fetal growth

Question 1

what is the most simple test to determine size of infant

Answer 1

palpation OF HUMAN ABDOMEN

Symphysis Fundal Height

(istance between the pubic symphysis and the top of the uterus)

Question 2

Changes in SPH with gestational age reflects ……

Answer 2

generic changes in uterine size but it is vulnerable to a variety of errors

Question 3

SPH lower than they should be may result from

Answer 3

wrong last menstrual period date

transverse lie

oligohydramnios

Question 4

SPH higher than they should be may result from

Answer 4

wrong last menstrual period

multiple pregnancy

maternal obesity

Question 5

Initial information on the actual size of the fetus was based on…

Answer 5

miscarriages

did not take account of the possible causative relationship between low fetal growth leading to miscarriage

Question 6

Two primary components responsible for the extent of fetal growth are…

Answer 6

Genetic potential

substrate supply

Question 7

describe how genetic potential contributes

Answer 7

derived from both parents

reflects the logical view that taller/ bigger parents will have infants that are different in size to parents who are shorter or lighter in build.

Mediated by factors under genetic control.

Question 8

describe how substrate potential contributes

Answer 8

sufficient nutrients are essential to achieve genetic potential.

Primarily based on placenta.

Question 9

define Fetal Growth

Answer 9

increase in mass that occurs between the end of the embryonic period and birth.

Question 10

Fetal growth is assessed by 4 biometrical parameters….

Answer 10

biparietal diameter (BPD)

head circumference (HC)

abdominal circumference (AC)

femur length (FL).

Question 11

what are these 4 biometrical parameters combined to give

Answer 11

estimated fetal weight (EFW).

Question 12

what curves are plotted from these biochemical markers

Answer 12

Normative growth curves have been constructed from these ultrasound measurements (expressed in centiles).

Question 13

what are these biochemical markers used to identify clinically

Answer 13

normal intrauterine growth

detect risk of obstetric and neonatal complications.

Question 14

why is the use of centiles important

Answer 14

allows compensation for different sizes of infants that are growing and developing normally

allows plot of serial measuremnets

Question 15

what can be used for more individual assessment of growth

Answer 15

Customised fetal growth charts

based on fetal weight curves for normal pregnancies and adjusted to reflect maternal variation

Question 16

how are customised Fetal Growth charts optimised

Answer 16

presenting a standard free from pathological factors such as diabetes and smoking.

Question 17

Normal fetal growth is characterised by three main phases….

Answer 17

Cellular hyperplasia (increased cell numbers): 4-20 weeks

Hyperplasia and hypertrophy (increased cell size): 20-28 weeks

Hypertrophy dominates: 28-40 weeks

Question 18

Best practice is therefore to date the pregnancy by…

Answer 18

ultrasound

determining the Crown-Rump length

variations in fetal size are more limited at this stage of development

Question 19

why is Last Menstrual Period (LMP) not as reliable for dating a pregnancy

Answer 19

Confounding factors include:

Irregular length of periods; abnormal endometrial bleeding; the use of oral contraceptives;

also unplanned pregnancies may not take note of LMP

Question 20

what are possible consequences of incorrect dating

Answer 20

pregnancy being inappropriately identified as Large or Small for gestational age

delivery timings and methods (induction or Caesarean section) may not be correct;

glucocorticoids are given prior to preterm delivery to enhance lung surfactant production and subsequent lung function.

Question 21

Maternal factors influencing fetal growth

Answer 21

poverty, mother’s age, drug use, alcohol, smoking etc.

Question 22

name possible mechanisms by which these factors affect growth

Answer 22

predispose to LBW, risk taking behaviour, age = longer labour periods, alcohol affects brain/CNS, increase risk os still birth

Question 23

name some symptoms of Fetal alcohol syndrome (FAS)

Answer 23

variety of distinctive facial features, brain abnormalities, and cognitive deficits, learning behaviours affected

Question 24

how can smoking cause issues

Answer 24

Nicotine results in less blood flow to the fetus because it constricts the blood vessels.

Carbon monoxide reduces the oxygen flow to the fetus.

Question 25

difference between male/female size

Answer 25

Males are generally bigger

Question 26

second and subsequent infancy pregnancies are…

Answer 26

generally heavier

Question 27

what Hormones have a role in regulating fetal growth

Answer 27

cortisol, thyroxine, pituitary growth hormone

Question 28

how do these fetal hormones promote growth and development in utero

Answer 28

altering both the metabolism and gene expression of the fetal tissues.

They ensure that fetal growth rate is commensurate with the nutrient supply

ensure prepartum maturation occurs in preparation for extra-uterine life.

Question 29

Cortisol effects

Answer 29

Tissue differentiation

Question 30

Insulin effects

Answer 30

increases mitotic drive and tissue availability for tissue accretion (gradual growth via layer accumulation)

IGF-II to IGF-I

Question 31

thyroxine effects

Answer 31

tissue differentiation and accretion

Question 32

IGF1 is responsible for

Answer 32

the growth of the newborn.

Question 33

what does IGF-II do

Answer 33

regulates early embryonic development

Question 34

what do Fetal glucocorticoids do

Answer 34

affects tissue differentiation and prenatal development of the organs such as, for example, lungs (maturation of the surfactant)

Question 35

feto-placental factors affecting growth

Answer 35

Genotype – genetic potential
Gender (B>G)
Hormones
Previous pregnancy

Question 36

when is growth velocity greatest

Answer 36

mid third trimester (32-34 weeks)

Question 37

define Low birth weight

Answer 37

Less than 2,500g at delivery

Question 38

define Small for gestational age (SGA)

Answer 38

The infant has a birth weight <10th centile