A 32 year old G1 P0. Gestation week 40+4 admitted to hospital in early spontaneous labour. VE on admission at 22.00: Cx fully effaced, 2 cm dilated, vx-2. Normal pregnancy. External CTG tracing is normal on admission.
pH | pCO2 | BE | |
Artery | 7.26 | 8.4 | -4.1 |
Vein | 7.31 | 8.3 | -3.2 |
Between 00:18 and 01:20 there is a pseudosinosoidal pattern, a temporary sine-wave pattern. It recurs at 03:20-06:28 and thereafter spontaneous accelerations can be seen, which is a sign that the fetus is well oxygenated.
A pseudosinusoidal pattern is a normal pattern and must not be confused with abnormal sinusoidal pattern. Sinusoidal pattern has higher amplitude. It is unusual but can be seen in severe fetal anemia.