Foetal growth restriction (FGR) is a major challenge in obstetric care owing to its strong association with perinatal morbidity, mortality, and long-term neurodevelopmental and metabolic complications [1]. FGR affects approximately 10% of pregnancies [2] and is difficult to consistently detect, with global reports indicating suboptimal antenatal detection rates [3]. This condition arises from multifactorial aetiologies, including maternal, placental, and foetal factors as well as broader social determinants such as maternal age, socioeconomic status, and healthcare access [1]. Therefore, the accurate assessment of foetal growth is a fundamental objective of antenatal care and is critical for improving pregnancy outcomes [1].

Studies conducted in Saudi Arabia have primarily focused on hospital-based populations to investigate maternal risk factors and neonatal outcomes [4, 5]. A recent study from Jazan, Saudi Arabia reported a community-based FGR prevalence of 1.9% [6], although it did not focus on pregnancies managed at primary healthcare centres (PHCCs). Consequently, national-level evidence on the prevalence and detection of FGR in PHCC settings remains limited.

Health system reforms under Saudi Arabia’s Vision 2030 have led to the creation of regional health clusters aimed at enhancing quality of care and reducing hospital burden [7]. Within this framework, the Eastern Health Cluster introduced a unique Safe Birth Pathway that redefined the responsibilities of PHCCs. In this model, intermediate-risk pregnancies are managed outside hospitals at PHCCs by board-certified obstetricians until 36 weeks of gestation, whereas low-risk pregnancies are managed by primary healthcare physicians in accordance with the national PHCC model [8]. This expanded role of the PHCC has been implemented in Eastern Province, where the Safe Birth Pathway was introduced under the regional health cluster framework. This model differs from that described by Munshi [9] in which PHCCs were limited to managing low-risk pregnancies, with intermediate- and high-risk cases referred to hospitals.

The present study focused on FGR because it is a leading risk factor for stillbirth [10]. Although early detection does not eliminate all perinatal risks, it enables close monitoring and timely intervention, which are critical for improving outcomes [11]. However, missed diagnoses are common and often linked to limitations in routine antenatal screening, such as misinterpretation of estimated foetal weight (EFW) and inadequate use of symphysis-fundal height measurements [12].

These diagnostic limitations are particularly pronounced in PHCCs that lack ultrasound capability. In Dammam, a major city within the Eastern Health Cluster, none of the 22 PHCCs currently operates on-site ultrasound clinics staffed with qualified personnel trained in foetal growth assessment. Such clinics require both functional ultrasound equipment and a specialist trained in obstetric ultrasonography to ensure accurate detection of FGR. The absence of these services significantly limits access to structured foetal growth evaluations, particularly for low-risk pregnant women managed entirely within PHC settings.

The Safe Birth Pathway guides antenatal care delivery under Saudi Arabia’s national maternal care protocol, which includes risk stratification and referral of PHCCs to hospitals. Although it was designed to standardise care and reduce preventable adverse outcomes, its current structure does not require onsite ultrasound for PHCCs. Therefore, when FGR is suspected, patients must be referred to a hospital for further evaluation, which may lead to delays in diagnosis and timely interventions.

The Eastern Province has been at the forefront of healthcare reform with the establishment of a dedicated regional health cluster that expands antenatal services within PHCCs. As part of this expansion, a pilot ultrasound clinic was established in Dammam City to evaluate the readiness of PHCCs to detect FGR, as early detection is the cornerstone of follow-up, as emphasised by Atallah, et al. [12].

To date, no study has evaluated the prevalence and antenatal detection of FGR in patients with PHCCs in Saudi Arabia. Despite ongoing national efforts to expand maternal services at the primary care level, this study aimed to address this gap. We hypothesised that systematic ultrasonography of PHCCs would enable effective antenatal FGR detection and yield prevalence estimates comparable to international data.

Accordingly, this study aimed to determine the prevalence and antenatal detection rate of FGR among pregnant women receiving care at PHCCs in Dammam, Saudi Arabia.

Between January and May 2024, all pregnant women in their first trimester attending 22 PHCCs in Dammam were referred to a newly established central ultrasound clinic for routine gestational age assessment (dating scan) in accordance with a standardised protocol introduced as part of the Safe Birth Pathway.

A total of 418 women who underwent routine first trimester scans were included in the study. After receiving a detailed explanation of the study objectives and procedures, 232 participants provided written informed consent.

The inclusion criteria were as follows: (1) first trimester pregnancy at the time of recruitment, (2) confirmed singleton pregnancy, and (3) normal second-trimester foetal anomaly scan. The exclusion criteria were known foetal congenital anomalies and multiple gestations.

Foetal anomaly scans were not conducted at the participating PHCCs but were instead performed at a designated maternity hospital between 18 and 22 weeks of gestation. The confirmation of a normal anomaly scan was based on hospital reports submitted by the participants during follow-up visits. Participants who did not have a documented anomaly scan report were initially retained in the study. However, if a major congenital anomaly was subsequently identified postnatally, the case was excluded from the analytical dataset in accordance with predefined exclusion criteria. This ensured that all included pregnancies were free of structural anomalies, either antenatally or postnatally, thereby maintaining consistency in the study sample.

As an accurate assessment of foetal growth requires reliable gestational dating, this study included only first-trimester pregnancies. This approach ensures a consistent baseline for evaluating foetal size and detecting growth restrictions. However, as recruitment was limited to women presenting early in pregnancy and attending routine dating scans, the findings may not be generalisable to all pregnant women receiving care at PHCCs, particularly those who present later in gestation or are not referred for early ultrasonography.

This dating clinic is planned to remain operational beyond the study period, providing an ongoing system for accurate gestational age assignment across all PHCCs and enabling future quality improvements and research initiatives.

The required sample size was calculated using the following formula:

n = Z² × p(1 – p) / d²

Assuming an expected FGR prevalence of 10% (P = 0.10), 95% confidence level (Z = 1.96), and 5% margin of error (d = 0.05), the minimum required sample size was 139 participants.

The recruitment target was increased to account for potential losses to follow-up and incomplete data. Ultimately, 232 women were enrolled, which reduced the effective margin of error to approximately 3.86%, and improved the precision of the prevalence estimates.

Calculations were performed using a standard statistical formula and verified using the OpenEpi online tool (www.openepi.com).

Each participant underwent two standardised ultrasonography examinations: the first between 24 and 31 weeks and the second between 32 and 36 weeks of gestation. At the time of the study, the participating PHCCs did not have onsite ultrasound clinics. A central ultrasound service was established as part of this project to provide dating scans as part of routine care, whereas growth scans were incorporated exclusively for research purposes. Upon completion of the study, only the dating scan service was retained as part of routine antenatal care and growth scans were discontinued.

These assessments enable the evaluation of both early- and late-onset FGR according to the Delphi consensus classification [13]. The EFW was calculated using Hadlock’s three-parameter formula (head circumference, abdominal circumference, and femur length) [14]. FGR was diagnosed based on the Delphi consensus criteria, incorporating the following biometric measurements and Doppler indices: umbilical artery pulsatility index (PI > 95th percentile), middle cerebral artery PI (< 5th percentile), and cerebroplacental ratio (< 5th percentile).

All ultrasonography scans were performed by the principal investigator, a board-certified consultant obstetrician trained and certified in obstetric ultrasonography, using a Samsung HERA W9 instrument (Samsung Electronics Co., Ltd., Suwon, South Korea) to ensure consistency and reliability across cases.

All antenatal FGR diagnoses were prospectively made by the principal investigator during scheduled assessments and documented in participants’ medical records.

Participants with FGR were referred to a maternity hospital for further management. Neonatal outcomes, including birth weight and sex, were obtained from the medical records of the PHCCs and maternity hospitals. For participants who delivered outside the PHCC network, structured telephone interviews were conducted to obtain neonatal data. During these calls, participants were invited to share brief feedback on their antenatal care experience, providing additional qualitative insights into the barriers to and facilitators of follow-up.

Antenatal detection was defined as any case in which the participant was referred to a maternity hospital during pregnancy with a documented suspicion of FGR and the diagnosis was later confirmed after birth based on either birth weight below the 3rd percentile or birth weight below the 10th percentile in combination with abnormal Doppler findings.

Cases were classified as undetected antenatally if FGR was not identified during antenatal assessments, either because the participant did not return for follow-up growth scans, or because the condition was not recognised at the time of scanning. In these cases, FGR was retrospectively diagnosed based on the postnatal data.

The prevalence of FGR among women receiving care at PHCCs in Dammam, Saudi Arabia was 9%, which is comparable to the global prevalence estimate of approximately 10% [2]. The antenatal detection rate was 63.2%, achieved using structured ultrasound assessments based on the Delphi consensus criteria [13]. However, 36.8% of cases were diagnosed postnatally, primarily because of missed third-trimester growth scans.

Although the prevalence rate determined in our study is consistent with those of other international reports [2], a study from Jazan, Saudi Arabia, reported a significantly lower prevalence of 1.9% [6]. This discrepancy may be explained by the differences in the study population, methodology, or diagnostic criteria. Other studies conducted in Riyadh and Jeddah have been largely hospital based, focusing primarily on maternal risk factors and neonatal outcomes rather than on population-level prevalence [4, 5]. Unlike these hospital-centred studies, our study uniquely evaluated FGR detection within PHCCs, highlighting the system-level challenges specific to primary care settings.

To the best of our knowledge, no published study has specifically evaluated FGR detection rates in PHCCs. In our study, the antenatal detection rate was 63.2%, which compares favourably with both hospital-based data and dedicated cohort studies. For instance, in the French REPERE cohort [3], antenatal detection rates for small-for-gestational-age foetuses remained below 50%, underscoring diagnostic challenges, even in high-resource settings. Similarly, a recent study in South Africa demonstrated the feasibility of implementing Doppler-based screening protocols for PHCCs between 28 and 34 weeks of gestation to identify at-risk foetuses [16]( 2022). These findings support the view that, with appropriate protocolization and capacity building, PHCC-based FGR detection, as demonstrated in our model, could improve the performance of hospital-based systems.

The relatively high proportion of missed FGR cases in this study could be primarily attributed to the absence of routine third trimester growth scans within PHCCs. Informal feedback from participants after delivery suggests divergent patterns in care-seeking behaviours between the risk groups. Intermediate-risk women managed by obstetricians generally benefit from structured appointments. In contrast, some low-risk women managed by primary care physicians reported challenges, such as self-booking requirements, inconsistent provider availability, and limited appointment slots. Although not systematically collected or quantified, these anecdotal insights highlight potential system-level barriers to patient engagement and continuity of care, which are recognised as key determinants of antenatal care adherence [17, 18].

Thus, despite Vision 2030-driven expansion of PHCC responsibilities and the Safe Birth Pathway’s emphasis on risk stratification and early detection, gaps remain in service delivery. Specifically, the absence of routine third trimester ultrasound limits timely FGR diagnosis and undermines the effectiveness of these reforms. This indicates the need to reevaluate structural policies and resource allocation within the PHC system to align actual service delivery with national policy goals.

A major strength of this study was its prospective cohort design, which allowed for a systematic assessment of FGR in real-world PHCC settings [19]. This study also achieved a high follow-up completion rate of 90.5%, which enhanced the reliability of prevalence and detection estimates. Finally, the implementation of standardised ultrasonography using the Delphi consensus criteria [13], performed by a certified consultant obstetrician, ensured diagnostic accuracy and minimised variability.

In addition, this study is among the few in Saudi Arabia that has investigated FGR identification specifically at the PHCC level rather than in hospital-based settings/populations. By focusing on system-level performance rather than individual maternal risk factors, this study provides unique insights into the feasibility and challenges of implementing structured foetal growth surveillance in PHCCs.

This study has some limitations. First, the relatively small number of confirmed FGR cases may limit the generalisability of our results to a broader populations [20]. Second, although maternal and foetal risk factors were included in the questionnaire, they were not analysed because the primary aim was to assess system-level detection performance rather than individual predictors. Third, qualitative observations of care-seeking behaviour were derived from informal, unstructured postnatal conversations rather than systematic data collection and should therefore be interpreted as exploratory insights only. Additionally, the sample was derived from women referred for dating ultrasonography rather than from all PHCC attendees, potentially introducing a selection bias [21]. Recruitment was non-random and limited to a defined period and single city, which may limit generalisability to other PHCCs or regions [22]. Finally, all ultrasound assessments were performed by a single investigator. Although this ensured standardisation, it may have introduced observer bias despite internal consistency.

Our findings highlight the need to strengthen antenatal care pathways in PHCCs. First, the research findings present a strong case for the integration of routine third-trimester growth scans into national antenatal care protocols, as evidence shows that universal third-trimester ultrasound substantially improves FGR [23]. Second, a more efficient healthcare model could establish a dedicated ultrasound clinic within each PHCC network (e.g. one clinic serving a single-city network). All pregnant women, regardless of risk classification (low or intermediate risk), were referred to these clinics for dating and routine third-trimester growth scans between 32 and 36 weeks of gestation (anomaly scans should be performed in hospital-based settings). Network-based clinics should be staffed with trained sonographers competent in growth and Doppler assessments, and authorised to directly refer patients to hospitals in cases of abnormal results, thereby minimising delays in identifying FGR. In suspected FGR cases with normal Doppler findings, the affected women were observed and evaluated on a designated day by a visiting obstetrician, ensuring timely evaluation without unnecessary hospital referrals. Third, establishing dedicated antenatal clinics led by certified family physicians within PHCCs would ensure that antenatal care is delivered in a setting specifically designed for pregnancy follow-up, rather than in general outpatient clinics. Such dedicated clinics could enhance continuity of care and improve the overall patient experience. Finally, patient engagement strategies such as reminder systems, flexible appointment scheduling, and clear care pathways should be implemented to reduce barriers to follow-up. These recommendations align with the World Health Organization guidelines, which emphasise flexible scheduling, reminders, and continuity of care as key strategies to improve antenatal attendance and promote positive pregnancy experience [24]. The proposed system-level interventions are consistent with the National Health Transformation Goals and can significantly improve maternal and neonatal outcomes in Saudi Arabia.

Future studies should explore the scalability and cost-effectiveness of introducing routine third trimester growth scans at the PHCC level, particularly in network-based ultrasound clinics. Multicentre studies across different regions of Saudi Arabia are needed to assess whether this model can be adapted nationwide and to evaluate its impact on maternal and neonatal outcomes. Further research is needed to investigate patient engagement strategies, such as digital reminders and streamlined appointment systems, to determine their effectiveness in improving follow-up adherence and detecting FGR [24]. Finally, qualitative studies focusing on the antenatal care experiences of pregnant women followed-up in PHCCs may elucidate barriers and facilitators, informing the design of patient-centred interventions.

The prevalence of FGR in pregnant women, followed by that of PHCCs, was approximately 9%. Importantly, nearly two-thirds of the FGR cases were identified antenatally, including cases from both the low- and intermediate-risk groups, indicating that PHCCs play a meaningful role in identifying affected pregnancies. PHCCs may be the first-line of treatment for FGR detection and follow-up, underscoring the importance of investing in their capacity. Strengthening PHCCs with adequate equipment, trained personnel, and structured care pathways would not only enhance the early detection of FGR but also establish these centres as active partners to alleviate the burden on hospital services and improve maternal and neonatal outcomes. These improvements are consistent with the objectives of Vision 2030 in Saudi Arabia, which emphasises strengthening primary healthcare services, prioritising preventive care, and enhancing maternal and neonatal health outcomes nationwide [7].