Hemostatic Profile in Pregnant Women: A Cross-Sectional Study at the Amissa Bongo University Hospital Center in Franceville, Gabon

Introduction

Pregnancy represents a period of major physiological changes, characterized notably by a profound and dynamic reorganization of the hemostatic system. This biological adaptation serves a dual, delicate, and protective objective: to prevent hemorrhagic risks, particularly during childbirth and the postpartum period, while maintaining a precarious balance to avoid thrombotic complications [1]. Specifically, this state of relative hypercoagulability translates into a significant increase in procoagulant factors (such as fibrinogen and factors VII, VIII, and X), a physiological resistance to activated protein C, and a moderate but frequent decrease in platelet count, commonly referred to as gestational thrombocytopenia [2].

In sub-Saharan Africa, this physiological hemostatic profile is frequently disrupted and exacerbated by a set of specific contextual and environmental factors. Among these are the high prevalence of anemia, gestational malaria, malnutrition, and unequal access to quality prenatal care [3]. In Gabon, despite notable progress in maternal health, illustrated by a 40% reduction in maternal mortality between 2000 and 2020, postpartum and intrapartum hemorrhages remain the leading cause of maternal death, accounting for approximately 28% of cases [4]. This epidemiological reality underscores the imperative need for rigorous hemostatic monitoring adapted to local realities.

However, there is a glaring lack of scientific data accurately describing the hemostatic profile of pregnant women in Gabon. This gap is particularly marked in the interior provinces, such as HautOgooué, where demographic and epidemiological specificities may differ from those observed in the capital. Furthermore, applying reference values established in Western populations can lead to clinical interpretation errors, either by inappropriately medicalizing benign physiological variations or by overlooking early warning signs of severe pathologies, such as disseminated intravascular coagulation (DIC) [5]. Consequently, this absence of local data considerably limits the optimization of transfusion protocols and the implementation of effective preventive strategies against hemorrhagic or thrombotic complications [6].

It is within this context that the present cross-sectional study was undertaken, with the primary objective of describing the hemostatic profile (prothrombin time, activated partial thromboplastin time, and platelet count) of pregnant women in their third trimester, followed at the Amissa Bongo University Hospital Center (CHU) in Franceville. Secondarily, this research aimed to identify sociodemographic and clinical factors (such as age, parity, or place of residence) potentially associated with the observed biological abnormalities. Ultimately, the results of this work should contribute to the development of context-specific reference thresholds, which are essential for improving obstetric care and ensuring maternal safety in our healthcare environment.

Materials and Methods

Study Setting

The study was conducted at the Amissa Bongo University Hospital Center (CHUAB) in Franceville (Haut-Ogooué, Gabon), the main referral center for obstetrics in the southeastern part of the country.

Design and Period

A descriptive cross-sectional study conducted from January to June 2025.

Study Population

Inclusion Criteria:

All pregnant women presenting at the Amissa Bongo University Hospital Center in Franceville for their prenatal care or delivery were included in this study, provided they cumulatively met the following conditions: being in the third trimester of pregnancy, defined by a gestational age of 28 weeks or more; being aged 15 to 49 years, the age range corresponding to the period of reproductive activity; residing stably in the Franceville health zone for at least three months, to ensure consistent clinical follow-up and minimize biases related to geographical variations in care practices; and having provided written informed consent after being fully informed about the objectives and conduct of the study.

Exclusion criteria:

Conversely, women presenting with factors likely to significantly alter their hemostatic profile, independently of gravid physiology, were excluded from the study. More specifically, exclusion applied to patients with a documented thromboembolic history (deep vein thrombosis, pulmonary embolism), those currently receiving anticoagulant therapy (heparin, direct oral anticoagulants), multiple pregnancies (twins or more), as well as patients with known constitutional or acquired hemorrhagic pathologies, such as hemophilia, hereditary or acquired thrombocytopathies, von Willebrand disease, or severe pre-existing thrombocytopenia (< 100,000 platelets/mm³) unrelated to pregnancy. Finally, women with known severe hepatic pathology (cirrhosis, acute hepatitis), likely to alter the synthesis of coagulation factors, as well as those who had experienced an episode of pre-eclampsia or eclampsia during the current pregnancy, were excluded, as these conditions are associated with specific hemostatic abnormalities that would have biased the analysis of the physiological profile.

Sample Size

The 80 included patients corresponded to all eligible women consulting during the study period (exhaustive sampling).

Data Collection

Data were collected using a structured and pre-tested questionnaire, administered face-to-face by trained personnel. This collection focused on three main areas: sociodemographic data (age, residence, parity, prenatal care), medical and surgical history (hemorrhages, thromboses, chronic pathologies), and biological parameters. The latter were evaluated according to standardized protocols, including Prothrombin Time (PT, Quick method, ref. 70–100%), Activated Partial Thromboplastin Time (aPTT, ref. 25–35 s), and platelet count (Sysmex XN-1000® analyzer, ref. 150–400 K/µL). Finally, strict pre-analytical conditions were rigorously applied during sampling to guarantee the reliability and reproducibility of the biological results.

Operational Definitions

Gestational thrombocytopenia: Platelets < 150 K/µL without any other identifiable cause [6].

Low PT: < 70% of activity.

Prolonged aPTT: > 35 seconds.

Statistical Analysis

Data were analyzed using R software version 4.4.0. Quantitative variables are presented as medians [IQR]; categorical variables as counts (%). Comparisons used the Mann-Whitney U test or Fisher’s exact test (significance threshold: p < 0.05).

Ethical Considerations

The study was approved by the USTM Ethics Committee (ref.: 143/2024/CER-USTM). Written informed consent was obtained from each participant.

Results

Sociodemographic Characteristics

The median age was 27 years [22–34]. The distribution was balanced between primiparas (31.3%) and multiparas (68.8%). The majority resided in an urban area (85.0%) and benefited from regular prenatal care (92.5%). Only 12.5% of the patients reported a personal history of hemorrhage (Table 1).

Table 1: Sociodemographic and clinical characteristics of the population (n = 80)

IQR: Interquartile range

None: Unremarkable / No history

Descriptive Analysis of Global Hemostatic Parameters in the Population (n = 80)

Table 2 presents the global hemostasis parameters for our 80 patients, revealing a profile at the limits of physiological values, yet marked by a notable prevalence of abnormalities. Regarding plasma coagulation, the median Prothrombin Time (PT) was established at 71% [IQR: 67–77], at the lower limit of normal, while the median Activated Partial Thromboplastin Time (aPTT) reached 34 s [IQR: 31–38], brushing against the upper threshold. Similarly, the median platelet count (158 K/µL [IQR: 139–210]) remained in the lower limits, consistent with physiological gestational thrombocytopenia. However, pathological extreme values were observed, such as severe hypoprothrombinemia (minimum PT of 12%), significant aPTT prolongations (up to 57 s), and profound thrombocytopenia (55 K/µL). Even more concerning, nearly half of the patients (46.3%) presented with a PT < 70%, 35.0% with an aPTT > 35 s, and 41.3% with thrombocytopenia (< 150 K/µL).

Table 2: Global hemostatic parameters (n = 80)

Distribution of Thrombocytopenia According to Clinical Severity Thresholds

Table 3 details the distribution of patients according to different clinical thresholds of platelet count, highlighting both the prevalence and severity of platelet abnormalities within our cohort. While the majority of pregnant women (58.8%, n = 47) had a platelet count within normal limits (150–400 K/µL), it is important to emphasize that over 40% of the sample (41.2%) presented with a variable degree of thrombocytopenia. This platelet decrease was predominantly mild (100–149 K/µL), affecting 35.0% of the patients (n = 28). However, more concerning forms were also identified. Moderate thrombocytopenia (50–99 K/µL) was observed in 5.0% of the women (n = 4). Critically, one isolated case (1.3%) presented with severe thrombocytopenia (< 50 K/µL).

Table 3: Distribution of thrombocytopenia according to clinical thresholds

Note: No severe thrombocytopenia (< 50 K/µL) was documented after verification of the raw data.

Influence of Hemorrhagic History on the Current Hemostatic Profile

To evaluate the impact of a hemorrhagic history on the current state of coagulation, a comparative analysis of hemostatic parameters was performed between patients with a history of hemorrhage (n = 10) and those without (n = 70), as detailed in Table 4. Statistical analysis revealed a significant difference regarding Prothrombin Time (PT). Indeed, patients with a history of hemorrhage presented a significantly lower median PT (67% [IQR: 64–70]) compared to the group without such history (72% [IQR: 68–77]), corresponding to a median difference of -5 percentage points (p = 0.032). Conversely, no statistically significant difference was observed for the Activated Partial Thromboplastin Time (aPTT) (p = 0.410) or for the platelet count (p = 0.280). Although the median platelet count appears numerically lower in the group with a history (146 K/µL vs. 159 K/µL), this trend does not reach the threshold of statistical significance.

Table 4: Comparison of hemostatic parameters according to hemorrhagic history (Mann-Whitney test, significance threshold p < 0.05)

Analysis of Associations between Clinical/Sociodemographic Factors and Hemostatic Abnormalities

To identify potential clinical or sociodemographic determinants associated with the hemostatic abnormalities observed in our cohort, a bivariate analysis was performed between the main explanatory variables (history of hemorrhage, parity, place of residence, age) and the biological parameters of interest (PT, aPTT, platelet count). The results of this analysis are summarized in Table 5. Among all the associations tested, only one reached the threshold of statistical significance. Patients reporting a personal history of hemorrhage presented a significantly lower median Prothrombin Time (PT) (67% vs. 72%; p = 0.032). Conversely, no significant association was found between the occurrence of thrombocytopenia and age (p = 0.680), parity (p = 0.340), or place of residence (p = 0.520). Furthermore, a non-significant trend was observed between multiparity and the prevalence of prolonged aPTT (42.3% in multiparous women vs. 28.0% in primiparous women; p = 0.190).

Table 5: Association between clinical/sociodemographic factors and hemostatic abnormalities (n = 80)