Reference Intervals of Renal Function Set Established for Healthy Pregnant Women.

BACKGROUND: This cross-sectional study aimed to explore the variation trend of renal function for healthy pregnant women at different gestational ages and aimed to establish RIs for renal function set tests according to the trimester of pregnancy. METHODS: A total of 120 healthy pregnant women and 40 healthy non-pregnant women were enrolled in this study and divided into early trimester (1 - 13 weeks of gestation, n = 40), second trimester (14 - 27 weeks of gestation, n = 40), third trimester (≥ 28 weeks of gestation, n = 40), and a non-pregnant women group (n = 40). Analytes of UA, BUN, Cr, ß2-MG, Cys-C, RBP, NAG, CO2, HCY, C1q, and NGAL were measured by using the analytical systems of the Second Xiangya Hospital. The RIs were defined by using non-parametric 95% intervals. RESULTS: The RIs for UA, Cr, ß2-MG, NAG, CO2, Hcy, and C1q were established for the first and second trimester group and the third trimester group. There were huge differences after pregnancy. The RIs for BUN were different for the 1 - 13 weeks group and the after 14 weeks group. There were significant differences for NGAL in pregnant and non-pregnant women, but not for Cys-C and RBP. CONCLUSIONS: The RIs for renal function tests in pregnant women were established, thus providing clinical reference intervals for the clinicians.

Trimester-specific association between fetal growth and physical activity in pregnant women: total physical activity vs moderate-to-vigorous exercise.

OBJECTIVE: To investigate the trimester-specific associations between maternal total physical activity level vs moderate-to-vigorous exercise and fetal growth disorders. METHODS: We analyzed 2062 mother-neonate pairs participating in the longitudinal China Medical University Birth Cohort Study. The Pregnancy Physical Activity Questionnaire was used to assess the physical activity level of women during the three trimesters. A higher level of total physical activity was defined as meeting or exceeding the cohort-specific 75th percentile, and a higher level of exercise was defined according to the Physical Activity Guidelines for Americans. Fetal growth disorder was defined as small-for-gestational age (SGA) or large-for-gestational age (LGA) at birth. RESULTS: Of the neonates included in this study, 7.1% were SGA and 15.5% were LGA. A higher level of total physical activity during the first trimester (adjusted relative risk (aRR), 0.62 (95% CI, 0.42-0.91)) and second trimester (aRR, 0.62 (95% CI, 0.41-0.95)) was associated with a lower risk of SGA, and a higher level of total physical activity during the third trimester was associated with a lower risk of LGA (aRR, 0.73 (95% CI, 0.54-0.97)). When analyzing physical activity by subtype, a higher level of occupational physical activity during the first and second trimesters was associated negatively with SGA risk, and higher levels of occupational and low-intensity physical activity during the first trimester were associated negatively with LGA risk. No significant association was found between maternal adherence to the Physical Activity Guidelines for Americans and risk of fetal growth disorders. CONCLUSIONS: A higher total physical activity level during the first and second trimesters was associated with a decreased risk of SGA, whereas a higher total physical activity level in the third trimester was associated with a decreased risk of LGA. Pregnant women should be advised to increase their total physical activity levels instead of focusing on engaging in only moderate-to-vigorous exercise. © 2024 International Society of Ultrasound in Obstetrics and Gynecology.

Assessment of Thermal and Mechanical Indices as Acoustic Output Parameters Used in Obstetric Ultrasound in Saudi Arabia.

BACKGROUND: Patient safety is paramount in ultrasound procedures, particularly in obstetric ultrasounds involving both the mother and fetus. The thermal and mechanical indices (TI and MI) serve as crucial indicators of the acoustic output during ultrasound. Clinicians and specialists must know these indices and ensure they are within safe ranges. This study aimed to assess the parameters of acoustic output power employed in obstetric ultrasound (thermal and mechanical index). METHODOLOGY: A cross-sectional observational study conducted at Maternity and Children's Hospital in Al-Madina Al-Munawwarah, the data was collected from obstetric scanning of 411 pregnant females using a data collection sheet including gravida and women's age, gestational age, scan mode, scan time, and thermal and mechanical index (TI and MI) values. RESULTS: The study found that there were significant differences in safety indices measurement between different modes; in Pulsed Doppler, mean Thermal Index Bone (TIb) had the highest value (1.60±0.40), and the Mechanical Index (MI) was the lowest (0.68±0.33). There were insignificant differences in safety indices values in different modes in different trimesters. The thermal indices of soft tissue and bony structure (TIs and TIb) of brightness mode (B-mode) were constant in all trimesters, but the MI in the first trimester was lower than in the other trimesters. CONCLUSION: This study found significant differences in TIs, TIb, and MI in different modes of obstetric ultrasound. Pulsed Doppler ultrasonography had the highest TIb value and a lower MI value. The ultrasound acoustic exposure output parameters were within the standard's recommended limit.

Evaluation of anterior segment parameters between pregnancy trimesters and postpartum with pentacam scheimflug imaging: a prospective study.

PURPOSE: To evaluate the effect of pregnancy on the anterior chamber, corneal parameter, and intraocular pressure measurements; and compare the results between trimesters, postpartum and non-pregnant healthy age-matched women. METHODS: This prospective study included 41 pregnant women and 53 non-pregnant women. Four measurements were taken from the pregnant women, in each trimester and postpartum third month, and once from the control group. Of the individuals included in the study, anterior chamber depth (ACD), anterior chamber volume (ACV), K1 (flat keratometry), K2 (steep keratometry), Kmean (mean value of K1 and K2), anterior chamber angle (ACA), central corneal thickness (CCT), thinnest corneal thickness (TCT), astigmatism value (AST), corneal volume (CV), biometry, axial length (AL), spherical equivalent (SFEQ), intraocular lens power (ILP), VA (visual acuity) datas were recorded. RESULTS: We observed a statistically significant decrease in K2, CCT, ACD, AL and CV in the postpartum period (p = 0.025, p < 0.001, p = 0.029, p = 0.005, p = 0.004 respectively) and a statistically significant increase in ACV, CCT, and TCT as the gestational week progressed in the pregnant group (p = 0.007, p < 0.001, p = 0.025, respectively). A statistically significant decrease in IOP towards to the third trimester, and an increase in the postpartum period was observed (p < 0.001). We did not observe statistically significant changes in K1, Kmean, AST, ACA, VA, ILP, and SFEQ values. CONCLUSION: It is important to investigate the physiological changes that may occur during pregnancy, distinguish them from pathological changes, and avoid unnecessary treatment. We consider that it's also important to guide the timing of anterior segment surgeries such as cataract and refractive surgery and to prescribe glasses/contact lenses.

Trajectory of gestational weight gain is related to birthweight: The TAWS cohort study in China.

Few studies have reported the timing and amount of gestational weight gain (GWG) to prevent large-for-gestational-age (LGA) or small-for-gestational-age (SGA). This study aimed to evaluate the association of GWG velocity in each trimester with LGA or SGA based on data from the Taicang and Wuqiang cohort study (TAWS, n = 2008). We used a linear mixed model to evaluate the association of trimester-specific GWG velocity with birthweight categories and stratified by prepregnancy body mass index category and parity. For normal-weight pregnant women, mothers with LGA births had higher GWG velocities than mothers with appropriate-for-gestational-age (AGA) births in the first trimester (0.108 vs. 0.031 kg/week, p < 0.01), second trimester (0.755 vs. 0.631 kg/week, p < 0.01) and third trimester (0.664 vs. 0.594 kg/week, p < 0.01); in contrast, mothers with SGA births had lower GWG velocities than mothers with AGA births in the second trimester (0.528 vs. 0.631 kg/week, p < 0.01) and third trimester (0.541 vs. 0.594 kg/week, p < 0.01). For normal-weight pregnant women with AGA births, multiparous women had lower GWG velocities than primiparous women in the second (0.602 vs. 0.643 kg/week, p < 0.01) and third trimesters (0.553 vs. 0.606 kg/week, p < 0.01). Therefore, for normal-weight women, LGA prevention would begin in early pregnancy and continue until delivery and the second and third trimesters may be critical periods for preventing SGA; in addition, among normal-weight pregnant women with AGA births, multiparous women tend to have lower weight gain velocities than primiparous women.

B-flow/spatiotemporal image correlation M-mode ultrasound provides novel method to quantify spiral artery remodeling during normal human pregnancy.

OBJECTIVES: During human pregnancy, placental extravillous trophoblasts replace vascular smooth muscle and elastic tissue within the walls of the uterine spiral arteries, thereby remodeling them into distensible low-resistance vessels to promote placental perfusion. The present study determined whether B-flow/spatiotemporal image correlation (STIC) M-mode ultrasonography provides an in-vivo imaging method able to digitally quantify spiral artery luminal distensibility as a physiological index of spiral artery remodeling during the advancing stages of normal human pregnancy. METHODS: A prospective, longitudinal, observational study was conducted to quantify spiral artery distensibility (i.e. vessel luminal diameter at systole minus diameter at diastole) by B-flow/STIC M-mode ultrasonography during the first, second and third trimesters in 290 women exhibiting a normal pregnancy. Maternal serum levels of placental growth factor (PlGF) and soluble fms-like tyrosine kinase-1 (sFlt-1), growth factors that modulate important events in spiral artery remodeling, were quantified in a subset of the women in the first, second and third trimesters of pregnancy. RESULTS: Median (interquartile range (IQR)) spiral artery distensibility increased progressively between the first (0.17 (0.14-0.21) cm), second (0.23 (0.18-0.28) cm) and third (0.26 (0.21-0.35) cm) trimesters of pregnancy (P < 0.0001 for all). Median (IQR) spiral artery volume flow increased progressively between the first (2.49 (1.38-4.99) mL/cardiac cycle), second (3.86 (2.06-6.91) mL/cardiac cycle) and third (7.79 (3.83-14.98) mL/cardiac cycle) trimesters (P < 0.001 for all). In accordance with the elevation in spiral artery distensibility, the median (IQR) ratio of serum PlGF/sFlt-1 × 103 levels increased between the first (7.2 (4.5-10.0)), second (22.7 (18.6-42.2)) and third (56.2 (41.9-92.5)) trimesters (P < 0.001 for all). CONCLUSIONS: The present study shows that B-flow/STIC M-mode ultrasonography provides an in-vivo imaging technology to quantify digitally the structural and physiological expansion of the walls of the spiral arteries during the cardiac cycle as a consequence of their transformation into compliant vessels during advancing stages of normal human pregnancy. © 2024 International Society of Ultrasound in Obstetrics and Gynecology.

Changes in rate-pressure product associated with pregnancy.

BACKGROUND: In nonpregnant individuals, the rate-pressure product, the product of heart rate and systolic blood pressure, is used as a noninvasive surrogate of myocardial O2 consumption during cardiac stress testing. Pregnancy is considered a physiological cardiovascular stress test. Evidence describing the impact of pregnancy on myocardial O2 demand, as assessed by the rate-pressure product, is limited. OBJECTIVE: This study aimed to describe changes in the rate-pressure product for each pregnancy trimester, during labor and delivery, and the postpartum period among low-risk pregnancies. STUDY DESIGN: This was a retrospective cohort study that assessed uncomplicated pregnancies delivered vaginally at term. We collected rate-pressure product (heart rate × systolic blood pressure) values preconception, during pregnancy for each trimester (at ≤13 weeks + 6/7 days, at 14 weeks + 0/7 days through 27 weeks + 6/7 days, and at ≥28 weeks + 0/7 days), during the labor and delivery encounter (hospital admission until complete cervical dilation, complete cervical dilation until placental delivery, and after placental delivery until hospital discharge), and during the outpatient postpartum visit at 2 to 6 weeks after delivery. We calculated the percentage change at each time point from the preconception rate-pressure product (delta rate-pressure product). We used a mixed-linear model to analyze differences in the mean delta rate-pressure product over time and the influence of prepregnancy age, prepregnancy body mass index, and neuraxial anesthesia status during labor and delivery on these estimates. RESULTS: Our cohort comprised 316 patients. The mean rate-pressure product increased significantly from preconception starting at the third trimester of pregnancy and during labor and delivery (P≤.05). The mean delta rate-pressure product peaked at 12% and 38% in the third trimester and during labor and delivery, respectively. Prepregnancy body mass index was inversely correlated with the mean delta rate-pressure product changes (estimate, -0.308; 95% confidence interval, -0.536 to -0.80; P=.008). In contrast, neither the prepregnancy age, nor neuraxial anesthesia status during labor had a significant influence on this parameter. CONCLUSION: This study validates the transient but significant increase in the rate-pressure product, a clinical estimate of myocardial O2 demand, during uncomplicated pregnancies delivered vaginally at term. Pregnant individuals with lower prepregnancy body mass index experienced a sharper increase in this parameter. Patients who receive neuraxial anesthesia during labor and delivery experience similar changes in the rate-pressure product as those who did not.

[Association between maternal plasma one-carbon biomarkers during pregnancy and fetal growth in twin pregnancies].

Objective: To characterize the relationship between the levels of plasma methyl donor and related metabolites (including choline, betaine, methionine, dimethylglycine and homocysteine) and fetal growth in twin pregnancies. Methods: A hospital-based cohort study was used to collect clinical data of 92 pregnant women with twin pregnancies and their fetuses who were admitted to Peking University Third Hospital from March 2017 to January 2018. Fasting blood was collected from the pregnant women with twin pregnancies (median gestational age: 18.9 weeks). The levels of methyl donors and related metabolites in plasma were quantitatively analyzed by high-performance liquid chromatography combined with mass spectrometry. The generalized estimation equation was used to analyze the relationship between maternal plasma methyl donors and related metabolites levels and neonatal outcomes of twins, and the generalized additive mixed model was used to analyze the relationship between maternal plasma methyl donors and related metabolites levels and fetal growth ultrasound indicators. Results: (1) General clinical data: of the 92 women with twin pregnancies, 66 cases (72%) were dichorionic diamniotic (DCDA) twin pregnancies, and 26 cases (28%) were monochorionic diamniotic (MCDA) twin pregnancies. The comparison of the levels of five plasma methyl donors and related metabolites in twin pregnancies with different basic characteristics showed that the median levels of plasma choline and betaine in pregnant women ≥35 years old were higher than those in pregnant women <35 years old, and the differences were statistically significant (all P<0.05). (2) Correlation between plasma methyl donor and related metabolites levels and neonatal growth indicators: after adjusting for confounding factors, plasma homocysteine level in pregnant women with twins was significantly negatively correlated with neonatal birth weight (ß=-47.9, 95%CI:-94.3- -1.6; P=0.043). Elevated methionine level was significantly associated with decreased risks of small for gestational age infants (SGA; OR=0.5, 95%CI: 0.3-0.9; P=0.021) and low birth weight infants (OR=0.6, 95%CI: 0.4-0.9; P=0.020). Increased homocysteine level was associated with increased risks of SGA (OR=1.5, 95%CI: 1.0-2.2; P=0.029) and inconsistent growth in twin fetuses (OR=1.9, 95%CI: 1.0-3.7; P=0.049). (3) Correlation between the levels of plasma methyl donors and related metabolites and intrauterine growth indicators of twins pregnancies: for every 1 standard deviation increase in plasma choline level in pregnant women with twin pregnancies, fetal head circumference, abdominal circumference, femoral length and estimated fetal weight in the second trimester increased by 1.9 mm, 2.6 mm, 0.5 mm and 20.1 g, respectively, and biparietal diameter, abdominal circumference and estimated fetal weight increased by 0.7 mm, 3.0 mm and 38.4 g in the third trimester, respectively, and the differences were statistically significant (all P<0.05). (4) Relationship between plasma methyl donor and related metabolites levels in pregnant women with different chorionicity and neonatal birth weight and length: the negative correlation between plasma homocysteine level and neonatal birth weight was mainly found in DCDA twin pregnancy (ß=-65.9, 95%CI:-110.6- -21.1; P=0.004). The levels of choline, betaine and dimethylglycine in plasma of MCDA twin pregnancy were significantly correlated with the birth weight and length of newborns (all P<0.05). Conclusion: Homocysteine level is associated with low birth weight in twins, methionine is associated with decreased risk of SGA, and choline is associated with fetal growth in the second and third trimesters of pregnancy.

Cumulative effects of temperature on blood pressure during pregnancy: A cohort study of differing effects in three trimesters.

BACKGROUND: Little is known about the non-linear cumulative effects of temperature on blood pressure (BP) during pregnancy. We investigated the differing effects of daily ambient temperature on BP for up to 30 days in three trimesters. METHODS: The first, second, and third trimester analyses included 2547, 2299, and 2011 pregnant women, respectively, from a prospective cohort in Nanjing from January 2017 to January 2020. BP was measured at each follow-up visit. The individual daily temperature exposures were calculated for 30 days prior to the follow-up date. The Distributed Lag Non-linear Model was used to investigate the relationship between temperature and BP in each trimester. RESULTS: Temperatures under 15 °C elevate systolic, diastolic BP, and mean arterial pressure (SBP, DBP, and MAP) in the first trimester, while temperatures above 15 °C reduce SBP in the second and third trimesters. By using Distributed Lag Linear Models, we estimated that with a 1 °C decrease in daily temperature, the SBP and DBP increased by 0.32 (95 % CI: 0.12, 0.52) and 0.23 (95 % CI: 0.07, 0.39) mmHg, respectively, in the first trimester with a 20-day cumulative lag, while with a 1 °C increase in daily temperature, the SBP decreased by 0.23 (0.35, 0.10) mmHg in the third trimester with a 30-day cumulative lag. The significant effects of temperature mainly manifested between 2 and 4 weeks of exposure. CONCLUSIONS: Temperature has different effects on BP over three trimesters. Protective measures to reduce cold-related BP rise will help reduce the risk of hypertensive disorders of pregnancy.

Attention-guided deep learning for gestational age prediction using fetal brain MRI.

Magnetic resonance imaging offers unrivaled visualization of the fetal brain, forming the basis for establishing age-specific morphologic milestones. However, gauging age-appropriate neural development remains a difficult task due to the constantly changing appearance of the fetal brain, variable image quality, and frequent motion artifacts. Here we present an end-to-end, attention-guided deep learning model that predicts gestational age with R2 score of 0.945, mean absolute error of 6.7 days, and concordance correlation coefficient of 0.970. The convolutional neural network was trained on a heterogeneous dataset of 741 developmentally normal fetal brain images ranging from 19 to 39 weeks in gestational age. We also demonstrate model performance and generalizability using independent datasets from four academic institutions across the U.S. and Turkey with R2 scores of 0.81-0.90 after minimal fine-tuning. The proposed regression algorithm provides an automated machine-enabled tool with the potential to better characterize in utero neurodevelopment and guide real-time gestational age estimation after the first trimester.

Maternal non-steroidal anti-inflammatory drug exposure during pregnancy and risk of miscarriage: a systematic review and meta-analysis.

BACKGROUND: Numerous studies have suggested that non-steroidal anti-inflammatory drugs (NSAIDs) might be associated with increased risk of miscarriage. However, these results are conflicting and inconclusive. METHODS: We performed this systematic review and meta-analysis to assess the relationship between NSAIDs exposure and risk of miscarriage. A systematic literature search was conducted to identify relevant studies published from the time of database inception until June 2021. RESULTS: A total of ten studies involving 207,341 pregnant women were subjected to meta-analysis. There was no statistically significantly increased risk of miscarriage with the use of NSAIDs during pregnancy (OR = 1.37, 95% CI 0.99-1.88, p = 0.057). However, our findings showed that women exposed to NSAIDs around the time of conception were at increased risk of miscarriage (OR 2.32, 95% CI 1.16-4.66, p = 0.018). Furthermore, no significant association between NSAID use and miscarriage was evident during the first trimester of pregnancy (OR = 1, 95% CI = 0.83-1.2, p = 0.996), possibly attributable to the small sample size. CONCLUSION: Our findings indicate that NSAID exposure around the time of conception might be a risk factor for miscarriage. Further studies are needed to evaluate whether the risk varies by the type, dosage, or timing of NSAID exposure.

Determination of hand grip strength and its correlates during pregnancy: a cross-sectional study.

BACKGROUND: Pregnancy results in many changes, including reduced hand grip strength (HGS). However, good HGS is required for physical functions such as carrying and breastfeeding the baby after birth. The aim of this study was to determine the factors that may predict HGS during pregnancy. METHODS: The study was a cross-sectional study approved by the Research Ethics Committees of Kano State Ministry of Health and Aminu Kano Teaching Hospital in Kano, north-west, Nigeria. Pregnant women at the designated hospitals were included in the study if they had no serious comorbidities or any known neurological condition that affects the hands and the neck. Demographic characteristics and independent (predictor) variables (age, weight, height, BMI, maternity leave status, number of full-term deliveries, number of preterm deliveries, number of live births, number of abortuses, gravidity, trimester, systolic blood pressure, diastolic blood pressure, inter arm systolic BP difference [IASBP], inter arm diastolic BP difference [IADBP], and heart rate) of each of the participants were recorded by experienced therapists. The data were analysed using descriptive statistics, t-test, Pearson correlation coefficient and standard multiple regression. RESULT: One hundred and sixty-one pregnant women with mean age, 25.04 ± 4.83 years participated in the study. In the dominant hand, 120 participants (74.5%) had weak grip strength. In the non-dominant hand, 135 participants (83.9%) had weak grip strength. For the dominant hand, the total variance explained by the whole model was significant, 28.5%, F(11, 161) = 1.187, R2 = 0.081, p = 0.300 . In the final model, none of the variables significantly predicted HGS. However, systolic blood pressure contributed to the model more than any other variable (Beta = -0.155). For the non-dominant hand, the total variance explained by the whole model was not significant, 33.1%, F(11, 161) = 1.675, R2 = 0.111, p = 0.089 . In the final model, only systolic blood pressure (Beta = -0.254, p = 0.023) significantly predicted hand grip strength. CONCLUSION: Cardiovascular events or changes during pregnancy (such as change in systolic blood pressure) may be related to HGS in pregnant women. It is therefore, important for clinicians to pay attention to this, in planning rehabilitation strategies for pregnant women.

Prevalence of physical activity and associated factors among pregnant women: a cross-sectional population-based study in southern Brazil / Prevalência de atividade física e fatores associados entre gestantes: estudo transversal de base populacional no sul do Brasil

Abstract Objectives: to describe the prevalence of sufficient leisure-time physical activity (LPA) in the trimesters of pregnancy and to test its association with sociodemographic and contextual characteristics. Methods: cross-sectional study that in 2019 analyzed data from 3580 pregnant women residing in Santa Catarina, Brazil. LPA was categorized as "active" (150 minutes or more of LPA/week) and "inactive" (less than 150 minutes). Results: the prevalence for the recommended level of LPA was 15.3% (CI95%= 14.1-16.4) before pregnancy, gradually declining to 7.8% (CI95%= 7.3-8.7), 7.3% (CI95%= 6.58.2), and 5.8% (CI95%= 5.1-6.7) in the following trimesters of pregnancy. Higher level of education was associated with the four outcomes, increasing the chance of being active by 79% in the third trimester of pregnancy. In the second trimester, living in a neighborhood that stimulates physical activity increased the chance of being active by 39%. In the third trimester, having received guidance from a health professional was associated with an increase of 60% in the chance of practicing LPA. Conclusion: the prevalence of recommended LPA is low among pregnant women and living in a neighborhood favorable to outdoor practices, greater education level and receiving guidance from health professionals increased the chance of pregnant women to be active.

Resumo Objetivos: descrever a prevalência de atividade física no lazer (AFL) suficiente nos trimestres da gravidez e testar sua associação com características sociodemográficas e contextuais. Métodos: estudo transversal que analisou em 2019 dados de 3.580 gestantes residentes em Santa Catarina, Brasil. AFL foi categorizada como "ativa" (150 minutos ou mais de LPA / semana) e "inativa" (menos de 150 minutos por semana). Resultados: a prevalência para o nível recomendado de AFL foi de 15,3% (IC95%= 14,116,4) antes da gravidez, diminuindo gradualmente para 7,8% (IC95%= 7,3-8,7), 7,3% (IC95%= 6,5-8,2), e 5,8% (IC95%= 5,1-6,7) nos trimestres seguintes da gravidez. Maior escolaridade foi associada aos quatro desfechos, aumentando a chance de ser ativa em 79% no terceiro trimestre da gravidez. No segundo trimestre, morar em um bairro que estimula a atividade física aumentou em 39% a chance de ser ativa. Já no terceiro trimestre, ter recebido orientação de profissional de saúde esteve associado a um aumento de 60% na chance de praticar AFL. Conclusão: a prevalência de AFL recomendada é baixa entre gestantes e morar em bairro favorável a atividades ao ar livre, maior escolaridade e receber orientação de profissionais de saúde aumentam a chance de gestantes serem ativas.

Swedish intrauterine growth reference ranges for estimated fetal weight.

Fetal growth restriction is a strong risk factor for perinatal morbidity and mortality. Reliable standards are indispensable, both to assess fetal growth and to evaluate birthweight and early postnatal growth in infants born preterm. The aim of this study was to create updated Swedish reference ranges for estimated fetal weight (EFW) from gestational week 12-42. This prospective longitudinal multicentre study included 583 women without known conditions causing aberrant fetal growth. Each woman was assigned a randomly selected protocol of five ultrasound scans from gestational week 12 + 3 to 41 + 6. Hadlock's 3rd formula was used to estimate fetal weight. A two-level hierarchical regression model was employed to calculate the expected median and variance, expressed in standard deviations and percentiles, for EFW. EFW was higher for males than females. The reference ranges were compared with the presently used Swedish, and international reference ranges. Our reference ranges had higher EFW than the presently used Swedish reference ranges from gestational week 33, and higher median, 2.5th and 97.5th percentiles from gestational week 24 compared with INTERGROWTH-21st. The new reference ranges can be used both for assessment of intrauterine fetal weight and growth, and early postnatal growth in children born preterm.

Mid-trimester prediction of spontaneous preterm birth with automated cervical quantitative ultrasound texture analysis and cervical length: a prospective study.

The objective of this study was to evaluate a novel automated test based on ultrasound cervical texture analysis to predict spontaneous Preterm Birth (sPTB) alone and in combination with Cervical Length (CL). General population singleton pregnancies between 18 + 0 and 24 + 6 weeks' gestation were assessed prospectively at two centers. Cervical ultrasound images were evaluated and the occurrence of sPTB before weeks 37 + 0 and 34 + 0 were recorded. CL was measured on-site. The automated texture analysis test was applied offline to all images. Their performance to predict the occurrence of sPTB before 37 + 0 and 34 + 0 weeks was evaluated separately and in combination on 633 recruited patients. AUC for sPTB prediction before weeks 37 and 34 respectively were as follows: 55.5% and 65.3% for CL, 63.4% and 66.3% for texture analysis, 67.5% and 76.7% when combined. The new test improved detection rates of CL at similar low FPR. Combining the two increased detection rate compared to CL alone from 13.0 to 30.4% for sPTB < 37 and from 14.3 to 42.9% sPTB < 34. Texture analysis of cervical ultrasound improved sPTB detection rate compared to cervical length for similar FPR, and the two combined together increased significantly prediction performance. This results should be confirmed in larger cohorts.

The Association between Gestational Weight Gain in Each Trimester and Pregnancy Outcomes in Twin Pregnancies.

OBJECTIVE: Adequate maternal weight gain in twin pregnancies is associated with improved outcomes such as increased fetal growth and decreased incidence of preterm birth. However, it remains unclear when gestational weight gain has the greatest influence on pregnancy outcomes. Our objective was to identify at which time in a twin pregnancy does inadequate maternal weight gain have the greatest association with adverse pregnancy outcomes. STUDY DESIGN: This is a retrospective cohort study of women with twin pregnancies and normal prepregnancy body mass index (BMI, 18.5-24.9 kg/m2) who delivered at ≥24 weeks' gestation by a single maternal-fetal medicine practice between 2005 and 2017. Baseline characteristics and pregnancy outcomes were compared between women with and without adequate average gestational weight gain (weight gain per week based on the 2009 Institute of Medicine recommendations). This analysis was performed for weight gain over the entire pregnancy, as well as from 0 to 16, 16 to 24, and 24 weeks to delivery. Multivariable regression analysis was performed to control for potential confounding variables. RESULTS: A total of 609 women with twin pregnancies and normal prepregnancy BMI were included, of whom 386 (63.4%) had adequate average gestational weight gain over the entire pregnancy and 223 (36.6%) did not. Inadequate average gestational weight gain between 0 and 16 weeks' gestation was associated with a higher incidence of birthweight less than the 10th percentile for gestational age (adjusted odds ratio [aOR]: 1.67; 95% confidence interval [CI]: 1.11-2.51) and less than the 5th percentile for gestational age (aOR: 2.10; 95% CI: 1.29-3.40). Inadequate gestational weight gain between 16 and 24 weeks was associated with lower birthweight of the larger twin (ß: -0.09; p = 0.04). Inadequate weight gain from 24 weeks to delivery was associated with spontaneous preterm birth <37 weeks' gestation (aOR: 1.67; 95% CI: 1.13-2.47), <34 weeks' gestation (aOR: 4.32; 95% CI: 2.45-7.63), <32 weeks' gestation (aOR: 9.07; 95% CI: 3.66-22.48), and a lower incidence of preeclampsia (aOR: 0.31; 95% CI: 0.16-0.63). CONCLUSION: In twin pregnancies, gestational weight gain between 0 and 16 weeks as well as between 16 and 24 weeks is most associated with fetal growth, whereas gestational weight gain after 24 weeks is most associated with preterm birth. This may help elucidate the mechanism of action of the impact of gestational weight gain in twin pregnancies.

Changes in corneal biomechanics during pregnancy in Chinese healthy female.

PURPOSE: To evaluate the changes of corneal biomechanics and the intraocular pressure during pregnancy in a Chinese healthy female population. METHODS: A total of 222 unrelated Chinese females were recruited: 52 non-pregnant, 15 pregnant in the first trimester, 68 pregnant in the second trimester, and 87 pregnant in the third trimester. The intraocular pressure and corneal biomechanical parameters, including corneal-compensated intraocular pressure, Goldmann-correlated intraocular pressure, corneal hysteresis, and corneal resistance factor, were measured by an Ocular Response Analyzer G3. Central corneal thickness was measured by Lenstar (LS900). RESULTS: Corneal hysteresis and corneal resistance factor were significantly higher in pregnant women at the second and third trimesters. Corneal-compensated intraocular pressure was lower in women at the third trimester of pregnancy (p = 0.023), but the difference became insignificant after adjustment for corneal hysteresis. Central corneal thickness was marginally higher in pregnant women than non-pregnant women (p = 0.032). There was a negative correlation between corneal-compensated intraocular pressure and corneal hysteresis (r = -0.337, p < 0.001) and a positive correlation between central corneal thickness and corneal hysteresis (r = 0.711, p < 0.0001). After adjustment for corneal-compensated intraocular pressure, corneal hysteresis remained significantly higher in the second and third trimesters of pregnant women than non-pregnant women (p = 0.031, p = 0.005). CONCLUSION: This study revealed a significant increase in corneal hysteresis and corneal resistance factor in the second and third trimesters. The increase of corneal hysteresis was independent of corneal-compensated intraocular pressure, indicating pregnant females have unique characteristics in corneal-compensated intraocular pressure and corneal biomechanical properties that may be related to glaucoma and corneal ectatic diseases in pregnancy.

HYPOXIA AND REPRODUCTIVE HEALTH: Oxygen and development of the human placenta.

Development of the human placenta takes place in contrasting oxygen concentrations at different stages of gestation, from ~20 mmHg during the first trimester rising to ~60 mmHg at the start of the second trimester before gradually declining to ~40 mmHg at term. In view of these changes, the early placenta has been described as 'hypoxic'. However, placental metabolism is heavily glycolytic, supported by the rich supply of glucose from the endometrial glands, and there is no evidence of energy compromise. On the contrary, the trophoblast is highly proliferative, with the physiological low-oxygen environment promoting maintenance of stemness in progenitor populations. These conditions favour the formation of the cytotrophoblastic shell that encapsulates the conceptus and interfaces with the endometrium. Extravillous trophoblast cells on the outer surface of the shell undergo an epithelial-mesenchymal transition and acquire invasive potential. Experimental evidence suggests that these changes may be mediated by the higher oxygen concentration present within the placental bed. Interpreting in vitro data is often difficult, however, due to the use of non-physiological oxygen concentrations and trophoblast-like cell lines or explant models. Trophoblast is more vulnerable to hyperoxia or fluctuating levels of oxygen than to hypoxia, and some degree of placental oxidative stress likely occurs in all pregnancies towards term. In complications of pregnancy, such as early-onset pre-eclampsia, malperfusion generates high levels of oxidative stress, causing release of factors that precipitate the maternal syndrome. Further experiments are required using genuine trophoblast progenitor cells and physiological concentrations to fully elucidate the pathways by which oxygen regulates placental development.

Physical activity before and during pregnancy: A cohort study.

OBJECTIVE: To estimate physical activity (PA) in healthy women before and during pregnancy and to evaluate the features associated with moderate PA (MPA). METHODS: A prospective cohort study was conducted on women selected 14 weeks of pregnancy during 2013-2015 in primary public health service centers in southern Spain. Type, duration, and frequency of PA (IPAQ questionnaire in first, second, and third trimesters [T1, T2, T3]) were measured. Variables associated with MPA were evaluated using multiple logistic regressions controlling for age, pre-pregnancy obesity, level of education, number of living children, pre-pregnancy PA, and adherence to Mediterranean diet (AMD). RESULTS: Out of 463 women, MPA was estimated in 64% pre-pregnancy, and 54%, 61%, and 59% in T1, T2, and T3, respectively. MPA was associated with greater AMD in T2 (adjusted odds ratio [aOR] 1.17, 95% confidence interval [CI] 1.04-1.33) and T3 (aOR 1.16, 95% CI 1.02-1.31), previous PA (aOR 13.5, 95% CI 8.12-22.5 in T1; aOR 2.61, 95% CI 1.72-3.96 in T2; aOR 2.59, 95% CI 1.65-4.05 in T3), and pre-pregnancy obesity (aOR 2.97, 95% CI 1.28-6.89 in T1; aOR 2.69, 95% CI 1.23-3.60 in T3). CONCLUSION: PA decreased at the beginning of pregnancy, but compliance remained over 50%. MPA was associated with diet, pre-pregnancy PA, and obesity.

Maternal cardiac adaptation and fetal growth.

BACKGROUND: Pregnancies with small-for-gestational-age fetuses are at increased risk of adverse maternal-fetal outcomes. Previous studies examining the relationship between maternal hemodynamics and fetal growth were mainly focused on high-risk pregnancies and those with fetuses with extreme birthweights, such as less than the 3rd or 10th percentile and assumed a similar growth pattern in fetuses above the 10th percentile throughout gestation. OBJECTIVE: This study aimed to evaluate the trends in maternal cardiac function, fetal growth, and oxygenation with advancing gestational age in a routine obstetrical population and all ranges of birthweight percentiles. STUDY DESIGN: This was a prospective, longitudinal study assessing maternal cardiac output and peripheral vascular resistance by bioreactance at 11+0 to 13+6, 19+0 to 24+0, 30+0 to 34+0, and 35+0 to 37+0 weeks' gestation, sonographic estimated fetal weight in the last 3 visits and the ratio of the middle cerebral artery by umbilical artery pulsatility indices or cerebroplacental ratio in the last 2 visits. Women were divided into the following 5 groups according to birthweight percentile: group 1, <10th percentile (n=261); group 2, 10 to 19.9 percentile (n=180); group 3, 20 to 29.9 percentile (n=189); group 4, 30 to 69.9 percentile (n=651); and group 5, ≥70th percentile (n=508). The multilevel linear mixed-effects model was performed to compare the repeated measures of hemodynamic variables and z scores of the estimated fetal weight and cerebroplacental ratio. RESULTS: In visit 2, compared with visit 1, in all groups, cardiac output increased, and peripheral vascular resistance decreased. At visit 3, groups 1, 2, and 3, compared with 4 and 5, demonstrated an abrupt decrease in cardiac output and increase in peripheral vascular resistance. From visit 2, group 1 had a constant decline in estimated fetal weight, coinciding with the steepest decline in maternal cardiac output and rise in peripheral vascular resistance. In contrast, in groups 4 and 5, the estimated fetal weight had a stable or accelerative pattern, coinciding with the greatest increase in cardiac output and lowest peripheral vascular resistance. Groups 2 and 3 showed a stable growth pattern with intermediate cardiac output and peripheral vascular resistance. Increasing birthweight was associated with higher cerebroplacental ratio. Groups 3, 4, and 5 had stable cerebroplacental ratio across visits 3 and 4, whereas groups 1 and 2 demonstrated a significant decline (P<.001). CONCLUSION: In a general obstetrical population, maternal cardiac adaptation at 32 weeks' gestation parallels the pattern of fetal growth and oxygenation; babies with birthweight<20th percentile have progressive decline in fetal cerebroplacental ratio, decline in maternal cardiac output, and increase in peripheral vascular resistance.