Statutory Maternity Pay (SMP): general information - time limits for producing medical evidence
The employee must produce medical evidence of the date the baby is due.
Although a birth certificate is acceptable as proof that a baby has been born, the employer still needs evidence of the date the baby was due, this is usually form MAT B1 (Maternity Certificate).
Normally the evidence of the week the baby is due is on the MAT B1 but other medical evidence is acceptable providing it shows the date the baby is due. It cannot be issued before the start of the 20th week before the week the baby is due and must be given to the employer within 21 days from the start of the SMP pay period. In exceptional circumstances this can be extended to 13 weeks, but no more. If there is good reason for the evidence being produced late it must be accepted by the employer provided the evidence is produced by what would be the end of the 13th week of the SMP pay period.