My wife's close friend and colleague (not a member of the Chassidic community) was pregnant. On one of her pre-natal visits, the doctor informed her that she had a serious shortage of amniotic fluid in her gestational sack. He told her the baby was endangering her life and suggested she abort it. Hearing this, she was filled with despair and anxiety. She called my home one evening and told me about her travail. She asked me if I would be visiting the Ohel soon---the gravesite of the Lubavitcher Rebbe---and if so, would I please pray on her behalf. I responded that it was not in my schedule to go there for the next day or two; however, I would immediately send her name and mother's name to someone at the Ohel, who would pray on her behalf.
After hanging up the phone and doing as I had promised, I paused for a few moments, pondering her predicament. I then decided to write a letter to the Rebbe on her behalf. In this letter, I wrote her name and her mother's name, described the situation, and asked the Rebbe for advice and a blessing. I pulled down from my shelf one of many volumes of the Rebbe's Igros Kodesh, a series of books of his correspondences.* I placed the letter between the pages of this arbitrarily chosen volume. I then proceeded to recite a kapitel (chapter) of Tehilim on the woman's behalf.
Afterward, I opened the book to the page where I had placed my letter and I began to read. The Rebbe's letter on that page began as follows (in Hebrew):
"In response to your letter…. At an auspicious time, I will mention (in prayer) those about whom you write, at the gravesite of my holy father-in-law, the Rebbe---according to their needs, as you have written."
(The letter concluded:) "…May G-d, blessed be his name, complete the days of your wife's pregnancy in a normal and easy manner. May she give birth to a living and healthy child at its appropriate time---(and may the birth occur) in a normal and easy manner. With blessings for good tidings in all the afore-mentioned."
At the end of the letter, there was an additional note:
"P.S.: Pertaining to those pregnant women about whom you write, it would be proper that they inspect the mezuzos in their homes (if they have not been checked in the course of the past 12 months), ascertaining that they are all kosher according to Jewish Law."**
I swiftly called the woman back. I described to her what I had done, in addition to forwarding her name to the Ohel. I proceeded to recite to her, verbatim, the Rebbe's letter.
When I concluded, she replied to me, with a voice choked with emotion: "Reb Dovid! Thank you!" Then she asked, "Do you mean to say that you placed my letter into an arbitrary volume and page, and this is what that page said?"
I replied in the affirmative.
"Didn't you first look in the index for letters regarding pregnancy?"
"No, I did not," I replied.
"What was the advice, again?" she asked, and I repeated it to her.
The next day, she removed her mezuzos and brought them to a qualified scribe to be inspected. When she inquired about the results of the inspection, the scribe reported that the mezuzah installed at the front door was invalid since it was filled with water. Upon hearing this, she was struck with a fascinating insight. There was excess water in the mezuzah, invalidating it, and a shortage of water for her baby, endangering both her and the baby.
Soon after this, she replaced the front door mezuzah with a new, kosher mezuzah. Also, the blessing of the Rebbe had infused her with confidence and determination to continue with the pregnancy to full term. She made it clear to her doctor that she had no intention of aborting the child.
The pregnancy concluded successfully, and the baby was born "in its proper time," healthy, viable and ready to kiss the mezuzah on the front door when she entered for the first time. Mazal tov!
*Since the passing of the Rebbe in 1994, some Chassidim and other followers, seeking advice and blessing, write a letter and place it randomly into one of the Rebbe's volumes of letters for an answer.
**This answer was found in letter 6,861 in Igros Kodesh, Vol. 18 pg. 373
From the forthcoming book by Rabbi Aaron L. Raskin.