Last week it was announced the services was being stopped in the North of Ireland in 2019 and the work transferred to Alder Hey hospital in Liverpool.
It would mean grieving parents and their families having to travel to England to paediatric post mortems.
The Foyle MLA said: “Whilst I welcome the response from Mr Pengelly that alternative Paediatric Pathology solutions are being explored, including a cross-border option and the possibility of using new emerging technologies, I lament the fact that these discussions did not commence sooner.
“I am also currently awaiting a response from ROI Health Minister, Simon Harris TD, having written to him underlining the benefits of collaboration on this issue.
“If these considerations had been taken on board initially, we could have avoided this situation altogether.
“I hope that a decision is reached as quickly as possible to resolve the deficit in local paediatric pathology services and in turn prevent further distress to families here in their darkest hour.”