preferred_name: Twin gestation, monochorionic/monoamniotic (one placenta, one amniotic sac)
preferred_name_lc: twin gestation, monochorionic/monoamniotic (one placenta, one amniotic sac)
label: Twin gestation, monochorionic/monoamniotic (one placenta, one amniotic sac)
label_lc: twin gestation, monochorionic/monoamniotic (one placenta, one amniotic sac)