Green’s Dictionary of Slang

(US/W.I.) to make pregnant; thus bigged, pregnant.

1934		E. Caldwell Tobacco Road (1958) 29: Lov’s going to big her [...] he acts like an old stud-horse.
1942		Z.N. Hurston Dust Tracks On a Road (1995) 600: It did not take me long to know what was meant when a girl was spoken of as ‘ruint’ or ‘bigged’.
1954		(con. 1920s–30s) J.O. Killens Youngblood (1956) 105: Boy, you bet not get that white gal bigged.
1957		H. Simmons Corner Boy 85: Tell her not to come crying around here when she gets all bigged from messing around with you.
1969		‘Iceberg Slim’ Mama Black Widow 158: If she cum frum th grave and let thet peckahwood big her.
1989		M. Amis London Fields 283: One of the many messages that pulses off Lizzyboo has something to do with babies. It says: Big me. I’m big already but make me bigger.