Parents pls advice me. My 2 yr old wakes up every night around 12-1, hysterically laughing and she even says bye bye and stuff. I initially thought she was dreaming so I would pat her back, but she keeps her eyes open while she is smiling and laughing. What is actually happening?

Like what Yuna mentioned, your baby may be having night terrors. These are different from nightmares. Nightmares usually start when children who are 3 to 4 years old, and children wake up from them feeling scared (and could remember the nightmare). But with a night terror, it usually happens during deep sleep when the baby is not dreaming. The baby’s sleep suddenly gets disrupted and he/she may suddenly start crying or screaming in distress. The baby is not aware that he/she is crying (or in your case, laughing etc), and is not likely to remember this the next morning. Fortunately, night terror is not found to have any harmful effects on babies and will outgrow them. To help, simply make sure that your baby is safe, comfort him/she (if needed) and she will eventually quiet down.