And there was no possibility of returning after the birth, one woman told the hearing at the start of more than 4,000 claims of wrongful dismissal.
The Ministry of Defence could face a bill for millions of pounds in an avalanche of sex discrimination claims.
Two test cases which opened at Croydon, south London, are to set compensation levels after a European Court of Justice ruling removed the pounds 11,000 ceiling in British sex discrimination cases and exclusion of services personnel.
Jacqui Thornber, of Leicester, told the tribunal there was no possibility of returning to her RAF career after the birth of her child. Her case was adjourned to 15 September.
The other claimant, Deborah Miller, 28, of Nafferton, Humberside, has called for pounds 54,000 compensation after her discharge when pregnant with her daughter Amy in 1987.
She said she was discharged within two days of telling her commanding officer at RAF Buchan, Aberdeenshire, of her pregnancy. Her case was adjourned until 8 October.