Or HaChaim on Genesis 25:22/אור החיים על בראשית כ״ה:כ״ב

1 ויתרצצו הבנים בקרבה, The children were quarrelling inside her, etc. Both the expression ויתרצצו, "they quarrelled" and the words למה זה אנכי, "why am I therefore" need examination. Rashi explains that "if the pain involved in giving birth is so intense, why did I bother to pray to become pregnant?" It is difficult to reconcile our image of the pious and righteous Rebeccah with Rashi's comment, i.e. that she did not think the pain worth her while in order to become a mother. Also, if that had been her real concern, how did G'd's response alleviate her problem? Our rabbis have offered many and various explanations none of which are acceptable as the plain meaning of the verse. The plain meaning of the word ויתרצצו is based on the root רצץ, to crush. Since there were two fetuses in her womb she felt as if her womb was being crushed. She was afraid that she could not complete her pregnancy and would have a miscarriage as a result. Her question then was rhetorical, i.e. "what good was my becoming pregnant if this pregnancy will not be completed successfully?" The words: "she went to ask G'd," mean that she prayed to G'd to let her complete her pregnancy without mishap. She felt that the miracle of her becoming pregnant after all these years surely should not be wasted by her not giving birth to a healthy child.