A chemical contraceptive in pill form. It contains synthetic estrogen and progestogen, similar to progesterone. Both are contained in each pill. The inhibits ovulation and makes the endometrium inhospitable for the implantation of a fertilized egg. Also, the cervical mucus may be altered, becoming a hostile environment for the sperm. The combination pill is no longer marketed because of a variety of undesirable side effects, combination oral contraceptive drug.