Nope.

There was no blanket proscription on women writing and/or being published. There were restrictions on women's activities, including writing activities, yes, but no proscription. Here are some restriction examples:

• The church, drawing upon the Pauline prohibition of women preaching, said that women must not write about matters of faith.
• In 1579 the Fifth Council stated that nuns should be given neither ink nor writing materials in their cells so that all writing could be overseen by a scriptorium supervisor.
• Women were excluded from education, thus excluded from the academic channels of publication.

And naturally, like the pharaoh I outlined in my Kick-Ass Women from History series, there was an awful lot of outright erasure of women's contributions using tactics like destruction (common, since the printing press wasn't available to make mass publication a thing) and reattribution to a man.

This didn't stop women from writing works that got published however. Marguerite Porete published the mystical treatise The Mirror of Simple Souls. (It was found to be heretical and she was burned at the stake and her works destroyed.) Perpetua of Carthage's prison diary from the 3rd century was published and is one of the oldest extent works written by Christian women. Hrotsvit of Gandersheim wrote plays, poems and historical works in the 10th century. Hildegard of Bingen wrote extensive works of theology, music, and even medicine in the 11th and 12th centuries. In fact here's a list in rough chronological order of women who wrote famous works that were circulated during medieval times onward:

• Dhuoda (9th century)
• Héloïse (11th-12th)
• Marie de France (12th)
• Clemence of Barking (12th)
• Trota of Salerno (12th)
• Mechthild of Magdeburg (13th)
• Hadewijch (13th)
• St. Bridget of Sweden (14th)
• St. Catherine of Siena (14th)
• Julian of Norwich (14th-15th)
• Margery Kempe (14th-15th)
• Christine de Pizan (14th-15th)