My best friend and I have been extremely close since our first year of college when we lived in the same dorm and shared a ragtag group of friends. Though the entire group looked like it was comprised of the castoffs from various other social groups, she and I decided we were the “cool kids” of the group and bonded. Years later we are still living under the impression that we essentially share the same brain. This, however, did not prepare me for the moment when, seven weeks before her baby was due, she ran out of the bathroom with a wad of toilet paper in her hand and presented me with what looked like a chunk of bloody Jello.

Trying to withhold the shudders, I asked her what it was and if she needed to go to the doctor. She told me it was her cervical plug and she thought that meant the baby was coming within the next few days. We called her doctor, and even though she wasn’t told to come in, we went into panic mode. By the end of the day, the nursery was filled with preemie-sized clothes, and we had put in an order for special vanilla-scented pacifiers meant to stimulate hunger for premature babies. Five weeks later the little one made her grand appearance. What happened to the cervical plug? Didn’t her losing her plug mean the baby was on her way out?

The cervical plug is a flexible plug of mucus that develops in the cervix during pregnancy. As it sounds, the plug seals off the opening to the uterus throughout pregnancy. It was once believed this plug was essential for “holding” the baby in the uterus and once the mucus plug came loose the cervix would no longer be able to stay closed, resulting in the birth of the baby in no more than two weeks. Studies have indicated, however, this is not the case. As opposed to acting as a true plug, preventing the birth of the baby while in place, the cervix plug is another layer of protection a woman’s body puts into place to keep the baby safe and healthy.

An in vitro study of the cervical mucus plug demonstrated this mucus has antibacterial properties that prevent infections ascending from the vagina. The study explored the antibacterial response of the plug to specific strains of infection including Staphylococcus saprophyticus, E coli, Streptococcus pyogenes and Pseudomonas aeruginosa. Researchers concluded the mucus plug is not related to keeping the cervix closed, but rather protecting the growing baby from potentially devastating consequences.

Source: Hein Merete, et al. An in vitro study of antibacterial properties of the cervical mucus plug in pregnancy, American Journal of Obstetrics and Gynecology, Volume 185, Issue 3, pp 586-592, September 2001.