Philip J. Budd interprets Numbers 5:11-31 as a ritual that causes an abortion if the woman is guilty of adultery.
Philip J. Budd, "Numbers," in Eerdmans Commentary on the Bible, ed. James D.G. Dunn and John W. Rogerson (Grand Rapids, MI: Eerdmans, 2003), 133
A miscarriage is apparently expected should the woman be guilty (5:22). In the light of what she is required to drink (vv. 23-24) it may be supposed that any such eventuality would be improbable, but the psychological strains to which she is subjected should not be underestimated, and the risk of a serious miscarriage of justice is real. In v. 28, for example, there is at least a possibility that infertility will be interpreted as an indication of guilt, and the concluding comment (v. 31). . . .is a reminder of the exploitation and disadvantage to which women have often been exposed.