The Handbag group consists of four female-targeted websites - getlippy.com, allaboutyou.com, a specialist pregnancy site gomamatoday.com and handbag.com.
The group claims to generate over 30 million page impressions per month with its portfolio of sites.
According to the Guardian, sources close to the deal claim the group acquisition cost £22 million. Although the company will not disclose how much it paid for Hangbag.com.
The sites will join NatMags' extensive portfolio of web titles, which already includes: babyexpert.co.uk, cosmopolitan.co.uk, goodhousekeeping.co.uk, menshealth.co.uk, and netdoctor.co.uk.
NatMags is owned by the Hearst Corporation, which has the capacity to provide backing for a major expansion into the US market for the UK-based sites.
Duncan Edwards, chief executive of NatMags said: "NatMags is totally committed to being as important to our customers online as we are in print, and this acquisition is a significant step forward in achieving this goal.
"It's a pleasure to welcome Nancy Cruickshank, managing director of Handbag, and her team to the Hearst community, and we look forward to bringing all our resources to bear on the business."
Nancy Cruickshank added: "We are incredibly excited and optimistic about the opportunities that NatMags will now offer the business. We aim to deliver an even more compelling product to readers and advertisers alike by joining together our traditional and digital publishing expertise."
Handbag.com was launched in 1999 as a joint venture between retailer Boots and the Daily Telegraph.
The Barclay brothers’ company The Press Holdings Group then became the sole owner, in 2005, a year after they purchased the Telegraph.