http://revach.net/article.php?id=2041

Section: Halacha   Category: Tshuvos
Minchas Yitzchok: An Unexplained Minhag and a Jewish Motherís Nachas

The Heishiv Moshe (OC 13) brings a Rashba that says we should not dismiss even the seemingly silly and eccentric customs that are passed down from generation to generation through the “Babbas”, or old women.  Based on this Rashba a pregnant should not to go to the cemetery, as is the custom.

Nevertheless in response to a questioner the Minchas Yitzchok (10:42:2) takes a stab at finding a source for this minhag.  The Rokeach (366) says that although a Kohen may not enter a cemetery, the pregnant wife of a Kohen may do so since it is a “Sfek Sfeika”; a double doubt. Firstly the child may be a female and female Kohanim are permitted to go into a cemetery.  Secondly, even if it is a boy the child may be a stillborn and therefore it is not a problem.  Others hold that since it could present a problem in the future it is best avoided despite the “Heter” of the Rokeach.

While there is a discussion among the Acharonim if a child in its mother’s womb can become Tamei nevertheless we see from the Rokeach that such a concept does exist. Similarly we find by the Parah Adumah that they raised children in a totally sterile environment in order for them to be able to perform certain tasks which they employed only children that were Tahor from birth.  Maybe, suggests the Minchas Yitzchok, based on the Rokeach, since we assume it is every Jewish mother’s wish to see her son participate in the rare and great mitzva of Para Adumah when Moshiach comes bimheira biyameinu, the women have a custom to avoid cemeteries.