Fetal Wellbeing Dr Hsu Chong NIHR Clinical Lecturer in Obstetrics & Gynaecology Warwick Medical School

Lecture Learning Outcomes Define the fetal period Outline the developmental processes that occur during the fetal period Understand the chronology of development of the major body systems Describe the factors that influence viability Describe the pattern of increase of fetal size, weight and body proportion Outline techniques used to assess fetal growth and development Describe processes involved in control of amniotic fluid volume Describe the changes in fetal physiology that occur at birth

Lecture Synopsis This lecture will describe the timing and development of the major body systems and how the growth and development of the fetus is assessed during a normal pregnancy.

Why bother? Stillbirth rate /1000 (CEMACE 2009) – Unexplained 28% Intrauterine Growth Restriction – Major congenital anomaly 9%

Gardosi et al. BMJ 2013.

Ultrasound in Obstetrics

Ultrasound

Periods of assessment of fetal wellbeing 1 st 2 nd 3 rd Intrapartum monitoring

First trimester Fetal period- Week 9 to birth Assessment of gestational age using Crown to Rump Length (CRL) Measurement of the nuchal translucency (weeks ) CRLNuchal translucency + +

Fusion of the neural tube Spinal cord Image from STRATOG

Gut herniation

Mid-trimester ultrasound 18+0 to 20+6 Fetal anatomy Placental site alyresource/whats-in-the-hexagons1/about-the- scan/the-base-menu

Symphysio-fundal height

Fetal growth Estimated weight calculated from – Head circumference – Abdominal circumference – Femur length

Fetal growth Symmetric vs asymmetric growth restriction – HC and AC similar – Reduction in AC to preserve brain development Small for gestational age Fetal growth restriction – Growth under 10 th centile

Biophysical profile Components – Fetal movement – Resting tone – Breathing movements – Amniotic fluid volume

Doppler ultrasound Colour flow doppler Red: racing toward probe Blue: ”cold” i.e moving away

Uses of Doppler ultrasound Assessment of fetal wellbeing – Measure flow in umbilical artery Assessment of fetal anaemia – Measure flow in Middle Cerebral Artery ? Timing of delivery

Does intervention improve outcome?

Timing of delivery vs risks of prematurity Intramuscular corticosteroids reduce risk of death and disability – Type II pneumocyte maturation Grace Hayes Grace Research Fund Grace Hayes Grace Research Fund

The Epicure studies Moore et al. BMJ

The Epicure studies Moore et al. BMJ

Birthweight as a factor influencing survival Draper et al. BMJ

Cardiotocography

Baseline and acceleration

Variability

Deceleration

NICE classification of Fetal Heart Rate features CG55 Intrapartum care

CTG High negative predictive value – i.e when normal, fetal acidaemia unlikely – When abnormal, fetus acidaemia could still be unlikely Used antenatally – Changes may reflect the end stage process of chronic hypoxia

Fetal scalp blood sampling

Intrapartum – Fetal scalp sampling Capillary sample Immediate delivery indicated when pH less than 7.20

Summary Ultrasound is main investigation for assessment of fetal well being Assessment of anatomy Growth assessment & umbilical artery dopplers may aid decision to deliver Continuous CTG monitoring required for high risk pregnancies

In your spare time Youtube videos – The human body (BBC production with Sir Richard Winston) UNSW site for embryological and fetal development – ent Mid trimester scan – hexagons1/about-the-scan/the-base-menu Premature labour- patients’ perspective – RCOG guideline No 31 – Small for gestational age fetus, Investigation and Management