The end of the first stage of labour, where the circular shaped uterine cervix dilates to full dilatation (average diameter around 10 cm), signals the start of the second stage of labour which aims to expel the term fetus. In the majority of childbirth cases, the fetus will exhibit a number of distinct motions, most of which are head rotations. These motions are commonly known as the mechanisms or “cardinal movements” of labour.
Various attempts have been made in the past to create a computer-based simulation of the second stage of labour where the cardinal movements are shown in the same way as they happen in real childbirth. The benefits of such a simulation would be major, as a subject-specific version would be capable of simulating the real event beforehand and as such predict potential problems like for example shoulder dystocia*. This would allow the obstetrician or midwife to prevent such problems from happening by, for example, deciding to perform an elective Caesarean Section.
Dr. Rudy Lapeer and his team have successfully developed a dynamic childbirth simulator called BirthView. It is based on an explicit Finite Element Method (FEM) called TLED (Total Lagrangian Explicit Dynamics) and the partial Dirichlet-Neumann mechanical contact method.
The research is summarised in a paper published in Biomechanics and Modeling in Mechanobiology and can be found here: https://link.springer.com/article/10.1007/s10237-018-01109-x
* Shoulder Dystocia (SD) is an obstetric complication where the baby’s shoulder impacts with the pubic symphysis of the maternal pelvis bringing the expulsion of the baby to a halt. There are a number of manoeuvres that aim to resolve SD but if these fail then an emergency Caesarean Section needs to be performed.