Small for Dates Pregnancy Flashcards
What are the two main causes of a small for dates pregnancy?
Preterm delivery, and being small for gestational age
What is the definition of preterm delivery?
Delivery earlier than 37 weeks gestation
What are some causes for a small for gestational age pregnancy?
IUGR and being constitutionally small
At what point is a foetus viable?
24 weeks
Define the following: a) extreme preterm? b) very preterm? c) moderate-late preterm?
a) 24-27+6 weeks b) 28-31+6 weeks c) 32-36+6 weeks
What is the long-term survival outcome of a foetus born at a) 24 weeks? b) 26 weeks?
a) 40% b) 77%
What are the survival outcomes of a preterm baby born beyond 32 weeks?
> 95%, essentially the same as for a baby born at term
What are some general groups of causes of preterm birth?
Infection, over-distension, vascular, intercurrent illness, cervical incompetence, idiopathic
What are some factors which may cause over-distension of the uterus leading to preterm birth?
Multiple pregnancy, polyhydramnios
What is a vascular cause which may result in preterm birth?
Placental abruption
What is the strongest risk factor for preterm birth?
The mother has already had a baby born preterm (20% risk if once, 40% risk if twice)
What social factors are risk factors for preterm birth?
Poor socioeconomic status, smoking, drug use (especially cocaine)
In what ethnic group is preterm birth more common in?
Black women
What are some risk factors for preterm birth relating to a) age of the mother? b) weight of the mother? c) parity of the mother?
a) young age (i.e. teenage) b) low BMI c) parity 0 or > 5
How does preterm labour present?
Painful contractions and backache +/- vaginal discharge
Preterm labour with bleeding suggests what might be the underlying cause?
Antepartum haemorrhage
Preterm labour with loss of lots of fluid vaginally suggests what might be the underlying cause?
Preterm premature rupture of membranes (P-PROM)
A small for gestational age foetus can be identified based on what?
Antenatal risk factors and screening during antenatal care
What is the definition of small for gestational age?
An abdominal circumference or estimated foetal weight below the 10th centile on a growth chart
If you have a suspicion of SGA, what investigation is used to give an estimate of foetal size which can give an estimate of foetal weight?
Ultrasound
What is the relationship between SGA and IUGR?
They are not the same thing, though IUGR is more common in foetuses which are SGA than foetuses which are not
What is intra-uterine growth restriction?
There is failure of the foetus to achieve its full growth potential, baby is on a lower centile than would be expected
What is seen in a) symmetrical IUGR? b) asymmetrical IUGR?
a) small head and small abdomen b) normal head and small abdomen
Why does asymmetrical IUGR occur? What are some diagnoses that this may suggest?
Because the baby is preserving brain growth and development at the cost of other organs. Could point towards a chromosomal abnormality or placental problem.