Pendahuluan Berat bayi lahir rendah merupakan salah satu masalah kesehatan yang banyak terjadi pada bayi baru lahir dan dapat meningkatkan risiko komplikasi pada bayi baru lahir. 54% penyebab kematian bayi adalah latar belakang gizi.. Bayi dengan BBLR mempunyai peluang meninggal 10-20 kali lebih besar dari pada bayi yang lahir dengan berat lahir cukup. Dampak dari BBLR antara lain peningkatan risiko hipotermia, hipoglikemia, gangguan pernapasan, hiperbilirubinemia, dan lain-lain, serta meningkatkan risiko gangguan perkembangan motorik dan kognitif, gangguan pertumbuhan, serta penyakit kronis. Prevelensi Kasus BBLR tahun 2021-2023 di Kota Metro terus mengalami kenaikan. Hasil penimbangan tahun 2021 terdapat 4,8% mengalami BBLR, pada tahun 2022 terdapat 5,1% mengalami BBLR dan pada tahun 2023 terdapat 6.0% mengalami BBLR. Rendahnya status gizi ibu hamil selama kehamilan dapat mengakibatkan berbagai dampak tidak baik bagi ibu hamil dan bayinya diantaranya adalah bayi lahir dengan BBLR. Penelitian ini bertujuan untuk mengetahui hubungan status gizi dan kenaikan berat badan ibu selama hamil terhadap BBLR.Metode Penelitian ini merupakan penelitian observasional dengan desain case control dan dilaksanakan pada bulan Mei 2025 di RSUD Jenderal Ahmad Yani Kota Metro. Populasi penelitian ini adalah seluruh ibu dan bayi baru lahir di rumah sakit. Sampel penelitian ini berjumlah 80 responden terdiri atas 40 kelompok kasus (BBLR) dan 40 kelompok kontrol (Tidak BBLR). Sampel dipilih menggunakan alat ukur kuesioner untuk memperoleh data menggunakan analisis univariat dan bivariat menggunakan uji Chi Square dengan tingkat kemaknaan (��) 0,05%.Hasil penelitian dari 80 responden menunjukkan ibu dengan status gizi dalam kategori beresiko BBLR (25,0%) dan ibu dengan status gizi dalam kategori tidak beresiko BBLR (75,0%), sedangkan ibu dengan kenaikan berat badan selama hamil dalam kategori tidak sesuai IMT (77,5%) dan kategori sesuai IMT (22,2%). Hasil uji statistik diperoleh hasil adanya hubungan antara status gizi p-value = 0,003; OR = 13,000 dan kenaikan berat badan ibu selama hamil p-value = 0,001 ; OR = 4,660 dengan berat bayi lahir rendah.Kesimpulan penelitian adanya hubungan status gizi dan kenaikan berat badan ibu selama hamil dengan kejadian BBLR. Saran Perlu edukasi untuk upaya menurunkan dan mencegah kejadian BBLR dengan melakukan pemeriksaan rutin agar dapat membantu dalam mendeteksi dini status gizi ibu hamil serta melakukan pemantauan selama kehamilan. Kata kunci : IMT, status gizi, kenakan berat badan, BBLR ABSTRACT Introduction Low birth weight is a common health problem in newborns and can increase the risk of complications in newborns. 54% of infant deaths are caused by nutritional background. Babies with low birth weight have a 10-20 times greater chance of dying than babies born with adequate birth weight. The impacts of low birth weight include an increased risk of hypothermia, hypoglycemia, respiratory disorders, hyperbilirubinemia, and others, as well as an increased risk of impaired motor and cognitive development, growth disorders, and chronic diseases. The prevalence of low birth weight cases in Metro City from 2021-2023 continues to increase. The results of weighing in 2021 showed 4.8% experiencing low birth weight, in 2022 there were 5.1% experiencing low birth weight and in 2023 there were 6.0% experiencing low birth weight. The low nutritional status of pregnant women during pregnancy can result in various adverse effects for pregnant women and their babies, including babies born with low birth weight. This study aims to determine the relationship between nutritional status and maternal weight gain during pregnancy with low birth weight.Method This research is an observational study with a case control design and was conducted in May 2025 at General Ahmad Yani Regional General Hospital, Metro City . The population of this study was all mothers and newborns at the hospital. The sample of this study amounted to 80 respondents consisting of 40 case groups (LBW) and 40 control groups (Not LBW). The sample was selected using a questionnaire measuring tool to obtain data using univariate and bivariate analysis using the Chi Square test with a significance level (��) of 0.05%.The results of the study from 80 respondents showed that mothers with nutritional status in the category at risk of LBW (25.0%) and mothers with nutritional status in the category not at risk of LBW (75.0%), while mothers with weight gain during pregnancy in the category not according to BMI (77.5%) and the category according to BMI (22.2%). The results of the statistical test obtained the results of a relationship between nutritional status p-value = 0.003; OR = 13,000 and maternal weight gain during pregnancy p-value = 0.001; OR = 4,660 with low birth weight.The conclusion of the study is that there is a relationship between nutritional status and maternal weight gain during pregnancy with the incidence of LBW. Suggestion : Education is needed to reduce and prevent the incidence of LBW by conducting routine check-ups to help in early detection of the nutritional status of pregnant women and conducting monitoring during pregnancy. Keywords : BMI, nutritional status, weight gain, LBW