(Bloomberg) -- As parliamentary debate about Brexit grinds on, the U.K.’s embattled National Health Service warned of the disruption the divorce would cause to its blood-donation drive.

Blood collection sessions in the port cities of Dover and Folkestone will be canceled for two weeks before and six weeks after Brexit day on March 29, according to the NHS’s Blood Donation unit.

“In the event of issues in Calais and other freight ports, this could lead to significant traffic in Kent and may prevent donation teams from reaching or leaving venues in the area,” according to the tweet from @GiveBloodNHS. It won’t affect blood stocks, it said.

Pharma companies are already stockpiling, reserving space on flights, and finding alternate shipping routes for supplies of life-saving drugs in case a no-deal Brexit clogs ports and customs stations with shipments. The NHS is also developing contingency plans for blood collection, scheduling replacement sessions at other locations.

©2019 Bloomberg L.P.