A 29-year-old G2P2 female gives birth to a healthy baby boy at 39 weeks of gestation via vaginal delivery. Immediately after the delivery of the placenta, she experiences profuse vaginal hemorrhage. Her prior birthing history is notable for an emergency cesarean section during her first pregnancy. She did not receive any prenatal care during either pregnancy. Her past medical history is notable for obesity and diabetes mellitus, which is well controlled on metformin. Her temperature is 99.0°F (37.2°C), blood pressure is 95/50 mmHg, pulse is 125/min, and respirations are 22/min. On physical examination, the patient is in moderate distress. Her extremities are pale, cool, and clammy. Capillary refill is delayed. Which of the following is the most likely cause of this patient’s bleeding?

Chorionic villi attaching to the myometrium

Chorionic villi invading into the myometrium

Placental implantation over internal cervical os

Chorionic villi attaching to the decidua basalis

Chorionic villi invading into the serosa

29-year-old G2P2002 presents with foul-smelling lochia and fever. She is post-partum day three status-post cesarean section due to eclampsia. Her temperature is 101 F, and heart rate is 103. She denies chills. On physical exam, lower abdominal and uterine tenderness is present. Leukocytosis with left shift is seen in labs. Which of the following is the next best step in management?

Intravenous clindamycin and gentamicin treatment

Prophylactic intravenous cefazolin treatment

Intramuscular cefotetan treatment

A 27-year-old woman, gravida 3, para 2, at 41 weeks' gestation is admitted to the hospital in active labor. Her pregnancy has been uncomplicated. Both of her prior children were delivered by vaginal birth. She has a history of asthma. Current medications include iron and vitamin supplements. After a prolonged labor, she undergoes vaginal delivery. Shortly afterwards, she begins to have heavy vaginal bleeding with clots. Her temperature is 37.2°C (98.9°F), pulse is 90/min, respirations are 17/min, and blood pressure is 130/72 mm Hg. Examination shows a soft, enlarged, and boggy uterus on palpation. Laboratory studies show: Hemoglobin 10.8 g/dL Hematocrit 32.3% Leukocyte Count 9,000/mm3 Platelet Count 140,000/mm3 Prothrombin time 14 seconds Partial thromboplastin time 38 seconds Her bleeding continues despite bimanual uterine massage and administration of oxytocin. Which of the following is the most appropriate next step in management?

Administer carboprost tromethamine

Immediately following prolonged delivery of the placenta at 40 weeks gestation, a 32-year-old multiparous woman develops vaginal bleeding. Other than mild asthma, the patient’s pregnancy has been uncomplicated. She has attended many prenatal appointments and followed the physician's advice about screening for diseases, laboratory testing, diet, and exercise. Previous pregnancies were uncomplicated. She has no history of a serious illness. She is currently on intravenous infusion of oxytocin. Her temperature is 37.2°C (99.0°F), blood pressure is 108/60 mm Hg, pulse is 88/min, and respirations are 17/min. Uterine palpation reveals a soft enlarged fundus that extends above the umbilicus. Based on the assessment of the birth canal and placenta, which of the following options is the most appropriate initial step in patient management?

Manual exploration of the uterus

A 37-year-old woman, gravida 4, para 3, at 35 weeks' gestation is admitted to the hospital in active labor. Her three children were delivered by Cesarean section. One hour after vaginal delivery, the placenta is not delivered. Manual separation of the placenta leads to profuse vaginal bleeding. Her pulse is 122/min and blood pressure is 90/67 mm Hg. A firm, nontender uterine fundus is palpated at the level of the umbilicus. Hemoglobin is 8.3 g/dL and platelet count is 220,000/mm3. Activated partial thromboplastin time and prothrombin time are within normal limits. Which of the following is the most likely underlying mechanism of this patient's postpartum bleeding?

Defective decidual layer of the placenta

Consumption of intravascular clotting factors

A 44-year-old G2P2 African American woman presents to her gynecologist for dysmenorrhea. She reports that for the past few months, she has been having severe pain during her menses. She also endorses menstrual bleeding that has been heavier than usual. The patient reports that her cycles are regular and occur every 30 days, and she denies both dyspareunia and spotting between her periods. Her last menstrual period was two weeks ago. In terms of her obstetric history, the patient had two uncomplicated pregnancies, and she had no difficulty becoming pregnant. She has never had an abnormal pap smear. Her past medical history is otherwise significant for hyperlipidemia and asthma. On physical exam, the patient’s uterus is tender, soft, and enlarged to the size of a pregnant uterus at 10 weeks of gestation. She is non-tender during vaginal exam, without cervical motion tenderness or adnexal masses. Her BMI is 24 kg/m2. A urine pregnancy test is negative. Which of the following is the most likely diagnosis for this patient?

Presence of endometrial glands and stroma in uterine myometrium

Presence of endometrial glands and stroma outside the uterus

Benign smooth muscle tumor of the uterus

Hyperplastic overgrowths of endometrial glands and stroma

Malignant invasion of endometrial cells into uterine myometrium

A 39-year-old woman, gravida 4, para 4, comes to the physician because of a 5-month history of painful, heavy menses. Menses previously occurred at regular 28-day intervals and lasted 3 days with normal flow. They now last 7–8 days and the flow is heavy with the passage of clots. Pelvic examination shows a tender, uniformly enlarged, flaccid uterus consistent in size with an 8-week gestation. A urine pregnancy test is negative. Which of the following is the most likely cause of this patient's findings?

Endometrial tissue within the uterine wall

Malignant transformation of endometrial tissue

Endometrial tissue within the ovaries

Fourth stage of labor for USMLE Step 2 CK: High-Yield OB/GYN Lessons

Fourth Stage of Labor - The Recovery Kickstart

Timing: First 1-4 hours immediately following placental delivery.
Physiology: Uterine involution begins; myometrial contractions compress vessels to achieve hemostasis.
Maternal Monitoring (q15min for 1st hr):
- Uterus: Palpate fundus for tone (firm, midline) & location (at/below umbilicus).
- Lochia: Assess flow (rubra); saturation of >1 pad/hour suggests PPH.
- Vitals: BP & pulse checks for signs of hypovolemia.
- Perineum: Inspect for hematoma formation or suture dehiscence.

⭐ Uterine atony is the leading cause of early postpartum hemorrhage (PPH). Prophylactic oxytocin and fundal massage are key preventive measures.

Postpartum Fundal Assessment Technique

Maternal Assessment - The Postpartum Check-In

Frequency: Vitals & fundal checks every 15 min for the first hour, then every 30 min for the second hour.
Uterine Assessment:
- Palpate fundus for tone and location (should be firm, midline, at/below umbilicus).
- A boggy (soft) uterus signifies atony. First action: Fundal massage.
Lochia Assessment:
- Check color (rubra), amount, and clots.
- Saturation of a perineal pad in <1 hour suggests excessive bleeding.
Perineal Assessment:
- Inspect for hematomas, swelling, or signs of infection at laceration/episiotomy sites.
Bladder: Encourage voiding; a full bladder can displace the uterus and cause atony.

⭐ High-Yield: Uterine atony is the #1 cause of early postpartum hemorrhage. Always perform fundal massage as the initial management step for a boggy uterus.

Postpartum Hemorrhage - The Red Alert

Definition: Estimated Blood Loss (EBL) >1000 mL or blood loss with signs/symptoms of hypovolemia within 24 hours of birth.
Etiology (The 4 T's) 📌
- Tone: Uterine atony (>70% of cases). Boggy, enlarged uterus.
- Trauma: Lacerations, uterine rupture.
- Tissue: Retained placenta or clots.
- Thrombin: Coagulopathy (pre-existing or acquired).

Management
- First-line: Bimanual uterine massage & IV oxytocin.
- Second-line Uterotonics: Methylergonovine, Carboprost, Misoprostol.

⭐ Exam Favorite: Avoid Methylergonovine (Methergine) in patients with hypertension or preeclampsia due to its vasoconstrictive effects.

Postpartum Interventions - The Action Plan

Uterine Assessment & Massage: Immediately palpate fundus; perform firm massage to maintain tone and express clots.
Uterotonics: Administer Oxytocin (IV/IM) prophylactically to prevent postpartum hemorrhage (PPH).
Perineal Care & Repair: Inspect for and repair any lacerations or episiotomies.
Hemodynamic Monitoring: Closely monitor vital signs, uterine tone, and lochia amount for at least 1-2 hours. Check every 15 minutes.

⭐ Uterine atony is the most common cause of early postpartum hemorrhage, responsible for over 70% of cases.

Bimanual uterine compression for uterine atony

High‑Yield Points - ⚡ Biggest Takeaways

The fourth stage spans the first 1-4 hours postpartum, a critical period for physiologic stabilization.

The most significant risk is postpartum hemorrhage (PPH), most commonly from uterine atony.

Management involves frequent assessment of uterine tone (fundal massage), vital signs, and lochia.

Oxytocin is continued to maintain firm uterine contraction and ensure hemostasis.

This period is crucial for initiating maternal-infant bonding (e.g., skin-to-skin contact).

Persistent bleeding with a firm uterus suggests genital tract lacerations.

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