I appreciate your query.
The symptoms that you mention could be early preterm labour pains.
In any case, you should definitely go to the ER for a check up, because you cannot ignore it, if they are really preterm labour pains.
True preterm labour pains are intermittent, not relieved by analgesics, radiate from back to front, associated with hardening of the uterus
, and accompanied by some vaginal discharge
Since you are having IUGR
also alongside, please visit your ER and be reassured.
also might present in this way, but the only way to rule it out is to have an internal check up.
All the best.