Sudden water break at 19th week.

Hi Dr, I lost mine IVF baby in 19th week due to silently water break. Embical cord was out and No water left. It just happened in 5min without any single pain other or symtoms God Know why did it happen. WE BOTH ARE GOING MAD She was on Protegsteron support for first 3 month She has spotting in first month and 2nd month but it was implantation issue which dr scanned and confirmed Every report was normal including NIPT, 3DScan, Double marker , Triple marker Only issue was that her WBC used to be hugh but Dr told me that it is common in early pregancy. 1 major changes happened….Wife was 96Kg before IVF…the reduced to 89kg during first month ….then today( after this unfirtunely obsraortion) 1. How can this cervix open without any single sumntpms 2. Apart of sticking, can we do own to avoid this 3. Did Weight gain could be reason We are waiting for MSRA REPORT Please suggest…I know if i connect …I can get answer …but please help me to get answer for these…once