Embryo Project Encyclopedia Articles

In 1999, Joseph Bruner, Susan B. Drummond, Anna L. Meenan, and Ina May Gaskin published, “All-fours Maneuver for Reducing Shoulder Dystocia During Labor,” in the medical journal, Obstetrical and Gynecological Survey. In the article, the authors described a birthing technique named the all-fours maneuver, or the Gaskin maneuver, and explained its effectiveness in treating fetal shoulder dystocia as compared to other maneuvers. Shoulder dystocia occurs when the neonate’s head has exited the vaginal canal, but the shoulders get stuck behind the woman’s pelvic bone, which prevents the birth of the neonate’s body. Healthcare practitioners’ use of previous methods to dislodge the fetal shoulders sometimes resulted in fetal and maternal injury. The all-fours maneuver differed from previous methods by positioning the laboring woman on her hands and knees rather than on her back. Through the article, the authors established the all-fours maneuver as a safe, fast, and effective technique for reducing shoulder dystocia.

Implantation is a process in which a developing embryo, moving as a blastocyst through a uterus, makes contact with the uterine wall and remains attached to it until birth. The lining of the uterus (endometrium) prepares for the developing blastocyst to attach to it via many internal changes. Without these changes implantation will not occur, and the embryo sloughs off during menstruation. Such implantation is unique to mammals, but not all mammals exhibit it. Furthermore, of those mammals that exhibit implantation, the process differs in many respects between those mammals in which the females have estrous cycles, and those mammals in which the femals have menstrual cycles. Females in the different species of primates, including humans, have menstrual cycles, and thus similar processes of implantation.