Ahhh mommy, 3kg in 4 months tu normal je actually, a few of my mum friends gained around that too! During pregnancy our body naturally holds more water, blood volume increases, plus placenta and baby lah, so weight gain is expected even if we eat the same. Kalau you're eating normally and baby's growing well, takde perlu checkup lebih sering lagi from your routine visits, tapi if you're really worried it's always okay to mention to your doctor at the next appointment and let them assess, they'll put your mind at ease!