“Second Generation” Prostaglandins: Midtrimester Pregnancy Termination by Intramuscular Injection of a 15-Methyl Analog of Prostaglandin F2α**Supported by The Upjohn Company, Kalamazoo, Mich.††Presented at the Thirty-First Annual Meeting of The American Fertility Society, April 3 to 5, 1975, Los Angeles, Calif.