Maternal Serum Galectin-1 in the First Trimester as a Potential Biomarker for Early Prediction of Pre-Eclampsia: A Prospective Study

Introduction

Pre-eclampsia is a severe pregnancy complication characterized by new-onset hypertension and proteinuria after 20 weeks of gestation, significantly contributing to maternal and perinatal morbidity and mortality worldwide [1,2]. Affecting approximately 2–8% of pregnancies, pre-eclampsia is associated with numerous adverse pregnancy outcomes, including placental abruption, fetal growth restriction, preterm delivery, and maternal cardiovascular complications [3–6]. Early prediction and diagnosis of pre-eclampsia remain critical clinical challenges, as timely identification of high-risk pregnancies allows for enhanced antenatal surveillance and preventive interventions, potentially reducing maternal and fetal risks. Current clinical strategies predominantly rely on maternal history and biophysical markers; however, these methods have limited predictive accuracy in early pregnancy stages [7–9]. Consequently, identifying reliable first-trimester biomarkers is a promising approach for early prediction of pre-eclampsia.

Trophoblast cells play a crucial role in placentation through regulated differentiation, migration, and invasion into the maternal endometrium, which are processes essential for establishing adequate uteroplacental blood flow [10,11]. Disruption or impairment of trophoblast differentiation and invasion is strongly involved in the pathogenesis of pre-eclampsia [12]. Appropriate trophoblast invasion promotes spiral artery remodeling, reducing vascular resistance and enhancing maternal blood supply to the developing placenta [13]. Failure in these processes significantly contributes to placental hypoperfusion, ischemia, and subsequent systemic maternal endothelial dysfunction, which are characteristics of pre-eclampsia [14]. Therefore, molecules involved in trophoblast biology, particularly those regulating trophoblast differentiation, invasion, and angiogenesis, are potential biomarkers for early prediction of pre-eclampsia.

Galectin-1 is a member of the galectin family of carbohydrate-binding proteins, which has emerged as a critical regulator of placental development and maternal-fetal immune tolerance [15,16]. Highly expressed at the maternal-fetal interface during early pregnancy, galectin-1 is pivotal in promoting trophoblast stem cell differentiation, migration, invasion, and angiogenesis [17]. Notably, decreased galectin-1 expression has been observed in placental tissues and maternal serum samples from pregnancies complicated by pre-eclampsia and fetal growth restriction, suggesting its involvement in the underlying pathophysiology [17,18]. Experimental studies have demonstrated that downregulation or functional blockade of galectin-1 leads to impaired trophoblast invasion and deficient spiral artery remodeling, resulting in a pre-eclampsia-like phenotype in animal models [18]. Consequently, maternal serum galectin-1 levels measured during the first trimester may be a valuable biomarker for early identification of pregnancies at high risk of developing pre-eclampsia.

The present prospective cohort study aimed to investigate maternal serum galectin-1 levels measured in the first trimester as a potential biomarker for the early prediction of pre-eclampsia. Establishing galectin-1 as an effective early predictive biomarker could significantly enhance clinical surveillance strategies and inform preventive interventions aimed at reducing the incidence of pre-eclampsia, ultimately improving pregnancy outcomes and maternal health.

Material and Methods

STUDY POPULATION:

Ethical approval of this study was obtained from the Institutional Review Board of the First Affiliated Hospital of Chengdu Medical College (No. 24327428), and the study complied with the ethical principles outlined in the Declaration of Helsinki. All participants gave their informed consent before commencement of the study. Women attending routine antenatal care between 8 and 13 weeks of gestation from January 2021 to December 2023 were screened for study enrollment. Inclusion criteria consisted of singleton pregnancy, gestational age confirmed by ultrasonography, and provision of written informed consent. Women with pre-existing chronic hypertension, diabetes mellitus, autoimmune disorders, renal diseases, or multiple gestations were excluded to avoid confounding variables that could potentially influence galectin-1 levels.

Sample size estimation was based on previous studies assessing biomarker efficacy in predicting pre-eclampsia. Assuming a pre-eclampsia prevalence of approximately 5%, with a statistical power of 80% and an alpha significance level of 5%, the minimal required cohort size was calculated to be 925 participants. However, this study enrolled 2176 participants, as depicted in Figure 1.

DIAGNOSIS OF PRE-ECLAMPSIA:

All participants were prospectively followed throughout pregnancy until delivery. The diagnosis of pre-eclampsia was established according to criteria outlined by the International Society for the Study of Hypertension in Pregnancy (ISSHP) [19]. Specifically, pre-eclampsia was diagnosed when new-onset hypertension (defined as systolic blood pressure ≥140 mmHg or diastolic blood pressure ≥90 mmHg measured on at least 2 occasions at least 4 hours apart) occurred after 20 weeks of gestation, accompanied by proteinuria (≥300 mg in a 24-hour urine collection or a urinary protein-to-creatinine ratio ≥0.3). Women who fulfilled the blood pressure criteria without proteinuria were diagnosed with pre-eclampsia if they had 1 or more features of organ dysfunction, including renal impairment, hepatic involvement, neurological complications, or hematologic abnormalities.

CLINICAL CHARACTERISTICS AND LABORATORY ASSESSMENTS:

Pregnant women were enrolled at 8–13 weeks of gestation, and comprehensive demographic and clinical data were systematically collected, including maternal age, smoking status, body mass index (BMI), parity, medical history, and blood pressure measurements. Gestational age was confirmed by an ultrasound examination performed at the time of enrollment.

Peripheral venous blood samples were collected after an overnight fast. Samples were centrifuged at 2000 g for 10 minutes to separate serum, after which serum was aliquoted and stored at −80°C until further analysis. Routine laboratory evaluations included fasting blood glucose, serum creatinine, liver function tests (alanine aminotransferase [ALT] and aspartate aminotransferase [AST]), and a complete blood count. These routine laboratory tests were conducted using automated analyzers in accordance with standard protocols at the Clinical Laboratory of the First Affiliated Hospital of Chengdu Medical College.

MEASUREMENT OF SERUM GALECTIN-1, SFLT-1, AND PLGF:

Maternal serum levels of galectin-1, sFlt-1, and PlGF were measured at 8–13 weeks of gestation using commercially available enzyme-linked immunosorbent assay (ELISA) kits (ab260053, Abcam Co. Ltd., Shanghai, China; DVR100C, R&D Systems, Minneapolis, MN, USA; DPG00, R&D Systems, Minneapolis, MN, USA). The measurement procedures were conducted according to the manufacturer’s instructions. Briefly, appropriately diluted serum samples were added to ELISA plates pre-coated with anti-human galectin-1 monoclonal antibodies and incubated at room temperature for 2 hours. Following extensive washing, horseradish peroxidase-conjugated detection antibodies were added and incubated for 1 hour. After further washing, a substrate solution was applied, and the plates were incubated in the dark for 30 minutes. The reaction was terminated by adding a stop solution, and absorbance was measured at 450 nm using a microplate reader (BioTek Instruments, Winooski, VT, USA). Each sample was assayed in triplicate, and the mean value was used for statistical analysis. Both intra-assay and inter-assay coefficients of variation were controlled to be less than 10%. Detailed procedures are listed in the supplementary materials.

STATISTICAL ANALYSES:

Statistical analyses were performed using SPSS software (version 31.0; IBM Corp., Armonk, NY, USA). Data are expressed as means±standard deviations for normally distributed variables and comparisons between groups were conducted using Student’s t-test.

Logistic regression analysis was used to evaluate the association between galectin-1 levels and the subsequent development of pre-eclampsia. Univariate analysis was initially performed, followed by multivariate logistic regression to adjust for potential confounding factors, and adjusted odds ratios (ORs) with corresponding 95% confidence intervals (CIs) were calculated.

To assess the value of serum galectin-1 levels for early prediction of pre-eclampsia, receiver operating characteristic (ROC) curve analysis was performed. The area under the ROC curve (AUC), along with its 95% CI, was calculated to evaluate the overall predictive accuracy. The optimal cutoff value for galectin-1 was determined using Youden’s index, which maximizes the sensitivity and specificity. All statistical tests were two-tailed, and P values less than 0.05 were considered statistically significant.

Results

BASELINE CHARACTERISTICS OF THE STUDY POPULATION:

A total of 2176 pregnant women were enrolled in this study, of whom 196 subsequently developed pre-eclampsia, and 1980 had normotensive pregnancies. Maternal age, pre-pregnancy BMI, TG, LDL-C, sFlt-1, PlGF, neonatal birth weight, and gestational age at delivery were significantly different between the 2 groups (Table 1). However, gestational age at enrollment, diastolic blood pressure, systolic blood pressure, TC, ALT, AST, HDL-C, serum creatinine, and uric acid were not significantly different between the 2 groups (Table 1).

MATERNAL SERUM GALECTIN-1 LEVELS IN THE FIRST TRIMESTER:

Maternal serum galectin-1 levels were significantly lower in women who later developed pre-eclampsia compared to those with normotensive pregnancies (Figure 2). This trend was consistent when stratified by early-onset pre-eclampsia (≤34 weeks) and late-onset pre-eclampsia (>34 weeks), with significantly lower values observed in early-onset pre-eclampsia compared to late-onset pre-eclampsia (Figure 2).

RELATIONSHIP BETWEEN SERUM GALECTIN-1 LEVELS AND PRE-ECLAMPSIA:

The galectin-1 levels were categorized into 3 groups according to their tertile distribution, with the highest group used as the reference for comparison. Results demonstrated a progressive rise in pre-eclampsia incidence from 3.84% in the highest group to 18.48% in the lowest group (Table 2). Logistic regression analysis was used to explore the relationship between galectin-1 levels and the risk of developing pre-eclampsia. Women in both the middle and lowest groups showed an elevated risk of developing pre-eclampsia compared to those in the highest group. The odds ratios for pre-eclampsia were calculated as 2.83 (95% CI: 1.04–4.27, P=0.001) for the middle group and 4.45 (95% CI: 3.34–6.67, P=0.003) for the lowest group (Table 2).

IDENTIFICATION OF POTENTIAL RISK FACTORS FOR PRE-ECLAMPSIA:

Univariate and multivariate analyses were conducted to identify potential risk factors for pre-eclampsia. Univariate analysis demonstrated that maternal age, pre-pregnancy BMI, systolic blood pressure, galectin-1, sFlt-1, and PlGF were significantly associated with the risk of pre-eclampsia (Table 3). However, when these variables were included in a multivariate logistic regression model and adjusted for potential confounders, including maternal age, pre-pregnancy BMI, systolic blood pressure, and levels of galectin-1, PlGF, sFlt-1, TC, TG, and LDL-C, the results demonstrated that only galectin-1, PlGF, and sFlt-1 remained independently associated with pre-eclampsia. The adjusted odds ratios (ORs) were 4.35 (95% CI: 2.84–6.12, P=0.001) for galectin-1, 1.53 (95% CI: 1.14–1.82, P=0.014) for PlGF, and 2.47 (95% CI: 1.03–5.27, P=0.002) for sFlt-1 (Table 3). These findings indicated that galectin-1, PlGF, and sFlt-1 were independent risk factors for pre-eclampsia.

PREDICTIVE PERFORMANCE OF GALECTIN-1 FOR PRE-ECLAMPSIA:

To evaluate the value of galectin-1 in predicting pre-eclampsia, receiver operating characteristic (ROC) curve analysis was conducted. The predictive performance of galectin-1 was compared with 2 established biomarkers – PlGF and sFlt-1 [20].

The results demonstrated that galectin-1 had superior predictive capability, with an AUC of 0.84 (95% CI: 0.65–0.94), outperforming both sFlt-1 and PlGF (Figure 3A, Table 4). Specifically, the AUCs for sFlt-1 and PlGF were 0.73 (95% CI: 0.51–0.87) and 0.64 (95% CI: 0.41–0.72), respectively. Galectin-1 also achieved the highest sensitivity and specificity, which were 82.32% and 78.47% at a cutoff value of 34.42 ng/ml. In comparison, sFlt-1 yielded a sensitivity of 73.45% and specificity of 65.34% with a cutoff value of 63.58 ng/mL, while PlGF demonstrated a sensitivity of 62.54% and specificity of 61.62% at a cutoff value of 32.52 ng/mL (Figure 3A, Table 4). These findings show galectin-1 is a promising and reliable biomarker for the prediction of pre-eclampsia.

The predictive performance of galectin-1 was further evaluated for early-onset and late-onset pre-eclampsia. The results indicated that galectin-1 exhibited greater predictive performance for early-onset pre-eclampsia, with an AUC of 0.91 (95% CI: 0.73–0.98, P=0.002), compared to an AUC of 0.76 (95% CI: 0.51–0.84, P=0.001) for late-onset pre-eclampsia (Figure 3B, Table 5). The sensitivity and specificity were 88.56% and 85.27% at a cutoff value of 32.41 ng/ml for early-onset pre-eclampsia, while they were 75.64% and 72.41% at a cutoff value of 34.31 ng/ml for late-onset pre-eclampsia (Figure 3B, Table 5).

CORRELATIONS BETWEEN GALECTIN-1 LEVELS AND ADVERSE PREGNANCY OUTCOMES:

Previous research has established an association between pre-eclampsia and a variety of adverse pregnancy outcomes, including fetal growth restriction, cesarean delivery, small-for-gestational-age infants, low birth weight, postpartum hemorrhage, preterm birth, reduced Apgar scores, neonatal pneumonia, admission to the neonatal intensive care unit, and neonatal respiratory distress syndrome. Therefore, logistic regression analyses were performed to evaluate the association between maternal serum galectin-1 levels and the risk of these complications. Galectin-1 levels were stratified into tertiles, with the highest tertile serving as the reference group. The results revealed that women with the middle and lowest tertiles of galectin-1 levels had a significantly increased risk of adverse pregnancy outcomes listed above (Table 6). However, no statistically significant associations were found for neonatal pneumonia, neonatal respiratory distress syndrome, or neonatal intensive care unit admission (Table 6).

Discussion

Pre-eclampsia remains one of the most severe complications of pregnancy, contributing substantially to maternal and perinatal morbidity and mortality worldwide [1,2]. Despite advances in prenatal screening and obstetric care, reliable biomarkers for the early prediction of pre-eclampsia during the first trimester are still lacking in routine clinical practice [7]. This study aimed to evaluate the predictive value of maternal serum galectin-1 levels for pre-eclampsia measured in the first trimester. Our findings indicate that lower galectin-1 levels are significantly associated with the subsequent development of pre-eclampsia, suggesting that galectin-1 is a promising biomarker in the first trimester for identifying women at increased risk for pre-eclampsia.

Galectin-1 is a β-galactoside-binding protein, highly expressed at the maternal-fetal interface, and plays critical roles in trophoblast differentiation, immune regulation, angiogenesis, and spiral artery remodeling. Previous studies have reported reduced Gal-1 expression in placental tissues and maternal serum from pregnancies complicated by pre-eclampsia, supporting its involvement in the pathogenesis of this disorder [17,18]. Consistent with these reports, our study demonstrated that galectin-1 levels were significantly lower during the first trimester in women who later developed pre-eclampsia, with even more pronounced reductions observed in cases of early-onset pre-eclampsia (Figure 2). These results support the hypothesis that galectin-1 deficiency may precede the clinical onset of pre-eclampsia and reflect impaired trophoblast invasion and uteroplacental malfunction, both of which are considered key contributors to early development of the disease [21,22].

Multivariate logistic regression analysis confirmed that decreased galectin-1 levels were independently associated with pre-eclampsia, even after adjusting for established confounders such as maternal age, parity, BMI, and serum lipid levels (Table 3). Notably, galectin-1 demonstrated superior predictive performance compared to both PlGF and sFlt-1, achieving a higher AUC of 0.84, with sensitivity and specificity values of 82.32% and 78.47%, respectively (Figure 3A, Table 4). These findings underscore the potential of galectin-1 as a robust and clinically valuable biomarker for early prediction of pre-eclampsia, offering the possibility to enhance or complement current predictive strategies.

The mechanism by which galectin-1 influences the pathogenesis of pre-eclampsia likely involves its regulatory role in trophoblast function and maternal immune tolerance [23,24]. Galectin-1 has been shown to promote extravillous trophoblast migration and invasion, which are critical processes for spiral artery remodeling, a process frequently disrupted in pre-eclampsia [15,25]. Experimental mouse models have demonstrated that galectin-1 blockade leads to reduced trophoblast invasiveness and impaired placental vascular development, resulting in a pre-eclampsia phenotype [18]. Therefore, low galectin-1 concentrations may reflect a failure to establish adequate placental perfusion during early pregnancy, ultimately contributing to the development of pre-eclampsia later in gestation.

Our stratified analysis further revealed that galectin-1 was particularly effective in predicting early-onset pre-eclampsia, a more severe subtype associated with higher rates of adverse maternal and neonatal outcomes [26]. The AUC for early-onset pre-eclampsia was 0.91, compared to 0.76 for late-onset pre-eclampsia, suggesting that galectin-1 is more sensitive to detecting placental dysfunctions that originate earlier in gestation (Figure 3B, Table 5). This distinction holds clinical significance, as early identification of high-risk women provides a broader window for implementing preventive strategies, such as low-dose aspirin therapy, enhanced surveillance, and lifestyle interventions that can reduce the incidence of pre-eclampsia [27,28].

A previous study demonstrated that low serum galectin-1 levels in the second trimester predict the subsequent development of pre-eclampsia [29]. However, that study measured galectin-1 levels retrospectively after the onset of pre-eclampsia. In contrast, we measured galectin-1 levels prospectively in the first trimester, facilitating early prediction and allowing potential clinical interventions to prevent pre-eclampsia. Another study reported elevated placental galectin-1 expression in severe pre-eclampsia [30], which appears contradictory to our observation of reduced maternal serum galectin-1 levels during the first trimester. This discrepancy may reflect differences in the timing of sampling, tissue specificity, and the severity of pre-eclampsia investigated. Moreover, that study had a relatively small sample size of only 40 participants, which limits statistical power and generalizability.

Other biomarkers, such as sFlt-1 and PlGF, have also been evaluated for their potential to predict pre-eclampsia. Research reported in the New England Journal of Medicine indicated that an sFlt-1/PlGF ratio of 38 or less could reliably exclude the likelihood of developing pre-eclampsia within one week, achieving a negative predictive value of 99.3% (95% CI: 97.9–99.9%), along with a sensitivity of 80.0% and specificity of 78.3%. In contrast, ratios above 38 indicated a positive predictive value of 36.7% (95% CI: 28.4–45.7%) for developing pre-eclampsia within 4 weeks, accompanied by a sensitivity of 66.2% and specificity of 83.1% [31]. However, this previous research primarily addressed short-term risk predictions in pregnant women between 24 and 36 weeks of gestation, potentially limiting its effectiveness in preventing pre-eclampsia during that specific period. In contrast, our investigation found galectin-1 is a promising biomarker for identifying the risk of pre-eclampsia as early as the first trimester, thus enabling obstetricians to implement preventive interventions at a much earlier stage.

We also examined the association between galectin-1 levels and a range of adverse pregnancy outcomes commonly linked to pre-eclampsia [32,33]. Women in the lowest tertile of Gal-1 concentration had a significantly higher risk of fetal growth restriction, low birth weight, preterm birth, postpartum hemorrhage, and low Apgar scores (Table 6). These results further support galectin-1’s role in maintaining placental function and fetal well-being, which are closely related to the pathophysiology of pre-eclampsia.

This study has several limitations that should be acknowledged. First, this was a single-center study, which may limit the generalizability of the results to broader populations. Second, although adjustments were made for multiple potential confounders, unmeasured variables such as genetic predisposition, socioeconomic factors, and environmental exposures can influence galectin-1 levels and pre-eclampsia risk. Lastly, while ELISA-based measurement of galectin-1 is reliable, variability in commercial assay kits and pre-analytical conditions could affect reproducibility in other clinical settings.

Conclusions

This study demonstrates that low maternal serum galectin-1 concentrations in the first trimester are significantly associated with the subsequent development of pre-eclampsia. Galectin-1 showed good predictive performance in early prediction of pre-eclampsia in the first trimester, particularly for early-onset pre-eclampsia. These findings support the potential of galectin-1 as a promising biomarker for early prediction of pre-eclampsia. It could improve early risk stratification and guide timely interventions, ultimately reducing the incidence of pre-eclampsia.