Step 1: Because the stem asks for the statement that is NOT true, we evaluate each option about handling a dead fetus retained in utero and pick the incorrect one.
Step 2: Most women go into labour on their own after fetal demise; roughly four out of five deliver within a couple of weeks. Saying only half expel in two weeks is too low, marking option A as the inaccurate choice.
Step 3: Retained dead products can trigger a consumptive coagulopathy, so serial fibrinogen checks are appropriate, making that statement correct. Likewise, when labour does not start, induction with uterotonic agents is the favored approach.
Step 4: Operative delivery by caesarean is generally avoided and kept for selected cases, so its limited role is a true statement. The odd one out is the 50% figure.
\[\boxed{\text{In 50% of cases spontaneous expulsion occurs in 2 weeks}}\]