This will be a prospective cohort study conducted in two different altitudes in Nepal. The high-altitude site is in Jumla, approximately 2514 m above the sea level, and a low altitude city is Dharan, located at 350 m from sea level.~The investigators will screen the eligible participant admitted to the in-patient obstetric unit. The investigator will also record patient baseline characteristics, preoperative anxiety, antenatal depression, presence of chronic pain conditions or preexisting headache. Spinal anaesthesia will be administered in the sitting position at the L3-L4 or L4-L5 interspace using a 25-G pencil point spinal needle (Pencan® 25-gauge).~The diagnosis of post-dural puncture headache will be based on the international headache society ICDH-3 criteria
The aim of this study is to examine the effects of altitude (high altitude versus low altitude) on incidence and severity of postural puncture headache (PDPH) following spinal anaesthesia for caesarean delivery. The investigators hypothesized that the risk of PDPH would be higher in highlander parturients than in lowlander parturients.