***TASK***
the task is to simplify the input abstract of a biomedical literature

***INPUT***
the input is the abstract of a biomedical literature

***OUTPUT***
the output is the simplified abstract for the input abstract of a biomedical literature

***DOCUMENTATION***

***EXAMPLES***

Input: No differences were found in contraceptive effectiveness for the 13 COC pairs for which this outcome was reported. Compared to the higher-estrogen pills, several COCs containing 20 μg EE resulted in higher rates of early trial discontinuation (overall and due to adverse events such as irregular bleeding) as well as increased risk of bleeding disturbances (both amenorrhea or infrequent bleeding and irregular, prolonged, frequent bleeding, or breakthrough bleeding or spotting). While COCs containing 20 μg EE may be theoretically safer, this review did not focus on the rare events required to assess this hypothesis. Data from existing randomized controlled trials are inadequate to detect possible differences in contraceptive effectiveness. Low-dose estrogen COCs resulted in higher rates of bleeding pattern disruptions. However, most trials compared COCs containing different progestin types, and changes in bleeding patterns could be related to progestin type as well as estrogen dose. Higher follow-up rates are essential for meaningful interpretation of results.
Output:

In July 2013, we did computer searches for randomized trials of pills with 20 µg estrogen versus more estrogen. We did not find any new trials. For the initial review, we also wrote to researchers and makers of birth control pills to find other trials. Studies had to be written in the English language, include at least three cycles, and focus on birth control. The trials had to report on pregnancy, bleeding problems, or stopping the pills early. We also looked at side effects. More women taking the pills with less estrogen quit the studies early. The women on less estrogen also had more bleeding problems than those taking pills with more estrogen. Pregnancy rates seemed to be the same between groups, but the studies may not have been large enough to know for sure. This review did not focus on the rare events needed to test whether birth control pills with 20 µg estrogen were safer. Also, most trials compared pills with different types of the hormone progestin, which could also affect bleeding patterns. The high losses in many trials make the results hard to interpret.