The aim of this study was to assess the long-term metabolic effects of gestational exercise on women with overweight/obesity and their offspring 8–10 years post-intervention. We conducted a follow-up of a randomized controlled trial that originally investigated the effects of prenatal exercise on the incidence of gestational diabetes mellitus. Mother‒offspring pairs underwent comprehensive metabolic evaluations, including anthropometric measurements (weight, skinfold thickness, and body composition), blood pressure assessment, oral glucose tolerance tests, insulin release tests, and lipid profiling. A total of 118 mothers and 110 offspring were included in this longitudinal follow-up study. Compared with the controls, the mothers in the exercise group demonstrated superior glycemic control, with lower fasting plasma glucose [5.00 (4.61, 5.23) vs. 5.08 (4.89, 5.52) mmol/L, adj. P < 0.001], 2-h plasma glucose [6.54 (5.64, 8.10) vs. 7.17 (6.28, 9.59) mmol/L, adj. P < 0.001], fasting insulin [9.14 (6.38, 14.40) vs. 12.5 (9.52, 16.10) mU/L, adj. P < 0.001], and 2-h insulin [52.85 (40.60, 105.50) vs. 100.85 (66.90, 146.00) mU/L, adj. P < 0.001] levels, along with reduced insulin resistance [homeostasis model assessment of insulin resistance, HOMA-IR: 1.96 (1.47, 3.29) vs. 3.00 (2.10, 3.94), P = 0.008]. The mothers in the exercise group also exhibited improved body composition, including a lower body mass index (27.15 ± 3.25 vs. 29.45 ± 4.24 kg/m2, adj. P = 0.001), a lower fat percentage (36.31 ± 5.21

What is already known about this topic?:Elevated ferritin levels have been associated with increased insulin resistance, impaired insulin secretion, and heightened risk of type 2 diabetes in non-pregnant populations. However, the relationship between ferritin concentrations and the development of gestational diabetes mellitus (GDM) remains poorly understood. What is added by this report?:This study identified a U-shaped association between serum ferritin measured at 11-13 weeks of gestation and GDM risk, demonstrating that both low and high ferritin levels predict increased GDM incidence. Additionally, elevated ferritin concentrations at 16-19 weeks and 24-27 weeks of gestation were independently associated with greater GDM risk. What are the implications for public health practice?:These findings underscore the critical importance of monitoring serum ferritin throughout the first and second trimesters for early identification and prevention of GDM. Enhanced strategies are needed to improve clinical understanding and optimize the utility of ferritin assessment in prenatal care.

Background: Timely and accurate prenatal diagnosis of placenta accreta spectrum (PAS) is pivotal for improving maternal and fetal outcomes. However, the timing of PAS detection and its association with outcomes have rarely been explored. This study examined the association between the gestational week at which PAS was first detected by ultrasound and the clinical characteristics and outcomes of the disorder. Methods: This retrospective cohort study included PAS patients at a tertiary referral center over a 5-year period. Patients who underwent cesarean section with prenatal PAS diagnosis were classified according to the gestational age of the earliest ultrasound PAS detection (<28 weeks or ≥28 weeks). Patient characteristics and outcomes were obtained from the inpatient medical records. Univariate and multivariate robust-error-variance Poisson regression models were used to explore the associations between the timing of ultrasound diagnosis and the risk of intraoperative hemorrhage (≥1500 mL) as well as blood-product transfusion volume (≥800 mL). Results: The study included 166 PAS patients, of whom 39.2% were diagnosed before 28 weeks, and 77.1% delivered at or beyond 34 weeks (median: 35 weeks). Patients with PAS detected before 28 weeks (early detection group) experienced significantly higher intraoperative blood loss volume (median: 1500 mL vs. 800 mL) and red blood cell transfusion volume (median: 586 mL vs. 70 mL). In regression analysis, patients in the early-detection group were significantly more likely to experience blood loss ≥1500 mL and red blood cell transfusion ≥800 mL, and these associations remained significant after adjustment for invasive PAS and hysterectomy. When ultrasound-detection weeks were divided into 6 categories, early detection (<20, 20–24, and 24–28 weeks) was associated with a significantly higher risk of excessive blood loss and increased transfusion volume. Conclusions: PAS detected during the second trimester was associated with more adverse outcomes than cases identified later, highlighting the need for tailored management strategies. The association between gestational age of PAS detection and clinical outcomes warrants further investigation at both clinical and etiological levels.

Rectus sheath hematoma (RSH) is a rare cause of abdominal pain during pregnancy. In our case, a healthy pregnant woman presented with right upper abdominal pain at 33 weeks of gestation. Ultrasound showed a heterogeneous hypoechoic mass in the abdominal wall, which was suspected of being a rectus sheath hematoma. After half a day of conservative therapy, the progressive decrease in hemoglobin level suggested active bleeding into her rectus sheath. Consequently, surgery was initiated under general anesthesia. During the operation, we found that the right musculus rectus abdominis was ruptured and actively bleeding. The hematoma was removed, and the broken end of the bleeding rectus abdominis muscle was ligated. After the operation, a blood transfusion was given, and the patient was discharged from the hospital as scheduled. A healthy newborn was delivered by elective cesarean section at 39 weeks of gestation. We present this case to enhance the recognition of RSH during pregnancy. Although relatively rare, this condition manifests itself with an acute onset and severe symptoms. Timely and accurate diagnosis and management may effectively reduce the incidence of preterm delivery.

Cervical incompetence occurs when the cervix fails to maintain its normal morphology and function during second-trimester, leading to recurrent second-trimester miscarriages or preterm births. To standardize and guide the clinical diagnosis and treatment of cervical insufficiency in China, the Perinatal Medicine Branch of the Chinese Medical Association and the Obstetrics Group of the Chinese Society of Obstetrics and Gynecology developed this consensus by referencing related research evidence and so on. This consensus provides evidence-based analysis and recommendations on key clinical issues including the diagnosis of cervical incompetence, indications for cervical cerclage, surgical techniques, timing of intervention, perioperative management, and adjunctive therapies, offering evidence-based guidance for obstetric clinical practice.Practice guideline registration:International Practice Guidelines Registry and Transparency Platform (PREPARE-2024CN1155)

Pregnancy is a highly coordinated process that relies on the precise regulation of the extracellular matrix, cells, and various molecules at the maternal-fetal interface. As the fetus grows and amniotic fluid increases, the uterus undergoes adaptive remodeling, a process in which biomechanics plays an indispensable role. This review aims to systematically explore the biomechanical characteristics of the uterus and specifically elucidate the crucial regulatory roles of mechanical signals such as stiffness, shear stress, tension, and compression force in both physiological and pathological pregnancies. We focus on the remodeling of the extracellular matrix, the mechanical property changes of the maternal-fetal interface, and the associated mechanotransduction pathways, such as PIEZO1, integrins, and YAP/TAZ. Finally, we summarize the cutting-edge technologies used to investigate uterine biomechanics and discuss the clinical translational potential of targeting mechanical signaling pathways as novel diagnostic and therapeutic strategies for pregnancy complications. This review provides a comprehensive analysis of how biomechanical cues regulate uterine function at the molecular, cellular, and tissue levels.

Fetal premature atrial contractions (PACs) are the most common fetal arrhythmia, accounting for up to 90% of cases. Although predominantly benign and self-limiting, PACs carry a small but significant risk of adverse outcomes, including progression to supraventricular tachycardia (SVT), and heart failure. This review synthesizes current evidence on the epidemiology, etiology, and risk stratification of fetal PACs. We highlight the importance of M-mode and Doppler echocardiography in diagnosis and in distinguishing PACs from atrioventricular block (AVB). A risk-stratified management pathway is proposed: low-risk cases (isolated PACs, normal ventricular rate, no structural abnormalities) require weekly heart rate monitoring and routine obstetric care; high-risk cases-characterized by blocked PACs, bigeminy/trigeminy, frequent PACs, bursts of tachycardia, atrial septal aneurysm, heart failure, or associated congenital heart disease-warrant enhanced surveillance, multidisciplinary consultation, and consideration of antiarrhythmic therapy or timely delivery. Postnatal follow-up is essential to confirm resolution and manage late-onset SVT. Accurate diagnosis and risk-adapted intervention are critical to optimizing perinatal outcomes.

Abstract. Objective:. To investigate gestational age–specific variations in cervical length (CL) and evaluate the predictive ability of CL for preterm delivery (PTD) across different trimesters. Methods:. This retrospective longitudinal study included a total of 8659 women who delivered singleton live births between June 1, 2022, and December 31, 2024, at Peking University First Hospital. Associations between CL measured at ≤ 19+6, 20–24+6, and 28–33+6 gestational weeks and PTD were evaluated using receiver operating characteristic curve analysis and log-rank tests. Results:. CL showed substantial variability across gestational ages, with pronounced shortening observed during 28–33+6 weeks. Significant differences in CL distribution between women with PTD and those with term delivery emerged as early as 20–24+6 weeks. The predictive value of CL for PTD increased with advancing gestational age. Optimal CL thresholds for predicting PTD ≤ 34+6 weeks were 28 mm, 15 mm, and 10 mm at ≤ 19+6, 20–24+6, and 28–33+6 weeks, respectively, while corresponding thresholds for PTD < 37 weeks were 28 mm, 26 mm, and 10 mm. Women with CL below these cut-offs had significantly lower probabilities of term delivery. The 26-mm threshold at mid-gestation (20–24+6 weeks) closely aligned with the conventional 25-mm definition of short cervix, supporting the validity of the minimum P approach. The consistent 10-mm threshold in late gestation suggests that lower diagnostic cut-offs after 28 weeks may be required to guide clinical management. Conclusion:. CL progressively decreases with increasing gestational age and has emerged as a more potent predictor of PTD after 20 weeks of gestation. A short cervix in late pregnancy may be more appropriately defined as < 10 mm at 28–33+6 gestational weeks.

Background:Hypertensive disorders of pregnancy (HDP) are associated with adverse long-term maternal health outcomes, yet comprehensive evidence quantifying their impact on all-cause and cause-specific mortality, particularly among women with preeclampsia/eclampsia (PE/E) and gestational hypertension (GH), remains limited. Hence, we conducted a systematic review and meta-analysis to quantify the risks of all-cause and cause-specific mortality in women with a history of HDP. Methods:This study was conducted as a systematic review and meta-analysis. PubMed, Web of Science, Embase, and the Cochrane Library were searched from inception to 31 December 2024 and updated on 31 January 2026. Observational studies examining the association between HDP (particularly GH and PE/E) and subsequent all-cause mortality or disease-specific mortality were included. Pooled risk ratios (RRs) and 95% confidence intervals (CIs) were calculated using a random-effects model. Heterogeneity was assessed using I2 statistics and explored through subgroup analyses. Study quality was evaluated using the Risk of Bias in Non-randomised Studies of Interventions (ROBINS-I) tool. Publication bias was assessed using Begg's and Egger's tests and funnel plots. Certainty of evidence was assessed by the Grading of Recommendations Assessment, Development and Evaluation (GRADE). The study protocol was registered with the International Prospective Register of Systematic Reviews (PROSPERO) (number: CRD42024523936). Findings:53 studies were included in the systematic review, and 29 non-duplicated datasets comprising 14,221,347 individuals were included in the meta-analysis. A history of HDP was related to a 45% increased risk of all-cause mortality (RR = 1.45, 95% CI = 1.30-1.61; I2= 91.3%). Women with prior PE/E showed a 64% increased risk (RR = 1.64, 95% CI = 1.38-1.96; I2= 92.4%), whereas GH was associated with a 34% increased risk (RR = 1.34, 95% CI = 1.18-1.53; I2= 89.7%) of all-cause mortality. HDP and PE/E were also associated with mortality from cardiovascular diseases, endocrine, nutritional, metabolic disorders, genitourinary diseases, infections, and nervous system diseases. Subgroup analyses demonstrated consistent association across study characteristics and adjustment models. After excluding pregestational chronic hypertension, the association was attenuated but remained statistically significant (RR = 1.43, 95% CI = 1.23-1.66; I2= 93.5%). Heterogeneity was substantial. No evidence of significant publication bias was found. Certainty of evidence was rated as very low certainty. Interpretation:Women with a history of HDP, particularly PE/E, have a higher risk of all-cause mortality and cause-specific mortality. These findings highlight the importance of lifelong health monitoring in this population. Future studies should focus on recommended postpartum management protocols and long-term lifestyle intervention strategies to reduce long-term risks. Funding:Supported by the Noncommunicable Chronic Diseases-National Science and Technology Major Project and National High-Level Hospital Clinical Research Funding.

BACKGROUND:Maternal morbidity and mortality are one of the key indicators of social development and are among the most challenging public health problems. This study aimed to analyze the trends and burden of maternal disorders in China from 1990 to 2023. METHODS:The crude and age-standardized prevalence, mortality, and disability-adjusted life years (DALYs) for maternal disorders from 1990 to 2023 were analyzed using data on maternal disorders in China from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2023. The changing trends of prevalence, mortality, and DALYs were evaluated by the average annual percentage change (AAPC) calculated using a log-transformed linear regression model. The ranks of the leading causes for maternal disorders in terms of prevalence, mortality, and DALYs in 1990, 2015, and 2023 were estimated to determine the impact of changes in the fertility strategy on maternal disorder patterns as China implemented the two-child policy in 2015. RESULTS:In 2023, the age-standardized prevalence, mortality, and DALYs of maternal disorders among reproductive women aged 15-49 years in China were 193.04 (95% confidence interval [CI]: 192.56-193.54), 0.30 (95% CI: 0.28-0.32), and 27.78 (95% CI: 27.59-27.97) per 100,000 population, respectively. The prevalence showed a declining trend with fluctuations, and the mortality and DALYs both showed consistent decrease from 1990 to 2023, with AAPCs of -1.41 (95% CI: -1.92 to -0.90), -10.64 (95% CI: -11.18 to -10.11), and -9.37 (95% CI: -9.87 to -8.88), respectively. In terms of the leading cause of death among the 10 available maternal disorders in GBD, maternal hemorrhage ranked first in 1990 (3.53 per 100,000) but decreased to third in 2015 (0.10 per 100,000) and 2023 (0.05 per 100,000). Among the 10 available maternal disorders in GBD 2023, the prevalence of maternal hypertensive disorders changed from first in 1990 to second both in 2015 and 2023. The other direct maternal disorders became the leading causes of prevalence and DALY during 2015 to 2023. Indirect maternal deaths ranked as the leading cause of mortality during 2015 to 2023. CONCLUSIONS:There has been a substantial decline in prevalence, mortality, and burden of maternal disorders in China during the past three decades. However, additional efforts are needed for decreasing the burden of maternal disorders, especially for maternal hypertensive disorders.

Autophagy is a conserved degradation process in eukaryotic cells that is regulated by autophagy-related genes. During autophagy, lysosomes break down cytoplasmic proteins and damaged organelles. This process plays a pivotal role in cell growth and development, protection against metabolic stress and oxidative damage, and the maintenance of cellular homeostasis through the recycling of cellular components. Pregnancy encompasses crucial events such as decidualization, embryo implantation, and fetal growth. Abnormal autophagy has been implicated in several pregnancy complications and can significantly impact both maternal and fetal health. Understanding the relationship between autophagy and complicated pregnancies could open new avenues for potential therapeutic interventions to improve maternal and fetal outcomes. In this review, we summarize the intricate relationship between autophagy and pregnancy complications, elucidate the role of autophagy in gestation, and discuss the clinical significance of autophagy in mitigating or preventing pregnancy-related disorders.

INTRODUCTION:The first-trimester combined screening test for preterm preeclampsia (preterm-PE) has been implemented in Mainland China. This study aims, first, to evaluate the applicability of multiple of the median (MoM) models based on biomarkers developed and utilized in a European population for prospective preterm-PE screening in Mainland China; second, to assess the criteria for biomarker adjustment; and third, to establish criteria for continuous quality assurance in the screening process. MATERIAL AND METHODS:In this prospective multicenter cross-sectional study, 22 066 singleton pregnancies undergoing preterm-PE screening at 11 + 0-13 + 6 weeks were recruited from six tertiary hospitals in Mainland China. Mean arterial pressure (MAP) and placental growth factor (PlGF) were measured and converted to their equivalent MoM values using Fetal Medicine Foundation MoMing models incorporated in commercial software. PlGF levels were also determined using immunoassays developed in China. MoM and log10MoM distributions in the initial screened subjects were assessed for (1) central tendency and dispersion and (2) whether biomarker MoM distributions needed to be recentered. Biomarker central tendency and temporal stability both before and after recentering were assessed using Cumulative Sum plots. Distribution central tendency was considered good if its median MoM was between 0.95 and 1.05 and acceptable if between 1.05 and 1.10. RESULTS:After excluding the initial 400 pregnancies from each center, all PlGF, but not all MAP MoM distributions, required recentering. Post-recentering, the overall distribution median (95% confidence interval) MoM values for MAP and PlGF were 1.003 (1.001, 1.004) and 1.004 (0.996, 1.013), respectively. CONCLUSIONS:Chinese centers performing combined PE screening should assess biomarker MoM distributions in their initial cases to ensure that they conform to the expected central tendencies assumed in the risk estimation models.

Gastric cancer during pregnancy is uncommon but associated with a high maternal mortality rate. Symptoms are often non-specific, leading to delayed diagnosis due to pregnancy-related limitations in diagnostic approaches. The present report describes the case of a 35-year-old pregnant patient diagnosed with advanced gastric cancer. Although supportive therapies were administered, the condition of the patient deteriorated and they ultimately passed away shortly thereafter. The report highlights how early detection is vital for improving outcomes, underscoring the importance of prompt evaluation of maternal symptoms and targeted diagnostic examinations. Moreover, treatment strategies should be tailored according to the cancer stage and the developmental stage of the fetus. Notably, metastatic sites of gastric cancer during pregnancy can include the placenta, ovaries, lungs, bones and breasts, with fetal metastasis posing a notable clinical concern.

Placenta Accreta Spectrum (PAS) is a severe obstetric disorder characterized by excessive trophoblast invasion into the uterine myometrium, leading to life-threatening hemorrhage at delivery. While closely monitored, the molecular drivers of its progression remain poorly defined, hindering predictive and therapeutic strategies. Here, we employed longitudinal quantitative proteomics on maternal plasma from five PAS patients across gestation. We identified Keratin 6A (KRT6A) as a key biomarker whose plasma levels increase with PAS progression. Immunohistochemistry confirmed the specific upregulation of KRT6A in trophoblasts at the maternal-fetal interface in PAS. Functional studies demonstrated that KRT6A overexpression significantly enhances the migration and invasion capabilities of trophoblast cell lines in vitro, without affecting proliferation or apoptosis. Integrative bioinformatics analysis linked KRT6A to the activation of the MYC signaling pathway, a known driver of invasiveness. Our data establish KRT6A as a plasma biomarker correlating with PAS severity and a functional regulator of trophoblast invasiveness. These findings suggest a novel mechanism wherein KRT6A-mediated enhancement of trophoblast invasion, potentially via MYC signaling, contributes to PAS pathogenesis. This work provides a potential circulating biomarker for monitoring PAS progression and implicates KRT6A as a candidate therapeutic target for mitigating excessive placental invasion.

Abstract Gestational diabetes mellitus (GDM) serves as a diagnostic “stress test” for maternal physiology, exposing underlying metabolic vulnerabilities that imply a potential lifelong cardiometabolic trajectory for both mother and offspring. Mothers with a history of GDM face a 6-to-10-fold increased risk of developing type 2 diabetes mellitus and a 1.4-to-2.0-fold higher risk of cardiovascular disease, chronic hypertension, and chronic kidney disease. These risks are further compounded by factors such as obesity, hypertension, or adverse postpartum weight gain. For offspring, in utero exposure to hyperglycemia is thought to contribute to developmental programming that increases obesity risk—rising from approximately 1.1-fold in early childhood to 2.0-fold by adolescence—and predisposes them to early-onset dysglycemia. Although modest associations between in utero GDM exposure and both neurodevelopmental disorders and early cardiovascular events have been documented, these outcomes appear highly dependent on the postnatal environment. Despite the heterogeneity in findings among observational studies and variations in GDM diagnostic criteria, GDM should be regarded as a critical marker of long-term intergenerational risk for these adverse cardiometabolic and developmental outcomes. This review advocates for a clinical paradigm shift, positioning GDM as a sentinel event that requires a transition from episodic pregnancy care toward sustained, life-course cardiometabolic surveillance and preventative strategies for both mother and offspring.

Placenta accreta spectrum (PAS) is a leading cause of life-threatening obstetric hemorrhage, yet early diagnosis remains challenging. Traditional non-invasive prenatal testing (NIPT) is limited to fetal aneuploidy screening, while its potential for maternal placental disorders is underexplored. We conducted a multicenter nested case–control study to investigate whether machine learning-driven genome-wide cell-free DNA (cfDNA) promoter profiling, derived from routine NIPT data, could extend the utility of NIPT to enable early prediction and subtype risk stratification of PAS. NIPT data were analyzed from 1060 individuals with a history of uterine surgery (126 increta/percreta, 139 accreta, and 795 controls after propensity score matching). A training set of 280 participants was used for feature selection with recursive feature elimination across five machine learning algorithms, and the best-performing model was validated in an internal cohort, a PLUS cohort with deeper sequencing, and two external cohorts generated on independent platforms. Pairwise differential analyses identified 211 candidate genes with altered promoter coverage. After feature selection, we developed the 4P-model, a 15-gene multiclass risk stratification model, to differentiate increta/percreta, accreta, and controls with a macro-average AUC of 0.973. Robust performance was reproduced across three NIPT platforms and the PLUS cohort, with AUCs of 0.882–0.946. These findings support that machine learning facilitates the translation of genome-wide cfDNA promoter signals embedded in NIPT data into early prediction and risk stratification of PAS. This noninvasive and scalable approach extends the diagnostic window, offering a clinically feasible tool for timely referral, improving perinatal outcomes.

Background:Placenta accreta spectrum (PAS) is a leading cause of severe maternal and neonatal complications, yet its risk pathways remain incompletely understood. We aimed to evaluate the association between the number of prior caesarean sections (CS) and adverse maternal and neonatal outcomes in PAS, and to quantify the mediating role of placenta previa (PP) in this relationship. Methods:Based on a retrospective cohort of 231 patients with PAS (61 with no prior CS, 124 with one CS, and 46 with ≥2 CS), we performed multivariate logistic regression to assess associations between CS history and pregnancy outcomes and conducted mediation analysis to estimate the proportion of the CS effect mediated by PP. Results:Patients with ≥2 prior CS had significantly higher rates of second-trimester surgical abortion, percreta, and higher PAS severity scores. While PP, embolisation, blood transfusion, and prolonged hospitalisation were more common in women with any CS history, their frequencies did not increase proportionally with the number of CS. Multivariate analysis demonstrated that a higher number of prior CS was independently associated with increased risks of invasive PAS, massive intraoperative haemorrhage and transfusion, and preterm delivery. Mediation analysis showed that PP contributed to 8.62% of the association between CS history and invasive PAS, 16.93% for transfusion, 32.83% for preterm birth, and 11.40% for neonatal intensive care unit admission. Conclusions:A higher number of previous CS procedures in our sample was associated with higher risks of several adverse maternal outcomes in PAS. Neonatal outcomes, however, were not significantly influenced by the number of prior CS procedures and were more strongly affected by the gestational age at delivery. These relationships were partially mediated by PP, highlighting its important, but incomplete role in the pathway linking prior CS to PAS-related complications.

Background:Maternal haemoglobin (Hb) is a potential biomarker of maternal and neonatal health. Little is known about trimester-specific associations between maternal Hb concentrations and adverse pregnancy outcomes. Here, we assessed the magnitude and shape of these associations and further estimated developmental trajectories of maternal Hb concentrations during pregnancy. Methods:In this prospective, observational cohort study, we enrolled pregnant women at 11-13 weeks of gestation from 13 hospitals of northern China between October 2020 and June 2024. We classified maternal Hb concentrations in the first, second, and third trimester (i.e. 11-13, 24-27, and 36-40 weeks' gestation, respectively) into three groups: <110 g/L, 110-129 g/L, and ≥130 g/L, respectively. We used logistic regression models, restricted cubic spline analysis, and group-based trajectory models to examine the association between maternal Hb concentrations and pregnancy outcomes. Results:Among 10 201 participants, maternal Hb concentrations of ≥130 g/L in the first, second, and third trimester were associated with increased odds of gestational diabetes mellitus and hypertension in pregnancy. Maternal Hb concentrations of <110 g/L in the second trimester were associated with higher odds of postpartum haemorrhage (odds ratio (OR) = 1.38; 95% confidence interval (CI) = 1.04-1.83). Maternal Hb concentrations of ≥130 g/L in the third trimester were associated with higher odds of small-for-gestational-age (OR = 1.48; 95% CI = 1.23-1.79) and low birth weight (OR = 1.55; 95% CI = 1.11-2.16). We further identified a U-shaped relationship between maternal Hb concentrations in the third trimester and small-for-gestational age (P-value for nonlinearity = 0.002). Lastly, high Hb trajectories during pregnancy were associated with higher odds of caesarean delivery (OR = 1.21; 95% CI = 1.10, 1.34), small-for-gestational age (OR = 1.41; 95% CI = 1.16, 1.72) and low birth weight (OR = 1.46; 95% CI = 1.03, 2.05). Conclusions:Both higher and lower maternal Hb concentrations were associated with higher odds of adverse pregnancy outcomes. Our findings emphasise the importance of longitudinal monitoring of maternal Hb concentrations throughout pregnancy. Registration:ClinicalTrials.gov: NCT04486456.