Obstetrics and Gynecology Flashcards
What is the recommended folic acid regimen for women planning for pregnancy?
Prepregnancy planning
Low risk: 0.5mg daily
At risk: 5mg daily
At risk includes women with a past or family history of neural tube defect, anticonvulsant drugs, or prepregancy diabetes.
How can gestational age be measured?
From the 1st day of last normal menstrual period (LMNP)
Ultrasound measuring the crown-rump length (CRL) is the most accurate from 6-12 weeks gestation.
How is EDC usually calculated? Under what condition?
LMNP + 40 weeks
This assumes regular period every 28 days
What investigations should be performed in early pregnancy
- FBE: assess for thalassemia and anemia
- Blood group and screen: screen for Rh isoimmunization
- CST: assess for any cervical pathology
- Urine MCS: assess for asymptomatic bacteremia
- Serology: screen for syphilis, rubella, varicella, Hep B/C, HIV, etc.
- Ultrasound scan:
- 12 weeks: screen for fetal aneuploidy, identify multiple pregnancy
- 19 weeks: screen structural defects, placental localisation
Typical antenatal visit schedule
- Initial visit: 8-10w
- Follow-up: 12-14w
- Every 4 weeks: 20-28w
- Every 2 weeks: 28-36w
- Every week: 36w - delivery
What do you do if a pregant mother has no immunity to varicella, rubella? Or infected with syphilis, Hep B, C, HIV?
Live vaccines (e.g. rubella, varicella) can’t be given to mothers. Treat mothers in puerperineum.
Syphilis can be treated during pregnancy, with penicillin with aims to cure.
Steps could be taken to reduce vertical transmission for Hep B/C and HIV, such as administering antiviral medications and avoid fetal contact with mother’s blood.
What vaccinations should be taken during pregnancy? At what weeks?
Pertussis (Tdap): between 20-32 weeks
Influenza and COVID-19: anytime
When can fetal movement usually be felt? How can a mother assess them?
> 17w in multigravida, >19w in first pregnancy
- Check with meals: movements usually happen 30min-1h after meals
- Count to 10: if less than 10 movements per day, contact hospital
- Usual pattern: subjective, if baby much quieter than usual
What should be assessed during a typical antenatal visit in an uncomplicated pregnancy?
- Maternal weight
- Blood pressure
- Abdominal examination: fundal height, fetal lie, presentation, station, etc
- Measure fetal heart rate
- Urinalysis: proteinuria and glycosuria
Preeclampsia may present with proteinuria before the onset of hypertension.
Further antenatal testing after the first trimester
- Glucose tolerance test: at 28 weeks
- Repeat blood group antibody screen (for Rh- patients): at 28 weeks
- GBS swab: at 36 weeks
Prevention of red cell isoimmunisation (D antigen)
Anti-D immunoglobulin is given to Rh negative mothers to prevent any recognition of fetal antigen D and the production of anti-D antibodies by the mother’s immune system (which could cause fetal hemolysis in future pregnancies)
**Usually given in 3rd trimester (28 and 34 weeks). **
Could also be given when there is:
1. Bleeding in pregnancy (msicarriage, abortion, antepartum hemorrhage)
2. Trauma (amniocentesis, CVS, MVA, etc)
3. Pueperineum (after testing neonate for Rh status)
What management can be done if a mother tested positive for GBS?
Intrapartum IV antibiotics (usually penicillin)
Cephazolin can be used instead for cases of penicillin allergy.
Weight gain targets during pregnancy
Conditions at increased risk with higher maternal BMI
HTN in pregnancy, GDM, C-section, perinatal mortality, preterm birth
Define hyperemesis gravidarum
severe, persistent nausea and vomiting leading to a loss of >5% of pre-pregnancy weight and ketonuria with no other identifiable cause
Medications to treat N/V in early pregnancy
- Vitamin B6 (Pyridoxine): first line
- Consider adding doxylamine or metoclopramide
- Last resort: corticosteroids
Treatment of hyperemesis gravidarum
-
Acute Management (for moderate-severe cases)
- Hospitalization
- Intravenous Fluids: correct dehydration and maintain electrolyte balance.
-
Pharmacological Interventions:
-
Antiemetic Medications:
- Vitamin B6 (Pyridoxine): first line if tolerates oral intake
- For severe cases: IV metoclopramide or ondansetron
- Vitamin B1 replacement
-
Antiemetic Medications:
- Other
- Referral to dietician
- Consider enteral feeding for severe cases
- Discharge as patient tolerates light diet and fluids
Differential diagnoses for bleeding in early pregnancy
- Not pregnant and normal menstrual period
- Intrauterine pregnancy: viable or non-viable
- Ectopic pregnancy
- Incidental: cervical polyps/cancer, other genitourinary causes
Management for early bleeding for early pregnancy
- Perform TVUS
- Confirmed intrauterine pregnancy: assess fetal viability
- Confirmed ectopic pregnancy: manage accordingly
- Unlocalised: measure b-hCG levels:
- If<1500 IU/L: early intrauterine vs ectopic
- Consider admission and repeat b-hCG levels in 48h
- > 1500 IU/L: ectopic pregnancy
- Consult senior obstetrician
- If<1500 IU/L: early intrauterine vs ectopic
Clinical features of a miscarriage.
- Vaginal bleeding
- Abdominal pain: Cramping or abdominal pain
- Tissue passing: In some cases, women may pass clots or tissue from the vagina.
- Loss of pregnancy symptoms: If miscarriage occurs in early pregnancy, there may be a sudden loss of pregnancy symptoms, such as breast tenderness or morning sickness.
Classification of miscarriage
Management of miscarriage based on types
- Threatened miscarriage:
- Expectant management
- Avoid strenous physical activity
- Repeat US in one week
- Complete miscarriage: no intervention needed
- Inevitable, incomplete, missed miscarriage
- Expectant management
- Pharmacological: misoprostol - cervical ripening for expulsion of conception products
- Surgical: dilation and curettage
Anti-D immunoglobulin for Rh(D)-negative patients
Diagnosis of miscarriage
- TVUS: Findings consistent with a spontaneous abortion may include:
- Absence of fetal cardiac activity
- Gestational sac ≥ 25 mm without an embryo
- Previously visualized IUP not observed (empty uterus)
- Downtrending b-hCG levels
Three possible outcomes of tubal pregnancy
- Tubal abortion: accompanied by colicky pain and bleeding; conceptus is extruded out the fimbrial end
- Tubal rupture: associated with severe intraperitoneal bleed and acute abdo pain
- Missed tubal abortion: embryo dies and absorbed
Diagnosis of ectopic pregnancy
- TVUS visualisation
- If not visualised through US: b-hCG levels>1500 indicates EP
Management of ectopic pregnancy
- Acute intervention:
- IV access
- Pain relief
- Fluid replacement
- Blood group typing and antibody screen
- Serial b-hCG monitoring
- Medical management:
- IM Methotrexate
- Assess renal and liver function - before and after giving MTX
- IM Methotrexate
- Surgical management (laparoscopic vs laparostomy)
- Salphingectomy
- Salphigostomy
Clinical features of ectopic pregnancy
- Vaginal bleeding
- Abdominal pain or cramping
- PV discharge
- Enlarged or tender uterus
- Pregnancy symptoms (N/V, amenorrhea, etc)
Management of ruptured ectopic pregnancy
- Acute stabilization
- IV access and flui
Screening and diagnostic tests for aneuploidy
- Screening tests
- Combined first trimester screening: 11-13 weeks
- Nuchal translucency
- Maternal serum tests: b-hCG, AFP
- NIPS (non-invasive prenatal screening) using cell-free DNA: from 10 weeks
- 2nd trimester:
- Maternal serum tests: AFP, oestriol, inhibin
- Morphology ultrasound
- Combined first trimester screening: 11-13 weeks
- Diagnostic test
- Chorionic villous sampling: from 11 weeks (higher risk)
- Amniocentesis: from 15 weeks
Advantage and disadvantage of CVS and amniocentesis
- CVS: Offers earlier results, but a slightly higher risk of miscarriage.
- Amniocentesis: Lower risk of miscarriage, but results take longer to obtain
Define antepartum hemorrhage
Vaginal bleed >20mL occuring after 20 weeks gestation
Initial management of antepartum hemorrhage
- IV access and fluid replacement therapy
- Blood group typing and antibody screen
- Monitor maternal and fetal vitals
- CTG and ultrasound for fetal wellbeing
Possible causes of APH
Placenta previa, vasa previa, placental abruption, cervical polyp, uterine rupture
Can a digital vaginal examination be performed in APH assessment?
Only after placenta has been localised and placenta previa has been ruled out
Define placenta previa
Occurs when the placental location in the lower uterine segment either partially or completely occludes internal os
Clinical features of placenta previa
- painless vaginal bleeding usually happens in the 2nd-3rd trimester
- soft, non-tender uterus
- in severe cases, signs of shock
Diagnosis of placenta previa
TVUS - usually identified at the 19-20 weeks scan
Follow-up US at 32-34 weeks to confirm persistence of placenta previa, and exclude vasa previa and placenta accreta
Management of placenta previa
- Asymptomatic:
- avoid sexual intercourse
- repeat US at 32-34 weeks
- if persistent - consider planned C-section at 37-38 weeks
- Symptomatic
- Initial management for APH
- > 37 weeks: IOL
- <37 weeks: preterm delivery or expectant management
- Tocolytics to postpone labour if <34w
- MgSO4 for neuroprotection if <30w
- Corticosteroid for lung maturity if <34w and not imminent
Define vasa previa
Presence of fetal vessels trasnversing over the internal os
Clinical features of vasa previa
- painless vaginal bleed
- usually occurs during labour, often with the rupture of membranes
- fetal distress and still birth
Diagnosis and management of vasa previa
Diagnosed antenatally with US or incidentally during ROM
Management:
- Early detection => planning for C-section delivery at around 36-37 weeks
- If preterm delivery expected, consider corticosteroids for fetal lung maturity
- In cases of incidental finding during labour:
- Emergency C-section delivery
- Blood group and screen - blood transfusion as needed
Define placental abruption
Partial or complete detachment of placenta from placental/decidual interface prior to labour
Risk factors for placental abruption
- HTN in pregnancy
- smoking, cocaine use
- trauma
Clinical feature of placental abruption
- Painful vaginal bleeding
- Acute abdominal or back pain
- Uterine tenderness and contractions
- Fetal distress and/or maternal hemodynamic compromise in severe cases
Management of placental abruption
- Mild abruption:
- hospital admission and expectant management
- serial US and anticipate expedited delivery
- Moderate abruption:
- IV access and blood group and screen
- Fluid replacement therapy and blood transfusion as needed
- Fetal monitoring with CTG
- Emergency or planned C-section delivery based on fetal and maternal wellbeing
- MgSO4 if <30w, Corticosteroid if <34w
- Severe abruption
- Fetal death in utero - vaginal or C-section to expel fetal remains
- Correct hypovolemia and hematological disturbances
Clinical features of uterine rupture
- Severe abdominal pain
- Fetal distress
- Sudden pause in contractions
- Vaginal bleeding
- Signs of shock
Uterine rupture generally occurs during active labor.
Signs of fetal distress in CTG
- Bradycardia: <110 bpm
- Tachycardia: >160 bpm
- Absent or minimal beat-to-beat variability: <6 or >25 bpm
- Late decelerations: A drop in the fetal heart rate that occurs after the peak of a uterine contraction.
- Prolonged Decelerations: A significant drop in the fetal heart rate that lasts longer than usual
- Variable decelerations: Abrupt drops in the fetal heart rate that may not correlate directly with uterine contractions, sometimes associated with cord compression.
Management of uterine rupture
- Initial stabilisation
- IV access and fluid replacement therapy
- Pain relief
- Avoid uterotonic agent (e.g. oxytocin, prostaglandin)
- Blood group and screen
- Surgical management
- Emergency laparotomy and C-section delivery
- Hysterectomy in uterus severely damaged
What tests can be performed to diagnose SGA or FGR?
Fundal height and ultrasound biometry (head and abdo circumference, femur length)
Define FGR and SGA
- Small for gestational age describes babies where the birth weight is less than the 10th percentile for gestation.
- Fetal growth restriction refers to babies that have faield to reach their optimal growth potential
Risk factors for FGR
Maternal hypertension, diabetes, smoking, obesity, and advanced maternal age
Management of SGA baby.
- General: serial US monitoring and referral to specialised fetal medicine or perinatal unit
- Labour:
- Delivery around 37-38 weeks
- Use of continous electronic fetal monitoring during labour
- Use of mechanical, rather than prostaglandin-based, method of cervical ripening
Define preterm labour and preterm birth.
- Preterm labour is defined as labour occurring prior to 37 weeks of gestation.
- Preterm birth is delivery of a baby prior to 37 completed weeks of gestation
Aetiology for preterm delivery
- SROM
- Infection
- Antepartum hemorrhage
- Multiple pregnancy
- Cervical insufficiency/trauma
- Uterine malformation
What is the earliest gestational age where neonatal survival is considered possible?
23 weeks
Management of women in active preterm labour
- Steroids to be given to all women <34 weeks’ gestation (2 doses 24h apart)
- Transfer to a hospital with appropriate level of neonatal care
- Antibiotics (usually ampicillin or amoxycillin) given to prolong pregnancy, reduced risk of maternal and neonatal infection (such as GBS and genital mycoplasma)
- Tocolytics given to women <34 weeks’ gestation at least 48h prior to delivery - allow adequate time for steroids to be given
- Infection surveillance
- Neuroprotection and neonatal review: give MgSO4 if <30 weeks gestation
Remember STATIN
Mention examples of tocolytics
CCBs: nifedipine
Beta-mimetics: terbutaline, salbutamol
Others: Glyceryl nitrate
Define PPROM
Preterm premature rupture of membranes (PPROM) is the spontaneous prelabour rupture of membranes before the onset of labour, prior to 37 weeks’ gestation
What is the most common symptom of PPROM?
The most common symptom of PPROM is a gush of clear fluid from the vagina.
What is the management approach for a woman with PPROM at less than 34 weeks of gestation?
For PPROM before 34 weeks, corticosteroids are administered to promote fetal lung maturity, and the woman is usually admitted to the hospital for close monitoring and possible administration of antibiotics to reduce the risk of infection.
What is the term used to describe PPROM that occurs after 37 weeks of gestation?
PPROM that occurs after 37 weeks is referred to as Term PROM (Premature Rupture of Membranes).
What is the management approach for a woman with PROM at term gestation (after 37 weeks)?
In term PROM, labor induction is usually recommended to avoid potential risks associated with prolonged rupture of membranes.
Define cervical insufficiency
Painless dilatation of the cervix leading to recurrent second-trimester pregnancy loss.
What are the risk factors for cervical insufficiency?
- History of previous cervical procedures (e.g., cone biopsy, cervical conization)
- previous preterm birth due to cervical insufficiency
- uterine anomalies
- history of multiple pregnancy losses in the second trimester.
What is a strong predictor of preterm birth on ultrasound?
Short cervical length prior to 28 weeks’ gestation
What is the management approach for cervical insufficiency?
Placement of a cervical cerclage (a stitch placed around the cervix) to provide mechanical support and prevent further cervical dilation.
Progesterone supplementation may also be considered - thought to supress smooth muscle activity adn reduce prostaglandin sythesis
At what gestational age is cervical cerclage typically performed?
Cervical cerclage is usually performed between 12 and 14 weeks of gestation, to reduce the risk of any miscarriages and allow time for the 12 weeks’ aneuploidy screen.
How do you assess suitability for labour?
Bishop’s score assessment
The main concern with PROM
Increased risk of maternal or neonetal infection with increased latency between time of ROM and birth
Management of PROM
Depends on GBS status, infection risk, fetal wellbeing, maternal preference
Early induction of labour, compared to waiting for spontaneous labour, has been associated with lower risk of neonatal infection and maternal chorioamnionitis in mothers who are GBS positive.
Define prolonged ROM and how to manage it.
ROM that occurs >18h before onset of uterine contractions in term or preterm pregnancies
Patients with prolonged ROM are given IV antibiotics due to the increased risk of maternal and neonatal infections.
Types of monozygotic twins based on cleavage timing
- Before Day 4: dichorionic diamniotic
- Day 4-8: monochorionic diamniotic
- Day 8-12: monochorionic monoamniotic
- After Day 12: conjoined twins