Boss/Miscarriage/Pregnancy

So i was pregnant with twins and lost one early on. Originally i was gonna tell my boss as soon as possible but with everything that happened ive been hush hush. It's not affecting my work and on my department there is only 1 other girl so its predominately male department. My question is when I do tell my boss should i mention that the reason i took so long was because i had lost one of the babies so he understands all the extra testing? Ive fairly close with all my coworkers so i dont doubt they will be happy for but i also dont want ro disclose more than i should.... Thoughts???