This highlights an issue that crops up occasionally in early birth registration records.
A few registrars used the word "late" to indicate a maiden name, rather than following the convention of preceding it with "formerly".
When the GRO index was compiled it seems that the indexers were told that maiden names would always be after "formerly", so in these occasional cases where "late" was used instead the maiden name field on the GRO index was left blank, even though the couple were married.