Which of the following is considered an implantation disorder?

• A. Tubal pregnancy
• B. Placenta previa
• C. Abruptio placentae
• D. All of the above

Answer: (D)

Disorders of implantation and placentation involve problems with where and how the embryo attaches and how the placenta forms and stays attached. A tubal pregnancy is an implantation outside the uterus in the fallopian tube, representing a failure of the embryo to implant in the uterine lining. Placenta previa occurs when the placenta implants in the lower part of the uterus, near or over the cervical opening, which is an abnormal location of placental attachment. Abruptio placentae is premature separation of the placenta from the uterine wall after implantation, a disruption of the placental attachment and its function. Because each condition stems from abnormal implantation or placental attachment, all of them are considered implantation disorders.