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.

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.

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.

Tracing the molecular pathogenesis of antiphospholipid syndrome.

Fetal loss induced by antiphospholipid antibodies (aPLs) in mice is a complement-driven inflammatory condition. Engagement of the complement receptor C5aR on neutrophils induces expression of the principal initiator of the blood clotting mechanism, tissue factor (TF), and blocking this downstream event of complement activation prevents antibody-induced fetal loss. In this issue of the JCI, the study by Redecha et al. clarifies that in mice, the contribution of TF to this pathogenic mechanism is independent of its role in coagulation and thrombosis, but involves inflammatory signaling through the receptor PAR2 (see the related article beginning on page 3453). The study not only sheds light on a critical effector mechanism of aPL-induced fetal loss, but also suggests that treatment with statins, which decrease TF and PAR2 expression, may hold promise as a therapeutic approach to antiphospholipid syndrome-associated pregnancy complications.

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.

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.

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.

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.

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.

Prenatal developmental toxicity studies of inhaled methyl iodide vapor in rabbits reveal a susceptible window of exposure inducing late gestational fetotoxicity.

Methyl iodide (MeI), an intermediate used in the manufacture of some insecticides and pharmaceuticals, is under review for U.S. registration as a non-ozone-depleting alternative to methyl bromide in the pre-plant soil fumigation market. Guideline (OPPTS 870.3700) developmental toxicity studies in New Zealand White (NZW) rabbits showed dose-dependent increases in the litter proportions of late fetal deaths and postimplantation loss and/or decreased fetal body weight following inhalation exposure of pregnant rabbits to MeI during gestation days (GD) 6-28. A subsequent phased-exposure study was performed to pinpoint the critical window of gestational exposure that produced the rabbit fetotoxicity. Artificially inseminated NZW female rabbits were exposed to 20 ppm MeI vapors by whole-body inhalation (6 h/day) throughout major organogenesis and fetal development (GD 6-28), during early gestation (GD 6-14) or mid-gestation (GD 15-22) only, or during 2-day intervals late in gestation (GD 23-24, 25-26, or 27-28). No maternal or developmental toxicity was elicited from maternal exposure during GD 6-14, 15-22, or 27-28. However, MeI-related fetotoxicity, including increased litter proportions of late fetal deaths with or without corresponding decreases in fetal body weight, were observed for females exposed during GD 6-28 (p < .01), 23-24 and 25-26. Although the increase in late-stage fetal death for each of the 2-day exposures on GD 23-24 and GD 25-26 was not statistically significant, as noted for the combined total of fetal deaths during the GD 6-28 exposure, it can be deduced that the gestational window of GD 23-26 was the most susceptible window of exposure for eliciting developmental toxicity in rabbits exposed to MeI vapors.

Investigating the behavioural and physiological indicators of neonatal survival in pigs.

Survival is reduced in low birth weight piglets, which display poor thermoregulatory abilities and are slow to acquire colostrum. Our aim was to identify additional behavioural and physiological indicators of piglet survival incorporating traits reflective of both the intrauterine and extrauterine environment. Data were collected from 135 piglets from 10 Large White x Landrace sows to investigate which physiological measurements (e.g. individual placental traits), and which behavioural measurements (e.g. the quantification of piglet vigour), were the best indicators of piglet survival. Generalised linear models confirmed piglet birth weight as a critical survival factor. However, with respect to stillborn mortality, piglet shape and size, as measured by ponderal index (birth weight/(crown-rump length)(3)), body mass index (birth weight/(crown-rump length)(2)), respectively, and farrowing birth order were better indicators. With respect to live-born mortality, postnatal survival factors identified as crucial were birth weight, vigour independent of birth weight, and the latency to first suckle. These results highlight the importance of the intrauterine environment for postnatal physiological and behavioural adaptation and identify additional factors influencing piglet neonatal survival.

Diabetic-associated stillbirth: incidence, pathophysiology, and prevention.

All forms of diabetes during pregnancy are associated with an increased risk for stillbirth, defined as fetal death at greater than 20 weeks. The incidence of stillbirth in women who have diabetes has decreased dramatically with improved diabetes care. Diabetic-associated stillbirth is associated with hyperglycemia, resulting in fetal anaerobic metabolism with hypoxia and acidosis. Prevention of stillbirth in women who have diabetes hinges on intensive multidisciplinary prenatal care with control of blood sugars and appropriate fetal surveillance.

Thrombophilia and adverse pregnancy outcome.

This article focuses on the clinical evaluation and management of women who have thrombophilia-related placental vascular complications, including fetal loss, pre-eclampsia, intrauterine fetal growth restriction, and placental abruption. All are major causes of maternal and fetal adverse outcomes.

Maternal physiology and complications of multiple pregnancy.

Approximately 1% to 3% of all pregnancies in the United States are multiple gestations. The vast majority (97-98%) are twin pregnancies. Multiple pregnancies constitute significant risk to both mother and fetuses. Antepartum complications-including preterm labor, preterm premature rupture of the membranes, intrauterine growth restriction, intrauterine fetal demise, gestational diabetes, and preeclampsia-develop in over 80% of multiple pregnancies as compared with approximately 25% of singleton gestations. This article reviews in detail the maternal physiologic adaptations required to support a multiple pregnancy and the maternal complications that develop when these systems fail or are overwhelmed.

Ultrasonographic appearance of the conceptus, fetal heart rate and profiles of pregnancy-associated glycoproteins (PAG) and prostaglandin F2alpha-metabolite (PGF2alpha-metabolite) after induction of fetal death with aglepristone during early gestation in cattle.

A higher incidence of fetal losses, especially after the use of artificial reproduction techniques, asks for more intensive monitoring of bovine pregnancies. In this study, a model for fetal death (FD) was created by administering the antiprogesterone aglepristone twice, at Day 47 and 48 of gestation (n=5). Control heifers received the solvent (n=5). The temporal relationships between changes in ultrasonographic appearance of fetal fluids and membranes, fetal heart rate (FHR) and peripheral plasma levels of pregnancy-associated glycoprotein (PAG) and PGF2alpha-metabolite as determined by radioimmunoassay associated with FD were monitored at eight hour intervals around treatment. For the analysis of plasma levels the period under study was divided into five epochs (T1: before injection of aglepristone/solvent; T2: from first to second injection; T3: from second injection to FD; T4: from diagnosis of FD to 56 h later; T5: from 56 h to 104 h after diagnosis of FD). Control heifers produced healthy calves at term, but in treated heifers, FD occurred on average at 58 (range 48-80) h after first injection of aglepristone. Fetal death was always preceded by a visible reduction of the amount of allantoic fluid and by segregation of the allantochorionic membrane from the endometrium. FHR remained rather constant in both groups, but a (non-significant) drop in FHR around 8h before FD was diagnosed in four of five treated animals. All fetuses were expulsed after FD. Levels of PAG remained constant or even slightly increased in controls, but decreased in treated animals from T2 onward: levels during T4 and T5 significantly differed from those during T1 and from values in controls during T4 and T5 (P<0.01). PGF2alpha-metabolite levels did not change in the controls, but in the treated group they were significantly higher during T3 when compared to T1 (P<0.05). After this increase, a sharp decrease in PGF2alpha-metabolite level occurred, reaching a significantly lower level at T5 when compared to control animals (P=0.01). It is concluded, that FD induced by aglepristone is preceded by ultrasonographic visible changes in fetal membranes and fluids and a rise in PGF2alpha-metabolite and is followed by a drop in PAG and PGF2alpha-metabolite.

Mechanism of foetal wastage following immunoneutralization of riboflavin carrier protein in the pregnant rat: disturbances in flavin coenzyme levels.

Immunoneutralization of maternal RCP results in a greater than 90% decrease in the content and the incorporation of [2-14C]riboflavin into embryonic FAD as well as a percentage redistribution of both embryonic FMN and riboflavin. This is unaccompanied by any discernible changes in flavin distribution pattern in the maternal liver. Embryonic alpha-glycerophosphate dehydrogenase and NADPH-cytochrome c reductase register significant decreases in activities in the RCP antiserum-treated rats. These alterations readily explain the arrest of foetal growth culminating in pregnancy termination in the antiserum-treated animals.

Thrombophilia and pregnancy.

Pregnancy is hypercoagulable state. The field of thrombophilia; the tendency to thrombosis, has been developed rapidly and has been linked to many aspects of pregnancy. It is recently that severe pregnancy complications such as severe preeclampsia intrauterine growth retardation abruptio placentae and stillbirth has been shown to be associated with thrombophilia. Recurrent miscarriage and has also been associated with thrombophilia. Finally, thromboembolism in pregnancy as in the non-pregnant state is linked to thrombophilia. In this review all aspects of thrombophilia in pregnancy are discussed, and also all prophylactic and therapeutic implications.