Obs Flashcards
How long is normal gestation?
37-42 weeks
What is the first stage of labour?
From the first true contractions (onset of labour) to 10cm dilation
What is the second stage of labour?
From 10 cm dilation until delivery
What is the third stage of labour?
From delivery until the birth of the placenta
What effects do prostaglandins have during labour?
- They play a key role in menstruation and labour by stimulating contraction of the uterine muscles.
- They also have a role in the ripening of the cervix before delivery
Which progesterone is used to induce labour as a pessary?
E2- dinoprostone
What are the 3 phases of stage 1 labour?
- Latent phase: From 0-3cm dilation. Progresses at about 0.5cm/hr. There are irregular contractions.
- Active phase: From 3-7cm dilation. About 1cm/hr and there are regular contractions
- Transition phase: From 7-10 cm dilation. Again progressing at roughly 1cm/hr, there are strong and regular contractions.
How long should stage 2 of labour last?
• Should take <3 hrs nullip and ,2hrs multip. Consider C-section or instrumentation 1 hr before these times
What causes contractions?
Oxytocin release (nerve stimulation as cervix stretches) Local prostaglandin release
What is involved in active management of phase 3 labour?
Active management involves giving a dose of intramuscular oxytocin to help the uterus contract and expel the placenta. Careful traction is applied to the umbilical cord to guide the placenta out of the uterus and vagina.
What would indicate active management in phase 3?
Haemorrhage or over 60 min delay in placental delivery
A ladies waters break, (SROM) but the liquor is smelly and green, what do you do?
Set up a continuous CTG- this is a sign of meconium in the amniotic fluid- you would be concerned of apsirational pneumonitis
What are you looking for in a foetal scalp blood to show F distress?
Acidosis- suggests hypoxia
DR C BRAVADO:
o Define Risk: Is it high or low risk
o Contractions: Are they regular?
o Baseline Rate: Try and visualise the baseline FHR. Normal is 110-160. Ten either side is non reassuring <100 or >180 is abnormal.
o Accelerations: Should be occasional jumps in FHR in response to environment
o Variability: >5 is normal. <5 for >40 mins is abnormal, for >90 mins is abnormal
o Decelerations: Early decel, in time with contraction, are normal. Late decel, 20-30 seconds after contraction, are suggestive of hypoxia. Variable decels suggest cord compression and are classified as abnormal is>50% atypical.
o Overall assessment
What reading of foetal scalp pH means C-section?
<7.2
What does 99% effective mean in regards to contraception?
99% means that id the average person used this method correctly with a regular partner for a single year, there would only be a 1% chance of pregnancy.
Specific RF for contraception?
- Breast cancer: Avoid any hormonal contraception and go for copper coil/barrier
- Cervical/ endometrial Ca: Avoid the IUD
- Wilson’s disease: Avoid the use of copper coil
A mother is breast feeding how long PP can they start the COCP?
Has to be >6 weeks, POP or implant is far safer.
How is early miscarriage defined?
<12 weeks gestation
How is late miscarriage defined?
12-24 weeks gestation
At what crown-rump length is a FHB expected?
> 7mm, if not present then repeat in 1 week to confirm non viable
What is the key investigation for suspected miscarriage?
TVUS
What is given to medically manage miscarriage?
Misoprostol (softens cervix and stimulates uterine contraction- prostaglandin analogue)
SE of misoprostol?
- Heavier bleed
- Pain
- Vomiting
- Diarrhoea
What is the legal framework around abortion?
TOP is legal as long as it occurs before the 24th week of gestation. (1990 Human fertilisation and embryology act)
• Mifepristone
antioprogesterone)- halts pregnancy and relaxes cervix
• Misoprostol
(prostaglandin analogue) 1-2 days later- softens the cervix and stimulates contraction. (if used in abortion over 10 weeks, give every three hours till expulsion)
What week does the uterus reach the height of the umbilicus?
20 weeks
What week does the uterus reach the Xiphisternum?
36 weeks
Which hormone leads to N+V- which pathologies are associate with hyperemesis gravidarum?
hCG,
Multiple pregnancies and molar pregnancies
Criteria for diagnosis of hyperemesis gravidarum?
Extended NVP plus all 3 of:
More than 5% weight loss before pregnancy
o Dehydration
o Electrolyte imbalance
How is severity of hyperemesis judged?
Severity is assessed using the Pregnancy-Unique Quantification of Emesis score. This gives a score out of 15:
o <7 Mild
o 7-12 Moderate
o >12 severe
Complementary treatment for hyperemesis?
- Ginger
* Acupressure on the wrist at point PC6
What might patients in hospital need if prolonged vomiting (minus electrolytes and anti-emetics IV)?
Thiamine supplementation (risk of wernicke korsakoff syndrome)
Name 2 antiemetics used to control N+V
- Prochlorperazine- (phenothiazine-block various receptors including D2 in CTZ and gut, H1 and muscarinic in the vomiting centre- big range of efficacy)
a. SE: Nausea, Postural Hypotension. (FGAP) - Cyclizine (H1receptor antagonist- H1 and antimuscarinic receptors predominate the vomiting centre and coms to the vestibular centre- good for motion sickness)
a. SE: drowsiness- dry mouth and throat - Ondansetron (serotonin 5-HT3 antagonists- High density in CTZ- chemoreceptor trigger zone and key release in the gut, usually these act to stimulate vagus nerve and vomiting- good for chemo causes of vom)
a. Rare- constipation, diarrhoea and vomiting - Metoclopramide (D2- receptor antagonist, D2 is main receptor in CTZ but also promote relaxation of peristalsis in stomach and LES- blocking this promotes gastric emptying and reduces stimulation of vom)
a. SE: Diarrhoea, EPSEs- especially young and children
• First trimester:
LMP 12 weeks gestational age
• Second trimester:
13 weeks 26 weeks gestational age
• Third trimester
27 weeks birth
At what gestation are foetal movements normally felt?
20+0
When is the booking clinic? (normal)
10+0
When is the dating scan? (normal)
Between 10+0 and 13+6
When is the first antenatal appointment? (normal)
16+0
When is the anomaly scan? (normal)
Between 18+0 and 20+6
When are the rest of the antenatal appointments? (normal)
25, 28, 31, 34, 36, 38, 40, 41 and 42 weeks
What can drinking in early pregnancy cause?
o Miscarriage
o Small for dates
o Preterm delivery
o Foetal alcohol syndrome
Foetal alcohol syndrome?
o Microcephaly o Thin upper lip o Short fat philitrum o Short palpebral fissure o Learning disablility o Behavioural difficulties o Hearing and vision issues o Cerebral palsy.
What bloods are taken at booking clinic?
• Blood group, Ab and rehesus D status
• FBC- anaemia
• Screen for thalassaemia (all women) and sickle cell disease (when women at high risk)
If indicated then HIV, Hep B, Syphilis
When are bloods taken for downs syndrome (combined test)?
11 weeks