Concours de fin de PACES — Maïeutique / Sages-Femmes (Université d'Antananarivo)

During female gametogenesis, at which specific stage of cell division are primary oocytes arrested during embryonic development until puberty?

• AMetaphase of meiosis I
• BProphase of meiosis I (diplotene stage)
• CMetaphase of meiosis II
• DTelophase of meiosis II

At ovulation, the mature secondary oocyte is released from the dominant follicle arrested in which phase of division, and what triggers the completion of this division?

• AProphase II, completed upon entry into the ampulla of the uterine tube
• BMetaphase I, completed upon expulsion of the follicular fluid
• CMetaphase II, completed upon penetration of a fertilizing spermatozoon
• DAnaphase II, completed upon contact with the endometrial glycocalyx

Which type of epithelium lines the lumen of the Fallopian tube (oviduct) and directly facilitates the transport of the ovum and early embryo?

• ASimple columnar epithelium with ciliated cells and secretory peg cells
• BStratified squamous non-keratinized epithelium
• CSimple cuboidal epithelium with prominent brush border
• DPseudostratified columnar epithelium with stereocilia

Which fibrillar collagen represents the predominant structural component of the uterine cervical extracellular matrix, providing mechanical strength that is remodeled prior to labor?

• AType IV collagen
• BType II collagen
• CType VII collagen
• DType I collagen

Which endocrine event directly triggers the mid-cycle surge of luteinizing hormone (LH) that induces ovulation?

• AA sudden drop in systemic progesterone removing negative feedback on gonadotropes
• BSustained high 17-beta-estradiol concentrations that switch hypothalamic-pituitary feedba…
• CExcessive secretion of inhibin A selectively stimulating hypothalamic GnRH pulse frequency
• DDirect autocrine stimulation of pituitary LH receptors by human chorionic gonadotropin

Which apical intercellular junctional complex establishes the selective paracellular permeability barrier in epithelial sheets?

• AAdherens junctions (zonula adherens)
• BDesmosomes (macula adherens)
• CTight junctions (zonula occludens)
• DGap junctions (nexus)

What is the genetic and cytoplasmic constitution of the first polar body extruded during female oogenesis?

• ADiploid (46 chromosomes) with equal half of the primary oocyte cytoplasm
• BTetraploid (92 chromatids) without nuclear membrane
• CHaploid (23 chromosomes, each with 2 sister chromatids) with minimal cytoplasm
• DHaploid (23 single-chromatid chromosomes) with abundant mitochondrial mass

In the two-cell, two-gonadotropin model of ovarian steroidogenesis, which enzyme is expressed exclusively in granulosa cells to synthesize estrogens?

• A17-alpha-hydroxylase
• BAromatase (CYP19A1)
• C21-hydroxylase
• D11-beta-hydroxylase

Which high-molecular-weight glycosaminoglycan, lacking sulfate groups, is abundant in Wharton's jelly of the umbilical cord and gives it turgidity to prevent vascular compression?

• AHeparan sulfate
• BChondroitin sulfate
• CHyaluronic acid (hyaluronan)
• DKeratan sulfate

Which histological feature is the definitive hallmark of early post-ovulatory secretory transformation in endometrial glands (cycle day 16-17)?

• APseudostratified columnar epithelium with abundant mitotic figures
• BSubnuclear glycogen-rich vacuoles pushing nuclei centrally
• CExtensive stromal granulocyte infiltration with vascular thrombosis
• DComplete breakdown of the functional layer with blood extravasation

What proteinaceous tripartite structure forms between paired homologous chromosomes during the pachytene stage of prophase I to mediate crossing over?

• AKinetochore-microtubule bridge
• BCentrosomal astral complex
• CNuclear lamellar lattice
• DSynaptonemal complex

Which major heterotrimeric glycoprotein of the basal lamina binds directly to alpha-dystroglycan and beta-1 integrins, anchoring the epithelial cytoskeleton to extracellular matrix?

• AElastin
• BLaminin
• COsteocalcin
• DFibrillin-1

In the human testis, which somatic cells form the blood-testis barrier via specialized tight junctions to protect developing haploid spermatocytes from autoimmune destruction?

• AInterstitial Leydig cells
• BSertoli cells
• CPeritubular myoid cells
• DSpermatogonia type B

What is the histological definition of the cervical transformation zone (zone de remaniement), and why is it clinically significant in obstetrical and gynecological practice?

• AThe transition between myometrium and cervical stroma at the internal os
• BThe squamocolumnar junction where endocervical columnar epithelium undergoes physiologica…
• CThe avascular zone of the posterior fornix where culdocentesis is performed
• DThe boundary between the stratified squamous epithelium of the vagina and keratinized vul…

What is the critical endocrine function of syncytiotrophoblast-derived human chorionic gonadotropin (hCG) during the first trimester of pregnancy?

• ADirectly stimulating fetal lung surfactant production by alveolar type II pneumocytes
• BInhibiting maternal prolactin release to prevent premature lactation
• CBinding to maternal LH receptors on the corpus luteum to prevent its regression and maint…
• DStimulating maternal parathyroid hormone synthesis to mobilize skeletal calcium

During anaphase of mitosis versus anaphase I of meiosis, which distinct chromosomal separation occurs?

• AIn mitosis, homologous chromosomes separate; in meiosis I, sister chromatids separate
• BIn both divisions, bivalents separate into four individual chromatids simultaneously
• CIn mitosis, sister chromatids separate; in meiosis I, homologous chromosomes separate whi…
• DMitosis separates non-homologous chromosomes, while meiosis I separates recombinant autos…

Which family of zinc-dependent endopeptidases is responsible for digesting interstitial collagens and proteoglycans during physiological cervical effacement and fetal membrane rupture?

• ACaspases
• BMatrix metalloproteinases (MMPs)
• CSerine transaminases
• DCytochrome P450 monooxygenases

What epigenetic mechanism is established during gametogenesis to ensure monoallelic, parent-of-origin-specific gene expression in the embryo (genomic imprinting)?

• AAlternative splicing of ribosomal RNA transcripts
• BRandom loss of maternal or paternal telomeres
• CReversible acetylation of the mitochondrial circular genome
• DDifferential cytosine DNA methylation at Imprinting Control Regions (ICRs)

Which molecular change during prolonged meiotic arrest is a major contributor to age-related oocyte non-disjunction?

• AGradual loss of chromosome cohesin complexes (REC8/SMC1B) leading to premature sister chr…
• BTotal loss of mitochondrial DNA transcription within the germinal vesicle
• COverexpression of the spindle assembly checkpoint protein MAD2 arresting all cells in tel…
• DEnzymatic hypermethylation of centromeric satellite DNA preventing spindle binding

In obstetrical Doppler ultrasound, what pathophysiological state is indicated by an elevated resistance index (RI) and diastolic notch in the maternal uterine arteries at 24 weeks gestation?

• ADecreased downstream placental resistance due to hypervascular chorioangioma
• BImpaired trophoblastic invasion of the maternal spiral arteries and high downstream vascu…
• CPhysiologically normal late second-trimester low-resistance uteroplacental remodeling
• DComplete occlusion of the maternal abdominal aorta below the renal bifurcation

What acoustic property determines the proportion of an ultrasound beam reflected at an anatomical interface between two different tissues?

• ADifference in radiation exposure dose
• BFrequency attenuation coefficient of air alone
• CMagnetic susceptibility gradient of the tissues
• DDifference in acoustic impedance (Z = density * propagation speed)

In Doppler velocimetry of the umbilical artery, why is the Doppler insonation angle (theta) between the ultrasound beam and blood flow kept as close to 0 degrees as possible?

• ABecause cos(0 deg) = 1, which maximizes the Doppler shift frequency and minimizes velocit…
• BBecause cos(0 deg) = 0, which eliminates acoustic thermal artifacts in the fetus
• CBecause perpendicular orientation (90 deg) provides the highest velocity measurement
• DBecause an angle of 0 degrees prevents sound wave refraction across the abdominal wall

In perinatal epidemiology, how is the Maternal Mortality Ratio (MMR) standardly defined and reported internationally?

• ANumber of maternal deaths per 1,000 total female hospital admissions
• BNumber of maternal deaths per 100,000 live births
• CPercentage of deaths among pregnant women due exclusively to trauma
• DNumber of maternal deaths per 10,000 total surgical procedures

In screening for gestational diabetes, what does the 'sensitivity' of a 50-gram glucose challenge test represent?

• AThe probability that a woman with a positive test result is diagnosed with diabetes on th…
• BThe probability of obtaining a negative test in a patient who is free of gestational diab…
• CThe probability of obtaining a positive screening test in a patient who truly has gestati…
• DThe overall percentage of all pregnant women tested who receive a normal test result

An epidemiological case-control study reports an odds ratio (OR) of 2.8 with a 95% confidence interval of [1.7, 4.6] for nulliparity as a risk factor for preeclampsia. What is the correct interpretation?

• ANulliparity is associated with a statistically significant 2.8-fold increase in odds of p…
• BNulliparity reduces the odds of preeclampsia by 2.8 times in nulliparous women
• CThe association is statistically insignificant because the upper limit of the confidence…
• DThe findings are invalid because odds ratios can only be calculated in randomized clinica…

What neuroendocrine reflex pathway mediates milk ejection (let-down) in response to suckling by a neonate?

• ANipple stimulation triggers cervical sympathetic ganglia to secrete prolactin from the in…
• BNipple tactile stimulation transmits sensory signals via spinal afferents to the hypothal…
• CSucking stimulates vagal afferents to increase gastric gastrin release, stimulating mamma…
• DCutaneous thoracic nerves directly release acetylcholine onto alveolar secretory cells wi…

What cardiovascular hemodynamic changes characterize normal human pregnancy by the end of the second trimester?

• ACardiac output drops by 25% while systemic vascular resistance doubles to maintain renal…
• BStroke volume and plasma volume decrease, resulting in resting sinus bradycardia
• CCardiac output increases by 30-50%, systemic vascular resistance decreases markedly, and…
• DBlood volume expands by only 5%, with systemic arterial blood pressure rising progressive…

Which placental hormone is the primary driver of maternal physiological insulin resistance during the second half of gestation?

• AHuman placental lactogen (hPL / human chorionic somatomammotropin)
• BLuteinizing hormone (LH)
• CHuman chorionic gonadotropin (hCG)
• DEstriol exclusively

According to the Hagen-Poiseuille equation for laminar fluid flow in a rigid tube (R = [8 * eta * L] / [pi * r^4]), how does a 50% reduction in vessel radius (r) affect vascular resistance to blood flow?

• AResistance increases by a factor of 2
• BResistance increases by a factor of 4
• CResistance decreases by 50%
• DResistance increases by a factor of 16

What physiological mechanism defines the Ferguson reflex during the second stage of active labor?

• AMechanical stretching of the lower uterine segment and cervix stimulates ascending neural…
• BDistension of the maternal urinary bladder activates spinal parasympathetic centers to ha…
• CUterine fundal compression stimulates fetal adrenal adrenaline secretion into maternal ve…
• DCompression of the maternal aorta causes reflex splanchnic vasoconstriction and oxytocin…

How is the Perinatal Mortality Rate standardly calculated according to the World Health Organization (WHO)?

• A(All fetal losses from conception to 40 weeks) / (Total pregnancies) * 100
• B(Late fetal deaths >= 28 weeks or >= 1000g + early neonatal deaths within first 7 days of…
• C(Infant deaths from day 28 to 1 year of life) / (Live births) * 1,000
• D(Maternal deaths + neonatal deaths up to 28 days) / (Total live births) * 10,000

Why is physiological dilatation of the maternal urinary tract (hydroureter and hydronephrosis) significantly more pronounced on the right side during pregnancy?

• AThe right kidney produces three times the volume of urine compared to the left kidney und…
• BThe right renal vein is longer and compresses the right ureter retroperitoneally
• CCongenital absence of ureteral peristalsis on the right side occurs universally in pregna…
• DDextrorotation of the enlarging gravid uterus compresses the right ureter against the ili…

Which two standardized biophysical safety indices displayed on medical ultrasound screens must be monitored by practitioners to prevent thermal and mechanical bioeffects in the fetus?

• AThermal Index (TI) and Mechanical Index (MI)
• BComputed Tomography Dose Index (CTDI) and Dose-Length Product (DLP)
• CSpecific Absorption Rate (SAR) and Magnetic Gradient (dB/dt)
• DAcoustic Radiation Force (ARF) and Hounsfield Number (HU)

In a clinical trial assessing the effectiveness of prophylactic tranexamic acid versus placebo in preventing postpartum hemorrhage (> 500 mL: yes/no), which statistical test is most appropriate to compare the event rates between the two independent treatment arms?

• APaired Student's t-test
• BPearson correlation coefficient
• CPearson's Chi-squared test (or Fisher's exact test)
• DLinear regression analysis

Which fundamental anatomical plane divides the human body into right and left halves?

• ASagittal (median) plane
• BCoronal (frontal) plane
• CTransverse (horizontal) plane
• DOblique plane

What fundamental pharmacokinetic parameter describes the volume of plasma completely cleared of a drug per unit of time by all eliminating organs?

• AVolume of distribution (Vd)
• BTotal body clearance (CL)
• CElimination half-life (t1/2)
• DBioavailability (F)

Which combination of physicochemical properties most strongly favors the rapid transplacental passage of a drug by simple passive diffusion?

• AHigh molecular weight (> 2000 Da), high hydrophilicity, and extensive binding to maternal…
• BStrong positive electrical charge and large molecular hydrodynamic radius
• CLow molecular weight (< 500 Da), high lipophilicity, low plasma protein binding, and un-i…
• DHigh degree of ionization at physiological pH 7.4

Which spinal cord segments give rise to the pudendal nerve, the principal somatic nerve supplying the perineum and external genitalia?

• AAnterior rami of L1, L2, and L3
• BPosterior rami of L4, L5, and S1
• CAnterior rami of S2, S3, and S4
• DAnterior rami of T10, T11, and T12

Which mechanism mediates the active transport of maternal immunoglobulin G (IgG) antibodies across the placental syncytiotrophoblast to confer passive immunity to the fetus?

• ASimple passive diffusion across paracellular water channels
• BReceptor-mediated transcytosis via the neonatal Fc receptor (FcRn)
• CFacilitated diffusion through GLUT1 hexose transporters
• DVoltage-gated calcium channel co-transport

In the female pelvis, what is the critical anatomical relationship between the ureter and the uterine artery near the level of the supravaginal cervix?

• AThe ureter passes directly anterior and superior to the uterine artery
• BThe ureter passes inferior and posterior to the uterine artery ('water under the bridge')
• CThe ureter penetrates the lumen of the uterine artery to form an arteriovenous fistula
• DThe ureter runs medial to the internal os within the cervical canal

Why are nonsteroidal anti-inflammatory drugs (NSAIDs) such as indomethacin and ibuprofen contraindicated in the third trimester of pregnancy?

• AThey directly induce fetal cleft palate and spina bifida when administered after 32 weeks
• BThey cause irreversible maternal adrenal suppression and Addisonian crisis
• CThey inhibit fetal prostaglandin synthesis, risking premature constriction of the ductus…
• DThey block maternal liver production of fibrinogen, causing disseminated intravascular co…

Which ATP-binding cassette (ABC) efflux transporter located on the apical (maternal-facing) membrane of the syncytiotrophoblast actively extrudes xenobiotics back into the maternal circulation?

• ACFTR (ABCC7)
• BP-glycoprotein (P-gp / ABCB1 / MDR1)
• CSGLT2 (SLC5A2)
• DAquaporin-1

What anatomical structure forms the superomedial boundary of the ischioanal (ischiorectal) fossa?

• AThe obturator internus muscle and obturator fascia
• BThe sacrotuberous ligament and gluteus maximus
• CThe inferior fascia of the pelvic diaphragm (levator ani and coccygeus)
• DThe perineal membrane (urogenital diaphragm)

In obstetrical pelvimetry, what pelvic movement is defined as nutation of the sacrum?

• AForward and downward rotation of the sacral base around the horizontal axis, swinging the…
• BBackward and upward tilting of the sacral base, widening the pelvic inlet while narrowing…
• CLateral sliding of the iliac bones without changing inlet or outlet dimensions
• DTorsion of the coccyx around the sacrococcygeal joint during leg abduction

Which two pelvic ligaments convert the greater and lesser sciatic notches of the hip bone into the greater and lesser sciatic foramina?

• AInguinal ligament and pectineal (Cooper's) ligament
• BIliofemoral and pubofemoral ligaments
• CSacrotuberous and sacrospinous ligaments
• DBroad ligament and cardinal ligament

Which anatomical portion of the Fallopian tube has the widest lumen and is the physiological site where fertilization normally takes place?

• AInterstitial (uterine) part
• BIsthmus
• CInfundibulum
• DAmpulla

What anatomical landmark on the internal surface of the ilium defines the lateral boundary of the pelvic inlet (détroit supérieur)?

• ACrista iliaca
• BPectineal line alone
• CPecten pubis
• DArcuate line (linea arcuata)

Under the influence of gestational hormones (relaxin and progesterone), what structural change occurs at the pubic symphysis to facilitate pelvic compliance during labor?

• AComplete synostosis and ossification of the pubic bones
• BAvascular necrosis of the superior pubic rami
• CSoftening and physiological widening of the interpubic fibrocartilage disc (up to 5-9 mm)
• DComplete spontaneous rupture of the posterior pubic ligament