The Shabbat prohibition of Sehita – squeezing – forbids extracting liquids from objects in which they are absorbed. Squeezing olives for oil, and grapes for juice, constitutes a Torah prohibition on Shabbat, whereas squeezing other fruits, such as berries and pomegranates, is forbidden on the level of Rabbinic enactment.
In light of this prohibition, the question arises concerning the use of baby wipes to clean infants on Shabbat. The wipes are doused with liquid that is extracted when they are pressed onto the infant when he is cleaned. Does this violate the Shabbat prohibition of Sehita?
In addressing this question, we must first clarify that what’s at stake is, at most, a Rabbinic prohibition. As mentioned, extracting liquids through squeezing is forbidden on Shabbat by force of Rabbinic enactment, except in the cases of olives and grapes, regarding which squeezing is forbidden by force of Torah law. Moreover, according to some authorities, the Torah prohibition applies only to extracting liquid that grew in its current location, such as in the case of fruits, which is obviously not the case when dealing with baby wipes.
This point is significant because of the fact that when one uses baby wipes, he has no interest in extracting liquid from the material. His intention is to use the liquid that is on the surface of the wipe, and he has no interest in extracting the absorbed liquid. And even if cleaning with a wipe necessarily results in the extraction of liquid, in which case this qualifies as "Pesik Resheh" (an act that automatically results in something that is forbidden on Shabbat), Halacha allows "Pesik Resheh" if there is only a Rabbinic violation at stake. Thus, since one has no interest in the absorbed liquid, and the extraction of liquid to begin with is forbidden on the level of Rabbinic enactment, it is permissible to clean with baby wipes on Shabbat. This is the ruling of Hacham Ovadia Yosef, based upon this and other considerations.
Hacham Ovadia adds, however, that when cleaning with baby wipes on Shabbat one must ensure to do so gently, and not to press down with force. If one presses the wipe against the child, he demonstrates his interest in extracting the absorbed liquid, in which case this becomes a situation of "Pesik Resheh De’niha Leh," which is forbidden even when dealing with a Rabbinic prohibition. Therefore, one must clean the child with the wipe gently, using only the liquid on the surface of the wipe, and it is then permissible even if absorbed liquid will inevitably be extracted.
Summary: It is permissible to clean a baby with baby wipes on Shabbat, as long as one does so gently and does not press down hard to extract absorbed liquid.