This situation often happens. The owner does not need to panic. You can pinch the kitten's umbilical cord gently to pull out the placenta, or wait for a moment to see if the female cat can expel the placenta on its own. If the female cat does not continue to give birth, , you can use an oxytocin injection to promote uterine contractions and expel the placenta. The female cat needs to expel all the placenta when giving birth to prevent the placenta from developing lesions in the uterus, which could lead to the death of the female cat.