Hubungan berat badan lahir terhadap pertambahan berat badan pada usia 12 bulan pada bayi yang dilahirkan di klinik Bidan Praktek Mandiri (BPM) di Kota Lubuklinggau Propinsi Sumatera Selatan tahun 2019 = Relationship between birth weight against weight gain 12 months of age in babies born in the independent Practice Midwife Clinics (BPM) in Lubuklinggau City, South Sumatra Province in 2019