The quick answer is miscarriage is no more common with women who have had a reversal than women who conceive without ever having their tubes tied and then reversed. Until recently, I told patients that 7% of all pregnancies end in miscarriage. Recent studies have shown that 10% not 7% of pregnancies end that way. It is also true that as a woman ages, miscarriage is more likely. At age 45, the chance of a pregnancy ending in miscarriage is 80%. If you never have had a miscarriage you are less likely to have one than a woman who has. As a male gynecologist I had to learn that pregnancy loss is often a very difficult blow for a woman to get over. As hard as it is, the realities are that it’s not that unusual and you need to keep trying.
If you are a physician reading this, I would refer you to Obstetrics and Gynecology Vol. 125,no.5, May 2015 pp1258-1264