Week 4 Flashcards
Para (P)
Refers to the number of times the woman has given birth after 24 weeks gestation, regardless of whether the foetus was alive or stillborn
Primiparous
technically refers to a patient that has given birth after 24 weeks gestation once before
Multiparous
Refers to a patient that has given birth after 24 weeks gestation two or more times
A pregnant woman with three previous deliveries at term
G4 P3
A non-pregnant woman with a previous birth of healthy twins
G1 P1
A non-pregnant woman with a previous miscarriage
G1 P0 + 1
A non-pregnant woman with a previous stillbirth (after 24 weeks gestation):
G1 P1
There are two vaccines offered to all pregnant women
- Whooping cough (pertussis) from 16 weeks gestation
2. Influenza (flu) when available in autumn or winter
Obstetricians describe the position of the baby’s head in relation to the mother’s ischial spines during the descent phase. Descent is measured in centimetres, from:
-5: when the baby is high up at around the pelvic inlet
0: when the head is at the ischial spines (this is when the head is “engaged”)
+5: when the foetal head has descended further out
Risks of prolonged and delayed delivery of placenta in labour
Haemorrhage, or more than a 60-minute delay in delivery of the placenta, should prompt active management. Active management can be associated with nausea and vomiting.
How does suckling ensure milk production?
Suckling reduces dopamine release → increases prolactin release
Strength and duration of suckling determines amount of prolactin released
This determines amount of milk available for subsequent feeds
When is prolactin produced in pregnancy?
Prolactin - stimulates milk production
Prolactin secreted from 16 weeks but breast tissue unresponsive - steroid block
What hormones block the response of breast tissue to prolactin before birth?
Progesterone and oestrogen remains high until delivery of placenta → where lactation can occur - After birth oestrogen and progesterone unblocks the response to prolactin from breast tissue - so prolactin drops in level as it doesn’t need to remain high - just steady level
There are typically two (and sometimes three) ultrasounds performed during in pregnancy
Dating scan – typically 8-9 weeks – if dates are uncertain (NIPT usually performed)
Combined screening test – USS and blood test performed between 11 and 13 weeks
Foetal structural abnormality scan – performed at 18-20 weeks
The combined screening test
should be offered to all pregnancy women. This is a test performed around 12 weeks of gestation (quoted ins one places as between 11 weeks and 2 days and 13 weeks and 6 days)
What does the combined screening test screen for?
>
Down Syndrome – trisomy 21 Edward’s syndrome – trisomy 18 Patau’s syndrome – trisomy 13
False positive rate – <5% (I.e. specificity of >95%)
Sensitivity – 85%
Amniocentesis
– if >15 weeks gestation
In this procedure, a needle is passed, usually under USS guidance, into the amniotic fluid, and roughly 10-20ml of fluid is aspirated (1ml for every week of gestation)
> Contains samples from fetal skin, urinary tract and lungs
When can amniocentesis be performed?
– if >15 weeks gestation
Complications of amniocentesis
Miscarriage rate = 0.5-1% Amniotic fluid leakage – 3% Uterine bleeding – 2% Maternal rhesus sensitisation Sepsis (rare)
Volume of distribution
equals the total amount of drug in the body / drug blood plasma concentration
Teratogenic drugs
> ACE inhibitors/ARB > Androgens > Antiepileptics > Cytotoxics > Lithium > Methotrexate > Retinoids > Warfarin
Adverse effects of drugs on labour abd the baby around term time
Progress of labour Premature closure of ductus arteriosus Opiates – respiratory depression Bleeding with Warfarin Withdrawal syndrome with opiates & SSRIs Sedation
Adverse effects of drugs on foetus in 1st trimester
Risk of early miscarriage
Organogenesis
Period of greatest teratogenic risk
Avoid drugs if at all possible unless maternal benefit outweighs risk to foetus
BP control in pregnancy (prescribed drugs)
BP falls during 2nd trimester If need to treat, use one of: o Labetalol o Methyldopa o (Nifedipine MR) Avoid ACE inhibitors / ARB Beta blockers may inhibit foetal growth in late pregnancy