MBBS Obstetrics & Gynecology Syllabus

Distinguish early, variable, and late decelerations on CTG and their associations.

Early decelerations mirror contractions (nadir with peak) — benign, due to head compression. Variable decelerations are abrupt, V-shaped, variable timing — due to cord compression. Late decelerations begin after the contraction peak and recover after it ends — associated with uteroplacental insufficiency/fetal hypoxia.

What are the five components of the biophysical profile (BPP) and the maximum score?

Fetal breathing movements, gross body movements, fetal tone, amniotic fluid volume, and the non-stress test (reactive FHR). Each scores 0 or 2, for a maximum of 10.

Define pre-eclampsia using the classic diagnostic criteria.

New-onset hypertension ($\geq 140/90\ \text{mmHg}$ on two occasions) after 20 weeks gestation, plus proteinuria ($\geq 300\ mg/24h$ or protein:creatinine ratio $\geq 30\ mg/mmol$) OR new-onset end-organ dysfunction (renal, hepatic, neurological, hematological, or uteroplacental).

What distinguishes gestational hypertension, pre-eclampsia, and eclampsia?

Gestational hypertension: new hypertension after 20 weeks without proteinuria or end-organ involvement. Pre-eclampsia: hypertension + proteinuria/end-organ dysfunction. Eclampsia: pre-eclampsia with new-onset generalized tonic-clonic seizures.

What is the first-line drug to prevent and treat eclamptic seizures, and a sign of its toxicity?

Magnesium sulfate ($MgSO_4$) is first-line. Toxicity signs include loss of deep tendon (patellar) reflexes, respiratory depression, and reduced urine output. The antidote is intravenous calcium gluconate.

What is the definitive treatment for pre-eclampsia/eclampsia?

Delivery of the fetus and placenta. Timing balances maternal stabilization against fetal maturity; severe disease or eclampsia warrants delivery regardless of gestation after maternal stabilization.

What constitutes HELLP syndrome?

Hemolysis, Elevated Liver enzymes, and Low Platelets — a severe variant/complication of pre-eclampsia. It may occur with only mild or even absent hypertension.

What are the standard 75 g oral glucose tolerance test (OGTT) cut-offs for diagnosing gestational diabetes mellitus (IADPSG/WHO)?

GDM is diagnosed if any one is met: fasting $\geq 5.1\ mmol/L$ ($92\ mg/dL$); 1-hour $\geq 10.0\ mmol/L$ ($180\ mg/dL$); 2-hour $\geq 8.5\ mmol/L$ ($153\ mg/dL$).

Name three major fetal/neonatal complications of poorly controlled gestational diabetes.

Macrosomia (and resultant shoulder dystocia/birth trauma), neonatal hypoglycemia, and polyhydramnios. Others include neonatal respiratory distress, hyperbilirubinemia, and increased risk of congenital anomalies (mainly with pre-existing diabetes).

What is the first-line management approach for gestational diabetes, and which medications are used if it fails?

First-line is diet and exercise (lifestyle modification) with glucose monitoring. If targets are not met, pharmacotherapy is added — metformin and/or insulin (insulin being the most effective and the standard if needed).

Define preterm labor by gestational age.

Onset of regular uterine contractions with cervical change occurring after 20 (or 24) weeks and before 37 completed weeks of gestation.

What is the role and timing of antenatal corticosteroids in preterm labor?

Antenatal corticosteroids (e.g., betamethasone or dexamethasone) are given between ~24 and 34 (up to 36) weeks to accelerate fetal lung maturation and reduce respiratory distress syndrome, intraventricular hemorrhage, and necrotizing enterocolitis. Maximal benefit is 24 hours to 7 days after administration.

What is the purpose of tocolytics in preterm labor, and name two examples?

Tocolytics delay delivery (typically up to 48 hours) to allow corticosteroids to act and permit transfer to a unit with neonatal care. Examples: nifedipine (calcium channel blocker), atosiban (oxytocin antagonist), and indomethacin (NSAID, used $<32$ weeks).

What is the role of magnesium sulfate in preterm labor (separate from its use in eclampsia)?

Magnesium sulfate is given for fetal neuroprotection when delivery is anticipated before ~32 weeks, reducing the risk of cerebral palsy in the preterm infant.

What is the difference between monozygotic and dizygotic twins, and which has higher risk?

Monozygotic (identical) twins arise from one fertilized egg that splits; dizygotic (fraternal) from two separate eggs/sperm. Monozygotic, especially monochorionic types, carry higher risks (e.g., twin-to-twin transfusion syndrome). Dizygotic twins are always dichorionic diamniotic.

How does the timing of zygote splitting determine chorionicity and amnionicity in monozygotic twins?

Split at days 0–3: dichorionic diamniotic (DCDA). Days 4–8: monochorionic diamniotic (MCDA). Days 8–13: monochorionic monoamniotic (MCMA). After day 13: conjoined twins.

What ultrasound sign distinguishes dichorionic from monochorionic twins in the first trimester?

The lambda (\$\lambda\$) / twin-peak sign indicates dichorionic; the T-sign indicates monochorionic. Chorionicity is most accurately determined before 14 weeks.

Define the three stages of normal labor.

First stage: onset of regular contractions to full (10 cm) cervical dilation (latent then active phases). Second stage: full dilation to delivery of the baby. Third stage: delivery of the baby to delivery of the placenta and membranes.

What are the cardinal movements (mechanism) of labor in a vertex presentation?

Engagement, descent, flexion, internal rotation, extension, external rotation (restitution), and expulsion.

What defines the latent and active phases of the first stage of labor?

Latent phase: from onset of contractions to ~4–6 cm dilation, slow cervical change. Active phase: from ~6 cm to full (10 cm) dilation, with more rapid progress (historically ~1 cm/hour or more).

What is the most common fetal presentation and position at term, and what is the denominator used?

Cephalic (vertex) presentation is most common (~95%). The denominator is the occiput; the most favorable position is occipito-anterior (OA).

What is intermittent auscultation versus continuous CTG, and when is continuous monitoring indicated in labor?

Intermittent auscultation (Doppler/Pinard) is used for low-risk labor. Continuous electronic fetal monitoring (CTG) is indicated in high-risk labor — e.g., meconium-stained liquor, abnormal FHR on auscultation, oxytocin use, pre-eclampsia, induced labor, prematurity, or suspected fetal compromise.

What does the mnemonic 'DR C BRAVADO' stand for in systematic CTG interpretation?

DR = Define Risk; C = Contractions; BRa = Baseline Rate; V = Variability; A = Accelerations; D = Decelerations; O = Overall impression (reassuring / suspicious / pathological).

What is normal CTG baseline variability, and what does reduced variability suggest?

Normal baseline variability is $5\text{–}25\ \text{bpm}$. Reduced variability ($< 5\ \text{bpm}$ for $>50$ min) may indicate fetal hypoxia/acidosis, fetal sleep, prematurity, or maternal sedation/drugs.

What is active management of the third stage of labor, and why is it done?

Active management includes a uterotonic (e.g., IM oxytocin) with delivery of the anterior shoulder/baby, controlled cord traction, and uterine massage after placental delivery. It reduces the risk of postpartum hemorrhage.

List the main absolute and common indications for cesarean section.

Examples include: cephalopelvic disproportion/obstructed labor, fetal distress, placenta previa/major hemorrhage, cord prolapse, transverse/abnormal lie, failed induction, previous classical cesarean, and certain malpresentations (e.g., breech). Maternal request and previous cesarean are relative indications.

What are the categories of cesarean section by urgency (RCOG classification)?

Category 1: immediate threat to life of mother or fetus (target decision-to-delivery $\leq 30$ min). Category 2: maternal/fetal compromise, not immediately life-threatening. Category 3: needs early delivery but no compromise. Category 4: elective, planned.

What is the most common type of uterine incision for cesarean section and its advantage over the classical incision?

The lower-segment transverse incision is most common. Compared to the classical (vertical upper-segment) incision, it has less blood loss, better healing, lower infection/rupture risk, and allows a future trial of vaginal birth after cesarean (VBAC).

Describe the major involutional change of the uterus in the postpartum period.

The uterus involutes from ~1000 g at delivery to ~50–100 g by 6 weeks. The fundus descends ~1 cm (one finger-breadth) per day, becoming non-palpable abdominally by ~2 weeks postpartum.

What are the three stages of lochia and their typical timing?

Lochia rubra (red, days 1–3/4, blood and decidua); lochia serosa (pinkish-brown, days ~4–10); lochia alba (yellow-white, ~day 10 to up to 6 weeks).

What hormonal change initiates lactation after delivery, and which hormones control milk production and ejection?

The fall in estrogen and progesterone after placental delivery removes inhibition of prolactin, initiating lactogenesis. Prolactin drives milk production; oxytocin causes the milk ejection (let-down) reflex via myoepithelial contraction.

Define primary postpartum hemorrhage (PPH) and list its four main causes (the '4 Ts').

Primary PPH is blood loss $\geq 500\ mL$ (vaginal) or $\geq 1000\ mL$ (cesarean) within 24 hours of delivery. The 4 Ts: Tone (uterine atony — most common), Trauma (lacerations/rupture), Tissue (retained placenta), and Thrombin (coagulopathy).

What is the most common cause of primary postpartum hemorrhage and its first-line management?

Uterine atony is the most common cause. First-line management: uterine massage and uterotonics — oxytocin (first-line), then ergometrine, carboprost (prostaglandin $F_{2\alpha}$), and misoprostol, with bimanual compression and fluid resuscitation as needed.

What defines secondary postpartum hemorrhage and what are its common causes?

Secondary PPH is abnormal/excessive bleeding from 24 hours to 6 (or 12) weeks postpartum. Common causes are retained products of conception and endometritis (uterine infection).

Rank the typical first-year failure (Pearl Index) order of common contraceptive methods from most to least effective.

Most effective: implant and intrauterine devices/LARC ($<1\%$), then injectables, combined oral contraceptive pill (~$0.3\%$ perfect / ~$9\%$ typical use), condoms (~$2\%$ perfect / ~$18\%$ typical), and least reliable: withdrawal and fertility-awareness methods.

What is the mechanism of action of the combined oral contraceptive pill (COCP)?

Estrogen and progesterone suppress the hypothalamic-pituitary axis, inhibiting FSH and LH and thereby preventing ovulation. They also thicken cervical mucus and thin the endometrium.

Name two absolute contraindications to the combined oral contraceptive pill.

Examples (UKMEC category 4): history of venous thromboembolism, migraine with aura, current breast cancer, uncontrolled hypertension, smoking $\geq 15$ cigarettes/day at age $\geq 35$, and $< 6$ weeks postpartum if breastfeeding.

What is the mechanism and copper vs. hormonal difference of intrauterine devices?

The copper IUD is spermicidal/toxic to ova and prevents fertilization and implantation (also the most effective emergency contraception). The levonorgestrel IUD thickens cervical mucus, thins the endometrium, and may suppress ovulation, reducing menstrual bleeding.

Define menorrhagia, metrorrhagia, and oligomenorrhea.

Menorrhagia: heavy menstrual bleeding ($>80\ mL$ or prolonged/frequent). Metrorrhagia: irregular bleeding between periods. Oligomenorrhea: infrequent menstruation with cycles $> 35$ days apart.

What is the structured classification system for causes of abnormal uterine bleeding?

The FIGO PALM-COEIN system. Structural (PALM): Polyp, Adenomyosis, Leiomyoma (fibroid), Malignancy/hyperplasia. Non-structural (COEIN): Coagulopathy, Ovulatory dysfunction, Endometrial, Iatrogenic, Not yet classified.

Define primary versus secondary dysmenorrhea.

Primary dysmenorrhea: painful menstruation without underlying pelvic pathology, due to excess prostaglandins; typically begins with menarche. Secondary dysmenorrhea: painful periods caused by pelvic pathology (e.g., endometriosis, fibroids, adenomyosis, PID), often beginning later in life.

What are uterine fibroids (leiomyomas), and how are they classified by location?

Fibroids are benign smooth-muscle tumors of the myometrium, estrogen-dependent. By location: submucosal (project into the cavity, cause heavy bleeding), intramural (within the wall), and subserosal (project outward, may be pedunculated).

What is the classic clinical triad/symptoms of endometriosis?

Cyclical pelvic pain — classically dysmenorrhea, dyspareunia (deep pain on intercourse), and dyschezia/dysuria — often with subfertility. Diagnosis is confirmed by laparoscopy; ectopic endometrial tissue causes "chocolate cysts" (endometriomas) on the ovary.

What is a follicular (functional) ovarian cyst, and how does it differ from a corpus luteum cyst?

A follicular cyst forms when a follicle fails to rupture/regress and continues to grow; usually $<5$ cm, asymptomatic, and resolves spontaneously. A corpus luteum cyst forms after ovulation when the corpus luteum fails to regress; it is more likely to cause pain or hemorrhage. Both are benign functional cysts.