Inflammation-induced fetal growth restriction in rats is associated with altered placental morphometrics

Introduction

Evidence links alterations in placental shape and size to fetal growth restriction (FGR). Here we determined whether alterations in placental morphometrics are linked to FGR induced by abnormal maternal inflammation.

Methods

We used an inflammation-induced model of FGR in which pregnant rats receive lipopolysaccharide (LPS) on gestational days (GD) 13.5–16.5. Fetal weights were matched to various parameters of placental morphometrics including weight, area, minor and major axes lengths and thickness.

Results

Compared with saline administration, LPS administration was associated with altered placental morphometrics, including reduced placental weight, decreased placental area and a trend towards reduced placental thickness. When data were dichotomized as FGR or normal-sized fetuses within treatment groups, a significant increase in the placental-weight-to-fetal-weight ratio and placental thickness was observed only in the saline-associated FGR subgroup. Multivariable linear regression revealed that the lengths of the major and minor placental axes were predictors of fetal weight, regardless of treatment modality. Subgroup regression analysis by treatment revealed that the lengths of the major and minor placental axes were predictors of fetal weight in the saline-treatment group while only the minor placental axis was a predictor of fetal weight in the LPS cohort. Finally, placental area and the length of the minor placental axis were correlated with implantation site location only in the saline-treatment group.

Discussion/conclusion

These findings indicate that inflammation-induced FGR is associated with alterations in placental morphometrics. Our data reveal that the mechanisms leading to inflammation-induced FGR may be different from the mechanisms leading to idiopathic FGR.     

胎盘血管瘤的临床特点及病理分析

目的　探讨胎盘血管瘤的临床特点及病理大体观特征。方法　对我院收治的 12例胎盘血管瘤患者的临床资料作回顾性分析。结果　 ( 1)在 12例病理诊断为胎盘血管瘤的患者中 ,5例临床诊断为胎盘血管瘤 ;2例临床误诊为胎盘早剥血肿 ;1例误诊为脂肪瘤 ;1例误诊为胎盘囊肿 ;3例分娩后漏诊 ,直至胎盘病理检查时发现而诊断。 4例产前曾行彩色多普勒超声检查 ,2例获得诊断 ,2例漏诊。 ( 2 ) 12例患者中 ,3例发生早产 ,其中 2例并发羊水过多 ;2例并发妊娠高血压综合征 ;2例死胎 ;1例胎儿畸形。新生儿 3例苍白窒息 ,1例青紫窒息。 ( 3)胎盘病理大体观检查 ,肿瘤大小 2cm×2cm× 2cm至 11cm× 8cm× 8cm ;9例患者肿瘤为单个 ,2例患者为 2个 ;6例肿瘤颜色为暗红色 ,3例灰红色 ,1例淡黄色 ,1例部分暗红、部分灰白 ,1例部分暗红、部分淡黄。结论　 ( 1)胎盘血管瘤可引起孕妇早产、羊水过多、死胎及新生儿窒息等并发症。 ( 2 )胎盘血管瘤在产前不易诊断 ,彩色多普勒超声是产前诊断胎盘血管瘤的惟一辅助手段。 ( 3)胎盘血管瘤大体观肿瘤体积大小不一 ,颜色大多为暗红色 ;也可因夹杂不同组织或供血不足而呈黄色或灰白色     

胎盘细胞凋亡与胎儿生长受限关系的研究

目的　探讨胎盘细胞调亡与胎儿生长受限 (FGR)发生的关系。方法　应用透射电镜和DNA缺口末端标记法检测 18例FGR患者 (FGR组 )及 14例正常妊娠妇女 (正常妊娠组 )的胎盘细胞凋亡情况。同时观察两组的胎盘重量及新生儿平均出生体重。结果　FGR组胎盘凋亡细胞核比率为12 1‰ ,电镜下凋亡细胞核呈明显致密状 ,染色质结块 ,胎盘平均重量为 (2 3 6± 2 4)g ,新生儿平均出生体重为 (2 0 71± 42 8)g;正常妊娠组胎盘凋亡细胞核比率为 7 3‰ ,胎盘平均重量为 (3 5 4± 63 )g ,新生儿平均出生体重为 (3 411± 5 88)g。FGR组胎盘凋亡细胞核比率明显高于正常妊娠组 (P <0 0 5 )。结论　胎盘细胞凋亡增加与FGR的发生有关     

Immunohistochemical detection of meconium in the fetal membrane, placenta and umbilical cord

Objective

To develop the immunohistochemistry specific for meconium in the placenta, fetal membrane and umbilical cord.

Study design

We previously reported the specific presence of zinc coproporphyrin I (ZnCP-I) in human meconium and demonstrated the possible diagnostic use of an elevation in maternal plasma ZnCP-I levels in cases of amniotic fluid embolism. In this study, we developed a new specific monoclonal antibody for ZnCP-I and applied it to the immunostaining of meconium in the placenta, fetal membrane, and umbilical cord.

Results

Immunoreactivity of ZnCP-I clearly and specifically identified meconium in the placenta, fetal membrane, and umbilical cord. It was especially useful in cases of severe chorioamnionitis to detect meconium in the macrophages surrounded by numerous neutrophils. In more than half of the cases, meconium was detected in clear amniotic fluid at delivery, suggesting previous exposure.

Conclusions

Immunohistochemical detection of ZnCP-I is a highly sensitive histological diagnosis of meconium.     

胎盘早剥胎心监护的图形分析

目的 分析胎盘早剥异常胎心监护图形特征,总结图像规律,以提高早期诊治胎盘早剥的能力.方法 选取2015年1月至2019年11月中山大学附属第一医院产科收治的胎盘早剥且胎心监护异常的56例病例,按出现胎心监护异常时临产情况分为已临产组(25例)和未临产组(31例),并对其胎心监护图形等资料进行分析;按胎盘早剥产前诊断与漏...     

胎儿生长受限的病因研究进展

胎儿生长受限（FGR）又称宫内生长受限（IUGR）,是指胎儿在母体、胎儿自身以及环境因素影响下未达到其生长潜能,是产科常见疾病之一,也是我国围生儿死亡的主要原因之一。FGR可以引起多种围生儿不良妊娠结局,包括胎儿窘迫、低出生体质量儿、早产等,且与多种远期或成年疾病相关,如代谢综合征、心血管疾病。预防FGR的发生对于提高人口素质有重要意义,但引起FGR的因素众多,主要包括母体因素、胎儿因素及胎盘、脐带因素,各种因素并不只以单一的形式存在,全面了解其发生因素有助于预防该疾病的发生。对FGR的病因进行综述,以期为该疾病的预防提供理论基础。。     

Maternal growth restriction and stress exposure in rats differentially alters expression of components of the placental glucocorticoid barrier and nutrient transporters

The placenta plays a major role in the development of fetal growth restriction, which affects 10% of pregnancies and contributes to chronic adult disease risk. We have reported that female rats born small develop cardiometabolic dysfunction only during pregnancy. The physiological tests performed during pregnancy induced a maternal stress response as indicated by increased maternal corticosterone concentrations. This stress effected placental growth compared to females who were unhandled during pregnancy. Maternal stress and growth restriction independently program F2 offspring metabolic dysfunction. This study investigated the effects of maternal stress and growth restriction on placental and fetal metabolic parameters that may contribute to F2 offspring metabolic disease. Maternal growth restriction reduced F2 fetal weight whilst maternal stress reduced placental weight. Stressed mothers had reduced insulin and increased glucose concentrations, changes that were reflected in the fetus. Fetal β-cell number was reduced by maternal growth restriction, but was increased by stress exposure. Maternal growth restriction reduced placental Slc2a1, Igf2, Slc38a2 and Nr3c1 gene expression. Maternal stress decreased the expression of Slc2a1, Igf2, Slc38a2, Nr3c1, Slc2a3, Slc2a4, Nr3c2, Hsd11b2, Crhr1 and Ogt. Maternal birth weight effects on fetal weight were likely due to changes in placental nutrient transporter and Igf2 expression. On the contrary, maternal stress induced a systemic effect by altering maternal metabolic parameters, placental gene expression and fetal glucose and insulin concentrations. This study highlights the importance of informing pregnant women on effective ways to cope with stress during pregnancy to prevent adverse long-term disease outcomes in their children.     

Fetal sex and indicated very preterm birth: results of the EPIPAGE study

OBJECTIVE: This study was undertaken to explore the association between fetal sex, mode of onset of labor, and principal cause of very preterm birth.Study design The analysis uses data on 2624 very preterm singleton births less than 33 weeks' gestation from a prospective study of all very preterm births in 9 French regions in 1997. RESULTS: Fifty-seven percent of the spontaneous births were male versus 50.8% of births after medical decision (P=.005). This pattern was explained by sex differences in causes of preterm birth. Male infants had a greater incidence of very preterm birth after spontaneous labor (relative risk [RR]=1.42 [1.21-1.66]), but one third less risk of indicated preterm birth associated with hypertension both with and without growth restriction (RR=0.73 [0.55-0.97] and 0.77 [0.60-0.97]). CONCLUSION: These results support previous reports of greater male susceptibility to preterm labor. The finding that pregnancies carrying female infants have a greater predisposition to indicated very preterm birth associated with hypertension has not been reported previously and merits further study.     

Sex-specific differences in placental global gene expression in pregnancies complicated by asthma

Background

Chronic maternal asthma is associated with reduced growth of the female fetus and normal growth of the male fetus. The mechanisms that control the differential effects of maternal asthma on the fetus have not been fully elucidated but alterations in placental function may play a role. In the current study we have used microarray platform to examine fetal sex-specific global changes in placental gene expression in pregnancies complicated by asthma as compared to non-asthmatic subjects.

Methods

Placental RNA was extracted from 11 control subjects and 38 asthmatic subjects. Labeled cDNA was hybridized to an oligonucleotide chip with 1700 double spotted well-characterized human genes. Global gene expression data analysis and visualization were performed using the Binary Tree-Structured Vector Quantization (BTSVQ) software. Functional relationships of differentially expressed genes were assessed using protein-protein interaction database I2D, network analysis and visualization software NAViGaTOR and Ingenuity Pathway Analysis software.

Results

Overall, 65 genes were found to be altered in placentae of pregnancies complicated by asthma. Of these, only 6 genes were altered in male placentae. There were 59 gene changes in female placentae of asthmatic mothers relative to control placentae. Some of the sex-specific genes were associated with growth, inflammation and immune pathways.

Conclusion

There are sex-specific alterations in placental gene expression in the presence of maternal asthma. Given that many of the identified genes in the female placentae were associated with or involved in cellular growth and tissue development, these may contribute to the sexually dimorphic difference in fetal growth in response to maternal asthma.     

The lifespan of men and the shape of their placental surface at birth

Background

Tall men generally lead longer lives than short men. Within the Helsinki Birth Cohort, however, there is a group of boys among whom being tall when they entered school was associated with reduced lifespan. These boys had birthweights and maternal heights above the median for the cohort; but they tended to be lighter at birth than their mother’s body mass index (weight/height²) in pregnancy predicted. We suggested that, while they had grown rapidly in utero, their growth had faltered at some point; and their tallness at age seven was the result of a resumption during infancy of their rapid growth trajectory. We here examine the size and shape of their placentas at birth to gain further insight into their path of fetal growth.

Methods

We examined all cause mortality in the 1217 men who had birthweights and maternal heights above the median for the cohort. Their birth measurements included placental weight and the length and breadth of the placental surface.

Results

Shorter length of the placental surface was associated with increased mortality (p = 0.002). There was no similar trend with the breadth. Mortality rose as the difference between the length and breadth decreased, that is as the surface became rounder. The hazard ratio was 1.10 (1.03–1.18, p = 0.007) for every cm decrease in the difference. Among men with a round placental surface (length-breadth difference 2 cm or less) increased mortality was associated with lower birthweight (p = 0.03 or 0.005 allowing for mother’s body mass index) and shorter gestation, but not with lower head circumference or length.

Conclusion

Reduced lifespan among men is associated with a particular path of early growth. After rapid growth in early gestation, associated with tall maternal stature, soft tissue growth falters in mid-gestation. Rapid growth resumes in late gestation and continues through infancy.     

关于临产前后胎盘与胎膜中细胞凋亡的研究

目的　探讨胎盘与胎膜中细胞凋亡与分娩发动的关系。　方法　对 18例未临产剖宫产和 19例顺产病例的胎盘与胎膜组织 ,应用 TU NEL 法检测凋亡细胞 ,并计算出凋亡指数。　结果　未临产组与临产组羊膜上皮细胞、绒毛膜滋养细胞、胎盘绒毛滋养细胞及蜕膜的细胞凋亡指数分别为(2 5 .49± 1.72 ) %与 (33.78± 1.33) %、(2 6 .74± 2 .0 5 ) %与 (36 .32± 1.96 ) %、(41.0 6± 1.96 ) %、与(49.12± 2 .5 5 ) %、(32 .6 9± 2 .2 7) %与 (38.6 2± 2 .2 5 ) % ,两组之间差异有极显著性 (P<0 .0 1)。　结论　分娩发动可能与胎盘和胎膜组织中的细胞凋亡指数增加有关。     

Fetal umbilical cord oxygen values and birth to placental weight ratio in relation to size at birth

OBJECTIVE: Our purpose was to examine regulatory linkages between fetal oxygenation and fetal and placental growth. We determined umbilical cord PO (2) and oxygen saturation, fractional oxygen extraction, and birth to placental weight ratio values in relation to size at birth for a large tertiary hospital population delivering at term. STUDY DESIGN: The computerized perinatal database of St Joseph's Health Care London, London, Ontario, was used to obtain the umbilical cord gases, pH, birth weight, placental weight, and other selected information for all term, singleton, liveborn infants between January 1990 and December 1999 (N = 27,043). Oxygen saturation values were calculated from the umbilical cord PO(2) and pH data with a previously derived empirical equation; fractional oxygen extraction values were calculated from the umbilical cord oxygen saturation data. Size at birth was divided into the following 5 birth weight categories using neonatal growth standards: fetal growth restriction, <3%; borderline fetal growth restriction, >or=3% and <10%; appropriate for gestational age, >or=10% and 90% and 97%. RESULTS: Infants in the borderline fetal growth restriction and fetal growth restriction groups had umbilical vein and artery PO(2) and oxygen saturation values that were stepwise lower than respective values for infants in the appropriate for gestational age group. Conversely, infants in the borderline large for gestational age and large for gestational age groups had umbilical vein PO(2) and oxygen saturation values that were stepwise higher than respective appropriate for gestational age group values; infants in these groups showed no change in arterial PO (2) and oxygen saturation values. Therefore infants in the borderline fetal growth restriction and fetal growth restriction groups had fractional oxygen extraction values that were stepwise higher than the appropriate for gestational age group value, whereas values for infants in the borderline large for gestational age and large for gestational age groups remained unchanged. Birth weight was disproportional to placental weight for infants in the borderline fetal growth restriction and fetal growth restriction groups when compared with that of the infants in the appropriate for gestational age group, with the birth to placental weight ratio values stepwise decreased. Conversely, birth weight was proportional to placental weight for infants in the borderline large for gestational age and large for gestational age groups with the birth to placental weight ratio values thus unchanged when compared with that of the infants in the appropriate for gestational age group. CONCLUSION: We conclude that fetal oxygenation is related to size at birth across the entire range of birth weights as studied at term from macrosomic to growth-restricted infants; this conclusion supports oxygen as a primary determinant of fetal growth. However, there are differences in the linkage between fetal oxygenation and metabolic rate or growth for these cohort groups that may relate to underlying etiologic processes.     

Macrosomia has its roots in early placental development

Introduction

We sought to determine if early placental size, as measured by 3-dimensional ultrasonography, is associated with an increased risk of delivering a macrosomic or large-for-gestational age (LGA) infant.

Methods

We prospectively collected 3-dimensional ultrasound volume sets of singleton pregnancies at 11–14 weeks and 18–24 weeks. Birth weights were collected from the medical records. After delivery, the ultrasound volume set were used to measure the placental volume (PV) and placental quotient (PQ = PV/gestational age), as well as the mean placental and chorionic diameters (MPD and MCD, respectively). Placental measures were analyzed as predictors of macrosomia (birth weight ≥4000 g) and LGA (birth weight ≥90th percentile).

Results

The 578 pregnancies with first trimester volumes included 44 (7.6%) macrosomic and 43 (7.4%) LGA infants. 373 subjects also had second trimester volumes available. A higher PV and PQ were both significantly associated with macrosomia and LGA in both the first and second trimesters. Second trimester MPD was significantly associated with both outcomes as well, while second trimester MCD was only associated with LGA. The above associations remained significant after adjusting for maternal demographic variables such as race, ethnicity, age and diabetes. Adjusted models yielded moderate prediction of macrosomia and LGA (AUC: 0.71–0.77).

Conclusions

Sonographic measurement of the early placenta can identify pregnancies at greater risk of macrosomia and LGA. Macrosomia and LGA are already determined in part by early placental growth and development.     

Fetal venous Doppler in pregnancies with placental dysfunction and correlation with pH at birth

Objectives: To determine the correlation between ph at birth and venous Doppler parameters in pregnancies with placental dysfunction. Methods: This was a prospective cohort study of 58 pregnancies with the diagnosis of placental dysfunction between 26 and 34 weeks of gestation. Inclusion criteria were singleton pregnancies, abnormal umbilical artery (UA) Doppler, fetal growth restriction diagnosed by estimated fetal weight <10th centile for gestational age, intact membranes, and absence of fetal congenital abnormalities. The Doppler measurements were the following: UA pulsatility index (PI), ductus venosus (DV) pulsatility index for veins (PIV), intra-abdominal umbilical vein (UV) time-averaged maximum velocity (TAMxV) and blood flow and left portal vein (LPV) time-averaged maximum velocity (TAMxV) and blood flow. All Doppler parameters were transformed into z-scores (SD values from the mean) according to normative references. Results: The UA pH at birth showed a negative significant correlation with the DV-PIV (p = 0.004) and the DV-PIV z-score (p = 0.004), while LPV TAMxV (p = 0.004), LPV TAMxV z-score (p = 0.002), LPV blood flow (p = 0.01), LPV blood flow normalized (p = 0.04) and UV blood flow (p = 0.04) positively correlated with pH at birth. Multiple regression analysis was performed and the DV-PIV z-score was the variable that independently correlated with pH at birth (p = 0.002). Conclusions: the present results suggest that changes in fetal venous blood flow, mainly DV and LPV are useful in the management of cases with early onset placental insufficiency and that venous Doppler parameters correlate with pH at birth.     

Altered placental tryptophan metabolic pathway in human fetal growth restriction

IntroductionTryptophan is a substrate for kynurenine pathway metabolism in the placenta. We investigated if kynurenine metabolites change over gestation, if they are different between pregnancies with normal and fetal growth restriction (FGR), and if the oxygen environment modulated kynurenine pathway activity in the human placenta.MethodsTryptophan, kynurenine, and downstream kynurenine metabolites were determined in maternal venous blood, umbilical cord blood, and placental samples obtained in 1st and 3rd trimester pregnancies including FGR, and in the media of placental explants incubated with 20% or 5–8% O₂ for 24, 48 or 72 h.ResultsAll the major kynurenine metabolites were present in cord blood, and in general were higher than in maternal blood. IDO and TDO mRNA and protein expression, responsible for kynurenine production from tryptophan, were significantly lower in placentas from FGR pregnancies compared with control. Explants prepared from 1st and 3rd trimester placentas actively produced all the major kynurenine pathway metabolites which, together with expression of IDO, TDO, KYN-OHase and 3HAO mRNAs, were significantly lower after 24 h exposure to 5–8% O₂ compared to 20% O₂ConclusionsExpression and activity of the kynurenine pathway is present in the placenta from early gestation, and is down-regulated by hypoxia and in FGR pregnancies.     

孕妇外周血及胎盘组织中胎儿有核红细胞出现频率与胎儿生长受限

目的　探讨孕妇外周血及胎盘组织中胎儿有核红细胞 (nucleated red blood cell,NRBC)的出现频率与胎儿生长受限 (fetal growth restriction,FGR)的关系。　方法　对 2 0例孕 2 8～36周 ,年龄 2 1～ 30岁 (包括 9例 FGR)的孕妇外周血进行不连续密度梯度离心 ,对分离后的细胞进行制片 ,显微镜下进行 NRBC计数 ,比较组间差异 ;追随至终止妊娠时 ,对胎盘组织进行切片 ,显微镜下进行 NRBC计数 ,比较组间差异 ;显微操作法获取 5例单个 NRBC行引物延伸预扩增 (PEP)和聚合酶链反应 (PCR) ,验证其胎儿细胞来源。　结果　 9例 FGR妊娠妇女外周血中 NRBC数目从 12个 / 7ml～ 4 0个 / 7ml不等 ,平均为 2 2 .6个 / 7m l。而同孕龄正常妊娠妇女外周血中 NRBC数目从 0个 / 7ml～ 10个 / 7ml不等 ,平均为 5 .4个 / 7ml,两者间差异有极显著性 (P<0 .0 0 1) ;FGR妊娠妇女胎盘绒毛间质血管中 NRBC数目从 2个 / 2 0 HP～ 5个 / 2 0 HP不等 ,平均为 2 .8个 / 2 0 HP。而正常妊娠妇女则从 0个 / 2 0 HP～ 2个 / 2 0 HP不等 ,平均为 0 .6个 / 2 0 HP,两者间差异有显著性 (P<0 .0 5 )。　结论　FGR妊娠妇女其外周血与胎盘组织中 NRBC数目明显升高     

Placental weight,digitally derived placental dimensions at term and their relationship to birth weight

Objective.?A few recent studies have investigated the relationship between birth weight and digitally derived placental dimensions, and no standardised methodology has been used. The aims of this study are to compare manually derived placental measurements with those derived digitally and to establish the relationship of birth weight to the placental weight and circumference.

Methods.?Three hundred fifty-one consecutive unselected women with singleton pregnancy delivering in a tertiary maternity unit at 37–42 weeks were recruited. Manual and digital placental axis measurements (using calibrated digital imaging and ‘Image J’ software) were obtained and the circumference derived. The relationship between the two methods was assessed using a Bland–Altman plot analysed. The relationship between z-scores of birth weight, placental weight and placental circumference was investigated.

Results.?Manually and digitally obtained placental long axis, short axis and circumference measurements show close correlation (r?=?0.70, 0.70 and 0.83, respectively). The z score of birth weight is significantly correlated with the z score of placental weight (r?=?0.59, p?<?0.001) and z score placental digital circumference (r?=?0.40, p?<?0.001). Birth weight:placental weight ratio is 7.20 and birth weight:placental circumference?=?64.57?g/cm.

Conclusion.?There is close though not perfect agreement between the manual and digital placental measurements. Birth weight is strongly correlated with placental weight and circumference at term.     

Fetal fibronectin as a predictor of spontaneous preterm birth: a European perspective

Preterm birth (PTB) is estimated to account for 6–10% of all births worldwide with 13 million PTBs occurring annually and 1 million resulting in death. The diagnosis of spontaneous preterm labor and accurate prediction of preterm delivery is notoriously difficult. Identification of effective risk assessment markers can potentially improve outcomes by enabling targeted therapy while allowing efficient use of resources and avoiding unnecessary interventions. Advances in perinatal medicine have not reduced PTB and effective measures that improve outcome are yet to be established. However, considerable progress has been made in the development of accurate methods (fetal fibronectin and cervical length assessment) to predict PTB in both symptomatic and asymptomatic high-risk women. The excellent negative predictive value of fFN has the ability to facilitate decision-making regarding admission, in utero transfer, administration of antenatal corticosteroids and/or tocolysis and has been shown to be cost-effective. This review describes the European perspective on the use of fFN and describes ongoing European clinical studies, which are appropriately designed with meaningful endpoints, which will undoubtedly facilitate a better understanding of test accuracy and cost-effectiveness within different populations.     

胎盘OB mRNA表达与胎儿体重调控机制的初步研究

目的　检测不同胎龄和不同出生体重儿的胎盘组织肥胖基因 (obese,OB) m RNA的表达以及对母儿血 leptin(瘦素 )的影响 ,初步分析胎盘瘦素在围产期调控胎儿体重及维持正常妊娠的机制。　方法　随机选取正常分娩的母儿血及其胎盘组织 6 0例 ,根据胎龄分为 :2 9～ 30周 5例 ,～ 32周 6例 ,～ 34周 7例 ,～ 36周 10例 ,37周～ 32例。根据新生儿体重分为 :10 0 0～ 1999g9例 ,～2 999g2 1例 ,～ 3999g30例 ,分别采用放射免疫法及 RT- PCR技术 ,检测母儿血瘦素水平及胎盘组织 OB m RNA表达。　结果　随胎龄增加胎盘 OB m RNA的表达量逐渐下降 ,早产儿明显高于足月儿 (0 .30± 0 .19与 0 .0 9± 0 .0 5 ,P<0 .0 1) ,不同体重胎盘 OB m RNA的表达量差异性有显著 (根据体重分组 ,分别为 0 .4 7± 0 .16 ,0 .2 1± 0 .15 ,0 .0 9± 0 .0 5 ,P<0 .0 0 1)。胎盘 OB m RNA的表达量与母儿血瘦素水平、出生体重、胎龄、胎盘重量呈负相关。　结论　胎盘 OB m RNA的表达量随胎龄、体重增加逐渐下降 ,提示胎盘合成、分泌的瘦素可能作为一种外源性瘦素 ,在妊娠过程中对母儿体内内源性瘦素的产生起着重要的负调控作用 ,为胎儿体重增加和适应宫外环境提供保障。