Nasution HS. THE RELATIONSHIP OF KNOWLEDGE AND ATTITUDE OF PREGNANT MOTHERS ABOUT THE BENEFITS OF ULTRASOUND ON THEIR PREGNANCY AT THE SILAU LAUT PUSKESMAS, SILAU LAUT DISTRICT IN 2021. midwifery [Internet]. 2022 Apr. 30 [cited 2026 Oct. 26];10(2):1816-20. Available from: https://www.midwifery.iocspublisher.org/index.php/midwifery/article/view/501