It must be stated that there are some authorities who are reluctant to permit abortion unless it is extremely necessary. This reluctance is due, often, to the fear that the operation itself might be harmful to the mother.
So far we have discussed the general question of abortion much as it has been discussed in the two previous responsa mentioned. Now, specifically, as to the relationship of Jewish tradition to the trimester rule set down by the Supreme Court of the United States , namely, that abortion should be most readily permitted in the first three months, less readily in the second three months, etc.
Jewish tradition makes no time division within the period of the nine months of pregnancy, except for the following: The first forty days of pregnancy are deemed the least important. The fetus is considered hardly to have developed, to have any form at all. This is based upon the Mishnah in Niddah, 3: 7, namely, that a woman who has a miscarriage within the forty days of her pregnancy does not need the period of purification that is needed after the birth of a child. For the whole remainder of the period of pregnancy the child is still not a nefesh, even up to the time of giving birth. This can be seen from the fact that until the child actually puts out its forehead, it may still be destroyed to save the life of the mother.
The second question is with regard to whether scientific experiments may be made upon a fetus that is delivered from its mother's body alive. The status of the fetus(nefel) is discussed considerably in the law, but the discussion deals almost exclusively with the question of burial and mourning. Does this fetus need all the burial and mourning rites? The answer is no, as far as mourning is concerned, though burial is, of course, required when it dies. But while it is alive it certainly may not be put to death, as can be seen from the law that if it so much as puts its forehead out, then even if it endangers its mother's life at birth, we may not put it to death. How much the more must it be spared if it has not endangered its mother's life at its birth. Of