Embryo Project Encyclopedia Articles

Roberto Caldeyro-Barcia studied fetal health in Uruguay during the second half of the twentieth century. Caldeyro-Barcia developed Montevideo units, which are used to quantify intrauterine pressure, or the force of contractions during labor. Intrauterine pressure is a useful measure of the progression of labor and the health of a fetus. Caldeyro-Barcia’s research on fetal health often contradicted common obstetric practices, prompting him to publically challenge practices such as induction of labor using oxytocin, forced pushing during labor, and birth position in which the woman lays on her back during labor. Caldeyro-Barcia’s methods of monitoring intrauterine pressure and development of Montevideo units furthered research in maternal and fetal health and improved the use of medical interventions during labor and delivery.

Fetus in fetu is a rare variety of parasitic twins , where the developmentally abnormal parasitic twin is completely encapsulated within the torso of the otherwise normally developed host twin. In the late eighteenth century, German anatomist Johann Friedrich Meckel was the first to described fetus in fetu, which translates to “fetus within fetus.” Fetus in fetu is thought to result from the unequal division of the totipotent inner cell mass , the mass of cells that is the ancestral precursor to all cells in the body. The unequal division is thought to occur during the formation of the blastocyst, which can also result in parasitic and conjoined twins . Fetus in fetu represents a developmental anomaly that has prompted developmental biologists to further examine the mechanisms for how twins arise.