Why is precipitous labor most often seen in multiparous women?

Correct Answer: C

Rationale: Step 1: In multiparous women, the uterus has gone through labor before, making muscle coordination more efficient. Step 2: Efficient muscle coordination helps in effective contractions, leading to faster labor progress. Step 3: Multiparous women have experienced labor before, allowing the uterus to contract more effectively. Step 4: This efficiency in muscle coordination is why precipitous labor is more often seen in multiparous women. Summary: A: The weakening of the cervix after each delivery is not a direct cause of precipitous labor. B: The ability of the cervix to dilate and efface simultaneously does not explain why precipitous labor is more common in multiparous women. D: The difficulty in knowing when labor begins is not a reason for the occurrence of precipitous labor in multiparous women.

Correct Answer: B

Rationale: The correct answer is B because a uterine resting tone of 30 mm Hg indicates excessive uterine activity, which can lead to uterine hyperstimulation and fetal distress during an oxytocin induction. A higher resting tone suggests the uterus is not relaxing adequately between contractions, potentially compromising fetal oxygenation. Choices A, C, and D are incorrect because a uterine resting tone of 17 mm Hg is within the normal range, contractions every 3 minutes lasting 60 seconds and every 5 minutes lasting 60 seconds are typical patterns during labor induction, and they do not necessarily indicate complications.

Correct Answer: B

Rationale: The correct answer is B: A 21-year-old gravida 2, para 1 with one previous low-transverse cesarean section for CPD. This candidate is the best choice for a trial of labor after cesarean (TOLAC) because a low-transverse incision has the lowest risk of uterine rupture during labor compared to classical, T-shaped, or vertical incisions. Additionally, the indication for the previous cesarean section being cephalopelvic disproportion (CPD) suggests that the pelvis may have been the limiting factor in the previous delivery, making a TOLAC a reasonable option. The other choices have higher risks of uterine rupture (classical incision, T-shaped incision) or indications that may increase the likelihood of complications during TOLAC (prematurity, late decelerations).

Correct Answer: A

Rationale: The correct answer is A because the mucus plug is expelled due to increased estrogen levels before contractions start. Estrogen stimulates the production of mucus that forms the plug, which is then released as a result of hormonal changes signaling the body to prepare for labor. This process occurs before labor contractions begin. Choice B is incorrect because the mucus plug is typically expelled before the membranes rupture during labor. Choice C is incorrect because effacement and dilation of the cervix do not directly cause the expulsion of the mucus plug. Choice D is incorrect because labor can begin even if the mucus plug has not been expelled, and the plug itself does not create a space for the fetus.

Correct Answer: A

Rationale: The active phase of labor begins at 6 cm dilation according to ACOG guidelines. At this point, the cervix is significantly dilated, signaling the transition to active labor. This stage is crucial as it signifies the acceleration of labor progress and typically involves stronger contractions leading to efficient cervical dilation. Choices B, C, and D are incorrect as they do not align with the established criteria for the active phase of labor. Choice B (3 cm) is too early for active labor, choice C (5 cm) is close but not quite at the threshold for active labor, and choice D (10 cm) is actually the full dilation stage, not the beginning of active labor. Hence, choice A (6 cm) is the correct answer.