From Rediscovering Childbirth by Sheila Kitzinger, one of the world’s foremost birth educators and activist:
“The expectant mother may wear a pregnancy sash to protect the baby. Navajo women wear a bright red sash for this purpose. In Mexico, the sash, the muneco, is also used by the visiting midwife. The pregnancy sash often has a sacred quality. The ‘girdle of Mary’ (referring back to the sash worn by the Virgin Mary), worn by Englishwomen in the Middle Ages, was handed down through mothers and daughters in the family, as was the ancient Greek girdle. We have already seen that the hara-obi is still worn by most women in Japan today and forms part of an important ceremony for pregnant women. The Jewish girdles were sometimes embroidered and later used for binding the Torah, the book of Judaic law.”
From Birth Traditions and Modern Pregnancy Care by Jacqueline Vincent Priya:
“Girdles(maternity sashes) are powerful amulets. In Japan a special sash or obi will be purchased. The pregnant woman takes this to the Shinto shrine to be blessed, after which she wears it continuously for the rest of pregnancy. It keeps the abdominal area warm and therefore, according to the tenets of Chinese/Japanese medicine, the mother free from illness.
From the time of the Druids to the nineteenth century, girdles with supernatural powers were used by women in Britain. Often they remained in the same family for generations.”
More on the Japanese obi (also from Sheila Kitzinger):
“In Japan…the fifth month of pregnancy, according to the Shinto religious calendar, is associated with the rite that celebrates the pregnancy and guards the baby against harm. It is an auspicious time for the presentation of…the hara-obi, the sash that protects her baby and keeps it ‘warm’. She goes into the Shinto temple with her mother-in-law, and often with both prospective grandmothers, to get the obi from the priest and have it blessed. The women pray together.”