BACKGROUND & AIMS: The response to activated protein C (APC) was investigated in 28 healthy women, non-carriers of the Arg506-Gln mutation in factor V, throughout pregnancy (gestation weeks 12, 20, 28, 32 and 37) and after the delivery. A suppression of APC response was observed which reached lowest values by week 28 (nAPC-ratio 0.78 +/- 0.13), sustained low up to the end of pregnancy and rose after delivery (1.11 +/- 0.22; P < 0.05). APC resistance (nAPC ratio < 0.75) was registered in 16 of the 28 women (57%). A reduction of APC ratio was directly related to its value in the non-pregnant state, being most pronounced in the women with the highest APC ratio. Factor VIII increased during pregnancy and correlated inversely to APC ratio (Z coefficient = -0.645, P < 0.0001). The correlation became weaker in the course of pregnancy, losing significance by week 32. This was explained by the differences in profiles of the two variablesthe lowest measured APC ratio preceded the peak of factor VIII in most cases. The most pronounced rise of factor VIII was found in the women with minimal levels of APC ratio between 0.8 and 0.7. These results allowed us to speculate that APC response is closely regulated during pregnancy, aiming to maintain a certain relevant level. Transitory reduction of APC response is connected to factor VIII and discussed as a prevalent mechanism of functional APC resistance during pregnancy.

背景与目标： 在整个妊娠期间 (妊娠第12、20、28、32和37周) 和分娩后，对28名健康妇女 (非因子V Arg506-Gln突变携带者) 的活化蛋白C (APC) 的反应进行了研究。观察到APC反应的抑制，其在第28周达到最低值 (nAPC比0.78 +/- 0.13)，持续到妊娠结束并在分娩后上升 (1.11 +/- 0.22; P <0.05)。28名女性中有16名 (57% 名) 出现APC耐药 (nAPC比值 <0.75)。APC比率的降低与其在非怀孕状态下的价值直接相关，在APC比率最高的女性中最为明显。因子VIII在怀孕期间增加，并与APC比率成反比 (Z系数 = -0.645，P <0.0001)。相关性在怀孕过程中变弱，到第32周失去意义。这可以通过两个变量的分布差异来解释，在大多数情况下，最低的APC比率先于因子VIII的峰值。在0.8和0.7之间APC比率最低的女性中发现了因子VIII的最明显升高。这些结果使我们能够推测APC反应在怀孕期间受到密切调节，旨在维持一定的相关水平。APC反应的暂时性降低与因子VIII有关，并被认为是怀孕期间功能性APC抵抗的普遍机制。

BACKGROUND & AIMS: :Cortisol is used in research as a biomarker of psychological stress. Logistical considerations argue for collecting as few samples as possible, balanced against diurnal rhythms and intra-individual variations. 100 pregnant women gave five saliva samples a day for 3 days, at waking, 30 min after waking, and 11:00 a.m., 5:00 p.m., and 9:00 p.m. Timing of collection was confirmed by monitors. Another sample was taken during a clinic visit. Using the 15 measures as the gold standard, correlations and mean area under the curve (AUC) were compared with subsets and the single clinic sample to evaluate alternate collection protocols. Five samples in 1 day, or protocols involving morning and night samples, had the highest correlations with mean AUC (correlation coefficient ranging from 0.82 to 0.88). Standardizing the clinic measurement to a single time of day did not substantially improve correlations with mean AUC. Correlations with measures of reported stress were also not strong.

背景与目标： : 皮质醇在研究中被用作心理压力的生物标志物。后勤方面的考虑主张收集尽可能少的样本，并与昼夜节律和个体内部变化保持平衡。100名孕妇每天在醒来时，醒来后30分钟以及上午11:00，下午5:00和下午9:00时每天提供五个唾液样本收集时间由监视器确认。在诊所就诊时采集了另一个样本。使用15项措施作为金标准，将相关性和曲线下平均面积 (AUC) 与子集和单个临床样本进行比较，以评估替代收集方案。1天内的5个样品或涉及早晨和夜间样品的方案与平均AUC的相关性最高 (相关系数范围从0.82到0.88)。将临床测量标准化为一天中的单个时间并没有显着改善与平均AUC的相关性。与报告的压力度量的相关性也不强。

BACKGROUND & AIMS: :Pregnancy is an evolutionarily important and mysterious process. The placenta, as the nutrient and gas exchange organ, plays an essential role during this process. In addition, the interaction between trophoblast and maternal immune cells at the maternal-fetal interface is also associated with successful pregnancy. Human leukocyte antigen (HLA) molecules on trophoblast cells are involved in protecting the fetus from maternal rejection. Trophoblast cells comprise three subpopulations, including syncytiotrophoblast cells, cytotrophoblast cells, and extravillous trophoblast cells, and these cells express different HLA molecules. Syncytiotrophoblast and extravillous trophoblast cells encounter maternal immune cells from different sources, such as blood or decidua. The increased γδ-T cells during human normal pregnancy indicate that these cells may play a role in this process. In peripheral blood, Vγ9Vδ2-T cells display cytotoxicity through the recognition of phosphoantigens derived from pathogens. However, HLA-E molecules protect the trophoblast cells from the cytotoxicity of Vγ9Vδ2-T cells through binding to the inhibitory receptor, CD94/NKG2A. In decidua, the main Vδ1-T cells maintain the pregnancy through the secretion of cytokines. In addition, the imbalance between Vγ9Vδ2-T and Vδ1-T cells, and the abnormal expression of the receptors on γδ-T cells were observed in adverse pregnancy.

背景与目标： 怀孕是一个进化上重要而神秘的过程。胎盘作为营养和气体交换器官，在此过程中起着至关重要的作用。此外，滋养细胞与母体-胎儿界面处的母体免疫细胞之间的相互作用也与成功怀孕有关。滋养细胞上的人类白细胞抗原 (HLA) 分子参与保护胎儿免受母体排斥。滋养层细胞包含三个亚群，包括合体滋养层细胞，细胞滋养层细胞和绒毛外滋养层细胞，这些细胞表达不同的HLA分子。合体滋养层细胞和绒毛外滋养层细胞会遇到来自不同来源的母体免疫细胞，例如血液或蜕膜。在人类正常怀孕期间增加的 γ δ-T细胞表明这些细胞可能在此过程中发挥作用。在外周血中，Vγ9Vδ2-T细胞通过识别源自病原体的磷酸抗原而显示出细胞毒性。然而，hla-e分子通过与抑制性受体CD94/NKG2A结合，保护滋养层细胞免受Vγ9Vδ2-T细胞的细胞毒性。在蜕膜中，主要的Vδ1-T细胞通过分泌细胞因子来维持妊娠。此外，在不良妊娠中观察到Vγ9Vδ2-T和Vδ1-T细胞之间的失衡以及 γ δ-t细胞上受体的异常表达。

BACKGROUND & AIMS: PROBLEM:It is unclear if the immunologic alterations induced by pregnancy could persist. METHOD OF STUDY:Antenatal rubella sero-negativity was correlated with gravidity, abortions and parity in 112 083 gravidae managed during 1997-2015, with further analysis stratified for factors known to influence rubella serology. RESULTS:The 10.2% sero-negative gravidae had different characteristics, and the incidence showed significant difference and positive trend (P<.001 for both) with gravidity, abortions and parity. The pattern remained consistent when analysis was stratified for advanced age, high body mass index and medical history, but was negated by hepatitis B virus infection except for abortions, and by high body mass index for parity. For gravidity 2-4, no difference in rubella sero-negativity was found between gravidae with all previous pregnancies ended in abortion vs delivery. CONCLUSION:Prior pregnancies diminished rubella immunity in a dose-dependent manner, which may be a reflection of the cumulative effect of pregnancy-associated maternal immunologic alteration.

背景与目标：

BACKGROUND & AIMS: :The objective of this study was to determine if very early ultrasonographic measurements obtained from human and baboon are comparable. For this purpose, the gestational, amniotic and yolk sacs, embryonic crown rump length (CRL) and heart rate were measured ultrasonographically between 35 and 47 days from the mean day of a three-day mating period in baboons (n=18) and between 42 to 58 days from fertilization as calculated from the CRL measurements in human pregnancies (n=82). Ultrasonographic measurements from both species were then plotted in the same graph using Carnegie stages of embryonic development as the independent variable to allow for visual comparisons. Mean gestational age at ultrasonographic studies was significantly different for humans and baboons (50.4 vs. 41 days, respectively; p>0.01). Significant correlations (p>0.01) were noted between ultrasonographic measurements and Carnegie stages of development in both humans and baboons. Only the gestational and the yolk sacs were significantly smaller in baboons than in humans (p>0.05). The findings that embryonic CRL, extra-embryonic space and heart rate are very similar between the 17th and 23rd Carnegie developmental stages make the baboon a promising surrogate of human pregnancy for investigations using celocentesis.

背景与目标： : 这项研究的目的是确定从人类和狒狒获得的非常早期的超声检查结果是否具有可比性。为此，妊娠、羊膜和卵黄囊，从狒狒的三天交配期的平均一天 (n = 18) 和受精后的42至58天之间，超声测量了胚胎冠的臀部长度 (CRL) 和心率 (n = 82)。然后使用卡内基胚胎发育阶段作为自变量，将两个物种的超声测量结果绘制在同一图中，以进行视觉比较。在超声检查研究中，人类和狒狒的平均胎龄显着不同 (分别为50.4天与41天; p>0.01)。在人类和狒狒的超声测量与卡内基发育阶段之间发现了显着的相关性 (p>0.01)。狒狒中只有妊娠和卵黄囊明显小于人类 (p>0.05)。在第17和第23卡内基发育阶段之间，胚胎CRL，胚胎外空间和心率非常相似的发现使狒狒成为人类怀孕的有前途的替代品，可用于使用celecentesis进行研究。

BACKGROUND & AIMS: :This study aimed to determine whether karyomapping can be applied to couples requiring preimplantation genetic diagnosis (PGD) for single gene disorder (SGD) and/or chromosomal rearrangement. 75/82 (91.5%) and 6/82 (7.3%) couples were referred for autosomal SGD and X-linked disease, respectively. One couple (1.2%) was referred for SGD and chromosomal rearrangement. Of 608 embryos, 146 (24%, 95% CI 21-28) day-3 and 462 (76%, 95% CI 72-79) blastocyst biopsies were performed. A total of 81 embryo transfers were performed; 16/81 (20%) were following day-3 embryo biopsy, 65/81 (80%) were following blastocyst biopsy and cryopreserved embryo transfer. Of 81 embryo transfers with known pregnancy outcome, 51 (63%, 95% CI 52-73) were on-going pregnancies, 6/81 (7%, 95% CI 3-15) resulted in first trimester miscarriages and 24/81 (30%, 95% CI 21-40) were failed implantations. Of the 51 on-going pregnancies, 15 (29%, 95% CI 19-43) couples had a singleton live birth at the time of write up. There have been no reports of abnormal prenatal, genetic testing or diagnosis of phenotype at birth. Karyomapping is reliable, efficient and accurate for couples requiring PGD for SGD and/or chromosomal rearrangement. Additionally, it provides aneuploidy screening, minimising risks of miscarriage and implantation failure.

背景与目标： : 这项研究旨在确定是否可以将核映射应用于需要单基因疾病 (SGD) 和/或染色体重排的植入前遗传学诊断 (PGD) 的夫妇。75/82 (91.5%) 和6/82 (7.3%) 夫妇分别被转诊为常染色体SGD和X连锁疾病。一对夫妇 (1.2%) 被指用于SGD和染色体重排。在608胚胎中，进行了146 (24%，95% CI 21-28) 第3天和462 (76%，95% CI 72-79) 胚泡活检。总共进行了81个胚胎移植; 16/81 (20%) 在第3天胚胎活检之后，65/81 (80%) 在囊胚活检和冷冻保存的胚胎移植之后。在81例已知妊娠结局的胚胎移植中，有51例 (63%，95% CI 52-73) 正在进行妊娠，6/81例 (7%，95% CI 3-15) 导致孕早期流产，24/81例 (30%，95% CI 21-40) 植入失败。在进行的51例怀孕中，有15例 (29%，95% CI 19-43) 夫妇在撰写文章时单胎活产。没有产前、基因检测或出生时表型诊断异常的报告。对于需要PGD进行SGD和/或染色体重排的夫妇，Karyomapping是可靠，高效和准确的。此外，它提供了非整倍性筛查，最大程度地减少了流产和植入失败的风险。

BACKGROUND & AIMS: :This article systematically reviews the literature pertaining to correlates of body dissatisfaction during pregnancy. A total of 8 electronic databases were searched and 251 papers identified, 56 of which met inclusion criteria. Full text scrutiny of these papers reduced the final list of reviewed papers to 22. Results of the review highlight that psychological factors were associated with body dissatisfaction during pregnancy, and noted the surfeit of studies examining the relationship was between body dissatisfaction and depression. It is concluded that the prevention of heightened body dissatisfaction during the reproductive phase will only be effective when models of risk factors have been examined systematically and rigorously.

背景与目标： : 本文系统地回顾了有关怀孕期间身体不满的相关文献。共检索8个电子数据库，鉴定出251篇论文，其中56篇符合纳入标准。对这些论文的全文审查将审查论文的最终清单减少到22篇。审查的结果强调，心理因素与怀孕期间的身体不满有关，并指出了大量研究身体不满与抑郁之间关系的研究。结论是，只有在系统和严格地研究了危险因素模型后，预防生殖阶段身体不满情绪加剧才有效。

BACKGROUND & AIMS: :Pregnancy encompasses substantial changes in vascular function to accommodate dramatic increases in blood volume and uteroplacental blood flow to the growing fetus. Despite increased hemodynamics, decreased peripheral resistance results in a reduction in mean arterial blood pressure. Vascular tone, and hence peripheral resistance, is determined by a delicate balance of constrictor and dilator capacities. In the normal physiological response to pregnancy, endothelial-derived hyperpolarization (EDH) has been shown to be a major contributor; both EDH and nitric oxide (NO) are predominantly involved in providing an increased vascular capacity for vasodilation. The ability of EDH and NO to adequately accommodate increased blood volume is tested in pathological states such as placental insufficiency or diabetes and both EDH and NO-dependent mechanisms seem to be impacted in these situations. Pregnancy complications also have an impact on the cardiovascular health of the offspring. In adult offspring born from complicated pregnancies, the data suggest that EDH mechanisms are largely maintained, whereas NO is commonly reduced. A diversity of EDH mechanisms may be useful in providing many targets for potential therapeutic avenues for compromised pregnancies; however, further research delineating the mechanisms of EDH and the interactions of NO and EDH, in normal and pathological pregnancies is required.

背景与目标： : 怀孕包括血管功能的重大变化，以适应血容量和子宫胎盘血流量的急剧增加。尽管血流动力学增加，但外周阻力降低会导致平均动脉血压降低。血管张力以及外周阻力是由收缩器和扩张器能力的微妙平衡决定的。在对妊娠的正常生理反应中，内皮衍生的超极化 (EDH) 已被证明是主要的贡献者; EDH和一氧化氮 (NO) 都主要参与增加血管舒张能力。在病理状态 (例如胎盘功能不全或糖尿病) 中测试了EDH和NO充分适应增加的血容量的能力，在这些情况下，EDH和NO依赖性机制似乎都受到影响。妊娠并发症也会对后代的心血管健康产生影响。在复杂怀孕出生的成年后代中，数据表明EDH机制在很大程度上得以维持，而NO通常会减少。EDH机制的多样性可能有助于为受损妊娠的潜在治疗途径提供许多靶标; 但是，需要进一步研究描述正常和病理性妊娠中EDH的机制以及NO和EDH的相互作用。

BACKGROUND & AIMS: BACKGROUND:Pharmacokinetic data for lopinavir in late pregnancy and in breastfeeding are limited, and no data for abacavir in breast milk are available. METHODS:Women in the Mma Bana Study initiated HAART from 18 to 34 weeks of gestation. We determined trough plasma and whole breast milk concentrations of lopinavir (LPV), abacavir (ABC), nevirapine (NVP), lamivudine (3TC) and zidovudine (ZDV) among separate subsets of pregnant and breastfeeding women, and in plasma of exposed infants. Lopinavir was measured 1 month after starting HAART or 1 month postpartum, and other drugs were measured 1 month postpartum. RESULTS:Sampling occurred a median of 14 h (range 11-17) from last maternal drug ingestion. Although 50% higher median LPV levels were seen in postpartum than antepartum plasma (8.29 μg/ml versus 5.51 μg/ml; P = 0.02), antepartum levels with standard LPV dosing were therapeutic for all women (> 1.0 μg/ml). Very low LPV levels (< 0.25 μg/ml) were detected in breast milk. Median ABC levels in breast milk were 85% of those in plasma (0.057 μg/ml versus 0.067 μg/ml). Breast milk concentrations of NVP and 3TC were 27% and 74% of plasma levels, respectively. At these trough maternal time points, only NVP was detectable in potentially inhibitory levels in breastfeeding infants, and most infants had non-detectable levels of LPV, ABC, ZDV and 3TC via maternal breast milk. CONCLUSIONS:Standard LPV dosing achieved therapeutic levels in pregnancy and no appreciable concentrations in breast milk. ABC is detectable in breast milk at similar concentrations to plasma, but does not result in appreciable infant exposure.

背景与目标：

BACKGROUND & AIMS: :This paper reviews US vital statistics to describe the increase in multiple births in the United States between 1977 and 1987 and clarify the participation of differing maternal ethnic and age groups to this trend. The projected needs for NICU beds and costs of handicaps are estimated based on the distribution of low birthweights in multiple gestations. The potential methods of changing the distribution of low birthweight infants in multiple pregnancies are discussed.

背景与目标： : 本文回顾了美国的生命统计数据，以描述美国1977年和1987多胞胎的增加，并阐明了不同的孕产妇种族和年龄组对这一趋势的参与。NICU床位的预计需求和残疾费用是根据多个妊娠中低出生体重的分布估算的。讨论了改变多胎妊娠中低出生体重婴儿分布的潜在方法。

BACKGROUND & AIMS: :This literature review and the recommendations therein were prepared for the American Gastroenterological Association Institute Clinical Practice and Economics Committee. The paper was approved by the Committee on February 22, 2006 and by the AGA Institute Governing Board on April 20, 2006.

背景与目标： : 本文献综述和其中的建议是为美国胃肠病学会研究所临床实践和经济委员会准备的。该文件得到了2006年2月22日委员会和AGA协会2006年4月20日理事会的批准。

BACKGROUND & AIMS: BACKGROUND:Thionamide induced agranulocytosis is associated with the presence of anti-neutrophil cytoplasmic antibodies (ANCA) in some patients. This poses a particular challenge when it occurs during pregnancy. AIMS:To report a case of a 31-year-old woman with Graves' disease who presented at 11 weeks gestation with propylthiouracil induced agranulocytosis. METHODS:After cessation of propylthiouracil the patient developed recurrent thyrotoxicosis, and underwent an elective subtotal thyroidectomy at 23 weeks gestation. RESULTS:The patient required postoperative thyroxine replacement therapy. Subsequent pregnancy was uneventful and she delivered a healthy baby boy at 41 weeks gestation. As part of our routine work up for agranulocytosis we measured C-ANCA levels, which were significantly elevated. CONCLUSION:This case highlights the association of propylthiouracil induced ANCA positivity and agranulocytosis. Second trimester subtotal thyroidectomy was safe and effective in treating this pregnant patient's thyrotoxicosis.

背景与目标：

BACKGROUND & AIMS: BACKGROUND:Breastfeeding does not reliably protect against pregnancy except during the first 6 months postpartum and only then if accompanied by amenorrhea. Reluctance to use other methods of contraception during lactation may result in unplanned pregnancy. The aims of this study were to describe, among women in rural Egypt attending for antenatal care the prevalence of pregnancy during breastfeeding, contraceptive practice and unintended pregnancy. Finally, the study assessed women's impressions of the effect of conception during breastfeeding on breast milk and on the health of the breastfed infant. STUDY DESIGN:A descriptive study using an interviewer-administered structured questionnaire for 2617 parous women attending a hospital in Egypt for antenatal care. RESULTS:More than 95% of women breastfed the child before their current pregnancy; 25.3% conceived while breastfeeding. Conception occurred during the first 6 months postpartum in 4.4%, before resumption of menstruation in 15.1% and while exclusively or almost exclusively breastfeeding in 28.1%. Only 10 pregnancies (1.5%) occurred when all the prerequisites of the lactational amenorrhea method of contraception (LAM) were present. Twenty-nine percent of pregnancies conceived during breastfeeding were unintended, 10% of women had considered terminating their pregnancy while 4.4% of them reported trying to do so. CONCLUSIONS:Pregnancy during breastfeeding is common in Egypt and is often unintended. There is great potential for using LAM, but it must be properly taught, and women should be encouraged to start using effective contraception as soon as any of the prerequisites of LAM expires.

背景与目标：

BACKGROUND & AIMS: :We investigated the expression of prion protein gene both on mRNA and protein levels in bovine and ovine female reproductive organs during gestation and various tissues of their fetuses. The fetal tissues of both species included brain, cotyledon, heart, intestine, kidney, liver, lung, and muscle. In cattle, prion protein gene (PRNP) transcripts were detected by semiquantitative RT-PCR in reproductive tissues such as ovary, oviduct, endometrium, myometrium, follicles, and granulosa cells. In various tissues of 2-month-old fetuses, higher expression levels were found in brain and cotyledon compared to the other tissues. To detect the expression of the gene transcript in in vivo preimplantation embryos and 1-month-old fetuses, real-time PCR was performed showing that the level of gene expression in zygote stage was significantly higher (p < or = 0.05) than that of the other stages. Sheep were categorized as resistant (RI) or high susceptible (R5) to scrapie according to their PRNP genotype. In both genotype groups, the PRNP mRNA was detectable in all tissues studied including ovary, oviduct, endometrium, myometrium, and caruncle of ewes and all tissues of 2-month-old fetuses of both groups. Comparison between reproductive organs demonstrates the highest expression level in caruncle tissue of R1 ewes, whereas the level was high in brain and low in liver of both R1 and R5 fetuses. In addition, real-time RT-PCR was performed in immature oocytes, mature oocytes, in vivo embryos at morula stage, and 1-month-old fetuses. The results showed that the relative expression levels of the ovine PRNP mRNA in mature oocytes and morula stage embryos were significantly lower than those in immature oocytes and 1-month-old fetuses (p < or = 0.05). Western blot analyses revealed the immunoreactive bands corresponding to the cellular prion protein (PrPc) in all maternal and fetal tissues examined of both cattle and sheep. Moreover, immunohistochemical staining implicated localization of the PrPc in ovarian cortex and ovarian medulla of both species. However, PrPc was not detected in oocyte, granulosa cells, theca cells, and corpus luteum in this study.

背景与目标： : 我们研究了妊娠期间牛和绵羊雌性生殖器官及其胎儿各个组织中prion蛋白基因在mRNA和蛋白质水平上的表达。这两个物种的胎儿组织包括大脑，子叶，心脏，肠，肾脏，肝脏，肺和肌肉。在牛中，通过半定量rt-pcr在生殖组织 (例如卵巢，输卵管，子宫内膜，子宫肌层，卵泡和颗粒细胞) 中检测到prion蛋白基因 (PRNP) 转录本。在2个月大的胎儿的各种组织中，与其他组织相比，大脑和子叶中的表达水平更高。为了检测基因转录本在体内植入前胚胎和1个月大的胎儿中的表达，进行了实时PCR，显示受精卵阶段的基因表达水平显着高于其他阶段 (p <或 = 0.05)。根据绵羊的PRNP基因型，绵羊被分为对瘙痒病的抗性 (RI) 或高敏感性 (R5)。在两个基因型组中，在所有研究的组织中都可以检测到PRNP mRNA，包括卵巢，输卵管，子宫内膜，子宫肌层和母羊以及两组2个月大胎儿的所有组织。生殖器官之间的比较表明，R1母羊的肉鸡组织中表达水平最高，而R1和R5胎儿的大脑中表达水平较高，肝脏中表达水平较低。此外，在未成熟卵母细胞，成熟卵母细胞，桑胚期的体内胚胎和1个月大的胎儿中进行了实时rt-pcr。结果表明，绵羊PRNP mRNA在成熟卵母细胞和桑胚期胚胎中的相对表达水平明显低于未成熟卵母细胞和1月龄胎儿 (p <或 = 0.05)。Western印迹分析显示，在所有检查的牛和羊的母体和胎儿组织中，与细胞病毒蛋白 (PrPc) 相对应的免疫反应带。此外，免疫组织化学染色暗示PrPc在两种物种的卵巢皮质和卵巢髓质中的定位。然而，在本研究中未在卵母细胞，颗粒细胞，卵泡膜细胞和黄体中检测到PrPc。

BACKGROUND & AIMS: OBJECTIVES:To evaluate maternal left ventricular (LV) systolic and diastolic function during normal pregnancy by non-invasive measures of LV contractility incorporating loading conditions. METHODS:Sixty-five women were examined using echocardiography, including tissue Doppler and two-dimensional speckle tracking, and subclavian artery pulse trace recordings at gestational weeks 14-16, 22-24 and 36, and at 6 months postpartum. RESULTS:The mean ± SD age of the women was 32.0 ± 4.6 years. Cardiac output and LV end-diastolic volume were on average 20% and 23% higher, respectively, during pregnancy, compared to that at 6 months postpartum (both, P < 0.01). LV ejection fraction, global peak systolic strain and rate-corrected LV velocity of circumferential fiber shortening (Vcfc) were 11%, 6% and 6% lower, respectively, at 36 weeks' gestation compared to at 6 months postpartum (all, P < 0.01). Afterload, measured as LV end-systolic wall stress (ESWS) increased by 10% between 14-16 and 36 weeks' gestation (P < 0.01). Analysis of the relationship between Vcfc and ESWS revealed that LV contractility was lower during pregnancy than at 6 months postpartum. Changes in diastolic function were demonstrated by 11% lower mitral early diastolic (E) wave velocity, 8% lower tissue Doppler early diastolic velocity (e') and 13% higher left atrial area (all P < 0.01) during pregnancy. Tissue Doppler E/e' remained unaltered (P = 0.78). CONCLUSIONS:During normal pregnancy, LV contractility is lower than it is at 6 months postpartum. This is associated with increased LV and left atrial area, whereas filling pressures are unchanged. These findings suggest that pregnancy exerts a larger load on the cardiovascular system than previously assumed.

背景与目标：