity to send major and minor efferents to a variety of brain centers particularly involved in autonomic control of the cardiovascular and respiratory activities. In this study we aimed to focus on the area postrema, which is so far little studied in humans, in a large sample of subjects aged from 25 gestational weeks to 10 postnatal months, who died of unknown (sudden unexplained perinatal and infant deaths) and known causes (controls). Besides we investigated a possible link between alterations of this structure, sudden unexplained fetal and infant deaths and maternal smoking. By the application of morphological and immunohistochemical methods, we observed a significantly high incidence of alterations of the area postrema in fetal and infant victims of sudden death as compared with age-matched controls. These pathological findings, including hypoplasia, lack of vascularization, cystic formations and reactive gliosis, were related to maternal smoking. We hypothesize that components from maternal cigarette smoke, particularly in pregnancy, could affect neurons of the area postrema connected with specific nervous centers involved in the control of vital functions. In conclusion, we suggest that the area postrema should be in depth examined particularly in victims of sudden fetal or infant death with smoker mothers.

Conditions associated with placental dysfunction.

Placental dysfunction is a term to describe suboptimal placental function leading to variations in the fetal supply of all its necessary required nutrients as well as the disruption in the cleansing of fetal catabolic products. The dysfunctional placenta may interrupt the manufacturing of other essential factors involved in pregnancy conservation, can compromise the fetal appropriate, atraumatic and sterile medium to grow, the immunologic shield from maternal antibodies and the normal amniotic fluid levels. Placental dysfunction can lead to a group of disorders representing a diverse and important category of pathological processes conducting to fetal and neonatal morbidity and mortality. The mechanisms by which these inflammatory processes cause death and disability are diverse and can be separated into four distinct classes: first, placental damage with loss of function; second, induction of premature labor; third, release of inflammatory mediators; fourth, transplacental infection. Several conditions have been associated with placental dysfunction: IUGR, hypertension, hypoxic-ischemic injury, preterm labor, and fetal death.

Entrecruzamiento de cordones en la gestación gemelar monocorial monoamniótica / Cord entanglement in monochorionic monoamniotic twin pregnancies

La gestación gemelar monocorial monoamniótica presenta alto riesgo de muerte fetal en relación a complicaciones generales de las gestaciones gemelares así como específicas de la monoamniocidad, siendo la más grave la muerte fetal por entrecruzamiento de cordones, el cual se presenta en prácticamente la totalidad de los casos. En el manejo de la gestación monocorial monoamniótica es fundamental un correcto diagnóstico precoz ecográfico, así como un manejo y vigilancia estricta para detectar signos de entrecruzamiento de cordones que permitan evitar la progresión a muerte fetal intraútero. La necesidad de hospitalización y el momento de finalización de la gestación siguen generando controversia en la literatura médica (AU)

Monochorial monoamniotic twins are at high risk of fetal death due to the general complications seen in multiple gestations, as well as those specific to this type of pregnancy. The most severe complication in these pregnancies is fetal death due to cord entanglement, which occurs in almost all cases. Early ultrasonographic diagnosis and intensive prenatal surveillance are essential for the early detection of cord entanglement and the prevention of fetal death. The need for in-hospital management and the exact gestational age for delivery continue to generate controversy in the literature (AU)

Stillbirth in diabetic pregnancies.

Pregnancy in women with pregestational diabetes is associated with high perinatal morbidity and mortality. Stillbirth accounts for the majority of cases with perinatal death. Intrauterine growth restriction, pre-eclampsia, foetal hypoxia and congenital malformations may be contributing factors, but more than 50% of stillbirths are unexplained. Majority of stillbirths are characterised by suboptimal glycaemic control during pregnancy. Foetal hypoxia and cardiac dysfunction secondary to poor glycaemic control are probably the most important pathogenic factors in stillbirths among pregnant diabetic women. There is thus a need for new strategies for improving glycaemic control to near-normal levels throughout pregnancy and for preventing and treating hypertensive disorders in pregnancy. Antenatal surveillance tests including ultrasound examinations of the foetal growth rate, kick counting and non-stress testing of foetal cardiac function are widely used. However, future research should establish better antenatal surveillance tests to identify the infants susceptible to stillbirth before it happens.

Spontaneous pregnancy loss mediated by abnormal maternal inflammation in rats is linked to deficient uteroplacental perfusion.

Abnormal maternal inflammation during pregnancy is associated with spontaneous pregnancy loss and intrauterine fetal growth restriction. However, the mechanisms responsible for these pregnancy outcomes are not well understood. In this study, we used a rat model to demonstrate that pregnancy loss resulting from aberrant maternal inflammation is closely linked to deficient placental perfusion. Administration of LPS to pregnant Wistar rats on gestational day 14.5, to induce maternal inflammation, caused fetal loss in a dose-dependent manner 3-4 h later, and surviving fetuses were significantly growth restricted. Pregnancy loss was associated with coagulopathy, structural abnormalities in the uteroplacental vasculature, decreased placental blood flow, and placental and fetal hypoxia within 3 h of LPS administration. This impairment in uteroplacental hemodynamics in LPS-treated rats was linked to increased uterine artery resistance and reduced spiral arteriole flow velocity. Pregnancy loss induced by LPS was prevented by maternal administration of the immunoregulatory cytokine IL-10 or by blocking TNF-α activity after treatment with etanercept (Enbrel). These results indicate that alterations in placental perfusion are responsible for fetal morbidities associated with aberrant maternal inflammation and support a rationale for investigating a potential use of immunomodulatory agents in the prevention of spontaneous pregnancy loss.

Ultrasonographically documented early pregnancy loss in an Asian elephant (Elephas maximus).

Early embryonic resorption or fetal loss is known to occur occasionally in captive elephants; however, this has mostly been reported anecdotally. The present study documents the case of a 24-year-old, multiparous Asian elephant cow that suffered embryonic death and resorption at around 18 weeks of gestation. From ovulation onwards, this female was sonographically examined 58 times. Blood was collected twice weekly for progestagen determination via enzyme immunoassay. On Day 42 after ovulation, a small quantity of fluid was detected in the uterine horn, which typically indicates the presence of a developing conceptus. Repeated inspections followed what appeared to be a normal pregnancy until Day 116. However, on Day 124, signs of embryonic life were absent. Progestagen concentrations started declining two weeks later, reaching baseline levels one month after embryonic death. Retrospectively, ultrasound examination revealed several abnormalities in the uterine horn. Besides an existing leiomyoma, multiple small cystic structures had formed in the endometrium at the implantation site and later in the placenta. These pathological findings were considered as possible contributors to the early pregnancy failure. PCR for endotheliotropic elephant herpes virus (EEHV) (which had occurred previously in the herd) as well as serology for other infectious organisms known to cause abortion in domestic animals did not yield any positive results. Although no definitive reason was found for this pregnancy to abort, this ultrasonographically and endocrinologically documented study of an early pregnancy loss provides important insights into the resorption process in Asian elephants.

Ependymal alterations in sudden intrauterine unexplained death and sudden infant death syndrome: possible primary consequence of prenatal exposure to cigarette smoking.

BACKGROUND: The ependyma, the lining providing a protective barrier and filtration system separating brain parenchyma from cerebrospinal fluid, is still inadequately understood in humans. In this study we aimed to define, by morphological and immunohistochemical methods, the sequence of developmental steps of the human ependyma in the brainstem (ventricular ependyma) and thoracic spinal cord (central canal ependyma) of a large sample of fetal and infant death victims, aged from 17 gestational weeks to 8 postnatal months. Additionally, we investigated a possible link between alterations of this structure, sudden unexplained fetal and infant death and maternal smoking. RESULTS: Our results demonstrate that in early fetal life the human ependyma shows a pseudostratified cytoarchitecture including many tanycytes and ciliated cells together with numerous apoptotic and reactive astrocytes in the subependymal layer. The ependyma is fully differentiated, with a monolayer of uniform cells, after 32 to 34 gestational weeks. We observed a wide spectrum of ependymal pathological changes in sudden death victims, such as desquamation, clusters of ependymal cells in the subventricular zone, radial glial cells, and the unusual presence of neurons within and over the ependymal lining. These alterations were significantly related to maternal smoking in pregnancy. CONCLUSIONS: We conclude that in smoking mothers, nicotine and its derivatives easily reach the cerebrospinal fluid in the fetus, immediately causing ependymal damage. Consequently, we suggest that the ependyma should be examined in-depth first in victims of sudden fetal or infant death with mothers who smoke.

Effect of excessive, hormonally induced intrauterine crowding in the gilt on fetal development on day 40 of pregnancy.

Selection for litter size may result in an increase in uterine crowding due to a faster increase in ovulation rate than in litter size. Increased ovulation rate does not result in a proportionally increased number of piglets born alive. In this study, the effect of ovulation rate on vitality characteristics of fetal-placental units at d 40 of pregnancy was investigated. For this, 43 Large White gilts were treated with hormones to induce superovulation. Average ovulation rate was 45.16 +/- 13.22; average number of vital fetuses at d 40 of pregnancy was 17.09 +/- 3.61 that weighed 11.26 +/- 1.99 g; their placenta weighed 31.88 +/- 14.79 g; and they occupied 11.69 +/- 4.90 cm of the uterus. Loss in oocytes (i.e., that did not result in a vital fetus at d 40) increased with increasing ovulation rate and occurred before (early mortality; P = 0.0003) and after implantation (late mortality, i.e., traces visible at d 40; P < 0.0001). With respect to the vital fetuses, increased ovulation rate resulted in decreased fetal (P = 0.0008) and placental weight (P = 0.0008) and decreased length of the area in the uterus that was occupied by the placenta (P = 0.0011). Strong correlations existed between placental and fetal weight [0.68; 95% confidence interval (CI) = 0.64 to 0.72], and placental weight and length (0.78; 95% CI = 0.74 to 0.82). Fetal-placental characteristics were weakly correlated to distance to the implantation sites of neighboring fetuses, a measure of crowdedness [-0.002 (95% CI = -0.042 to 0.038) with fetal weight to 0.16 (95% CI = 0.12 to 0.20) with placental length]. Increased ovulation rates, but more specifically increased late mortality rates, have negative effects on the remaining vital fetuses with respect to the fetal (P = 0.0085) and placental weight (P < 0.0001) and length of the implantation site (P = 0.0016). The most extreme effect was on placental weight, in which a uterus with <10 cases of late mortality was on average 25% greater than placental weight in a uterus with >18 cases of late mortality (P < 0.0001). Furthermore, increased ovulation rates resulted in decreased within litter variation for fetal (P = 0.0018) and placental weight (P = 0.0084). At increased ovulation rates, the number of live fetuses remained similar, but placental development is impaired and the growth of the fetus is retarded compared with reduced ovulation rate, with effects likely lasting into adult life.

Ductus venosus velocimetry in acute fetal acidemia and impending fetal death in a sheep model of increased placental vascular resistance.

We investigated whether hypoxemia without acidemia affects ductus venosus (DV) blood velocity waveform pattern in sheep fetuses with intact placenta and whether worsening acidemia and impending fetal death are related to changes in DV velocimetry in fetuses with increased placental vascular resistance. A total of 34 fetuses were instrumented at 115-136/145 days of gestation. Placental embolization was performed in 22 fetuses on the fourth postoperative day, 24 h before the experiment. The control group was comprised of 12 fetuses with intact placenta. The experimental protocol consisted of fetal hypoxemia that was induced by replacing maternal inhaled oxygen with medical air. To further deteriorate fetal oxygenation and blood-gas status, uterine artery volume blood flow was reduced by maternal hypotension. Fetuses that underwent placental embolization were divided into two groups according to fetal outcome. Group 1 consisted of 12 fetuses that completed the experiment, and group 2 comprised 10 fetuses that died during the experiment. DV pulsatility index for veins (PIV) and fetal cardiac outputs (COs) were calculated. Placental volume blood flow, fetal blood pressures, and acid base and lactate values were monitored invasively. On the experimental day, the mean gestational age did not differ significantly between the groups. In groups 1 and 2, the baseline mean DV PIV and fetal COs were not statistically significantly different from the control group. In the control group, the DV PIV values increased significantly with hypoxemia. In groups 1 and 2, the DV PIV values did not change significantly, even with worsening acidemia and imminent fetal death in group 2. During the experiment, the fetal COs remained unchanged. We conclude that fetal hypoxemia increases the pulsatility of DV blood velocity waveform pattern. In fetuses with elevated placental vascular resistance, DV pulsatility does not increase further in the presence of severe and worsening fetal acidemia and impending fetal death.

Study of the human hypoglossal nucleus: normal development and morpho-functional alterations in sudden unexplained late fetal and infant death.

This study evaluated the development and the involvement in sudden perinatal and infant death of the medullary hypoglossal nucleus, a nucleus that, besides to coordinate swallowing, chewing and vocalization, takes part in inspiration. Through histological, morphometrical and immunohistochemical methods in 65 cases of perinatal and infant victims (29 stillbirths, 7 newborns and 29 infants), who died of both unknown and known cause, the authors observed developmental anomalies of the hypoglossal nucleus (HGN) in high percentage of sudden unexplained fetal and infant deaths. In particular, HGN hypoplasia, hyperplasia, positive expression of somatostatin and absence of interneurons were frequently found particularly in infant deaths, with a significant correlation with maternal smoking.

Diverse placental pathologies as the main causes of fetal death.

OBJECTIVE: To estimate the occurrence of placental causes of fetal death in relation to different gestational ages and their clinical manifestations during pregnancy. METHODS: In a prospective cohort study conducted from 2002 to 2006, we studied 750 couples with singleton intrauterine fetal death after 20 weeks of gestation. Cause of death was classified according to the Dutch Tulip cause of death classification for perinatal mortality. Differences between groups for categorical data were evaluated by the Fisher exact test or chi test. RESULTS: The main causes were placental pathology (64.9%), congenital anomaly (5.3%), infection (1.9%), other (4.8%), and unknown (23.1%). The contribution of causes differed over gestational age periods. At lower gestational age, placental and unknown were the most dominant causes of death (34.8% and 41.7%, respectively); at higher gestational age, the relative importance of an unknown cause decreased and a placental cause increased (16.5% and 77.6%) (P<.001). Placental bed pathology was observed in 33.6% of all fetal deaths, with the highest occurrence between 24 0/7 and 31 6/7 weeks and a strong decline after 32 weeks. In contrast, contribution of developmental placental pathology (17.6%) increased after 32 weeks of gestation (P<.001), as did umbilical cord complications (5.2%) and combined placental pathology (5.4%). Solitary placental parenchyma pathology was less frequent (3.1%). Hypertension-related disease was observed in 16.1% (95% confidence interval [CI] 13.6-19.0) of the cohort, small for gestational age fetuses in 37.9% (95% CI 34.1-41.7), and diabetes-related disease in 4.1% (95% CI 2.8-5.8). CONCLUSION: Most fetal deaths were caused by a variety of placental pathologies. These were related to gestational age, and their clinical manifestations varied during pregnancy. LEVEL OF EVIDENCE: II.

Stillbirth classification--developing an international consensus for research: executive summary of a National Institute of Child Health and Human Development workshop.

Stillbirth is a major obstetric complication, with 3.2 million stillbirths worldwide and 26,000 stillbirths in the United States every year. The Eunice Kennedy Shriver National Institute of Child Health and Human Development held a workshop from October 22-24, 2007, to review the pathophysiology of conditions underlying stillbirth to define causes of death. The optimal classification system would identify the pathophysiologic entity initiating the chain of events that irreversibly led to death. Because the integrity of the classification is based on available pathologic, clinical, and diagnostic data, experts emphasized that a complete stillbirth workup should be performed. Experts developed evidence-based characteristics of maternal, fetal, and placental conditions to attribute a condition as a cause of stillbirth. These conditions include infection, maternal medical conditions, antiphospholipid syndrome, heritable thrombophilias, red cell alloimmunization, platelet alloimmunization, congenital malformations, chromosomal abnormalities including confined placental mosaicism, fetomaternal hemorrhage, placental and umbilical cord abnormalities including vasa previa and placental abruption, complications of multifetal gestation, and uterine complications. In all cases, owing to lack of sufficient knowledge about disease states and normal development, there will be a degree of uncertainty regarding whether a specific condition was indeed the cause of death.

Very early twin-to-twin transfusion syndrome and discordant activation of the renin-angiotensin system.

We present evidence of a first-trimester discordant renin-angiotensin system (RAS) response and structural abnormalities of the kidneys in twins with twin-to-twin transfusion syndrome (TTTS). A dark red fetus and a pale fetus were spontaneously delivered at 13.5 weeks of gestation following a double intra-uterine death. Pathological examination confirmed the placentation as monochorionic, with arteriovenous anastomoses on the chorionic plate. The donor twin had a normal heart and mildly hypoplastic kidneys, and the recipient twin had cardiomegaly and hypertrophic kidneys. Immunohistochemical analysis of the kidneys showed secretion of renin occurring in the donor but not in the recipient twin, more intense expression of angiotensin II receptor type 1 in the donor, and modifications of renal architectures in both twins. Renin protein appeared qualitatively higher in the placental territory of the recipient compared to that of donor. These findings indicate that hemodynamic discordance caused by vascular anastomoses may lead to serious physiologic and organic consequences as early as the first trimester. To our knowledge, this case presents the earliest first-trimester TTTS confirmed by a complete anatomopathological examination and is the first TTTS case to show a first-trimester discordant RAS response confirmed by immunohistochemistry.