Simplicity 6023 vintage sewing pattern, dated ca.1965.
Maternity One-Piece Dress in Misses' Sizes:
Maternity dress with let-out side seams has lowered round neckline, collar and back zipper closing. V. 1 with short set-in sleeves has rick-rack and button trim. V. 2 with short set-in sleeves has self fabric bow. Sleeveless V. 3 has contrasting collar & ribbon bow.
Size 12:
Bust 32 inches / 81 cm
Waist 25 inches / 64 cm
Hip 34 inches / 86 cm
Pattern is UNPRINTED tissue pieces with perforated symbol markings, checked complete. Envelope has a store stamp and a handwritten name on the front.
More '60s patterns here:
http://allthepreciousthings.com/collections/1960s