• External genitalia (vulva), vagina, uterus, fallopian tubes, ovaries
• Pelvic ligaments, blood supply, lymphatic drainage, nerve supply
• Pelvic floor and perineum

• Embryology: Mullerian (paramesonephric) and Wolffian (mesonephric) duct development
• Genital tract anomalies (uterine anomalies - septate/bicornuate/didelphys, vaginal agenesis, imperforate hymen, etc.)
• Intersex/disorders of sexual differentiation basics

• GnRH pulsatility
• Gonadotropins (FSH, LH) - synthesis, regulation, feedback mechanisms
• HPO (hypothalamic-pituitary-ovarian) axis

• Normal pubertal changes, Tanner staging, sequence of events
• Precocious and delayed puberty

• Menstrual cycle physiology (ovarian cycle, endometrial cycle)
• Hormonal changes across the cycle
• Normal menstrual parameters

• Primary vs secondary dysmenorrhoea
• Pathophysiology, causes, and management

• External genitalia (vulva), vagina, uterus, fallopian tubes, ovaries
• Pelvic ligaments, blood supply, lymphatic drainage, nerve supply
• Pelvic floor and perineum

• Embryology: Mullerian (paramesonephric) and Wolffian (mesonephric) duct development
• Genital tract anomalies (uterine anomalies - septate/bicornuate/didelphys, vaginal agenesis, imperforate hymen, etc.)
• Intersex/disorders of sexual differentiation basics

• GnRH pulsatility
• Gonadotropins (FSH, LH) - synthesis, regulation, feedback mechanisms
• HPO (hypothalamic-pituitary-ovarian) axis

• Normal pubertal changes, Tanner staging, sequence of events
• Precocious and delayed puberty

• Menstrual cycle physiology (ovarian cycle, endometrial cycle)
• Hormonal changes across the cycle
• Normal menstrual parameters

• Primary vs secondary dysmenorrhoea
• Pathophysiology, causes, and management

1. ANATOMY OF THE FEMALE REPRODUCTIVE SYSTEM

A. External Genitalia (Vulva)

• Mons pubis - fat pad over pubic symphysis, covered with hair after puberty
• Labia majora - homologous to scrotum; contains round ligament termination, Bartholin gland ducts open at its base
• Labia minora - no hair follicles, rich in sebaceous glands, forms prepuce and frenulum of clitoris anteriorly, fourchette posteriorly
• Clitoris - erectile organ, homologous to penis; has glans, body (corpora cavernosa), crura
• Vestibule - bounded by labia minora; contains urethral opening, vaginal opening, openings of Bartholin's (greater vestibular) and Skene's (paraurethral) glands
• Bartholin's glands - pea-sized, at 4 and 8 o'clock position of vestibule; secrete mucus for lubrication; site of Bartholin's cyst/abscess (exam favorite)
• Hymen - thin mucous membrane at vaginal introitus; imperforate hymen causes cryptomenorrhoea/hematocolpos

B. Vagina

• Fibromusculomembranous canal, 8-10 cm posterior wall, 6-7.5 cm anterior wall
• Extends from vestibule to cervix; forms fornices (anterior, posterior, two lateral) around cervix - posterior fornix is deepest, related to pouch of Douglas (site for culdocentesis)
• Lined by stratified squamous epithelium (non-keratinized), no glands - lubrication from cervical mucus + transudation
• pH 4.5 (acidic) due to Doderlein's bacilli converting glycogen to lactic acid - maintains vaginal flora, important in candidiasis
• Relations: anteriorly - bladder and urethra; posteriorly - pouch of Douglas, rectum; laterally - ureter, levator ani, pelvic fascia

C. Uterus

• Pear-shaped, hollow muscular organ; normal size: 3 x 2 x 1 inches (7.5 x 5 x 2.5 cm), weight ~50-80 g (nulliparous)
• Parts: fundus, body (corpus), isthmus, cervix
• Position: anteverted and anteflexed normally
• Layers: perimetrium (serous), myometrium (3 layers - outer longitudinal, middle oblique/figure-of-8 [important for hemostasis post-delivery - "living ligature"], inner circular), endometrium
• Endometrium: functional layer (stratum functionalis - shed during menses) and basal layer (stratum basalis - regenerates)
• Cervix: internal os, external os, endocervical canal lined by columnar epithelium; ectocervix lined by stratified squamous epithelium; squamocolumnar junction - site of cervical dysplasia/cancer, clinically vital
• Blood supply: uterine artery (branch of internal iliac) - crosses ureter anteriorly and superiorly at the level of cervix ~1.5-2 cm lateral to it ("water under the bridge" - crucial surgical landmark during hysterectomy)

D. Fallopian Tubes

• 10 cm long, 4 parts: interstitial, isthmus, ampulla (site of fertilization), infundibulum (with fimbriae, one attached to ovary - fimbria ovarica)
• Lined by ciliated columnar epithelium + secretory (peg) cells
• Blood supply: tubal branches of uterine and ovarian arteries

E. Ovaries

• Almond-shaped, 3 x 2 x 1 cm, only intraperitoneal organ not covered by peritoneum (covered by germinal epithelium)
• Attached by: mesovarium, infundibulopelvic (suspensory) ligament (carries ovarian vessels), ovarian ligament (to uterus)
• Blood supply: ovarian artery directly from aorta (L2 level) - important distinction from uterine artery

F. Supports of Uterus

• Level I: Cardinal ligaments (transverse cervical) + uterosacral ligaments - main supports, attach to cervix
• Level II: Pubocervical fascia (anterior), rectovaginal fascia (posterior)
• Level III: Perineal body, levator ani
• Round ligaments - maintain anteversion, not true supports for prolapse prevention
• Broad ligament - peritoneal fold, contains uterine vessels, ureter, round ligament, fallopian tube, ovarian ligament

G. Pelvic Floor

• Levator ani (pubococcygeus, iliococcygeus, puborectalis), coccygeus, perineal body - crucial for prolapse and obstetric perineal injury discussions

2. DEVELOPMENT AND DEVELOPMENTAL ANOMALIES

A. Embryological Basis

• Indifferent gonad stage until 6-7 weeks
• Mullerian (paramesonephric) ducts → female internal genitalia develop in the absence of Mullerian Inhibiting Factor (MIF/AMH) from testes
  • Upper 1/3 fused part → uterus, cervix, upper vagina
  • Unfused cranial parts → fallopian tubes
  • Fusion of lower parts + urogenital sinus → lower 2/3 vagina
• Wolffian (mesonephric) ducts regress in females (in absence of testosterone) - remnants: Gartner's duct cysts, epoophoron, paroophoron
• Urogenital sinus → lower vagina, vestibule, urethra, bladder
• External genitalia develop from genital tubercle, urogenital folds, labioscrotal swellings (default female pathway without DHT)

B. Developmental Anomalies (High-Yield for Exams)

1. Agenesis/hypoplasia - Mayer-Rokitansky-Kuster-Hauser (MRKH) syndrome - vaginal/uterine agenesis with normal ovaries and 46XX karyotype
2. Unicornuate uterus - failure of one duct to develop; may have rudimentary horn (communicating/non-communicating)
3. Uterus didelphys - complete failure of fusion → two separate uteri, two cervices, often septate vagina
4. Bicornuate uterus - partial non-fusion of fundus
5. Septate uterus - failure of septal resorption (most common anomaly, worst reproductive outcome, treated hysteroscopically)
6. Arcuate uterus - mild fundal indentation, usually clinically insignificant
7. DES (diethylstilbestrol)-related T-shaped uterus

• Vaginal agenesis (with MRKH)
• Transverse vaginal septum
• Longitudinal vaginal septum (with uterus didelphys)
• Imperforate hymen - presents at puberty with cyclical pain, hematocolpos/hematometra, primary amenorrhoea with normal secondary sexual characters

• Androgen Insensitivity Syndrome (testicular feminization) - 46XY, female phenotype, absent uterus, blind vaginal pouch
• Congenital Adrenal Hyperplasia - virilization of female fetus (46XX with ambiguous genitalia)

3. APPLIED PHYSIOLOGY - HORMONES OF HYPOTHALAMUS AND ANTERIOR PITUITARY

A. Hypothalamic Hormones

• GnRH (Gonadotropin Releasing Hormone) - decapeptide, secreted in pulsatile fashion from arcuate nucleus
  • Pulse frequency determines gonadotropin response: fast pulses favor LH, slow pulses favor FSH
  • Continuous (non-pulsatile) GnRH → downregulation of receptors → suppression (basis of GnRH agonist therapy for endometriosis, fibroids, precocious puberty)
• Other relevant: Dopamine (inhibits prolactin), TRH (can stimulate prolactin)

B. Anterior Pituitary Hormones

• FSH (Follicle Stimulating Hormone): stimulates granulosa cell growth, follicular development, aromatase activity (estrogen synthesis)
• LH (Luteinizing Hormone): triggers ovulation (LH surge), maintains corpus luteum, stimulates theca cell androgen production (two-cell two-gonadotropin theory)
• Both are glycoprotein hormones with common alpha subunit, specific beta subunit (shared with hCG, TSH)

C. Two-Cell, Two-Gonadotropin Theory (frequently asked)

• Theca cells: LH → cholesterol → androgens (androstenedione)
• Granulosa cells: FSH → aromatase converts androgens → estradiol
• This cooperation is essential for estrogen production in the growing follicle

D. HPO Axis Feedback

• Estrogen: negative feedback on FSH (low-mid follicular phase); positive feedback on LH at mid-cycle (triggers LH surge → ovulation) when estrogen is sustained above threshold for >48 hours
• Progesterone: negative feedback on both FSH and LH (luteal phase); enhances the estrogen-induced LH surge in a supportive role
• Inhibin (from granulosa cells): selectively inhibits FSH

4. PUBERTY

Definition

Sequence of Pubertal Events (Classic Order - "THAM" or similar mnemonic, exam favorite)

1. Thelarche (breast budding) - first sign, ~10-11 years
2. Adrenarche/Pubarche (pubic hair growth) - follows thelarche
3. Growth spurt - peak height velocity
4. Menarche - first menstruation, ~12-13 years (average in India ~12.5 years), typically 2-2.5 years after thelarche
5. Axillary hair - usually after pubic hair

Tanner Staging (Sexual Maturity Rating) - must know for exams

• Breast development: B1 (prepubertal) to B5 (mature)
• Pubic hair: P1 to P5

Hormonal Basis

• Gonadarche - reactivation of GnRH pulsatility (dormant since infancy - the "gonadostat" theory)
• Adrenarche - increase in adrenal androgens (DHEA, DHEAS) precedes gonadarche

Precocious Puberty

• Secondary sexual characters before 8 years (girls)
• Central (GnRH-dependent/true): premature activation of HPO axis - idiopathic (most common), CNS lesions
• Peripheral (GnRH-independent/pseudo): ovarian/adrenal tumors, McCune-Albright syndrome, exogenous hormones

Delayed Puberty

• No secondary sexual characters by 13 years, or no menarche by 15-16 years
• Causes: Hypogonadotropic (Kallmann syndrome, constitutional delay) vs Hypergonadotropic (Turner syndrome, gonadal dysgenesis)

5. MENSTRUATION (MENSTRUAL CYCLE PHYSIOLOGY)

Definition

Normal Parameters (memorize exactly - exam staple)

• Cycle length: 21-35 days (average 28 days)
• Duration of flow: 3-5 days (up to 7 days normal)
• Blood loss: 30-80 ml (average ~35 ml)
• First day of bleeding = Day 1 of cycle

Ovarian Cycle

1. Follicular phase (Day 1-14): FSH-driven recruitment of cohort of follicles → selection of dominant follicle → Graafian follicle; rising estrogen
2. Ovulation (~Day 14): LH surge (36 hours before ovulation - basis of ovulation predictor kits) triggers rupture of follicle
3. Luteal phase (Day 14-28, fixed 14 days): corpus luteum formed from ruptured follicle, secretes progesterone (+ estrogen); if no fertilization, corpus luteum regresses (corpus albicans) around day 24-26 → hormone withdrawal → menstruation

Endometrial Cycle (correlates with ovarian cycle)

1. Proliferative/follicular phase: estrogen-driven growth of endometrium (glands straight, stroma proliferates)
2. Secretory/luteal phase: progesterone causes glandular tortuosity, subnuclear vacuolation (early marker of ovulation on biopsy - Day 17), stromal edema, predecidual changes
3. Menstrual phase: hormone withdrawal → vasospasm of spiral arterioles → ischemia → shedding of functional layer; prostaglandins (PGF2α) cause vasoconstriction and myometrial contraction

Cervical Mucus Changes (used in fertility awareness, exam relevant)

• Periovulatory: thin, watery, clear, high spinnbarkeit (stretchability), ferning pattern on microscopy (estrogen effect)
• Luteal phase: thick, scanty, cellular (progesterone effect) - hostile to sperm

Key Hormonal Levels Across Cycle

• Estrogen: rises through follicular phase, peaks just before LH surge, dips at ovulation, secondary rise in luteal phase (from corpus luteum)
• Progesterone: negligible in follicular phase, rises sharply after ovulation, peaks mid-luteal (Day 21), falls before menses if no conception
• LH surge: single most reliable predictor of imminent ovulation

6. DYSMENORRHOEA

Definition

Classification

Primary Dysmenorrhoea (Spasmodic)

• No underlying pelvic pathology
• Onset: within 6 months to 2 years of menarche (once ovulatory cycles established)
• Occurs only in ovulatory cycles
• Pain: colicky/cramping, suprapubic, begins few hours before or with onset of menses, lasts 24-72 hours, may radiate to back and thighs
• Pathophysiology: excess prostaglandin (PGF2α) production from secretory endometrium → increased myometrial contractions, uterine ischemia, sensitization of pain nerve fibers; also increased vasopressin, leukotrienes implicated
• Associated symptoms: nausea, vomiting, diarrhea, fatigue, headache (systemic prostaglandin effects)
• Treatment:
  • NSAIDs (prostaglandin synthetase inhibitors) - first line, e.g., mefenamic acid, ibuprofen - most effective when started 1-2 days before menses
  • Combined oral contraceptive pills - suppress ovulation, thin endometrium, reduce PG production
  • Heat application, exercise
  • Reassurance - tends to improve with age and after childbirth

Secondary Dysmenorrhoea (Congestive)

• Due to underlying pelvic pathology
• Onset: later in life, often after years of pain-free periods
• Pain: dull, congestive, may start days before menses and persist after flow starts/stops, not necessarily colicky
• Causes (exam favorite list):
  • Endometriosis (most common cause)
  • Adenomyosis
  • Pelvic inflammatory disease/chronic pelvic infection
  • Uterine fibroids (especially submucous)
  • Endometrial/cervical polyps
  • Cervical stenosis
  • IUCD use (copper devices)
  • Pelvic congestion syndrome
• Treatment: treat the underlying cause; diagnostic laparoscopy often needed

Key Differentiating Points (frequently tested as a table)