Bauer Consumer Media made the announcement in a statement from Marcus Rich, group managing director Bauer Advertising and Bauer London Lifestyle Magazines.
The magazines have been suspended and Bauer said it would now enter into a month-long period of consultation with editorial staff.
The decision will affect 49 editorial staff in total, with 30 on First and 19 on NW. No commercial roles affected.
Bauer Consumer Media added that there would be no further comment until the consultation process has concluded.
The decision has been made by Bauer Consumer Media and not H Bauer, which is a separate business in the UK.
Next week's issue of First will go on sale Tuesday and the magazine will be suspended thereafter. The April issue of NW, which was rebranded from New Woman, will go on sale at the end of this month and will be suspended thereafter.
Emap sold its magazines and radio divisions to Bauer for £1.14bn in December.
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