If The Woman Is Defiled Her Body Will Swell and She Will Be Accursed Among The People (Numbers 5:27).
‘And when he has made her drink the water, then it shall come about, if she be defiled, and have committed a trespass against her husband, that the water which causes the curse shall enter into her and be bitter, and her body shall swell, and her thigh shall fall away, and the woman shall be a curse among her people.'
Having made her drink the water, the ceremony was then over and the consequences were left to God. She would leave the court of the Dwellingplace ostensibly an innocent woman, but all would know that if she was really guilty this would be revealed by what would follow. For if she was guilty and if she was defiled and was defiling the camp, the water would enter her and would be bitter, and, probably because of her deep sense of guilt, would also make her body swell and her uterus fall away and she would become a curse among the people. Being a curse among her people may simply mean that she was seen as cursed because she could produce no more children. Or it may signify her rejection by all decent people.
The psychosomatic effect on a guilty woman of going through this ceremony as well as of lying before Yahweh would be horrendous and would certainly have huge effects on the responses of her body. It would probably cause what she expected to happen actually to happen.
The result described could possibly signify that the woman had suffered a prolapsed uterus. In such a condition, which often occurs after multiple pregnancies, the pelvic floor collapses (in that case weakened by the pregnancies, and possibly in this case deeply affected and weakened by the trauma of her experience), and the uterus literally falls down. It may lodge in the vagina, or it may actually fall out of the body through the vagina. (It regularly happens to cattle and vets have to push it back in). If it does so, it becomes oedematous and swells up like a balloon. Conception becomes impossible, and the woman's procreative life is effectively over.
Alternatively the thought may be of a cancerous growth which would distend her stomach, affect her ability to bear children and make her infertile, and finally destroy her. Such cancerous growths do sometimes result from traumatic experiences.
Others have thought in terms of a phantom pregnancy which makes the body swell up, but that does not seem dramatic enough for what is described here. Others have seen it as a serious miscarriage, or thrombophlebitis. But the point is that it would produce effects which would prevent her from further defiling sexual behaviour in the future, and would prevent her from childbirth.
In the parallel in the chiasmus this condition contrasts with the spirit of jealousy which had taken hold of the husband. If his jealousy was justified this will be the result.