Which of the following is a contraindication for operative vaginal delivery?

Operative vaginal delivery, which includes the use of forceps or vacuum extraction, has specific contraindications based on maternal and fetal conditions. The presence of a bleeding disorder in the fetus poses significant risks during the use of such instruments. This is due to the potential for the fetus to experience hemorrhage or other complications if manual force is applied via these devices. Ensuring the safety of both the mother and the fetus is paramount, and a known bleeding disorder increases the risk of serious adverse outcomes, making the procedure inadvisable in such scenarios.

The other options do not present the same level of risk or contraindications. Knowing the position of the fetal head and ensuring that it is engaged are both important in determining the feasibility of an operative vaginal delivery, supporting safety and potential success rather than posing a direct contraindication. Additionally, being over 34 weeks gestation typically indicates that fetal development is adequate for delivery, which does not inherently contraindicate the use of operative intervention if other criteria are met.