Thank you for your query.
Decreased amniotic fluid
around the baby is called oligohydramnios
This condition , if not treated, is very harmful for the baby.
It can lead to growth restriction and even intra uterine death.
Common causes of oligohydramnios are - abnormalities in the baby leading to decreased urine production and decreased fluid around the baby, abnormalities of the placenta, maternal diseases like hypertension
YOu need to have detailed ultrasound to know whether there are any other associated anomalies in the baby.
Improve your rest, fluid intake, and increase intake of amino acids and protein in diet.
Go alongwith the advice given by your obstetrician.