I am so sorry for your loss! I too have an abdominal cerclage (TAC) and believe a D & C can be done without a problem. Who placed your TAC - Dr. Haney, Dr. Davis or someone else? Can you email them and ask for sure.
I found this from my abbyloopers Q & A with Dr. Haney -
16) If a miscarriage occurs prior to 12 weeks, can a woman “let nature take its course” or is it safe to request a D&C? What are the dangers of either method?
There is no one right answer to this question but the clinical course determines whether a D&C will be necessary. If the degenerating pregnancy tissue is spontaneously passing, then a D&C is typically not necessary while if the tissue remains in the uterus and bleeding persist for any length of time, a D&C may be required. The only issues of concern are excessive bleeding if the tissue is not passed and infection if the opening of the cervix with the attendant loss of mucus is prolonged. A D&C has minimal risk but does require minimal anesthesia.
This is Dr. Davis's response -
16. If a miscarriage occurs prior to 12 weeks, can a woman "let nature take its course" or is it safe to request a D&C?
Quick Take: A D&C (D&E) is possible
This is one of the big concerns about doing the TAC prior to pregnancy. Some statistics involving normal healthy women are useful here. Of all conceptions, only 50 to 60% will reach the third trimester. Up to 25% are lost before a woman knows she is pregnant. Of all women with a positive pregnancy test, 20 to 25% will miscarry. Of all women who reach eight weeks, 12 to 13% (one in eight) will miscarry. By 10 weeks this drops to 10% of a woman’s age (2.5% in a 25-year-old for example).
Prior to seven weeks, most women can safely wait and pass everything naturally. Many prefer a D&C, however. It can be hard waiting for mother nature to “take its course”. You never know where of when it will happen, how heavy the bleeding will be and it can take up to a month before it happens.
Once you get to 7 to 8 weeks, the amount of retained tissue is such that a D&C (or D&E – same thing) is advisable to avoid significant hemorrhage. As long as the TAC isn’t to tight, which it usually isn’t if placed laparoscopically, the cervix will accommodate up to a number 10 (10 mm) suction curette once there is no longer a viable pregnancy. This will handle up to a nine-week pregnancy. Beyond that, I recommend waiting about two weeks before doing the D&C. This will allow sufficient time for the tissues to break down allowing removal with a number 10 suction curette.
I hope this helps! Good luck!

Michelle