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Comparing umbilical cord arterial blood gas findings in pregnancies with and without gestational diabetes mellitus following elective cesarean section: a multicenter retrospective cohort study in Iran

BMC Pregnancy and Childbirth volume 25, Article number: 412 (2025) Cite this article

Abstract

Background

Gestational diabetes mellitus (GDM) is linked to adverse fetal outcomes like macrosomia and neonatal hypoglycemia, with its global incidence increasing. While prior research indicates GDM may impair placental function and fetal oxygen delivery, direct evidence is limited. This study compares umbilical cord arterial blood gas measurements in pregnancies with and without GDM.

Methods

This retrospective study analyzed medical records from four hospitals in Tehran, Rasht, Ahvaz, and Isfahan in Iran, focusing on term singleton pregnancies (gestational age ≥ 37 weeks) that underwent elective cesarean sections between January and July 2024. Exclusions included maternal age < 18 or > 45 years, pre-existing diabetes, thyroid, hypertensive, malignant, metabolic, or autoimmune disorders, intrauterine growth restriction, hypertensive disorders of pregnancy, and substance use during pregnancy. GDM was diagnosed using a 75-gram oral glucose tolerance test at 24–28 weeks. Primary outcomes included umbilical cord arterial blood gas measures (potential of hydrogen [pH], partial pressure of carbon dioxide [PCO2], partial pressure of oxygen [PO2], bicarbonate [HCO3], and base deficit). The neonatal outcomes were measured as secondary outcomes. Statistical analyses utilized Chi-square, Fisher’s exact, and independent t-tests.

Results

Data from 430 pregnancies, including 87 with GDM, were analyzed. Pregnancies with GDM showed significantly lower pH (7.33 ± 0.08 vs. 7.36 ± 0.06, P-value = 0.006) and greater base deficit (-1.82 ± 3.79 vs. -0.50 ± 2.74 mEq/L, P-value = 0.003). However, no significant between-group differences were observed in PCO2, PO2, or HCO3 (P-value > 0.05). Furthermore, we observed no significant differences in the mean birthweight, 1-minute, or 5-minute Apgar scores (P-values > 0.05), while neonates in the GDM group required more resuscitation (28.7% vs. 12.0%, P-value < 0.001) and neonatal intensive care unit admissions (34.5% vs. 16.9%, P-value < 0.001).

Conclusions

Pregnancies with GDM showed higher umbilical cord blood acidity, indicating impaired placental function and reduced fetal oxygenation. These findings underscore the need for enhanced monitoring, such as regular fetal surveillance and close glycemic control, along with timely interventions like early neonatal resuscitation protocols and preparedness for neonatal intensive care unit admissions, to mitigate impaired fetal oxygenation in GDM.

Trial registration

Not applicable.

Peer Review reports

Background

Gestational diabetes mellitus (GDM) is a pregnancy-related condition characterized by glucose intolerance, which can result in hyperglycemia [1, 2]. This condition has been associated with a spectrum of adverse fetal outcomes, including macrosomia, birth trauma, and neonatal hypoglycemia [3, 4]. The global prevalence of GDM is on the rise; in 2021, the worldwide incidence of diabetes during pregnancy was reported to be 21.1 million cases, with GDM accounting for 80.3% of these cases [5]. Given the increasing global incidence of GDM, its impact on childbirth has become an area of growing concern for healthcare professionals [6,7,8].

Preliminary microscopic studies on the impact of GDM on umbilical cord histology reveal significant structural alterations, including endothelial lining rupture, increased permeability, hemorrhages in umbilical arteries, and dilation of the umbilical vein, alongside degeneration of smooth muscle fibers in vessel walls and disrupted fiber distribution with large empty spaces in Wharton’s jelly [9, 10]. It is also established that GDM can substantially influence fetal metabolism, potentially leading to challenges with glucose regulation in neonates [11, 12]. Furthermore, impaired placental function in GDM can affect fetal oxygen delivery [13, 14]. These findings indicate that GDM may disrupt fetal oxygenation, increasing the risk of neonatal complications and potentially influencing long-term health outcomes [15, 16].

Umbilical cord arterial blood gas (ABG) analysis has become an essential diagnostic tool for evaluating the respiratory and metabolic status of neonates at birth [17,18,19]. By assessing key parameters such as the potential of hydrogen (pH), partial pressure of carbon dioxide (PCO2), partial pressure of oxygen (PO2), bicarbonate (HCO3), and base deficit (BD), it provides critical insights into the newborn’s acid-base balance, oxygenation adequacy, and potential metabolic disturbances [17,18,19]. This information is crucial for identifying conditions like hypoxia, respiratory acidosis, or metabolic acidosis [20]. These conditions can be associated with adverse neonatal outcomes, including hypoxic-ischemic encephalopathy, long-term neurodevelopmental impairments, and longer neonatal intensive care unit (NICU) admission, highlighting the importance of umbilical ABG analysis in timely diagnosis and intervention [21,22,23].

Previous studies on umbilical artery ABG in GDM pregnancies have yielded contrasting results, with some indicating no significant pH changes but reduced PO2 and PCO2, alongside elevated lactate levels in GDM neonates [24], while others report higher rates of umbilical cord blood acidosis in term GDM pregnancies [25]. Therefore, there is a clear gap in understanding the effects of GDM on umbilical ABG, which directly reflects fetal oxygenation status, highlighting the need for further research to clarify these critical aspects.

This study aimed to investigate differences in umbilical cord ABG values (pH, PCO2, PO2, HCO3, and BD) between term pregnancies with and without GDM undergoing elective cesarean section. As a secondary objective, neonatal outcomes (including birthweight, 1-minute and 5-minute Apgar scores, resuscitation at birth, and NICU admission) were compared between the two groups. We hope this study’s findings could offer critical insights into the impact of GDM on placental function and fetal oxygenation, informing clinical practice and optimizing management strategies for pregnancies complicated by GDM.

Methods

Study design and setting

This retrospective cohort study included all consecutive eligible patients who underwent elective cesarean sections at term across four referral university-based hospitals in Iran. The study spanned from January 1, 2024, to July 1, 2024, and involved hospitals in four cities: (a) Yas Hospital Complex, Tehran University of Medical Sciences, Tehran, Iran; (b) Al-Zahra Hospital, Guilan University of Medical Sciences, Rasht, Iran; (c) Razi Hospital, Jundishapur University of Medical Sciences, Ahvaz, Iran; and (d) Shahid Beheshti Hospital, Isfahan University of Medical Sciences, Isfahan, Iran. The medical records of these patients were reviewed for eligibility, and data collection was conducted on those who met the inclusion criteria. The study adhered to the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) guidelines [26].

Ethical considerations

The study protocol was approved by the institutional review board (IRB) and the ethics committee of Tehran University of Medical Sciences (reference code: IR.TUMS.MEDICINE.REC.1403.117). All study stages strictly followed the ethical principles outlined in the Declaration of Helsinki [27]. At the time of admission, informed verbal and written consent was obtained from all participants for the anonymous use and publication of their data.

Eligibility criteria

We reviewed the medical records from the four participating hospitals to identify all consecutive eligible singleton-term pregnancies (gestational age ≥ 37 weeks) that underwent elective cesarean section between January 1, 2024, and July 1, 2024. Elective cesarean sections were performed for various clinical reasons, including a history of previous cesarean delivery, breech or other abnormal fetal presentations, fetal macrosomia, and maternal factors such as personal preference, prior retinal detachment, or a history of myomectomy.

The strict eligibility criteria of including only term pregnancies undergoing elective cesarean sections in our study were designed to examine a more homogeneous population of neonates. This approach allowed us to directly assess the effects of GDM on neonatal ABG findings while minimizing the confounding effects of variables such as gestational age at birth and mode of delivery, which are known to influence ABG results [20, 28]. Given the high volume of elective cesarean sections performed in our study centers, we specifically chose this population for analysis. Elective cesarean sections, unlike emergency procedures, are performed in controlled settings with lower-risk pregnancies or based on maternal preference. This environment allows for a systematic assessment of neonatal outcomes immediately after birth [29, 30]. Thus, we aimed to investigate the association of GDM with umbilical cord ABG findings in this specific population, minimizing potential confounding from other comorbidities and delivery-related factors.

The exclusion criteria included maternal age under 18 or over 45 years, multiple pregnancies, vaginal delivery or emergency cesarean section during the current pregnancy, gestational age at delivery below 37 weeks, maternal history of pre-existing diabetes mellitus, maternal history of hypertensive, thyroid, metabolic, malignant, or autoimmune disorders, maternal smoking, opioid, or alcohol use during the current pregnancy, occurrence of gestational hypertension, preeclampsia, eclampsia, or premature rupture of membranes during the current pregnancy, confirmed diagnosis of intrauterine growth restriction, unavailable umbilical cord ABG analysis data, and patient refusal to consent to the anonymous publication of their data. Additionally, we excluded cases diagnosed with GDM before weeks 24–28 of gestation outside the International Association of Diabetes and Pregnancy Study Groups (IADPSG) [31] criteria for routine GDM screening.

Data collection

The following data were collected from each study participant: (a) demographic information including age and body mass index (BMI); (b) obstetric history such as gravidity, prior abortions, molar pregnancies, and cesarean sections; (c) current pregnancy details, including the type of conception (spontaneous or assisted reproductive techniques), gestational age at delivery, diagnosis of GDM, and GDM management (lifestyle modification or medical treatment with insulin); (d) umbilical cord ABG analysis results, including pH, PCO2, PO2, HCO3, and BD; and (e) neonatal outcomes, including sex, birth weight, 1- and 5-minute Apgar scores, need for resuscitation at birth, and NICU admission.

GDM was diagnosed uniformly across all participating centers based on the guidelines of IADPSG [31]. Routine glycemic screening for GDM was conducted between 24 and 28 weeks of gestation, using a 75 g oral glucose tolerance test (OGTT). For this test, venous blood samples were taken at fasting and 1 and 2 h after consuming a 75 g oral glucose load. The diagnosis of GDM was confirmed if at least one of the following glucose levels was observed: (a) fasting glucose ≥ 92 mg/dL, (b) 1-hour glucose ≥ 180 mg/dL, or (c) 2-hour glucose ≥ 153 mg/dL.

Study outcomes

The primary objective of this study was to compare umbilical cord ABG findings between pregnancies with and without GDM. A standardized protocol for umbilical cord blood collection was implemented across all four participating hospitals. This protocol involved immediate double-clamping of the umbilical cord at delivery, collection of blood from the umbilical artery using pre-heparinized syringes, and prompt analysis using calibrated blood gas analyzers at each site.

Additionally, as secondary outcomes of our study, we aimed to compare neonatal outcomes between the GDM and non-GDM cohorts. These outcomes included birthweight, 1-minute and 5-minute Apgar scores, the need for neonatal resuscitation at birth, and rates of NICU admissions.

Statistical analysis

The statistical analyses were conducted using the Statistical Package for the Social Sciences (SPSS®, IBM®, Armonk, NY, USA), statistics software, version 25.0. Categorical data were presented as frequencies (percentages), while continuous data were expressed as mean ± standard deviation [95% confidence interval]. To compare categorical variables between the study groups, the Chi-square test and Fisher’s exact test were used. For continuous variables, the independent t-test was employed. Additionally, Levene’s test for equality of variances was conducted for each independent t-test, and its results were considered when interpreting the t-test outcomes. A P-value of < 0.05 was deemed statistically significant for all analyses.

To ensure the robustness of our findings, we adjusted for multiple confounders, including age, BMI, gravidity, gestational age at delivery, and type of conception. For categorical variables that showed statistically significant differences between the GDM and non-GDM cohorts, we performed separate binomial multivariate logistic regression analyses. Additionally, we used multiple linear regression analyses for continuous variables with significant mean differences between the groups to account for potential confounding effects. It is noteworthy that in the logistic regression analyses assessing neonatal outcomes, the presence of an umbilical cord arterial pH < 7.2 was also included in the multivariate model to examine the independent predictive ability of GDM for these outcomes. Multicollinearity was assessed for all regression analyses using variance inflation factor and tolerance values, ensuring no significant multicollinearity among predictors. A P-value of < 0.05 was considered statistically significant for all analyses.

Furthermore, to assess the potential effects of GDM treatment on umbilical cord ABG findings and neonatal outcomes, we repeated the same analyses, comparing GDM pregnancies managed with lifestyle modifications versus those managed with medical anti-diabetic agents (insulin).

Results

Enrollment data

Data from 658 singleton-term pregnancies were collected from four hospitals between January 1, 2024, and July 1, 2024. After reviewing their medical records against the eligibility criteria, 228 patients were excluded, leaving a total of 430 participants for inclusion in this study. A detailed breakdown of the data collection process and reasons for exclusion is illustrated in Fig. 1.

Fig. 1
figure 1

Flow diagram for the process of patient selection

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The mean maternal age of the cohort was 31.8 ± 6.3 years, with a mean gestational age at delivery of 38.4 ± 0.8 weeks. Among the participants, 87 (20.2%) were diagnosed with GDM during their current pregnancy, while the remaining 343 (79.8%) did not have GDM. The detailed characteristics of the study participants are summarized in Table 1.

Table 1 Characteristics of the studied maternal population.a
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The GDM cohort was significantly older than the non-GDM cohort (33.2 ± 6.0 vs. 31.4 ± 6.3 years; P-value = 0.014), with a higher proportion of pregnancies resulting from assisted reproductive techniques compared to the non-GDM cohort (21.8% vs. 11.1%; P-value = 0.008). However, no significant differences were observed between the two groups in terms of BMI, gravidity, or gestational age at delivery (P-values > 0.05). Table 2 provides a comprehensive comparison of the baseline characteristics of the GDM and non-GDM cohorts.

Table 2 Comparing the demographic and clinical features, ABG findings, and neonatal outcomes in pregnancies with and without GDM.a
Full size table

Umbilical cord ABG findings

The GDM cohort demonstrated significantly lower mean pH (7.33 ± 0.08 vs. 7.36 ± 0.06; P-value = 0.006) and greater BD (-1.82 ± 3.79 vs. -0.50 ± 2.74 mEq/L; P-value = 0.003) compared to the non-GDM group, with both remaining significant after adjusting for confounders (P-values = 0.001 and < 0.001, respectively). However, no significant differences were found for PCO2 (47.59 ± 9.92 vs. 44.88 ± 19.81 mmHg; P = 0.215), PO2 (13.13 ± 5.33 vs. 13.05 ± 5.74 mmHg; P-value = 0.902), or HCO3 (22.85 ± 3.10 vs. 22.95 ± 2.58 mEq/L; P-value = 0.760) between the two cohorts (Table 2).

The results of our subgroup analysis of the GDM cohort, stratified by treatment approach (lifestyle modifications or medical therapy), are presented in Table 3. Our findings indicate no significant differences between the lifestyle modifications and medical management groups in umbilical cord ABG parameters, including pH, PCO2, PO2, HCO3, and BD (P-values > 0.05).

Table 3 Comparing the demographic and clinical features, ABG findings, and neonatal outcomes in pregnancies with GDM that received non-medical (lifestyle modification) and medical treatments
Full size table

Neonatal outcomes

No significant differences were observed in the mean birthweight, 1-minute, or 5-minute Apgar scores between the GDM and non-GDM cohorts (P-values > 0.05). However, a significantly higher percentage of neonates in the GDM group required resuscitation at birth (28.7% vs. 12.0%; P-value < 0.001) and NICU admission (34.5% vs. 16.9%; P-value < 0.001). These differences remained significant after adjusting for potential confounders, including maternal age, BMI, gravidity, gestational age at delivery, type of conception, and presence of an umbilical cord arterial pH < 7.2 (both P-values = 0.006) (Table 2).

Our further subgroup analysis, based on the GDM treatment method, found no significant differences in mean birthweight between the lifestyle modification and medication treatment groups (P-value = 0.062). However, we observed significantly higher 1-minute Apgar scores (8.2 ± 1.2 vs. 7.2 ± 1.3; P-value = 0.001) and 5-minute Apgar scores (9.4 ± 0.7 vs. 8.8 ± 1.0; P-value = 0.001), as well as a lower rate of resuscitation at birth (17.0% vs. 42.5%; P-value < 0.001) in the lifestyle group compared to the medication group. These differences remained significant after adjusting for potential confounders, including maternal age, BMI, gravidity, gestational age at delivery, type of conception, and presence of an umbilical cord arterial pH < 7.2 (P-values = 0.010, 0.021, and 0.021, respectively). Additionally, the lifestyle management group had a significantly lower rate of NICU admissions compared to the medication group (23.4% vs. 47.5%; P-value = 0.018), although this difference did not remain significant after adjustment for confounders (P-value = 0.066) (Table 3).

Discussion

Our findings demonstrated a significantly lower pH and greater BD in the umbilical cord blood of pregnancies complicated by GDM compared to non-GDM pregnancies. However, it is noteworthy that while the observed difference in umbilical cord pH is statistically significant (7.33 vs. 7.36), it may not represent a substantial clinical difference. Nonetheless, these results suggest that fetuses from GDM pregnancies may experience impaired oxygenation and a higher risk of hypoxia, contributing to increased umbilical cord blood acidity.

While research on the impact of GDM on umbilical cord ABG findings is limited, existing studies align with our results. A prospective cohort study of 593 non-diabetic and 80 GDM pregnancies reported a higher incidence of umbilical cord acidosis in GDM cases, with cord blood acidosis independently linked to adverse neonatal outcomes [25]. Also, another study analyzed data from a total of 2081 pregnancies undergoing elective cesarean sections and found a greater prevalence of acidemia in neonates born to mothers with GDM, further supporting our study’s findings [32].

The development of fetal acidosis in GDM is primarily driven by the hyperglycemic environment resulting from maternal insulin resistance and impaired glucose tolerance. In GDM, elevated maternal blood glucose levels transfer excess glucose across the placenta to the fetus [33]. This excessive glucose stimulates the fetal pancreas to produce increased amounts of insulin, a condition known as fetal hyperinsulinemia [33, 34]. While insulin enables the fetus to utilize glucose for energy and storage, the abundance of glucose simultaneously increases fetal metabolic activity [35]. A key consequence of this enhanced metabolic activity is an increased demand for oxygen [36]. However, GDM affects not only fetal metabolism but also placental function. One of the principal consequence of GDM is the development of placental insufficiency [36]. In GDM-affected pregnancies, the placenta may undergo both structural and functional alterations, including villous immaturity, thickening of the villous membrane, and decreased placental blood flow [34]. These changes impair the placenta’s capacity to efficiently transfer oxygen from the mother to the fetus [34]. As a result, chronic fetal hypoxia may develop, creating conditions favorable for the onset of metabolic acidosis.

In addition to these structural abnormalities, GDM also is associated with altered placental expression of growth factors and cytokines, triggering inflammatory responses and oxidative stress [34, 37]. These inflammatory processes can further degrade placental tissue, worsening placental insufficiency [37]. Oxidative stress, in particular, may lead to endothelial dysfunction within the placenta, further hindering blood flow and nutrient exchange between the maternal and fetal circulations [34, 38]. During episodes of hypoxia, the fetus begins to metabolize stored glycogen and fatty acids for energy. This metabolic shift generates acidic byproducts, such as ketones, which contribute to the development of acidosis [39]. The cumulative effect of these pathways results in a reduction in fetal blood pH, a hallmark of acidosis that can be identified through fetal arterial ABG analysis.

The clinical implications of umbilical cord acidosis in neonates born to mothers with GDM are substantial and necessitate careful scrutiny. Evidence indicates that neonates from GDM pregnancies have significantly lower umbilical cord pH levels compared to those born to non-diabetic mothers, underscoring the potential for adverse neonatal outcomes. Umbilical cord acidosis reflects chronic fetal hypoxia and metabolic stress, which can precipitate complications such as neonatal hypoglycemia, respiratory distress syndrome, and impaired cardiac function [32, 40]. Additionally, the presence of acidosis may be associated with long-term neurodevelopmental issues, including an elevated risk of cerebral palsy and cognitive deficits [41, 42].

These observations highlight the critical need for rigorous monitoring of maternal glucose levels throughout pregnancy and comprehensive surveillance of fetal well-being, especially during labor and delivery, to mitigate the risk of perinatal acidosis and enhance neonatal outcomes in GDM-complicated pregnancies [43, 44]. Strict maternal glycemic control through dietary modifications, insulin or oral hypoglycemic agents, and continuous glucose monitoring helps prevent maternal hyperglycemia, reducing fetal hyperinsulinemia and acidosis [45]. Enhanced fetal surveillance with non-stress tests, biophysical profiles, and umbilical artery Doppler studies allows early detection of distress and timely intervention [46]. Delivery timing should be individualized, with intrapartum glucose management optimizing maternal levels to minimize fetal metabolic disturbances [47]. Postnatal measures, including cord blood gas analysis, respiratory support, and glucose administration, aid in managing neonatal acidosis [17]. Preventing neonatal hypoglycemia through early feeding or intravenous dextrose, along with strategies to reduce respiratory distress syndrome, further lowers the risk [48, 49]. Integrating these approaches can significantly improve neonatal outcomes in GDM pregnancies.

Moreover, we observed significantly higher rates of resuscitation at birth and NICU admissions among neonates from GDM pregnancies compared to the non-GDM cohort. This finding suggests increased fetal distress and poorer neonatal outcomes, potentially resulting from the adverse effects of GDM on placental and umbilical cord structure and function, ultimately leading to disrupted fetal oxygenation during pregnancy. However, this association was observed despite no significant difference in Apgar scores between the GDM and non-GDM cohorts. Several explanations may account for this phenomenon. First, although the difference in Apgar scores did not reach statistical significance, both 1-minute and 5-minute Apgar scores were lower in the GDM cohort. With a larger sample size, this difference might have become statistically significant. Nevertheless, in line with our umbilical cord arterial blood gas findings, this trend suggests that neonates from GDM pregnancies may experience greater fetal oxygenation impairment, potentially leading to higher rates of respiratory distress syndrome, necessitating increased resuscitation at birth and NICU admissions. Additionally, GDM is known to be associated with increased risks of neonatal hypoglycemia [50, 51], seizures [52], and hyperbilirubinemia [53], which may also contribute to the higher rates of adverse neonatal outcomes observed in our GDM cohort.

This study has several strengths that enhance the reliability of our findings. First, data were collected from four centers across Iran, increasing the geographical generalizability of the results. Second, we employed strict eligibility criteria, focusing exclusively on term pregnancies undergoing elective cesarean sections without other comorbidities. This approach allowed us to isolate the specific association of GDM with umbilical cord ABG findings while minimizing the influence of confounding factors such as gestational age or delivery type. Third, the use of robust statistical methods enabled adjustment for potential confounders, further ensuring the validity and precision of our results.

However, these findings should be interpreted with caution, as they are limited to the specific population studied. By restricting the analysis to elective cesarean sections, the generalizability of the results to other delivery modes, such as emergency cesarean sections or vaginal deliveries, may be limited, potentially introducing selection bias. Larger and more comprehensive studies, including neonates born via all delivery methods and employing stratified and adjusted analyses to account for these variables, are necessary to provide a more thorough understanding of the association between GDM and neonatal acid-base status. Additionally, our sample size was relatively small, and the retrospective nature of the study precludes establishing causal relationships. Also, missing glucose control data and potential inter-hospital variations may also introduce bias into our findings. Therefore, Future studies with larger sample sizes and longitudinal designs are required to validate these findings and explore causal pathways with greater reliability.

Conclusions

Our findings demonstrated that term pregnancies complicated by GDM exhibit more acidic umbilical cord blood. These results suggest that fetuses from GDM pregnancies are more likely to experience impaired oxygenation and a higher risk of hypoxia. This compromised fetal oxygenation may partly explain the significantly higher rates of neonatal morbidities reported in GDM pregnancies. Therefore, enhanced monitoring through regular fetal surveillance and strict glycemic control, along with timely interventions such as neonatal resuscitation protocols and preparedness for NICU admissions, is essential to mitigate the adverse effects of GDM on placental function and neonatal outcomes.

Data availability

The analyzed dataset in this study will be provided in terms of reasonable requests to the corresponding author.

Abbreviations

ABG:

arterial blood gas

BD:

base deficit

BMI:

body mass index

GDM:

gestational diabetes mellitus

HCO3 :

bicarbonate

IADPSG:

International Association of Diabetes and Pregnancy Study Groups

IRB:

institutional review board

NICU:

neonatal intensive care unit

OGTT:

oral glucose tolerance test

PCO2 :

partial pressure of carbon dioxide

pH:

potential of hydrogen

PO2 :

partial pressure of oxygen

SPSS:

Statistical Package for the Social Sciences

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Acknowledgements

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Funding

No funding support was acquired for this project.

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Author notes

  1. Fatemeh Golshahi and Zufa Iqbal contributed equally to this work.

Authors and Affiliations

  1. Department of Ob & Gyn, Fellowship of Maternal-Fetal Medicine, Fetal & Neonatal Research Center, Yas Hospital Complex, Tehran University of Medical Sciences, Maternal, Tehran, Iran

    Fatemeh Golshahi, Behrokh Sahebdel, Nafiseh Saedi & Mahboobeh Shirazi

  2. School of Medicine, Tehran University of Medical Sciences, Tehran, Iran

    Zufa Iqbal

  3. Reproductive Health Research Center, Department of Obstetrics and Gynecology, School of Medicine, Guilan University of Medical Sciences, Rasht, Iran

    Zahra Hamidi Madani

  4. Department of Obstetrics and Gynecology, Jundishapur University of Medical Sciences, Ahvaz, Iran

    Zeynab Zamanpour

  5. Department of Obstetrics and Gynecology, Shahid Beheshti Hospital, Isfahan University of Medical Sciences, Isfahan, Iran

    Somayeh Khanjani

  6. Isfahan Cardiovascular Research Center, Isfahan University of Medical Sciences, Isfahan, Iran

    Jafar Golshahi

  7. Vali-e-Asr Reproductive Health Research Center, Family Health Research Institute, Tehran University of Medical Sciences, 1419733141, Tehran, Iran

    Pegah Rashidian

  8. Breastfeeding Research Center, Family Health Research Institute, Tehran University of Medical Sciences, Tehran, 1419733141, Iran

    Mohammadamin Parsaei

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  1. Fatemeh Golshahi
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Contributions

FG participated in the idea conceptualization, data collection, project administration, supervision, editing, and critical reviewing of the manuscript. ZI participated in the data collection, and writing the original draft of the paper, ZHM participated in the data collection, editing, and critical reviewing of the manuscript, ZZ participated in the data collection and writing the original draft of the paper, BS participated in the idea conceptualization, data collection, editing, and critical reviewing of the manuscript, NS participated in the data collection, editing, and critical reviewing of the manuscript, SK participated in the data collection, editing, and critical reviewing of the manuscript, JG participated in editing, and critical reviewing of the manuscript, MS participated in the idea conceptualization, data collection, editing, and critical reviewing of the manuscript, PR participated in data curation and writing the original draft of the paper, and MP participated in data curation, statistical analysis, data visualization, writing the original draft of the paper, editing, and critical reviewing of the manuscript. All authors read and approved the final version of the manuscript for publication.

Corresponding authors

Correspondence to Pegah Rashidian or Mohammadamin Parsaei.

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Ethics approval and consent to participate

The study protocol was approved by the institutional review board (IRB) and the ethics committee of Tehran University of Medical Sciences (reference code: IR.TUMS.MEDICINE.REC.1403.117). All study stages strictly followed the ethical principles outlined in the Declaration of Helsinki. At the time of admission, informed verbal and written consent was obtained from all participants for the anonymous use and publication of their data.

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Golshahi, F., Iqbal, Z., Madani, Z.H. et al. Comparing umbilical cord arterial blood gas findings in pregnancies with and without gestational diabetes mellitus following elective cesarean section: a multicenter retrospective cohort study in Iran. BMC Pregnancy Childbirth 25, 412 (2025). https://doiorg.publicaciones.saludcastillayleon.es/10.1186/s12884-025-07522-2

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Keywords

BMC Pregnancy and Childbirth

ISSN: 1471-2393

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