Day 14 OBGYN Flashcards
Obstetric History (6)
- pain
- bleeding (when, how much, have you had this before? a scan?)
•baby movements (from 26w)
•vaginal loss/discharge
•headaches, visual disturbances, generalised swelling (esp high BP)
•lower leg pain/swelling (esp high risk VTE)
Obstetric Family + Social History
(5)
Are there any twins in the family?
Do any medical conditions run in the family?
Where do you work?
Do you drink alcohol or smoke?
Do you feel safe and supported at home?
What changes occur towards the end of pregnancy?
(6)
Myometrium
- Stretching increases muscle excitability & contractility.
- Gap junctions are formed under the influence of oestrogen enabling transmission of electrochemical signals from cell to cell and a synchronized contraction wave
Cervix
- Decrease in collagen and an increase in water content enabling the cervix to soften, efface and dilate (ripen)
Hormones
- Increased concentrations of oestrogen stimulate the production and release of prostaglandins.
- Also promotes the formation of oxytocin receptors so that the myometrium is more sensitive to oxytocin.
- Prostaglandins and oxytocin are strong myometrial stimulants and play a major role in cervical ripening
What are the two phases of normal labour?
Latent phase
a period of time, not necessarily continuous, when there are painful contractions, and some cervical change, including cervical effacement (stretches) and dilatation up to 4cm
Established labour
regular painful contractions, and progressive cervical dilatation beyond 4cm
Stages of established labour (3)
1st From onset of established labour (4cm) to full dilatation of the cervix (10cm)
2nd From full dilatation to birth of the baby
3rd From birth of the baby to expulsion of the placenta and membranes
What is Mobilising?
Walking and upright positions in the 1st stage of labour to reduce the duration of labour and the risk of caesarean birth, the need for epidural.
What is Delayed cord clamping?
Delayed cord clamping and waiting for the cord to stop pulsating reduces the risk of anaemia in babies
Methods of Monitoring of mother
(4)
Contractions
Vaginal examinations
Vaginal loss
Vital signs
What is the purpose of monitoring the foetus?
The monitoring of babies in labour aims to identify hypoxia before it is sufficient to lead to damaging acidosis and long-term neurological adverse outcome for the baby
What are the methods of Monitoring a fetus (2)
Low risk women
Intermittent auscultation of the fetal heart using a Doppler ultrasound or Pinard stethoscope
High risk women
Continuous fetal monitoring using a cardiotocograph (CTG)
What is a Pinard stethoscope
- A Pinard horn is a type of stethoscope used to listen to the heart rate of a fetus during pregnancy.
- It is a hollow horn, often made of wood or metal
The Pinard horn was invented by Dr. Adolphe Pinard, a French obstetrician, during the 19th century.
What are the stages of the mechanism of labour
(6)
- Descent and Flexion
- Internal rotation
- Crowning
- Extension
- Restitution (external rotation of head)
- Delivery of anterior and then posterior shoulder
What are the narrowest foetal skull diameters?
What occurs during restitution?
What is the purpose of Manual perineum protection?
prevention of Oasi (Obstetric anal sphinter injury)
What are the indications for induction of labour?
(6)
What is a bishop score?
If your Bishop score is high, it means that there’s a greater chance that an induction will be successful for you. If your score is 8 or above, it’s a good indication that spontaneous labor would start soon.
What are the relative/absolute contraindications to induction of labour?
What are the methods of induction of labour in order of severity?
(4)
“Stretch and Sweep”
↓
Administration of vaginal prostaglandins (with normal CTG)
↓
Artificial Rupture of Membranes (ARM)
↓
IV infusion of Oxytocin (with normal CTG)
Which method of induction is used if a patient has an abnormal CTG?
artificial membrane rupture
ARM
What is the first stage of induction of labour?
“Stretch and Sweep”
360 degrees sweep of examiner’s finger between internal os and foetal membranes, separating them, promoting natural secretion of prostaglandins
What is used in the second line of labour induction?
Propess - a pessary on a string, placed in the posterior fornix which slow-releases over 24 hrs to promote cervical ripening. Can be removed in circumstances of uterine hyperstimulation (shown on CTG)
Prostin - a gel inserted into the posterior fornix and allowed to work over 6 hours. Not recommended for patients with previous caesarean section as cannot be removed in cases of hyperstimulation
What is the third line of labour induction?
ARM (amniotic rupture)
- Usually with a plastic amniohook but occasionally using a foetal scalp electrode
- also encourages natural production of prostaglandins and oxytocin
What is the fourth line option in the induction of labour?
Intravenous infusion of oxytocin
- timing of assessment for oxytocin depends on obstetric history, contractions present and maternal preference
- started at a low dose and titrated to contractions half-hourly
- Requires continuous electronic foetal monitoring (EFM
Methods of inducing labour-cervical ripening (3)
Propess: Dinoprostone(PGE2)10mg released over 24 hours
Prostin gel: Dinoprostone(PGE2) available in 1mg and 2mg doses released over 6 hours
Prostin tablet :Dinoprostone HSE (PGE2) 3mg, released over 6 hours
When is the first trimester?
First Trimester; 0 – 12 weeks
When is the second trimester?
Second Trimester; 12 – 28 weeks
When is the third trimester?
Third Trimester; 28 – 40 weeks
What is the difference between stillbirth and miscarriage?
Miscarriage; Loss of intrauterine pregnancy before 24 weeks
Stillbirth; Loss of intrauterine pregnancy after 24 weeks
Which vaginal changes are seen in pregnancy?
(4)
- Softening of the cervix (Goodell’s sign); 4 -6 weeks
- Bluish discolouration of the cervix and vagina due to engorgement of pelvic vasculature (Chadwick sign); 6 weeks
- Uterine enlargement
- Softening of the isthmus (Hegar’sign); 6 -8 weeks
What investigations can be performed at different stages of pregnancy?
HCG;
+ve in serum ~ 9 days post conception
+ve in urine ~ 28 days after LMP
Transvaginal USS;
5 weeks; gestational sac visible
6 weeks; fetalpoleseen
7-8 weeks; fetal heart beat visible
Transabdominal USS;
6-8 weeks IU pregnancy visible
How is Maternal cardiology different?
Increased CO, HR and blood volume (hyperdynamic circulation)
Decreased BP (especially diastolic, maximal in 2nd trimester) due to decreased peripheral vascular resistance (PVR)
Enlarging uterus compresses on IVC and pelvic veins causing Risk of hypotension (by decreasing venous return), varicose veins, haemorrhoids, leg oedema (due to increased venous pressure)
How is maternal haematology different?
Increased leukocyte count
- 5,000 to 12,000/uL in pregnancy
- Up to 25,000/uL in Labour/postpartum
- Often have improvement in autoimmune conditions
Gestational thrombocytopenia
- Occurs in 8% of gestations, possible due to accelerated platelet consumption
- Platelet count should normalize 2-12 weeks post delivery
How does the Respiratory System change?
Increased O2 consumption by 20%
Increased sensitivity to CO2 (progesterone effect on respiratory centre) àHyperventilation + respiratory alkalosis compensated by increased renal excretion of serum bicarbonate
Minute ventilation increase by 50%
Decreased TLC, FRC, RV
VC unchanged
TV increase by 33-50%
Alveolar ventilation increase by 65%
How is the maternal Gastrointestinal System different?
Increased GORD; decreased sphincter tone, delayed gastric emptying, increased intraabdominal pressure
Increased stasis in gallbaladder
Decreased GI motility and constipation
Upward displacement of the appendix (appendicitis may have atypical presentation)
Haemorrhoids caused by constipation and elevated venous pressure
What are the maternal changes to the genitourinary system?
(5)
Increased GFR by 50% (therefore decreased BUN and serum creatinine) but no change to UO due to increased tubular reabsorption
Glycosuria; with increased GFR glucose reabsorption can be surpassed.
Increased urinary frequency
Physiologic dilatation of ureters and renal pelvis (R>L) due to progesterone-induced smooth muscle relaxation + uterine enlargement
Increased incidence of UTI and pyelonephritis
Which maternal organs produce progesterone?
Produced by corpus luteum first 7 weeks, then placenta takes over
Maintains the endometrium
Absolutely necessary for pregnancy to continue
Where is HCG produced?
What is it formed from?
What is its function?
Produced by placental trophoblastic cells
Peptide hormone composed of 2 subunits; alpha(common to all glycoproteins) and beta(specific to HCG)
Maintains the corpus luteum
How do HCG levels change during pregnancy?
Plasma levels double every 1 -2 days, peak at 8-10 weeks and then falls to a plateau until delivery
What happens when HCG levels fall?
Levels below expected by dates àectopic, miscarriage or wrong dates
What are high HCG levels indicative of?
(4)
multiple gestation
molar pregnancy
trisomy 21
wrong dates
How does the maternal thyroid change?
(2)
Moderate enlargement and increased basal metabolic rate
Increased Total thyroxine and TBG
Free thyroxine index and TSH levels are normal
How do maternal adrenal glands change
Maternal cortisol rises throughout pregnancy (total and free)
Where is maternal prolactin produced?
What is its function?
Prolactin
Produced by the pituitary in response to increased oestrogen in pregnancy
Stimulates lactation
Where is Relaxin produced?
What is the function of Relaxin?
(4)
Produced by corpus luteum/ovary
Relaxes symphysis pubis and other pelvic joints
Helps soften and dilated the cervix
Inhibits uterine contraction
How does maternal skin change?
Striae gravidarum (atrophic linear scars- connective tissue changes)
How does the maternal neurological system change?
Increased incidence of carpal tunnel and Bell’s palsy
Which pigmentation changes are associated with motherhood?
Increased around areola and perineum
Linea nigra (midline abdominal pigmentation)
Spider angiomas
Palmar erythema
Causes of Antepartum Haemorrhage
bleeding of the genital tract, occurring from 20 weeks of gestation until birth.
complicates between 2 and 5% of all pregnancies
Placenta Abruption
Placenta previa
Uterine rupture
Vasa previa
Placenta acretta
Cervical lesion; ectropion, polyp
Others; infection, trauma, malignancy
What is Placenta Abruption?
(2)
premature separation of the normal-sited placenta from the uterus
Bleeding is often concealed, therefore vigilance is essential
Causes of placental abruption
(3)
acute inflammation and chronic vascular dysfunction
Inflammatory process mediated by cytokines
Cytokines produce matrix metalloproteinases in trophoblast destruction of extracellular matrices and disruption of cell–cell interactionsàAbruption
Investigations for Placenta Abruption
(3)
Investigation
FBC, U&Es, LFT,G&S (X-match 4 -6 units) Check for HELLP syndrome
Coag; Prothrombin time/activated partial thromboplastin time may be prolonged in the case of severe placental abruption indicating coagulopathy.
Fibrinogen concentration
Pregnancy is associated with hyperfibrinogenemia
modestly depressed fibrinogen levels may represent significant coagulopathy
A fibrinogen level of less than 200 mg/dl (2 g/l) suggests that the patient has a severe abruption
Kleihauer–Betke test;
detect fetal bld cells in maternal circulation. Helps with correct dose of Anti d (Rh neg mothers)
Diagnosis of Placenta Abruption
Imaging
Ultrasound
Screening for risk of abruption
Uterine artery dopplers for patients at risk for SGA fetuses
Environmental causes of Placenta Abruption
(8)
- Folic acid deficiency (essential for development of placenta vascular bed)
- Cocaine (can cause vasoconstriction and disrupt placenta adherence)
- Smoking
- PIH/PET (causes ishcaemic placenta disease)
- Thrombophilia
- Premature rupture of membranes (presence of inflammation + infection)
- Multiple pregnancy (sudden uterus decompression after delivery of first twin)
- Trauma
Treatment (3) of placenta praevia
Management
Give steroids between 34+0 and 35+6 weeks of gestation for a low‐lying placenta or placenta praevia
Method of delivery
C/S is the usual method of delivery if the leading placental edge is within 20 mm from the internal os in third trimester.
For minor previa, vaginal delivery can be attempted if fetal head below leading edge of placenta
Method of delivery
If uncomplicated à delivery should be considered between 36+0 and 37+0 weeks of gestation
What is Placenta Accreta (2)
Abnormally invasive placentation that can be categorised by depth of invasion – placenta accreta, increta and percreta.
decidua basalis, a layer that prevents invasion of the trophoblast cells deeper into the myometrium, can be damaged due to previous surgery à invasion to myometrium
Define Placenta accreta
Define Placenta increta
Define Placenta percreta
Placenta accreta
chorionic villi attach directly to the myometrium in the absence of decidua.
Placenta increta
placental villi invade deeper into the myometrium, but do not extend to the outermost layers of the uterus.
Placenta percreta
chorionic villi penetrate through the myometrium up to the serosa.
What is Vasa Previa
Why is it a problem
fetal vessels crossing the internal cervical os through the free placental membranes
vasa praevia is likely to rupture during active labour or iatrogenically with artificial rupture of membranes
Can lead to fetal haemorrhage, exsanguination and death
Vasa Previa
Risk factors?
Disgnosis?
Risk factors?
- IVF
Diagnosis?
- vasa praevia is occasionally detected intrapartum during vaginal examination when vessels are felt in the membrane
- USS
- Vasa praevia diagnosed in the second trimester resolves in approximately 20% of patients prior to delivery, therefore a repeat scan at 32 weeks is warranted.
How is Vasa Previa treated?
prophylactic hospitalisation from 30–32 weeks should be considered
Elective delivery via caesarean at 34–36 weeks with a course of antenatal steroids from 32 weeks is reasonable in an asymptomatic patient.
If there is bleeding from a known or suspected vasa praevia, especially with suspected fetal compromise, delivery should be immediate and usually by caesarean section category 1
What is Uterine Rupture?
What is the biggest risk factor?
- full-thickness loss of integrity of the uterine wall and visceral peritoneum.
- Most cases of uterine rupture occur during labour following previous caesarean section or other uterine surgery, such as myomectomy
Risk Factors for uterine rupture
(8)
- High parity
- Previous uterine surgery
- induction of labour
- Hyperstimulation
- Malpresentation
- Macrosomia
- Uterine abnormalities
- Trauma; RTA
Signs and Symptoms of Uterine Rupture
(5)
- non-specific and conventional signs may be absent
- women may compensate well for massive concealed haemorrhage.
- abdominal pain between uterine contractions
- cessation of uterine activity – particularly in second stage of labour – haematuria and blood-stained liquor.
- CTG abnormalities are associated with 55–87% of uterine ruptures.
How is Uterine Rupture treated?
- stabilisation of the mother and emergency delivery are crucial
- Emergency C/S
