A cause of shoulder presentation is

Correct Answer: C

Rationale: The correct answer is C: Oligohydramnios. Shoulder presentation occurs when the baby presents shoulder-first rather than head-first during birth. Oligohydramnios, a condition characterized by low levels of amniotic fluid, can lead to decreased uterine space, increasing the chances of abnormal fetal positioning. Macerated fetus (A) is associated with fetal decomposition, not shoulder presentation. Postdates pregnancy (B) is linked to increased risk of macrosomia but not shoulder presentation. Placenta abruption (D) is a separation of the placenta from the uterus, not a direct cause of shoulder presentation.

Correct Answer: B

Rationale: Postdatism refers to a pregnancy that extends beyond the normal gestation period of 280 days. The correct answer is B (294 days) as it is more than the standard 280-day term. Choice A (280 days) is the normal term, not postdatism. Choices C (290 days) and D (287 days) are also below the 294-day mark, making them incorrect for defining postdatism.

Correct Answer: B

Rationale: The correct answer is B: Trial of scar. This term specifically refers to the process of attempting a vaginal birth after a previous caesarean section. It involves monitoring the previous cesarean scar for any signs of complications during labor. A: Spontaneous vaginal delivery refers to giving birth vaginally without any previous cesarean section. C: Spontaneous vertex delivery simply describes the position of the baby's head during birth. D: Trial of birth is not a commonly used term in obstetrics and does not specifically relate to VBAC.

Correct Answer: C

Rationale: The correct answer is C: Mauriceau-Smellie-Veit maneuver for delivery of breech with an extended head. This maneuver involves flexing the head while still in the vagina to allow for easier delivery. The Burns Marshall maneuver (A) is for impacted fetal shoulders, Lovset maneuver (B) is for shoulder dystocia, and McRobert's maneuver (D) is for shoulder dystocia as well. The Mauriceau-Smellie-Veit maneuver is specifically designed for delivering a breech with an extended head, making it the correct choice in this scenario.

Correct Answer: B

Rationale: The correct answer is B because pressure applied on the cervix by the presenting part in obstructed labor leads to edema of the vulva. This pressure causes obstruction of blood and lymphatic flow in the area, resulting in swelling and edema. Prolonged effort by the mother (choice A) would not directly cause vulvar edema. An ill-fitting presenting part (choice C) may contribute to obstruction but does not explain the mechanism of edema. Large presenting diameters (choice D) stretching the vulva would not directly cause edema without pressure on the cervix.