Latar belakang: Upaya pemenuhan standar Antenatal Care menjadi bagian penting dalam mendukung penurunan Angka Kematian Ibu (AKI) melalui RPJMN 2025 – 2029 serta menjadi salah satu intervensi untuk mencegah stunting pada Strategi Nasional Percepatan Pencegahan dan Penurunan Stunting 2025–2029. Namun, pemenuhan standar ANC di Indonesia masih belum optimal dan menunjukkan ketimpangan antarwilayah sehingga diperlukan analisis determinan berdasarkan regionalisasi wilayah. Tujuan: Penelitian ini bertujuan untuk mengetahui determinan ketidaklengkapan pemenuhan standar ANC berdasarkan regionalisasi wilayah di Indonesia, yaitu Kawasan Barat Indonesia (KBI) dan Kawasan Timur Indonesia (KTI). Metode: Penelitian menggunakan desain crosssectional dengan data sekunder SKI 2023. Analisis dilakukan secara univariat, bivariat, dan multivariabel menggunakan regresi logistik dengan complex sample analysis. Hasil: Hasil penelitian menunjukkan proporsi ketidaklengkapan pemenuhan standar ANC sebesar 87,5% di KBI dan 85,7% di KTI. Pada KBI, faktor yang berhubungan signifikan meliputi tingkat pendidikan ibu, status pekerjaan ibu, paritas, status ekonomi, tempat pemeriksaan ANC, dan status keinginan kehamilan. Faktor paling dominan di KBI adalah status ekonomi terbawah, dengan aOR sebesar 2,41 dibandingkan kelompok ekonomi teratas. Pada KTI, faktor yang berhubungan signifikan meliputi wilayah tempat tinggal, usia ibu, status pekerjaan ibu, gravida, status ekonomi, tempat pemeriksaan ANC, tingkat kemudahan akses ke klinik/praktik mandiri, dan status keinginan kehamilan. Tingkat pendidikan ibu tetap dipertahankan dalam model akhir KTI sebagai variabel confounder. Faktor paling dominan di KTI adalah status keinginan kehamilan, dengan ibu yang memiliki kehamilan tidak diinginkan memiliki aOR sebesar 2,62 dibandingkan ibu dengan kehamilan diinginkan. Kesimpulan: Ketidaklengkapan pemenuhan standar ANC masih tinggi di KBI maupun KTI, dengan pola determinan yang berbeda antarwilayah. Penguatan program ANC perlu diarahkan pada kelengkapan kualitas pelayanan, pemerataan akses, serta perhatian khusus pada ibu dengan status ekonomi rendah dan kehamilan tidak diinginkan.

Background: Efforts to fulfill Antenatal Care (ANC) standards are an important component in supporting the reduction of maternal mortality through the 2025–2029 National Medium-Term Development Plan (RPJMN), as well as one of the interventions to prevent stunting under the 2025–2029 National Strategy for the Acceleration of Stunting Prevention and Reduction. However, the fulfillment of ANC standards in Indonesia remains suboptimal and shows disparities across regions, highlighting the need to analyze its determinants based on regionalization. Objective: This study aimed to identify the determinants of incomplete fulfillment of ANC standards based on regionalization in Indonesia, namely Western Indonesia Region (KBI) and Eastern Indonesia Region (KTI). Methods: This study used a cross-sectional design with secondary data from the 2023 Indonesian Health Survey (SKI). The analyses were conducted using univariate, bivariate, and multivariable analyses with logistic regression through complex sample analysis. Results: The results showed that the proportion of incomplete fulfillment of ANC standards was 87.5% in KBI and 85.7% in KTI. In KBI, the factors significantly associated with incomplete fulfillment of ANC standards were maternal education level, maternal employment status, parity, economic status, place of ANC examination, and pregnancy intention status. The most dominant factor in KBI was the lowest economic status, with an aOR of 2.41 compared with the highest economic group. In KTI, the factors significantly associated with incomplete fulfillment of ANC standards were area of residence, maternal age, maternal employment status, gravidity, economic status, place of ANC examination, accessibility to clinics/private practices, and pregnancy intention status. Maternal education level was retained in the final KTI model as a confounding variable. The most dominant factor in KTI was pregnancy intention status, with women who had unintended pregnancies having an aOR of 2.62 compared with those with intended pregnancies. Conclusion: Incomplete fulfillment of ANC standards remains high in both KBI and KTI, with different determinant patterns across regions. ANC program strengthening should be directed toward improving the completeness of service quality, equitable access, and special attention to mothers with low economic status and unintended pregnancies.