Credit: Adam Taylor/ Getty Images Photo: Derek and Meredith in “Can't Fight Biology”

Meredith was pretty peeved to find out that her uterus is apparently "hostile." But what does that even mean? Turns out, it has nothing to do with the disposition of Meredith Grey's anatomy. She has a hostile cervical mucus... which sounds even nastier.

Here's the deal: right before ovulation, a woman's cervix emits watery mucus, which helps the sperm reach the fallopian tubes and fertilize the egg. But if that mucus is too thick or too acidic, the sperm has difficulty doing its job. Some women with hostile uteri take guaifenesin (an ingredient found in cough syrup) to help the problem, but it's efficacy seems to be doubted in the scientific community. So it's better for them to consult fertility specialists. 

Grey’s Anatomy airs Thursdays at 9 p.m. ET/PT on ABC.


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