Ans. b. Fetal distress (Ref: Williams Obstetrics 24/e p340) Late decelerations, typical of fetal distress can be seen in the given fetal tocography. Methods of Monitoring Fetal Heart Rate Fetal stethoscope (Pinard) & Hand-held Doppler (Sonicaid) Cardiotocograph (CTG) Cardiotocography (CTG) CTG: Technical means of recording (-graphy) fetal heartbeat (cardio-) & uterine contractions (-toco-) during pregnancy, typically in third trimester. The machine used to perform the monitoring is called a Cardiotocograph, more commonly known as an Electronic Fetal Monitor (EFM). Two separate transducers perform recordings, one for the measurement of fetal heart rate & second one for uterine contractions. Types of measurement: Each of the transducers may be either external or internal. External measurement means taping or strapping the two sensors to the abdominal wall. This is called an indirect measure. Internal measurement (direct) requires a certain degree of cervical dilatation, as it involves insetting a pressure catheter into the uterine cavity, as well as attaching a scalp electrode to the childs head to adequately measure the electric activity of the fetal heart. Interpretation: Includes description of uterine activity (contractions), baseline fetal heart rate, baseline FHR variability, presence of accelerations, periodic or episodic decelerations The 3 primary mechanisms by which uterine contractions can cause a decrease in fetal heart rate are compression of fetal head, umbilical cord & uterine myometrial vesselsQ. Variability Baseline variability refers to the variation of fetal heart rate from one beat to the next. Variability occurs as a result of the interaction between nervous system, chemoreceptors. baroreptors & cardiac responsiveness. This is because a healthy foetus will constantly be adapting it's heart rate to respond to changes in it's environment. Normal variability is between 10-25 bpm To calculate variability you look at how much the peaks & troughs of the heart rate deviate from baseline rate (in bpm) Variability can be categorised as: Reassuring > 5 bpmQ Non-reassuring <5 bpm for between 40-90 minutesQ Abnormal <5 bpm for >90 minutesQ Accelerations Abrupt increase in baseline heart rate of >15 bpm for >15 secondsQ The presence of accelerations is reassuring Antenatally there should be at least 2 accelerations every 15 minutesQ Accelerations occurring alongside uterine contractions is a sign of a healthy foetusQ Decelerations Decelerations: Abrupt decrease in baseline heart rate of >15 bpm for > 15 seconds Types of deceleration Early deceleration * Start when uterine contraction begins & recover when uterine contraction stops * Due to increased foetal intracranial pressure causing increased vagal tone * Resolves once the uterine contraction ends & intracranial pressure reduces * Considered to be physiological & not pathological Variable deceleration * Seen as a rapid fall in baseline rate with a variable recovery phase * Variable in their duration & may not have any relationship to uterine contractions * Seen during labour & in patients with reduced amniotic fluid volume * Variable decelerations are usually caused by umbilical cord compression * The umbilical vein is often occluded first causing an acceleration in response * Then the umbilical artery is occluded causing a subsequent rapid deceleration * When pressure on the cord is reduced another acceleration occurs & then the baseline rate returns * Accelerations before & after a variable deceleration are known as the "shoulders of deceleration" * Variable decelerations can sometimes resolve if the mother changes position * The presence of persistent variable decelerations indicates the need for close monitoring Late deceleration * Begin at the peak of uterine contraction & recover after the contraction ends. * Indicates there is insufficient blood flow through the uterus & placenta, foetal hypoxia & acidosis due to reduced uteroplacental blood flow. * If foetal blood pH is acidotic it indicates significant foetal hypoxia & the need for emergency C-section Prolonged deceleration * A deceleration that last more than 2 minutes * If it lasts between 2-3 minutes it is classed as non-reassuring * It it lasts longer than 3 minutes it is immediately classed as abnormal * Action must be taken quickly,e.g.. Foetal blood sampling/emergency C-section Sinusoidal Pattern A smooth, regular, wave-like pattern, frequency of around 2-5 cycles a minute, stable baseline rate around 120-160 bpm, no beat to beat variability It indicates severe foetal hypoxia, severe foetal anaemia, foetal/ maternal haemorrhageQ Management: Immediate C-section is indicated for this kind of pattern. Significance: This type of pattern is rare, however if present it is very serious, it is associated with high rates of foetal morbidity & mortality. Outcome is usually poor.