Final answer:
The most common technique for terminating a second-trimester pregnancy is Dilation and Evacuation (D&E), due to its safety and effectiveness.
Step-by-step explanation:
The most common technique used for the termination of a pregnancy in the second trimester is Dilation and Evacuation (D&E). This surgical procedure involves dilating the cervix and removing fetal tissue using a combination of suction and surgical tools. It is generally considered the safest and most effective method for second-trimester abortions. Other methods such as Methotrexate administration, Prostaglandin administration, and Vacuum aspiration are more commonly used during the first trimester or under specific medical circumstances.