The Archbishop of Dublin, Diarmuid Martin, has said a woman is not an "incubator".
He made the comment as the case of a pregnant woman who is being kept on life support in a hospital outside Dublin is being heard in the High Court this morning.
The special sitting of the three-judge court is taking place as the woman's family want to end life support.
However, doctors caring for the woman - who is in her 20s and is 17 weeks pregnant - have expressed concern about the Constitutional rights of the foetus.
The family has been told that there is no prospect of survival of the mother.
It is understood her pregnancy is in its second trimester.
The action today is being taken by the woman's father, and the hearing is expected to hear from several interested parties.
Three judges will be sitting in the High Court for the out-of-term hearing.
Mr Martin told the Pat Kenny Show here on Newstalk he did not want to comment about the case currently before the courts, but gave his opinion on how the church views the general issue.
He said: "From the point of view of Catholic teaching in general medical ethics, there is no obligation to use extraordinary means to maintain a life.
"That applies both to the woman and to the child.
"A woman isn't simply an incubator, the relation between a woman and a child is a relationship and it is very clear that one has to examine at what stage is this foetus, what are the possibilities, is it right to use extraordinary means to prolong that life if it is not going to move.
"There are cases, unfortunately, in car accidents where a pregnant woman is kept alive so the child is born. Each of these cases has to be looked at individually, this is a very different case."
Dr Martin has found it a "pity" that cases like this go to the courts for a decision.
He said: "It should be within the area of the medical profession, but there seems to be a polarisation and a fear that if things go wrong then there will be a difficulty legally or with insurance and so on.
"It's a pity that these have to come to the courts. We should have a more robust, open and less conflictual situation."