There is no vaccine that only prevents against whooping cough. All whooping cough vaccines also contain diphtheria and tetanus. Depending on which vaccine you are offered, some may also contain polio. The vaccine given in pregnancy will be either:
ADACEL® - (emc) (medicines.org.uk) (external link)
Boostrix-IPV ®- (emc) (medicines.org.uk) (external link), or
Repevax®- (emc) (medicines.org.uk) (external link).