Pregnancy in a unilaterally ovariohysterectomised queen

Case Report

Uterine torsion is defined as twisting of the uterus or uterine horn perpendicular to its long axis.^1,2 As the occurrence is higher in gravid compared with non-gravid animals, pregnancy is suggested to be the main factor contributing to uterine torsion. ³ The aetiology of uterine torsion is unknown. Factors such as fetal movement, uterine contraction, rough handling during pregnancy, lack of tone of the pregnant uterus, lack of fetal fluids, flaccid uterine walls and a long flaccid mesometrium have been suggested as contributing factors.^1,2,4 Generally, total ovariohysterectomy is considered the best treatment for uterine torsion.^3,5,6 Successful pregnancy after unilateral hysterectomy has been achieved in the mare, bitch and doe.^6–10 As far as we are aware this procedure has not been described with a positive outcome in cats.

The aim of this report was to describe a case of successful pregnancy in a unilaterally ovariohysterectomised queen after uterine torsion.

A 4-year-old female Russian Blue cat weighing 4.7 kg, in poor general condition, was referred to the Clinic of Small Animal Diseases in Warsaw on day 62 of pregnancy. History revealed that the queen had given birth to 20 kittens in four litters (four, four, five and seven, respectively) during the previous 3 years. The cat had exhibited a lack of appetite for the previous 8 h and appeared mildly dehydrated with reduced skin elasticity. There was abdominal enlargement, especially on the right side, enlarged mammary glands with a small amount of thick milky secretion, and a small amount of mucoid vaginal discharge which, according to the owner, had been present for about 1 week. Ultrasound examination revealed a single live fetus in the left uterine horn, with a heart rate of 180–190 beats per min, a small amount of amniotic fluid and normal fetal movements. A single dead fetus was present in the right uterine horn and with some echogenic debris within the amniotic fluid. Haematological and biochemical blood parameters are given in Table 1. The cat was treated with intravenous (IV) 0.9% saline with glucose (Polfa) at a rate of 4 ml/kg/h and perioperative cefuroxime (Cephalexin; Scanvet) at 20 mg/kg subcutaneously. Anaesthesia was induced with intramuscular ketamine 5 mg/kg (Bioketan 5; Vetoquinol) and medetomidine (Cepetor; Scanvet) injection, and maintained with isoflurane (Forane; Baxter) in oxygen and nitrous oxide administered via endotracheal intubation and a non-rebreathing system. Perioperative analgesia was maintained with methadone (Physeptone; Martindale Pharmaceuticals) at a dose of 0.2 mg/kg IV and meloxicam (Metacam; Boehringer Ingelheim) at a dose of 0.3 mg/kg. A coeliotomy was performed. Following a midline incision both uterine horns were exteriorised. A 900º torsion of the right uterine horn was found directly proximal to the uterine bifurcation and an additional torsion of 360º was located near the right ovary (Figure 1). The affected horn had highly distended veins, oedema, signs of passive congestion and black discolouration. After repositioning of the right horn, an incision was made and the dead fetus (with fecal material in amniotic fluid) was removed. An incision was then made into the left horn from which a live female fetus was removed. Because of the major abnormalities found, and with segmental necrosis in the uterine wall, with the owner’s permission, resection of the right ovary, oviduct and uterine horn was performed (Figure 2). The abdomen was copiously lavaged with 0.9% saline (sodium chloride; Baxter), then closed using Polysorb 2-0 (Vetoquinol) with a standard midline closure technique. As the queen was not lactating, the kitten was bottle-fed but did not thrive and died on the second day. The cat made an uneventful recovery and was sent home 3 days postoperatively. Five months later (at which time the cat had regular oestrous cycles every 4 weeks) the owner decided to mate the cat again, and multiple matings took place on the 3rd day of her oestrus. Pregnancy was confirmed by ultrasound on day 21 and four normal fetal sacs were seen. Serum progesterone (P4) and total oestrogens (E2) were evaluated at days 7, 14, 21, 28, 35, 42 and 49 after mating. Throughout the pregnancy, concentrations of P4 fluctuated between 39.1 nmol/l and 58.8 nmol/l and thus luteal deficiency was not observed. The level of E2 ranged between 188 pmol/l and 338 pmol/l. Pregnancy was monitored by ultrasound. There was no visible asymmetry of the abdominal wall throughout pregnancy and on day 64 after mating the queen gave birth to four healthy kittens uneventfully. The kittens weighed between 88 g and 98 g and were healthy on physical examination. Lactation and kitten development continued normally and no deaths were reported after weaning. Two months later the queen became pregnant again and gave birth to a single male kitten 65 days after mating, which also developed normally.

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Table 1

Haematological and biochemical parameters in a 4-year-old Russian Blue queen with uterine torsion

Parameters	Reference range	Before operation*	1 day after*
Red blood cells (×1012/l)	5.5–10.0	4.5	5.6
Haematocrit (proportion of 1.0)	0.24–0.45	0.16	0.31
Haemoglobin (g/l)	80.0–140.0	49	79
MCV (fl)	39–55	59	54
Total WBC (×109/l)	7.0–20.0	28.9	22.1
Neutrophils (×109/l)	2.5–12.8	22.1	24.7
Bands (×109/l)	0.0–1.0	0	0.7
Lymphocytes (×109/l)	1.5–7.0	4.1	4.2
Monocytes (×109/l)	0.07–0.85	0.7	0.8
Eosinophils (×109/l)	0–1	1	1
Platelets (×109/l)	300–600	265	290
ALT (U/l)	15–60	123	95
Total protein (g/l)	69–79	54	66
Urea (mmol/l)	2.8–9.8	12.2	8.9
Creatinine (μmol/l)	40–177	182	175
Phosphorus (mmol/l)	1.0–2.4	3.2	2.6
Potassium (mmol/l)	3.5–5.8	6.5	5.9
Sodium (mmol/l)	145–156	143	149

*

Bold type indicates abnormal values

MCV = mean cell volume; WBC = white blood cell count; ALT = alanine aminotransferase

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Figure 1

Torsion of the right uterine horn

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Figure 2

Left uterine horn after two operations

Discussion

Uterine torsion has been described in horses, cattle, dogs and rats, and has been only rarely reported in cats.^{1–4,7,11,12} It has been observed in non-gravid and gravid cats in mid- to late gestation.^2,11,13 The successful outcome in cats depends on the degree of uterine torsion, effective pre- and postoperative medical supportive therapy, and prompt surgical intervention. ² Unilateral hysterectomy is generally not recommended owing to fear of uterine rupture following torsions, luteal deficiency and reduction of litter size in subsequent pregnancies.^6,8,9,14 To our knowledge this procedure has not been reported in queens. The mean number of puppies delivered by bitches after unilateral hysterectomy is 3.8 – approximately 50% less than the average number of puppies in litters of medium and large breed dogs. ¹⁴ In the present case, two pregnancies occurred without complications in a cat following unilateral ovariohysterectomy.

Conclusions

We conclude that while unilateral ovariohysterectomy did not seem to compromise subsequent pregnancies in this particular queen, this observation cannot necessarily be extrapolated to other cats. Additional research on a larger number of queens is required.