BACKGROUND & AIMS: :Synthetic non-conservative systems with parity-time (PT) symmetric gain-loss structures can exhibit unusual spontaneous symmetry breaking that accompanies spectral singularity. Recent studies on PT symmetry in optics and weakly interacting open quantum systems have revealed intriguing physical properties, yet many-body correlations still play no role. Here by extending the idea of PT symmetry to strongly correlated many-body systems, we report that a combination of spectral singularity and quantum criticality yields an exotic universality class which has no counterpart in known critical phenomena. Moreover, we find unconventional low-dimensional quantum criticality, where superfluid correlation is anomalously enhanced owing to non-monotonic renormalization group flows in a PT-symmetry-broken quantum critical phase, in stark contrast to the Berezinskii-Kosterlitz-Thouless paradigm. Our findings can be experimentally tested in ultracold atoms and predict critical phenomena beyond the Hermitian paradigm of quantum many-body physics.

背景与目标： : 具有奇偶时间 (PT) 对称增益-损失结构的合成非保守系统可以表现出伴随光谱奇异性的异常自发对称性破坏。最近关于光学和弱相互作用的开放量子系统中PT对称性的研究揭示了有趣的物理特性，但多体相关性仍然没有作用。在这里，通过将PT对称性的概念扩展到强相关的多体系统，我们报告了光谱奇异性和量子临界性的组合产生了一个奇异的普遍性类别，该类别在已知的临界现象中没有对应的。此外，我们发现了非常规的低维量子临界性，与Berezinskii-Kosterlitz-Thouless范式形成鲜明对比，由于非单调重归一化组在PT对称破坏的量子临界阶段流动，超流体相关性异常增强。我们的发现可以在超冷原子中进行实验测试，并预测量子多体物理学的Hermitian范式之外的关键现象。

BACKGROUND & AIMS: BACKGROUND:Fertility treatments are responsible for the rise in high order pregnancies in recent decades and their associated complications. Reducing the number of embryos returned to the uterus will reduce the rate of high order pregnancies. OBJECTIVES:To explore whether obstetric history and parity have a role in the clinician's decision making regarding the number of embryos transferred to the uterus during in vitro fertilization (IVF). METHODS:In a retrospective study for the period August 2005 to March 2012, data of twin deliveries > 24 weeks were collected, including parity, mode of conception (IVF vs. spontaneous), gestational age at delivery, preeclampsia, birth weight, admission to the neonatal intensive care unit (NICU), and Apgar scores. RESULTS:A total of 1651 twin deliveries > 24 weeks were record- ed, of which 959 (58%) were at term (> 37 weeks). The early preterm delivery (PTD) rate (< 32 weeks) was significantly lower with increased parity (12.6%, 8.5%, and 5.6%, in women with 0, 1, and ≥ 2 previous term deliveries, respectively). Risks for PTD (< 37 weeks), preeclampsia and NICU admission were significantly higher in primiparous women compared to those who had one or more previous term deliveries. Primiparity and preeclampsia, but not IVF, were significant risk factors for PTD. CONCLUSIONS:The risk for PTD in twin pregnancies is significantly lower in women who had a previous term delivery and decreases further after two or more previous term deliveries. This finding should be considered when deciding on the number of embryos to be transferred in IV.

背景与目标：

BACKGROUND & AIMS: :This study aimed to analyse the relationship between smoking and preterm birth (22-36 weeks) according to the main obstetric complications leading to the preterm birth, both overall and by parity. The EUROPOP study is a case-control study carried out between 1994 and 1997; 3,787 preterm and 5,602 full-term births were included, from maternity units in 10 countries, using the same protocol. Social, demographic and medical information was collected after delivery, from obstetric records and interviews with the mothers. Cases were classified according to the main obstetric complication (hypertension, haemorrhage, preterm premature rupture of membranes (PPROM), idiopathic spontaneous preterm labour, intrauterine growth retardation, all other causes). Multiple logistic regression analysis was used to control for confounders. Twenty four percent of cases and 20% of controls were smokers. Smoking during pregnancy, heavy smoking (>or=10 cigarettes per day) in particular, was a risk factor for preterm birth (aOR = 1.39, 95% CI:1.20-1.60). Smoking increased the risk of preterm delivery due to all obstetric complications other than hypertension. For these complications, the risk of preterm delivery associated with smoking was higher for multiparae (aOR = 1.46, 95% CI:1.24-1.71) than for primiparae (aOR = 1.18, 95% CI:1.00-1.38). In conclusion, smoking during pregnancy increases the risk of preterm birth among women with all obstetric complications except hypertension. This association is stronger in multiparae than in primiparae and the risk is higher for heavy smokers.

背景与目标： : 这项研究旨在根据导致早产的主要产科并发症 (总体和按胎次) 分析吸烟与早产 (22-36周) 之间的关系。EUROPOP研究是1994年和1997进行的病例对照研究; 使用相同的方案，包括来自10个国家的产科的3,787个早产和5,602个足月分娩。分娩后，从产科记录和与母亲的访谈中收集了社会，人口统计学和医学信息。根据主要的产科并发症 (高血压，出血，早产胎膜早破 (PPROM)，特发性自发性早产，宫内发育迟缓，所有其他原因) 对病例进行分类。采用多元logistic回归分析控制混杂因素。20 4% 的病例和20% 的对照是吸烟者。怀孕期间吸烟，尤其是大量吸烟 (每天> 或 = 10支香烟) 是早产的危险因素 (aOR = 1.39，95% CI:1.20-1.60)。由于高血压以外的所有产科并发症，吸烟增加了早产的风险。对于这些并发症，多发性 (aOR = 1.46，95% CI:1.24-1.71) 与吸烟相关的早产风险高于初产妇 (aOR = 1.18，95% CI:1.00-1.38)。总之，怀孕期间吸烟会增加除高血压以外的所有产科并发症妇女的早产风险。这种关联在多帕菌中比在初产妇中更强，并且重度吸烟者的风险更高。

BACKGROUND & AIMS: :In parity-time-symmetric (PT-symmetric) Hamiltonian theory, the optimal evolution time can be reduced drastically and can even be zero. In this article, we report our experimental simulation of the fast evolution of a PT-symmetric Hamiltonian in a nuclear magnetic resonance quantum system. The experimental results demonstrate that the PT-symmetric Hamiltonian system can indeed evolve much faster than the quantum system, and the evolution time can be arbitrarily close to zero.

背景与目标： : 在宇称时间对称 (PT-symmetric) 哈密顿理论中，最佳演化时间可以大幅减少，甚至可以为零。在本文中，我们报告了我们在核磁共振量子系统中PT对称哈密顿量快速演化的实验模拟。实验结果表明，PT对称哈密顿系统确实可以比量子系统更快地演化，并且演化时间可以任意接近零。

BACKGROUND & AIMS: BACKGROUND:To improve insurance coverage of mental health and substance-abuse services, the Federal Employees Health Benefits (FEHB) Program offered mental health and substance-abuse benefits on a par with general medical benefits beginning in January 2001. The plans were encouraged to manage care. METHODS:We compared seven FEHB plans from 1999 through 2002 with a matched set of health plans that did not have benefits on a par with mental health and substance-abuse benefits (parity of mental health and substance-abuse benefits). Using a difference-in-differences analysis, we compared the claims patterns of matched pairs of FEHB and control plans by examining the rate of use, total spending, and out-of-pocket spending among users of mental health and substance-abuse services. RESULTS:The difference-in-differences analysis indicated that the observed increase in the rate of use of mental health and substance-abuse services after the implementation of the parity policy was due almost entirely to a general trend in increased use that was observed in comparison health plans as well as FEHB plans. The implementation of parity was associated with a statistically significant increase in use in one plan (+0.78 percent, P<0.05) a significant decrease in use in one plan (-0.96 percent, P<0.05), and no significant difference in use in the other five plans (range, -0.38 percent to +0.23 percent; P>0.05 for each comparison). For beneficiaries who used mental health and substance-abuse services, spending attributable to the implementation of parity decreased significantly for three plans (range, -201.99 dollars to -68.97 dollars; P<0.05 for each comparison) and did not change significantly for four plans (range, -42.13 dollars to +27.11 dollars; P>0.05 for each comparison). The implementation of parity was associated with significant reductions in out-of-pocket spending in five of seven plans. CONCLUSIONS:When coupled with management of care, implementation of parity in insurance benefits for behavioral health care can improve insurance protection without increasing total costs.

背景与目标：

BACKGROUND & AIMS: OBJECTIVES:To determine fetal growth in low risk pregnancies at the beginning of the third trimester and to assess the relative importance of fetal gender and maternal parity. SETTING:Dutch primary care midwifery practice. STUDY DESIGN:Retrospective cohort study on 3641 singleton pregnancies seen at a primary care midwifery center in the Netherlands. Parameters used for analysis were fetal abdominal circumference (AC), fetal head circumference (HC), gestational age, fetal gender and maternal parity. Regression analysis was applied to describe variation in AC and HC with gestational age. Means and standard deviations in the present population were compared with commonly used reference charts. Multiple regression analysis was applied to examine whether gender and parity should be taken into account. RESULTS:The fetal AC and HC increased significantly between the 27th and the 33rd week of pregnancy (AC r2=0.3652, P<0.0001; HC r2=0.3301, P<0.0001). Compared to some curves, our means and standard deviations were significantly smaller (at 30+0 weeks AC mean=258+/-13 mm; HC mean=281+/-14 mm), but corresponded well with other curves. Fetal gender was a significant determinant for both AC (P<0.0001) and HC (P<0.0001). Parity contributed significantly to AC only but the difference was small (beta=0.00464). CONCLUSION:At the beginning of the third trimester, fetal size is associated with fetal gender and, to a lesser extent, with parity. Some fetal growth charts (e.g., Chitty et al.) are more suitable for the low-risk population in the Netherlands than others.

背景与目标：

BACKGROUND & AIMS: :We investigate the parity-time (PT) phase transition in photonic crystals with [Formula: see text] symmetry, with balanced gain and loss on dielectric rods in the triangular lattice. A two-level non-Hermitian model that incorporates the gain and loss in the tight-binding approximation was employed to describe the dispersion of the PT symmetric system. In the unbroken PT phase, the double Dirac cone feature associated with the [Formula: see text] symmetry is preserved, with a frequency shift of second order due to the presence of gain and loss. The helical edge states with real eigenfrequencies can exist in the common band gap for two topologically distinct lattices. In the broken PT phase, the non-Hermitian perturbation deforms the dispersion by merging the frequency bands into complex conjugate pairs and forming the exceptional contours that feature the PT phase transition. In this situation, the band gap closes and the edge states are mixed with the bulk states.

背景与目标： : 我们研究了具有 [公式: 参见文本] 对称性的光子晶体中的奇偶时间 (PT) 相变，在三角形晶格中的介电棒上具有平衡的增益和损耗。采用了在紧约束近似中包含增益和损耗的两级非Hermitian模型来描述PT对称系统的色散。在不间断的PT阶段，与 [公式: 参见文本] 对称性相关的双狄拉克锥特征得以保留，由于存在增益和损耗，其频移为二阶。对于两个拓扑上不同的晶格，具有真实本征频率的螺旋边缘状态可以存在于公共带隙中。在中断的PT相位中，非埃尔米特扰动通过将频带合并为复共轭对并形成具有PT相变特征的特殊轮廓来使色散变形。在这种情况下，带隙闭合，边缘状态与体状态混合。

BACKGROUND & AIMS: :Some adult human females show bone resorption (pitting) at the dorsal aspect of the pubis and preauricular area of the ilium. The etiology of pelvic bone resorption is attributed alternatively to reproduction and to pelvic anatomy. While most researchers infer that pelvic pitting is related to reproduction, only a few studies are based on women of known parity. Degree of pubic resorption is directly associated with both parity (Suchey et al.: Am. J. Phys. Anthropol. 51:517-539, 1979; Bergfelder and Hermann: J. Hum. Evol. 9:611-613, 1980) and age (Suchey et al.: Am. J. Phys. Anthropol. 51:517-539, 1979). The relationship between parity and degree of resorption of the preauricular area is equivocal, found to be significant by Dunlap (A Study of the Preauricular Sulcus in a Cadaver Population, Ph.D. dissertation, East Lansing, Michigan State University, 1981) but not by Spring et al. (Am. J. Phys. Anthropol. 79:247-252, 1989); both studies report that age is not associated with resorption of the preauricular area. Other mammals evidence public resorption, but the morphology of the preauricular area is less well known. This study addresses the issue on the etiology of pelvic bone resorption using a sample of Macaca mulatta (the free-ranging population from Cayo Santiago) for which parity and age at death are known for all specimens. The following results are reported. Resorption of the pubis is common among females but infrequent among males. Contrary to Rawlins (Am. J. Phys. Anthropol. 42:477-488, 1975), the degree of pubic resorption in female macaques is significantly related to both parity and age at death.(ABSTRACT TRUNCATED AT 250 WORDS)

背景与目标： : 一些成年女性在耻骨的背侧和the骨的耳前区表现出骨吸收 (点蚀)。骨盆骨吸收的病因可归因于生殖和骨盆解剖。虽然大多数研究人员推断骨盆凹陷与生殖有关，但只有少数研究是基于已知均等的女性。耻骨吸收的程度与宇称 (Suchey等人: Am. J. Phys. Anthropol. 51:517-539，1979; Bergfelder和Hermann: J. Hum. Evol. 9:611-613，1980) 和年龄 (Suchey等人: 上午。J. Phys. Anthropol. 51:517-539，1979)。地称与耳前区吸收程度之间的关系是模棱两可的，由Dunlap发现是显着的 (对尸体人群中的耳前沟的研究，博士学位论文，密歇根州立大学东兰辛，1981)，但不是Spring等人 (Am. J. Phys. Anthropol. 79:247-252，1989); 两项研究均报告年龄与耳前区域的吸收无关。其他哺乳动物证明公众吸收，但耳前区的形态鲜为人知。这项研究使用Macaca mulatta (来自Cayo Santiago的自由放养人群) 样本解决了骨盆骨吸收的病因学问题，所有标本都已知死亡年龄和死亡年龄。报告了以下结果。耻骨的吸收在女性中很常见，但在男性中很少。与罗林斯相反 (Am. J. Phys. Anthropol. 42:477-488，1975)，雌性猕猴的耻骨吸收程度与死亡时的同胎和年龄均显着相关。(摘要截短于250字)

BACKGROUND & AIMS: BACKGROUND:Chargaff's rule of DNA base composition, stating that DNA comprises equal amounts of adenine and thymine (%A = %T) and of guanine and cytosine (%C = %G), is well known because it was fundamental to the conception of the Watson-Crick model of DNA structure. His second parity rule stating that the base proportions of double-stranded DNA are also reflected in single-stranded DNA (%A = %T, %C = %G) is more obscure, likely because its biological basis and significance are still unresolved. Within each strand, the symmetry of single nucleotide composition extends even further, being demonstrated in the balance of di-, tri-, and multi-nucleotides with their respective complementary oligonucleotides. RESULTS:Here, we propose that inversions are sufficient to account for the symmetry within each single-stranded DNA. Human mitochondrial DNA does not demonstrate such intra-strand parity, and we consider how its different functional drivers may relate to our theory. This concept is supported by the recent observation that inversions occur frequently. CONCLUSION:Along with chromosomal duplications, inversions must have been shaping the architecture of genomes since the origin of life.

背景与目标：

BACKGROUND & AIMS: UNLABELLED:The aims of the study were to determine: (1) the relationship between parity and bone mineral density (BMD); (2) the relationship between parity and osteoporotic peripheral fractures. MATERIAL AND METHODS:The group studied included 730 postmenopausal women. Patients were separated into four groups according to the number of fullterm pregnancies, group 1: nulliparae, group 2: one to three pregnancies, group 3: four to five pregnancies, and group 4: six and more pregnancies. Additionally, patients were separated into three groups according to their ages, as <50 years, 50-59 years and >or=60 years. RESULTS:The median parity was 4 [0-20]. All the patients with parity greater than six had spine and hip BMD values significantly lower than values in the other groups (p<0.001). After adjustment for age and body mass index (BMI), decreased lumbar and total hip BMD were still associated to increased parity (analysis of covariance (ANCOVA), p=0.04 and 0.023, respectively). The relation between parity and lumbar BMD was highly significant among women aged <50 years (age-adjusted p=0.022), while there was no parity-spine BMD association in the other age groups. The relation between parity and hip BMD was seen only in the group 50-59 years (age-adjusted p=0.042). A positive history for peripheral fractures was present in 170 (23%) patients. There was relationship between parity and peripheral fractures neither in the whole population nor in the sub-groups according to age. DISCUSSION:The present study suggests that the BMD of the spine and hip decreases with an increasing number of pregnancies, and this situation shows variations in different age groups. However, there was no correlation between parity level and peripheral fractures.

背景与目标：

BACKGROUND & AIMS: OBJECTIVES:To clarify the correlation between preeclampsia and parity and to identify protective factors against preeclampsia in multiparous women with systemic lupus erythematosus (SLE). METHODS:We conducted a single-center, retrospective chart review study of 85 pregnant women. We used multiple logistic regression analysis to assess the association between parity and preeclampsia in women with SLE, and described the detailed clinical courses and management of four women with a history of severe preeclampsia and of a woman who experienced preeclampsia during her latest pregnancy. RESULTS:Multiparity was significantly associated with a low risk of preeclampsia (adjusted odds ratio: 0.08; 95% confidence interval: 0.01-0.95). One multiparous woman without a history of preeclampsia developed preeclampsia during her latest pregnancy; she had critical risk factors for preeclampsia, including chronic kidney disease and hypertension, and was not administered aspirin. In contrast, four multiparous women with a history of severe preeclampsia received adequate medications; they did not develop recurrent preeclampsia and delivered live newborns. CONCLUSIONS:Multiparity and maintenance therapy for SLE before and during pregnancy and preventive treatment for preeclampsia may improve outcomes in subsequent pregnancies.

背景与目标：

BACKGROUND & AIMS: :Chargaff's second parity rules for mononucleotides and oligonucleotides (CIImono and CIIoligo rules) state that a sufficiently long (> 100 kb) strand of genomic DNA that contains N copies of a mono- or oligonucleotide, also contains N copies of its reverse complementary mono- or oligonucleotide on the same strand. There is very strong support in the literature for the validity of the rules in coding and noncoding regions, especially for the CIImono rule. Because the experimental support for the CIIoligo rule is much less complete, the present article, focusing on the special case of trinucleotides (triplets), examined several gigabases of genome sequences from a wide range of species and kingdoms including organelles such as mitochondria and chloroplasts. I found that all genomes, with the only exception of certain mitochondria, complied with the CIItriplet rule at a very high level of accuracy in coding and noncoding regions alike. Based on the growing evidence that genomes may contain up to millions of copies of interspersed repetitive elements, I propose in this article a quantitative formulation of the hypothesis that inversions and inverted transposition could be a major contributing if not dominant factor in the almost universal validity of the rules.

背景与目标： : Chargaff的单核苷酸和寡核苷酸的第二个奇偶校验规则 (CIImono和CIIoligo规则) 指出，包含N个单核苷酸或寡核苷酸拷贝的足够长 (> 100 kb) 的基因组DNA链也在同一链上包含N个其反向互补的单核苷酸或寡核苷酸的拷贝。文献中非常支持规则在编码和非编码区域中的有效性，尤其是CIImono规则。由于对CIIoligo规则的实验支持还不那么完整，因此本文着重于三核苷酸 (三胞胎) 的特殊情况，研究了来自多种物种和王国的基因组序列的几个千兆字节，包括线粒体等细胞器和叶绿体。我发现，除某些线粒体外，所有基因组在编码和非编码区中都以非常高的准确性遵守CIItriplet规则。基于越来越多的证据表明基因组可能包含多达数百万个副本的穿插重复元素，我在本文中提出了一个定量的假设，即倒置和倒置转座可能是几乎普遍有效的主要因素，即使不是主导因素。规则。

BACKGROUND & AIMS: :Treatment options for gestational diabetes (GDM) are limited. In order to better understand mechanisms and improve treatments, appropriate animal models of GDM are crucial. Heterozygous db mice (db/+) present with glucose intolerance, insulin resistance, and increased weight gain during, but not prior to, pregnancy. This makes them an ideal model for GDM. However, several recent studies have reported an absence of GDM phenotype in their colony. We investigated several hypotheses for why the phenotype may be absent, with the aim of re-establishing it and preventing further resources being wasted on an ineffective model. Experiments were carried out across two laboratories in two countries (New Zealand and China), and were designed to assess type of control strain, diet, presence of the misty allele, and parity as potential contributors to the lost phenotype. While hyperleptinemia and pre-pregnancy weight gain were present in all db/+mice across the four studies, we found no consistent evidence of glucose intolerance or insulin resistance during pregnancy. In conclusion, we were unable to acquire the GDM phenotype in any of our experiments, and we recommend researchers do not use the db/+ mouse as a model of GDM unless they are certain the phenotype remains in their colony.

背景与目标： : 妊娠糖尿病 (GDM) 的治疗选择有限。为了更好地了解机制和改善治疗，合适的GDM动物模型至关重要。杂合子db小鼠 (db/) 在怀孕期间 (但不在怀孕之前) 表现出葡萄糖耐受不良，胰岛素抵抗和体重增加。这使它们成为GDM的理想模型。然而，最近的几项研究报告了其菌落中不存在GDM表型。我们调查了为什么表型可能不存在的几种假设，目的是重新建立表型并防止在无效模型上浪费更多资源。实验是在两个国家 (新西兰和中国) 的两个实验室中进行的，旨在评估对照菌株的类型，饮食，雾状等位基因的存在以及作为失去表型的潜在贡献者的胎次。尽管在这四项研究中，所有db/小鼠中都存在高瘦素血症和孕前体重增加，但我们没有发现怀孕期间葡萄糖耐受不良或胰岛素抵抗的一致证据。总之，我们在任何实验中都无法获得GDM表型，我们建议研究人员不要将db/小鼠用作GDM的模型，除非他们确定表型仍保留在其菌落中。

BACKGROUND & AIMS: OBJECTIVE:To define the prevalence of pelvic floor disorders in a non-institutionalised community and to determine the relationship to gender, age, parity and mode of delivery. DESIGN:A representative population survey using the 1998 South Australian Health Omnibus Survey. SAMPLE:Random selection of 4400 households; 3010 interviews were conducted in the respondents' homes by trained female interviewers. This cross sectional survey included men and women aged 15-97 years. RESULTS:The prevalence of all types of self-reported urinary incontinence in men was 4.4% and in women was 35.3% (P<0.001). Urinary incontinence was more commonly reported in nulliparous women than men and increased after pregnancy according to parity and age. The highest prevalence (51.9%) was reported in women aged 70-74 years. The prevalence of flatus and faecal incontinence was 6.8% and 2.3% in men and 10.9% and 3.5% in women, respectively. Pregnancy (> 20 weeks), regardless of the mode of delivery, greatly increased the prevalence of major pelvic floor dysfunction, defined as any type of incontinence, symptoms of prolapse or previous pelvic floor surgery. Multivariate logistic regression showed that, compared with nulliparity, pelvic floor dysfunction was significantly associated with caesarean section (OR 2.5, 95% CI 1.5-4.3), spontaneous vaginal delivery (OR 3.4, 95% CI 2.4-4.9) and at least one instrumental delivery (OR 4.3, 95% CI 2.8-6.6). The difference between caesarean and instrumental delivery was significant (P<0.03) but was not for caesarean and spontaneous delivery. Other associations with pelvic floor morbidity were age, body mass index, coughing, osteoporosis, arthritis and reduced quality of life scores. Symptoms of haemorrhoids also increased with age and parity and were reported in 19.9% of men and 30.2% of women. CONCLUSION:Pelvic floor disorders are very common and are strongly associated with female gender, ageing, pregnancy, parity and instrumental delivery. Caesarean delivery is not associated with a significant reduction in long term pelvic floor morbidity compared with spontaneous vaginal delivery.

背景与目标：

BACKGROUND & AIMS: :Pregnancy and childbirth are associated with hemodynamic changes and vascular remodeling. It is not known whether parity is associated with later adverse vascular properties such as larger arterial diameter, wall thickness, and lower distensibility. We used baseline data from 3283 women free of cardiovascular disease aged 45 to 84 years enrolled in the population-based Multi-Ethnic Study of Atherosclerosis. Participants self-reported parity status. Ultrasound-derived carotid artery lumen diameters and brachial artery blood pressures were measured at peak-systole and end-diastole. Common carotid intima-media thickness was also measured. Regression models to determine the association of carotid distensibility coefficient, lumen diameter, and carotid intima-media thickness with parity were adjusted for age, race, height, weight, diabetes mellitus, current smoking, blood pressure medication use, and total and high-density lipoprotein cholesterol levels. The prevalence of nulliparity was 18%. In adjusted models, carotid distensibility coefficient was 0.09×10−5 Pa−1 lower (P=0.009) in parous versus nulliparous women. Among parous women, there was a nonlinear association with the greatest carotid distensibility coefficient seen in women with 2 live births and significantly lower distensibility seen in primiparas (P=0.04) or with higher parity >2 (P=0.005). No such pattern of association with parity was found for lumen diameter or carotid intima-media thickness. Parity is associated with lower carotid artery distensibility, suggesting arterial remodeling that lasts beyond childbirth. These long-term effects on the vasculature may explain the association of parity with cardiovascular events later in life.

背景与目标： : 妊娠和分娩与血流动力学变化和血管重塑有关。尚不清楚奇偶性是否与后来的不利血管特性有关，例如较大的动脉直径，壁厚和较低的扩张性。我们使用了3283名年龄在45至84岁的无心血管疾病的女性的基线数据，这些女性参加了基于人群的多种族动脉粥样硬化研究。参与者自我报告的平价状态。在收缩期和舒张末期测量超声衍生的颈动脉管腔直径和肱动脉血压。还测量了颈总动脉内膜中层厚度。根据年龄，种族，身高，体重，糖尿病，当前吸烟，血压药物使用以及总和高密度脂蛋白胆固醇水平，调整了用于确定颈动脉扩张性系数，管腔直径和颈动脉内膜中层厚度与平价的关系的回归模型。nulliparity的患病率为18%。在校正模型中，产妇与未产妇相比，颈动脉扩张性系数低0.09 × 10-5 Pa-1 (P = 0.009)。在分娩妇女中，与2例活产妇女的最大颈动脉扩张系数和初产妇 (P = 0.04) 或较高胎次> 2 (P = 0.005) 的扩张系数存在非线性关联。对于管腔直径或颈动脉内膜中层厚度，未发现这种与奇偶性相关的模式。胎次与较低的颈动脉扩张性有关，表明动脉重塑持续到分娩后。这些对脉管系统的长期影响可能解释了胎次与以后生活中心血管事件的关联。