Labor and Delivery — MCQs

Labor and Delivery Indian Medical PG Practice Questions and MCQs

Question 631: Braxton Hicks contractions are:

A. A positive feedback system
B. Another term for labor contractions
C. Occur during most of the months of pregnancy (Correct Answer)
D. Result in hypoxia of the fetus

Explanation: **Explanation:** **Braxton Hicks contractions** (often called "false labor") are sporadic, rhythmic, and usually painless uterine contractions. They are a physiological phenomenon characterized by low intensity and low frequency. **Why Option C is correct:** Braxton Hicks contractions are not limited to the end of pregnancy; they actually **begin as early as the 6th week of gestation**. However, they are typically not felt by the mother until the second or third trimester. As the pregnancy progresses, they may become more frequent and noticeable, but they remain a normal physiological feature throughout most of the months of pregnancy. **Why the other options are incorrect:** * **Option A:** Labor is governed by a positive feedback loop (the Ferguson reflex), where cervical stretching triggers oxytocin release, leading to more contractions. Braxton Hicks contractions do not follow this cycle and do not intensify to result in delivery. * **Option B:** Unlike true labor contractions, Braxton Hicks contractions are **irregular**, do not increase in intensity or frequency, and—most importantly—**do not cause cervical effacement or dilation**. * **Option C:** These contractions are physiological and do not compromise placental blood flow or cause fetal hypoxia. **High-Yield NEET-PG Pearls:** * **Character:** They are typically confined to the lower abdomen and groin, whereas true labor pain starts in the back and radiates to the front. * **Response to Activity:** Braxton Hicks often disappear with walking or a change in position, while true labor contractions persist and intensify. * **Intensity:** They usually measure between **10–15 mmHg** on pressure monitoring (True labor contractions exceed 25–30 mmHg). * **Purpose:** They are thought to play a role in "toning" the uterine muscle and potentially softening the cervix (pre-labor ripening).

Question 632: Cephalopelvic disproportion (CPD) in the absence of gross pelvic abnormality can be diagnosed by which of the following methods?

A. Maternal height less than 158 cm
B. Trial of labor (Correct Answer)
C. X-ray pelvimetry
D. Pelvic examination

Explanation: **Explanation:** Cephalopelvic disproportion (CPD) is a functional mismatch between the size of the fetal head and the maternal pelvic capacity. In the absence of gross pelvic deformities, CPD is a **retrospective diagnosis** that can only be definitively confirmed through a **Trial of Labor (TOL)**. 1. **Why Trial of Labor is Correct:** Labor is a dynamic process. The "fit" depends on three factors: the Power (uterine contractions), the Passenger (fetal head molding and asynclitism), and the Passage (pelvic joint relaxation). Since molding of the fetal skull and the effectiveness of contractions cannot be predicted beforehand, a trial of labor allows these physiological mechanisms to occur. If progress fails despite adequate contractions, CPD is diagnosed. 2. **Why other options are incorrect:** * **Maternal height (A):** While short stature (<145–150 cm) is a risk factor for a small pelvis, it is not diagnostic. Many short women deliver vaginally without difficulty. * **X-ray pelvimetry (C):** Radiographic measurements assess static bone dimensions but fail to account for fetal head molding or soft tissue influence. It has a poor predictive value for actual labor outcomes and is no longer recommended for routine CPD diagnosis. * **Pelvic examination (D):** Clinical pelvimetry can identify an "inadequate" pelvis (e.g., a flat sacrum or narrow pubic arch), but it cannot predict if the fetal head will successfully navigate that space during active labor. **High-Yield Clinical Pearls for NEET-PG:** * **Definition of TOL:** Conducted in cases of suspected mid-pelvic contraction or borderline CPD under close supervision. * **Contraindications for TOL:** Presence of a contracted outlet, placenta previa, or a previous classical cesarean section. * **Success of TOL:** It is considered successful if a healthy baby is delivered vaginally. It is terminated if there is fetal distress or failure to progress (cervical dilation/descent).

Question 633: Persistent occipitoposterior presentation is common in which type of pelvis?

A. Android pelvis (Correct Answer)
B. Anthropoid pelvis
C. Gynaecoid pelvis
D. Platypelloid pelvis

Explanation: **Explanation:** The orientation of the fetal head during labor is significantly influenced by the shape of the pelvic inlet and the available space in the forepelvis. **1. Why Android Pelvis is Correct:** The **Android (masculine) pelvis** is characterized by a heart-shaped inlet with a narrow, triangular forepelvis and a wide hindpelvis. Because the anterior segment is cramped, the fetal head is forced to occupy the roomier posterior segment. This favors an **Occipitoposterior (OP)** position. Furthermore, the convergent side walls and prominent ischial spines in an android pelvis often lead to a failure of internal rotation, resulting in **Persistent Occipitoposterior** position or deep transverse arrest. **2. Analysis of Incorrect Options:** * **Anthropoid Pelvis:** This pelvis has a long anteroposterior diameter and a narrow transverse diameter. While it is the most common pelvis associated with a fetus *starting* in an OP position (Direct OP), the spacious AP diameter often allows for easier delivery or spontaneous rotation compared to the android type. * **Gynaecoid Pelvis:** The "ideal" female pelvis. It is round/oval with adequate space in all segments, favoring the Occipito-anterior (OA) position and smooth internal rotation. * **Platypelloid Pelvis:** A "flat" pelvis with a short AP and wide transverse diameter. This type typically leads to **Persistent Transverse** positions (asynclitism) rather than OP. **NEET-PG High-Yield Pearls:** * **Most common pelvis:** Gynaecoid (50%). * **Most common pelvis for OP position:** Anthropoid (initially), but **Persistent OP** is most classically linked to Android. * **Android Pelvis** is associated with the highest incidence of instrumental delivery (forceps/ventouse) and "Deep Transverse Arrest." * **Platypelloid Pelvis** is the rarest type and is associated with "Delayed Engagement."

Question 634: How is CPD (Cephalopelvic Disproportion) best assessed?

A. CT scan
B. Ultrasound
C. Radio pelvimetry
D. Clinical pelvic assessment (Correct Answer)

Explanation: **Explanation:** Cephalopelvic Disproportion (CPD) occurs when there is a mismatch between the size of the fetal head and the maternal pelvic capacity, making vaginal delivery difficult or impossible. **Why Clinical Pelvic Assessment is the Correct Answer:** Clinical assessment remains the "gold standard" because CPD is a **functional diagnosis** that can often only be definitively confirmed during the trial of labor. Clinical pelvimetry (assessing the pelvic inlet, cavity, and outlet via vaginal examination) combined with the **Muller-Hillis maneuver** (to check for head engagement) allows for a dynamic evaluation. Unlike static imaging, clinical assessment accounts for the molding of the fetal head and the relaxation of pelvic ligaments during labor. **Why Other Options are Incorrect:** * **CT Scan & Radio pelvimetry (A & C):** While these provide precise bony measurements, they are poor predictors of actual labor outcomes. They cannot account for fetal head molding or the "give" of the pelvic joints. Furthermore, radiopelvimetry involves unnecessary ionizing radiation. * **Ultrasound (B):** USG is excellent for estimating fetal weight and head circumference (biometry), but it cannot accurately predict how that head will navigate the birth canal. **High-Yield Clinical Pearls for NEET-PG:** * **Muller-Hillis Maneuver:** The most common clinical method to assess CPD. If the head can be pushed into the pelvis without overriding the symphysis pubis, CPD is unlikely. * **Trial of Labor (TOL):** Indicated in mild to moderate degrees of suspected CPD (specifically in borderline contracted pelvis). It is contraindicated in major degrees of CPD. * **Diagnosis of Exclusion:** True CPD is often diagnosed retrospectively when labor fails to progress despite adequate uterine contractions (Power), favorable fetal position (Passenger), and no obvious pelvic deformity (Passage).

Question 635: Arrest disorder is defined as the cessation of cervical dilatation in the active phase of labor of more than:

A. 1 hour
B. 1.2 hours
C. 1.5 hours
D. 2 hours (Correct Answer)

Explanation: **Explanation:** In modern obstetrics, labor abnormalities are categorized into **protraction disorders** (slow progress) and **arrest disorders** (complete cessation of progress). **1. Why Option D is Correct:** According to Friedman’s criteria, an **Arrest of Dilatation** is defined as the cessation of cervical dilatation for **2 hours or more** during the active phase of labor. For this diagnosis to be valid, the patient must have already entered the active phase (traditionally defined as ≥4 cm dilatation, though modern guidelines like Zhang’s often use 6 cm). This indicates a failure of the "power" (contractions), "passenger" (fetal size/position), or "passage" (pelvis). **2. Analysis of Incorrect Options:** * **Options A, B, and C:** These timeframes do not meet the diagnostic threshold for an arrest disorder. * **1.2 hours (Option B) and 1.5 hours (Option C)** are specific rates associated with **Protraction Disorders**. In the active phase, a primigravida should dilate at a rate of at least **1.2 cm/hr**, and a multigravida at **1.5 cm/hr**. If the rate is slower than this, it is "protraction," not "arrest." **3. NEET-PG High-Yield Pearls:** * **Arrest of Descent:** Failure of the fetal station to advance for **1 hour** or more. * **Active Phase definition:** While Friedman used 4 cm, the **WHO and ACOG** now define the start of the active phase at **6 cm** dilatation. * **Management:** Before diagnosing arrest in modern practice, ACOG recommends waiting for **4 hours** if contractions are adequate (measured via IUPC as >200 Montevideo units) or **6 hours** if contractions are inadequate and oxytocin is being used. * **Friedman’s Curve:** Remember that the active phase consists of the acceleration phase, phase of maximum slope, and deceleration phase. Arrest most commonly occurs during the phase of maximum slope.

Question 636: Fetal blood loss in abnormal cord insertion is seen in which of the following conditions?

A. Vasa previa (Correct Answer)
B. Decidua basalis
C. Battledore placenta
D. Succenturiate placenta

Explanation: **Explanation:** **Vasa previa** is the correct answer because it involves fetal vessels running through the membranes, unprotected by placental tissue or the umbilical cord (Wharton’s jelly), across the internal os. This condition is most commonly associated with **velamentous insertion of the cord** or a **succenturiate lobe**. When the membranes rupture (spontaneously or artificially), these exposed fetal vessels are easily lacerated, leading to rapid fetal exsanguination. Since the blood lost is entirely fetal, even a small amount can lead to fetal distress and death. **Incorrect Options:** * **Decidua basalis:** This is the maternal component of the placenta. Bleeding here is maternal in origin, typically seen in placental abruption. * **Battledore placenta (Marginal insertion):** The cord inserts at the margin of the placenta rather than the center. While it increases the risk of preterm labor, it rarely causes fetal vessel rupture or significant fetal blood loss. * **Succenturiate placenta:** This refers to an accessory lobe. While it is a *risk factor* for vasa previa (if the connecting vessels cross the os), the presence of the lobe itself does not imply fetal blood loss unless vasa previa is concurrently present. **High-Yield Clinical Pearls for NEET-PG:** * **Classic Triad:** Rupture of membranes + Painless vaginal bleeding + Fetal bradycardia/distress. * **Diagnosis:** Antenatally via **Transvaginal Color Doppler** (Gold Standard). * **Apt Test / Ogita Test:** Used to differentiate fetal hemoglobin from maternal hemoglobin in vaginal blood. * **Management:** If diagnosed prenatally, elective Cesarean section is planned at 34–35 weeks to avoid labor and membrane rupture.

Question 637: What is the commonest type of vertex presentation?

A. Left occipito transverse (Correct Answer)
B. Left occipito anterior
C. Right occipito anterior
D. Right occipito posterior

Explanation: **Explanation:** In vertex presentation, the position is determined by the relationship between the **occiput** (denominator) and the maternal pelvis. **Why Left Occipito-Transverse (LOT) is correct:** Statistically, **Left Occipito-Transverse (LOT)** is the most common initial position at the onset of labor. This is primarily due to the anatomical shape of the pelvic inlet. The transverse diameter of the pelvic inlet is wider than the anteroposterior diameter. Additionally, the presence of the sigmoid colon on the left side of the pelvis often pushes the occiput into a transverse or slightly anterior position. While many textbooks previously cited Left Occipito-Anterior (LOA) as the most common, modern obstetric studies and ultrasound data confirm that LOT is the most frequent starting position. **Analysis of Incorrect Options:** * **Left Occipito-Anterior (LOA):** This is the second most common position. It is often considered the "ideal" position for delivery, as the head is already partially rotated toward the symphysis pubis. * **Right Occipito-Anterior (ROA):** This occurs less frequently than LOA. The liver on the right side and the positioning of the descending colon on the left generally favor left-sided positions. * **Right Occipito-Posterior (ROP):** This is the most common **malposition** (not presentation). While it is the most frequent among posterior positions, it is significantly less common than LOT or LOA. **High-Yield Clinical Pearls for NEET-PG:** * **Most common position at onset of labor:** LOT. * **Most common malposition:** ROP (Right Occipito-Posterior). * **Most common mechanism of delivery:** The head usually enters in LOT, rotates 90° anteriorly during the second stage of labor to become Occipito-Anterior (OA) for delivery. * **Internal Rotation:** This occurs when the leading part (occiput) hits the pelvic floor and rotates toward the symphysis pubis.

Question 638: What is the definition of full-term pregnancy in terms of gestational weeks?

A. 37 completed to 38 6/7 weeks
B. 39 completed to 40 6/7 weeks (Correct Answer)
C. 41 completed to 41 6/7 weeks
D. 42 completed weeks

Explanation: **Explanation:** The definition of a "term" pregnancy was refined by the ACOG and SMFM to reflect the differences in neonatal outcomes across the 37–42 week window. The correct answer is **B (39 0/7 to 40 6/7 weeks)**, which is now formally defined as **Full Term**. Research indicates that neonates born during this specific window have the lowest risk of respiratory distress, sepsis, and NICU admissions compared to those born earlier. **Analysis of Options:** * **Option A (37 0/7 to 38 6/7 weeks):** This is defined as **Early Term**. While technically "term" in older classifications, these infants face higher risks of morbidity (e.g., transient tachypnea of the newborn) compared to full-term infants. * **Option C (41 0/7 to 41 6/7 weeks):** This is defined as **Late Term**. At this stage, there is an increased risk of meconium aspiration and placental insufficiency. * **Option D (42 0/7 weeks and beyond):** This is defined as **Post-term**. These pregnancies require close monitoring or induction due to the significantly increased risk of stillbirth and dysmaturity syndrome. **NEET-PG High-Yield Pearls:** 1. **Preterm:** Before 37 0/7 weeks. 2. **Full Term:** 39 0/7 to 40 6/7 weeks (The "Sweet Spot" for delivery). 3. **Naegele’s Rule:** Used to calculate the Expected Date of Delivery (EDD) = LMP + 7 days - 3 months + 1 year. 4. **Clinical Significance:** Elective inductions or Cesarean sections should not be performed before 39 weeks unless medically indicated, to ensure optimal fetal lung maturity.

Question 639: Deep transverse arrest is seen in all except?

A. Android pelvis
B. Epidural analgesia
C. Transverse lie (Correct Answer)
D. Uterine inertia

Explanation: **Explanation:** **Deep Transverse Arrest (DTA)** occurs when the fetal head has descended to the level of the ischial spines (deep in the pelvic cavity) but fails to rotate from the occipito-transverse position to the occipito-anterior position. **Why "Transverse Lie" is the correct answer:** For DTA to occur, the fetus must be in a **longitudinal lie** with a cephalic presentation. In a **transverse lie**, the long axis of the fetus is perpendicular to the mother’s, and the presenting part is usually the shoulder. Since the head does not engage or descend into the pelvis in a transverse lie, the mechanism of "arrest of rotation" at the level of the spines is impossible. **Analysis of Incorrect Options:** * **Android Pelvis:** This is the most common cause of DTA. The narrow fore-pelvis and convergent side walls prevent the natural internal rotation of the fetal head. * **Epidural Analgesia:** It causes relaxation of the pelvic floor muscles (levator ani). Since the resistance of these muscles is essential for the fetal head to rotate, epidural anesthesia significantly increases the risk of DTA. * **Uterine Inertia:** Weak uterine contractions (secondary uterine inertia) provide insufficient force to push the fetal head against the pelvic floor, failing to facilitate internal rotation. **High-Yield Clinical Pearls for NEET-PG:** * **Definition:** Arrest of internal rotation at the level of the ischial spines for >1 hour. * **Pelvic Type:** Most common in **Android** and **Anthropoid** pelvis. * **Management:** If the pelvis is adequate and there is no CPD, it can be managed by **Manual Rotation** or **Kielland’s Forceps**. If these fail or CPD is present, **Cesarean Section** is the definitive treatment. * **Prerequisite:** The head must be engaged for DTA to be diagnosed.

Question 640: In cases of unstable lie of the fetus, where is the placenta usually located?

A. Cornual
B. Lateral wall
C. Fundus
D. Lower segment (Correct Answer)

Explanation: **Explanation:** The correct answer is **Lower segment**. **Medical Concept:** The fetal lie is determined by the relationship between the long axis of the fetus and the long axis of the mother. An **unstable lie** refers to a situation where the fetal presentation frequently changes (e.g., from transverse to oblique to longitudinal) after 37 weeks of gestation. The primary reason for an unstable lie is the presence of a factor that prevents the fetal head from engaging or "fitting" into the pelvic brim. A **placenta previa** (placenta located in the lower uterine segment) acts as a physical barrier, occupying the space in the pelvic inlet. This prevents the fetus from assuming a stable longitudinal lie with the head well-applied to the cervix, leading to malpresentations or an unstable lie. **Analysis of Incorrect Options:** * **A, B, and C (Cornual, Lateral wall, Fundus):** These are all locations within the **upper uterine segment**. When the placenta is situated in the upper segment, the lower segment remains empty and spacious, allowing the fetal head to descend and engage normally. These positions are associated with a stable longitudinal lie. **Clinical Pearls for NEET-PG:** * **Most common cause of unstable lie:** While multiparity (lax abdominal muscles) is the most common cause, **placenta previa** is the most critical structural cause to exclude via ultrasound. * **Management:** If an unstable lie persists at 37–38 weeks, the patient is usually admitted. If the lie is still unstable at the onset of labor, a Cesarean section is often indicated to avoid cord prolapse. * **High-Yield Association:** Always rule out **pelvic tumors** (like fibroids) or **contracted pelvis** if a fetus remains high and mobile near term.

Practice by Chapter

Physiology of Labor

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Stages of Labor and Normal Progression

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Fetal Monitoring Techniques

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Pain Management in Labor

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Induction and Augmentation of Labor

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Operative Delivery (Forceps and Vacuum)

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Cesarean Section: Indications and Techniques

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Dystocia and Abnormal Labor Patterns

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Obstetric Emergencies

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Postpartum Hemorrhage Management

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