The off-on couple's representatives confirmed the pregnancy to the celebrity news Web site, but offered no further details.
Major, a former tabloid reporter who is in her first trimester, conceived the child while a restraining order against Michael Lohan, a recovering alcoholic and drug addict, was in effect. TMZ said the legal document was only lifted a few weeks ago.
The couple announced their engagement in 2010, but broke up and reconciled several times since. Their stormy relationship was documented on "Celebrity Rehab with Dr. Drew."
Lohan has four adult children, including Lindsay, with his ex-wife Dina Lohan.