Obstetrics Flashcards
1st Trimester
1-12 weeks
2nd Trimester
13-26/27 weeks
3rd trimester
28-40 weeks
Baseline foetal heart rate (FHR)
110- 160 bpm
Baseline FHR variability
Normal: 6-25 bpm
Reduced: 3-5 bpm
Absent: < 3bpm
Increased (salutatory): > 25 bpm
FHR accelerations
Transient increase in FHR of 15 bpm lasting 15 sec
FHR decelerations
transient episodes of decreased FHR below baseline more than 15 bpm for at least 15 sec
- often pathological
Types of FHR decelerations
Early
Variable
Prolonged
Late
Early FHR decelerations
- benign & physiological
- 4-8cm cervical dilation
- mirror contraction
Variable FHR decelerations
- repetitive/intermittent
- in association with other non-reassuring/abnormal features are pathological
Late FHR decelerations
- uniform, repetitive decrease
- slow onset at mid to end of contraction
- caused in the presence of hypoxia (foetus already hypoxic)
- decelerations less than 5-15 bpm
Reassuring CTG findings
- baseline FHR 110- 160
- No late or variable FHR decelerations
- Moderate FHR variability (6-25 bpm)
- age-appropriate FHR accelerations
Abnormal CTG findings any
ANY OF THE FOLLOWING
- Baseline FHR <100 bpm or >170 bpm
- Absent variability < 3 bpm
- Prolonged decelerations for > 3 bpm OR late OR complicated variables
Abnormal CTG findings >2
AT LEAST 2 OF THE FOLLOWING:
- Baseline FHR between 100-109 bpm
- Baseline FHR between 160 -170 bpm
- FHR variability is reduced (3-5 bpm for > 40 mins)
- Variable decelerations without complicating features
Abnormal CTG, what’s the next step
- Stop syntocinon (give blood to baby)
- foetal scalp sampling unless contraindicated (lactate high, pH low) give C-sec
CTG high risk vs low risk
High risk: mandatory obstetrical intervention
Low risk: limited value, and can lead to unnecessary obstetrical intervention
Pregnancy screening test
Before conception: Rubella
10-12 weeks: Chorionic villus sampling (CVS) Rh negative women need Rh D immunoglobulin (anti-D)
15-17 weeks: Maternal serum screening (alpha fetoprotein, estriol, and beta-HCG ) for Down syndrome
16-18 weeks: Amniocentesis
18-20 weeks: Ultrasound for identification of physical abnormalities (NTD)
First antenatal visit time frame
Within 10 weeks
Antenatal screening protocol
- every four weeks until 28 weeks
- every two weeks until 36 weeks
- every week until 40 weeks or delivery
Spina bifida investigation
US of foetal spine at 16-18 weeks
Tenderness of the right lower part of the uterus indicates
Indications to use ant-D
-Spontaneous abortion.
-External cephalic version.
-Significant closed intra-abdominal trauma.
-Termination of pregnancy.
-Chorionic Villus Sampling.
-Ectopic pregnancy.
-Threatened abortion after 12 weeks of gestation
Doppler studies result
- increase in end-diastolic flow velocity relative to peak systolic velocity
- S/D ratio to decreases with advancing gestation
Increase in S/D ratio is associated with
- increased resistance in the placental vascular bed
- can be noted in pr-eclampsia or festal growth retardation
- Nicotine and maternal smoking increase S/D ratio