From Fr. Z's Blog: http://wdtprs.com/blog/
I read in the monthly newsletter of the USCCB’s Committee on Divine Worship (Vol. 48, April 2012) the following:
CDWDS Confirms Rite for the Blessing of a Child in the Womb
The text of the Rite for the Blessing of a Child in the Womb, approved in English and Spanish by the USCCB in November 2008, has been confirmed by the Congregation for Divine Worship and the Discipline of the Sacraments; the English text was confirmed on December 8, 2011 (Prot. n. 1422/08/L), and the Spanish text followed on March 1, 2012 (Prot. n. 125/12/L). Timothy Cardinal Dolan, USCCB President, authorized its use in the liturgy as of March 26, 2012, the Solemnity of the Annunciation of the Lord.
This new blessing was originally developed in March 2008 by the USCCB Committee on Pro-Life Activities for inclusion in the Book of Blessings and Bendicional, and further refined by the Committee on Divine Worship and the body of Bishops. The introduction to the rite observes that the blessing of an unborn child “sustains the parents by imparting grace and comfort in time of concern and need, unites the parish in prayer for the unborn child, and fosters respect for human life within society.”
Within Mass, the blessing of a child in the womb takes place after the Prayer of the Faithful; an additional solemn blessing at the end of Mass is also provided, drawn from number 272 of the Book of Blessings. The blessing may also take place within a celebration of the Word of God, celebrated by a priest or deacon either in a church or at another suitable location (such as a hospital, the home of the parents, etc.).
In sending the recognitio for the Rite for the Blessing of a Child in the Womb, the Congregation also offered the following suggestion: “Supplementary materials for the faithful based on the themes of the ritual or even the text itself, such as a prayer card that could be prayed privately by an expectant mother, could certainly be created and distributed.” While there are no immediate plans to create such resources at a national level, diocesan efforts or even local efforts at the parish level could be undertaken at any time.
The text of the new Rite for the Blessing of a Child in the Womb/Rito de bendición de una criatura en el vientre materno will be made available on the USCCB website during the week before Mother’s Day (May 13, 2012), with a printed booklet to follow, published by USCCB Communications. (The two U.S. publishers of the Book of Blessings, Catholic Book Publishing Corp. and Liturgical Press, are also expected to publish editions of the rite.)