During which cervical mucus condition is a woman least likely to get pregnant?

The condition described in the correct choice involves cervical mucus that is opaque, thick, and sticky, and under the influence of progesterone. This type of cervical mucus is typically present during the luteal phase of the menstrual cycle, after ovulation has occurred. During this phase, progesterone levels increase, resulting in a more viscous and less hospitable environment for sperm. This thick mucus acts as a barrier, making it difficult for sperm to travel through the cervix and into the uterus, thus significantly reducing the chances of conception.

In contrast, cervical mucus influenced by estrogen (such as during the proliferative phase of the cycle) tends to be clear, watery, and stretchy. This type of mucus facilitates sperm movement, increasing the likelihood of pregnancy around the time of ovulation. Therefore, the conditions that are influenced by estrogen or are indicative of ovulation are considered conducive to conception.

The clarity and stretchiness of cervical mucus during ovulation (the other options) indicate a fertile window, enhancing the chance of sperm survival and passage, which is contrary to the scenario presented in the correct answer. Thus, the thick and sticky nature of the cervical mucus in the correct option supports the idea that, during that time, a woman is least likely to