O&G Basics Flashcards
Salpingitis
infection of fallopian tubes
Accelerations
Episodes of heart rate above baseline for at least 15 bpm and lasting at least 15sec
Decelerations
Episodic changes in fetal heart rate below baseline
Early: mirror image of contractions (caused by head compression, benign)
Variable: abrupt jagged dips below baseline (most common, caused by cord compression, observe)
Late: offset, following uterine contractions (suggest fetal hypoxia, if recurrent (i.e. >50% contractions), then can indicate fetal acidemia)
Late + decreased variability –> strongly suggestive of fetal acidemia
Multiparous
More than one pregnancy
Normal labour
Defined by cervix dilation rate, not contraction patter
Active phase of labour
Part of labour where dilation occurs more rapidly. Usually cervix dilated >4cm.
Dilation rate during this phase: >1.2cm/hr or >1.5cm/hr for 1+ previous deliveries
Labour
Cervical change accompanied by regular uterine contractions
Latent phase of labour
Initial part - Cervix mainly effaces (thins) rather than dilates (usually <4cm dilation)
Protraction of the active phase
Cervical dilation less than expected (i.e. <1.2 or 1.5cm/hr)
Arrest of the active phase
No progress in active phase for 2hrs
Stages of labour
- Onset to complete dilation (latent and active phases)
- Complete cervical dilation to delivery of infant
- Delivery of infant to delivery of placenta
Fetal heart rate
Normal: 110-160 bpm
Normal labour parameters (nulliparous)
Latent (cervix <4cm): <18-20hrs
Active (cervix >4cm): >1.2cm/hr
2nd stage (end dilation to delivery of infant): <2hrs (or <3hrs if epidural given)
3rd stage (infant –> placenta): <30mins
Normal labour parameters (>1 births)
Latent (cervix <4cm): <14hrs
Active (cervix >4cm): >1.5cm/hr
2nd stage (end dilation to delivery of infant): <1hr (or <2hrs if epidural given)
3rd stage (infant –> placenta): <30mins
3Ps
Power
Passenger
Pelvis
Prolongation of the latent phase of labour
Latent phase exceeds 18-20hrs (or 14hrs for 1+ previous pregnancy)
Cephalopelvic disproportion
Pelvis too small for the fetus (either abnormal pelvis or excessively large baby)
Adequate uterine contractions
Contractions every 2-3minutes, firm on palpation, lasting for at least 40-60seconds
>200 Montevideo units (200 mmHg total above baseline when contractions added in a 10min window)
Arrest of descent
Baby head does not engage the pelvis correctly
Located above the pelvic inlet, i.e. at plant of ischial spines
Bloody show
Dark vaginal blood mixed with mucous
Represents loss of the cervical mucous plug
Sign of impending labour
Sticky mucous differentiates from antepartum bleeding
Anthropoid pelvis
Pelvis with AP diameter > transverse diameter
Prominent ischial spines
Narrow anterior segment
Predisposes to fetal occiput posterior position
Placenta previa
Placenta lying close to or over the cervical opening
Placental abruption
Placenta detaches from the wall of the uterus early
Decidualisation
Preparation of the endometrium
Stromal cells undergo decidual cellr eaction: accumulation of glycogen and lipid in cytoplasm and cells become larger and more round
Stages of implantation
Hatching: shedding of zona pellucida
Apposition: first cell-cell contact, close apposition of trophoblast and luminal epithelium
Attachment/adhesion: cell contacts much closer, interdigitation between apical microvilli or uterine epithelium and apical memrbane of trophoblast
Invasion: trophoblast erodes the uterine surface epithelium
Syncytiotrophoblast
Outer layer of placental villi
Cytotrophoblast
Inner layer to syncytiotrophoblast. External to blastocyst. Trophoblastic stem cell.
“Layer of langerhans”
Where and when does implantation occur?
Ampulla of fallopian tube
Day 7 post-fertilisation
What is a morula and when does it form?
Cleaved zygote, becomes blastocyst on day 5
Day 3 post-fertiliation
When and where is hCG produced?
What is hCG function?
From approx day 7 post-conception
Syncytiotrophoblast
Prevents luteolysis/evolution of corpus luteum to corpus albicans
What does corpus luteum secrete? When does the placenta take over that compound’s production?
Progesterone
Placenta starts at 6wks, takes over at 8wks
What causes hCG to increase?
Pregnancy
Ectopic
Hydatiform mole
What are the functions of progesterone in pregnancy?
Maternal recognition of pregnancy, implanation and decidualisation
Maintains uterine and placental integrity and synthetic capacity
Inhibits uterine activity
Increases appetite, fat deposition, mammary development, modifies immune response
Normal levels: 10-35ng/mL
If levels are too low (<5-10ng/mL) –> 80-100% abortion rate
What is the bioavailability of estrogens?
Oestadiol: 100%
Oestriol: 10%
Oestrone: 1%
Parturition
Onset of birth
Tocolytic
drugs that relax smooth muscles and interfere with uterine contractions
Examples: Calcium channel blockers, Oxytocin R antagonists, COX inhibitors, PGF2 antagonists, B-adrenoceptor agonists
Preterm birth
<37 weeks
5-10% births
30% associated with infection
50% idiopathic
Where does ACTH act in adrenals? and what does it produce?
Zona fasciculata –> glucocorticoids
(Glomerulosa –> mineralocorticoids
Reticularis –> sex steroids)
Why does cortisol increase in pregnancy?
Placenta produces CRH in cytotrophoblast and syncytiotrophoblast which stimulates cortisol synthesis
What is the Ferguson (neuroendocrine) reflex?
Self-sustaining cycle of uterine contractions
Positive feedback pathway: pressure on cervical/vaginal walls –> oxytocin release –> stimulates strong waves of contraction through myometrium –> baby head puts further pressure on cervix –> further oxytocin release and contractions
What are the Stages of parturition and associated hormones? (hint: not phases of labour)
Quiescence (P)
Activation (E decr, P, CRH, PGE, uterine stretch)
Stimulation (oxytocin and PGF)
Expulsion (oxytocin)
When is the placenta thickness fully developed?
4 months
No new villi or lobules after 10-12weeks
Do get circumferential growth after this time.
Area:Volume increases from 28w to term.
What are the functions of the placenta?
Diffusion: O2, CO2, steroids, H2O
Active transport: glucose, AA
Transcytosis: materal Abs
Endocrine: progesterone production from ~6wks, estrogen, hCG, lactogen
Placenta Accreta
placenta extends into the myometrium