Dystocia refers to abnormalities or difficulties during childbirth, regardless of whether the cause is the mother or the fetus. There are three stages of labor, (1) the onset of uterine contractions and cervical dilation, (2) delivery of the fetus (lasting 4-24 hours), and (3) expulsion of the fetal membranes. In stage 1, there will be intermittent contractions without any signs of resistance. The female cat will appear very uncomfortable and may howl, shake/tremble, circle in search of a resting position, and begin licking the abdomen or vulva. Signs of stage 2 of labor include strong contractions, the cat moving into a squatting position, fluid leaking, and delivery of the fetus. Dystocia usually occurs in stage 2. However, in multiple births, stages 2 and 3 alternate, so dystocia may be intermittent.

1. Differential diagnosis

A variety of diseases and abnormalities must be considered. See Table 1.

　

　2. Preliminary diagnosis

Clinical symptoms:

When the following conditions occur, dystocia should be suspected.

The time between the discharge of black-green secretion (uterine chlorophyll) and the birth of the kitten exceeds 2 hours;

Ferguson's reflex is weakened or disappeared (the dorsal side of the vaginal wall appears feathery);

Continuous strong abdominal contraction for more than 30 minutes without fetal delivery;

Intermittent abdominal contractions for more than 4 hours without labor;

The kitten has continuous contractions in the birth canal for more than 10 minutes;

Kitten delivery interval exceeds 2 hours;

Howling during contractions and licking the vulva continuously

Second stage of acute depressive symptoms (often associated with uterine rupture),

Fresh vaginal bleeding that lasts for more than 10 minutes,

The gestation period after breeding exceeds 68 days.

Palpation:

This is the least accurate test, but it can determine fetal size to some extent.

Radiological examination

Can assess the size, number and position of the fetus. In some cases, fetal death can be determined by findings such as the presence of intrauterine gas, fetal skull collapse, or other bony malpositioning. The size and shape of the birth canal may also be assessed.

　

The picture above shows that intrauterine gas is a sign that the fetus has died. There was air around the fetus and the skull appeared to be ruptured. (b) Intrauterine gas is more evident around this fetus.

　

The picture above shows that the fetus’s head is pressed against the pelvic cavity and cannot move. (b) This is also an example of head entrapment, which occurs when the diameter of the fetal head is larger than the diameter of the pelvis. Note that this was a singleton birth. A prompt caesarean section was performed to save the kitten.

　3. Further diagnosis

Ultrasound examination: By observing the movement and heart contraction of the fetus, the viability of the fetus can be most accurately determined. Fetal distress is defined as fetal heart rate < 195 or > 260 beats/minute. This can also be determined by a response to treatment with oxytocin for uterine atony.

Diagnostic considerations: Fetal size is often underestimated using radiography or ultrasound. Radiological examinations are more accurate.

　4. Main treatment methods

Calcium: For hypocalcemia, give 10% calcium gluconate (0.2-1.5 ml/kg [5-15 mg/kg], slow intravenous injection) while monitoring for arrhythmias, especially bradycardia. .

Oxytocin: Dosage 0.25-4.0 U intramuscularly, every 20-30 minutes, up to three injections. Dosage increases are not recommended. Can be reused 60 minutes or more after the kitten is born.

Caesarean section: In the following circumstances, it is recommended to remove the kittens surgically:

Oxytocin and calcium are ineffective;

Presence of uterine disease (i.e. uterine atony, torsion or rupture),

The ratio of the pelvic cavity to the fetus hinders the delivery of the fetus.

It is recommended to use glycopyrrolate (0.01 mg/kg IM) or atropine (0.02-0.05 mg/kg IV, IM, SC) beforehand. Atropine is the first choice for fetal bradycardia. μ-opioid agonists are the first choice for premedication. Regional analgesic techniques such as lidocaine (2-4mg/kg) linear blocks can be used. For the benefit of the mother cat and kittens, the use of anesthetics with rapid metabolic clearance (propofol induction [4-6 mg/kg IV], sevoflurane or isoflurane maintenance) is strongly recommended. Give intravenous fluids to avoid hypotension and reduced fetal blood flow.

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The birth of this kitten with breech presentation is not abnormal. The fetus’s head is too big to be exposed.

Treatment Precautions

Caesarean section is a life-saving method for mother cats and kittens. Don’t delay, intervene promptly. Female cats can control labor autonomously, so environmental stress can prolong or delay the onset of labor.

5. Prognosis

If prompt medical or surgical intervention is taken, the prognosis for the mother cat and kittens is good.