Treponema pallidum crosses placenta
Transmission of Treponema pallidum from an infected woman to her fetus across the placenta may occur at any stage of pregnancy, but the lesions of congenital syphilis usually develop after the 4th month of gestation, when "fetal immunologic" competence begins to develop. Ref : Ananthanarayana textbook of Microbiology 9th edition Pgno : 372
After 36 weeks
After 28 weeks
After 2nd trimester
At any stage of pregnancy
Bacteriology