Russian-backed Syrian troops launched an offensive in late 2017 against jihadists and allied groups in Idlib, the last province in the country still fully outside the government's control.
The assault has seen tens of thousands flee, with many displaced multiple times.
In a new situation report published Tuesday, the UN's humanitarian coordination branch (OCHA) said it had recorded 212,140 instances of displacement between December 15 and January 16.
The largest displacement -- 58,338 people -- was to the village of Dana in Idlib province, but other waves of civilians fled to areas in the adjacent provinces of Aleppo and Hama.
In a first, OCHA said, around 6,700 families fled rebel-held areas of Hama province to nearby government-controlled territory.
Idlib and slivers of the neighbouring provinces are now hosting more than 1.1 million internally displaced Syrians, according to the UN.
As hostilities between Syrian troops and anti-regime forces escalate, OCHA said it had received reports of several health clinics in the area being rendered out of service in bombardment.
Other facilities, it warned, were "running low" on medical supplies.
"Facilities are strained due to the increasing caseload because of the recent displacement," the situation report said.
"The low winter temperatures and the lack of shelter is exacerbating the health situation of the IDPs (internally displaced people) causing winter-related illnesses."
More than 340,000 people are estimated to have been killed in the Syrian war, which began in 2011 as the regime brutally crushed anti-government protests.
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