Obstetrics and Gynecology Syllabus

What is the role of antenatal corticosteroids in preterm labor?

A course of betamethasone or dexamethasone given between 24 and 34 weeks accelerates fetal lung maturation (surfactant production), reducing neonatal respiratory distress syndrome, intraventricular hemorrhage, and mortality.

Why is magnesium sulfate given in preterm labor before 32 weeks?

For fetal neuroprotection — it reduces the risk and severity of cerebral palsy in the neonate. (It is also a tocolytic but is used here mainly for neuroprotection.)

Name common tocolytic agents used to delay preterm delivery.

Nifedipine (calcium channel blocker), indomethacin (NSAID/prostaglandin inhibitor, used $<32$ weeks), and terbutaline (beta-agonist). Tocolysis aims to delay delivery ~48 h to allow steroid benefit.

What are the three stages of labor?

First stage: onset of labor to full cervical dilation ($10\ \text{cm}$). Second stage: full dilation to delivery of the fetus. Third stage: delivery of the fetus to delivery of the placenta.

How are the latent and active phases of the first stage of labor distinguished?

Latent phase: slow cervical change up to about $6\ \text{cm}$. Active phase: more rapid dilation from $\approx 6\ \text{cm}$ to $10\ \text{cm}$, when contractions become regular and strong.

What are the seven cardinal movements of labor?

Engagement, Descent, Flexion, Internal rotation, Extension, External rotation (restitution), and Expulsion.

What are the components of a Bishop score and what does it predict?

Cervical dilation, effacement, station, consistency, and position. It predicts the likelihood of successful labor induction; a score $\geq 8$ suggests a favorable cervix.

How is fetal station defined?

The level of the fetal presenting part relative to the ischial spines, measured in centimeters from $-5$ (above spines) to $+5$ (below spines); station $0$ means the presenting part is at the ischial spines (engaged).

What is the mechanism and typical placement level of an epidural for labor analgesia?

Local anesthetic (often with an opioid) is injected into the epidural space, typically at the $L3\text{–}L4$ or $L4\text{–}L5$ interspace, blocking spinal nerve roots to relieve pain while allowing continuous dosing via catheter.

What is a pudendal nerve block used for and which nerve roots does it target?

It anesthetizes the perineum for the second stage of labor, operative vaginal delivery, or repair, by blocking the pudendal nerve derived from sacral roots $S2\text{–}S4$ near the ischial spine.

What is a key contraindication to neuraxial (epidural/spinal) anesthesia in labor?

Significant coagulopathy or thrombocytopenia (e.g., platelets typically $<70{,}000\text{–}80{,}000/\mu L$), local infection at the site, or maternal hemodynamic instability, due to bleeding/hematoma risk.

What are the indications for cesarean delivery?

Labor arrest/failure to progress, nonreassuring fetal status, malpresentation (e.g., breech), placenta previa, cord prolapse, prior classical uterine incision, and active maternal genital herpes.

What defines operative vaginal delivery and its two main instruments?

Assisted vaginal delivery using either forceps or a vacuum extractor to help deliver the fetal head during the second stage, indicated for prolonged second stage, nonreassuring fetal status, or maternal exhaustion.

What is the McRoberts maneuver and when is it used?

Sharp hyperflexion of the maternal hips onto the abdomen (often with suprapubic pressure) to relieve shoulder dystocia by flattening the sacrum and rotating the pubic symphysis to free the impacted anterior shoulder.

How is postpartum hemorrhage (PPH) defined?

Cumulative blood loss $\geq 1000\ \text{mL}$ OR blood loss accompanied by signs/symptoms of hypovolemia within 24 hours of delivery (regardless of route).

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

Uterine atony. First-line management includes uterine massage and uterotonics: oxytocin (first-line), followed by methylergonovine, carboprost (avoid in asthma), and misoprostol.

What are the "4 Ts" causes of postpartum hemorrhage?

Tone (uterine atony), Trauma (lacerations/hematoma), Tissue (retained placenta), and Thrombin (coagulopathy).

What normal physiologic changes occur during the immediate postpartum period regarding the uterus?

Uterine involution: the uterus contracts and descends about $1\ \text{cm}$ (one fingerbreadth) per day, returning to the pelvis by ~2 weeks and near pre-pregnancy size by ~6 weeks. Lochia progresses rubra → serosa → alba.

Which hormones drive lactation, and what are their specific roles?

Prolactin stimulates milk synthesis/production; oxytocin triggers the milk let-down (ejection) reflex by contracting myoepithelial cells. Suckling stimulates both via neuroendocrine reflex.

What is colostrum and why is it important for the newborn?

Colostrum is the thick, yellowish first milk produced in the first few days postpartum; it is rich in protein and secretory IgA antibodies, providing passive immunity, and has laxative properties aiding meconium passage.

How does breastfeeding provide natural contraception, and what is this called?

The lactational amenorrhea method (LAM): prolactin suppresses GnRH, inhibiting ovulation. It is most effective when the infant is exclusively breastfed, is under 6 months old, and the mother remains amenorrheic.

How are the postpartum "baby blues" distinguished from postpartum depression?

Baby blues: mild, transient mood lability affecting up to ~80% of mothers, resolving within ~2 weeks without treatment. Postpartum depression: persistent, more severe depressive symptoms lasting $>2$ weeks, impairing function, and requiring treatment.

When does postpartum depression typically onset and what screening tool is commonly used?

It typically begins within the first 4–6 weeks postpartum (can occur up to 12 months). The Edinburgh Postnatal Depression Scale (EPDS) is a widely used screening instrument.

What is postpartum psychosis and why is it a psychiatric emergency?

A rare, severe disorder (~1–2 per 1000 births) with rapid onset of hallucinations, delusions, disorganization, and risk of infanticide/suicide. It is a psychiatric emergency requiring hospitalization.

Who introduced antiseptic/aseptic surgical technique that transformed gynecologic surgery, and who is called the "Father of Modern Gynecology"?

Joseph Lister introduced antiseptic surgery. J. Marion Sims is historically called the "Father of Modern Gynecology" for developing the vaginal speculum and fistula repair techniques (though his ethics are now widely criticized).

What are the anatomical layers of the uterus from inner to outer?

Endometrium (inner mucosal lining that sheds during menstruation), myometrium (thick smooth muscle layer), and perimetrium/serosa (outer serosal covering).

What is the normal blood supply to the ovary?

The ovarian arteries arise directly from the abdominal aorta (below the renal arteries). The right ovarian vein drains into the inferior vena cava; the left ovarian vein drains into the left renal vein.

How are primary and secondary amenorrhea defined?

Primary amenorrhea: no menarche by age 15 with normal secondary sexual characteristics (or by 13 without them). Secondary amenorrhea: absence of menses for $\geq 3$ months in a previously regular woman or $\geq 6$ months if oligomenorrheic.

What is the first test to order in a woman presenting with secondary amenorrhea, and what are common causes?

A pregnancy test ($\beta$-hCG) — pregnancy is the most common cause. Other causes include hypothalamic dysfunction, hyperprolactinemia, thyroid disease, and polycystic ovary syndrome (PCOS).

What distinguishes primary from secondary dysmenorrhea?

Primary dysmenorrhea: painful menses with no underlying pelvic pathology, caused by excess prostaglandins ($PGF_{2\alpha}$) increasing uterine contractions. Secondary dysmenorrhea: pain due to identifiable pathology such as endometriosis, adenomyosis, or fibroids. First-line treatment for primary is NSAIDs.

What does the PALM-COEIN classification of abnormal uterine bleeding stand for?

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