Timing a Queen's C-Section: Progesterone and Fetal Heart

A planned cesarean in a queen is timed on two numbers, not on a calendar: progesterone below 2 ng/mL, and a fetal heart rate above 180 beats per minute. The first tells you the kittens are mature enough to breathe; the second tells you they are still comfortable. Operating inside 24 hours of the progesterone drop, while the heart rate holds, is the difference between a litter that nurses and a litter that needs resuscitation.

Why the date on the chart is not enough

Queens are induced ovulators, so heat cycle timing matters as much as the mating date: ovulation can follow mating by 24 to 48 hours; breeding dates are often uncertain by 2 to 4 days, and gestation runs 63 to 65 days from a single mating but 61 to 68 days across a litter. A radiograph at day 55 to 58 confirms the count and the skull sizes, but it cannot tell you whether the lungs are ready. Only progesterone and fetal heart rate answer that.

Elective surgery before day 61 risks premature kittens that cannot expand their lungs. Waiting past day 66 in a queen with a large litter risks stillbirth, because the placenta ages faster than the kittens do.

Progesterone: the 2 ng/mL line

Ask for the mating log in writing. If the stud is not yours, stud management records normally note every mating to the hour, and that record is what makes a day 58 progesterone series interpretable.

Sample serum progesterone daily from day 58 in a queen with a history of loss, or every 48 hours from day 60 otherwise. When the value falls below 2 ng/mL, luteal support is gone and parturition is expected within 24 hours, usually 12 to 24. Book the theater for that window rather than waiting for contractions.

Test timing matters: a single value of 2.4 ng/mL means test again in 12 hours, not operate. Two consecutive readings below 2.0, taken 12 to 24 hours apart, are the trigger. In queens that have already had a cesarean, drop the threshold discussion and schedule at 63 days with a progesterone check the morning of surgery.

Fetal heart rate: the 180 bpm floor

Normal feline fetal heart rate is 200 to 250 beats per minute. Measure with Doppler or ultrasound at each visit from day 58, counting over 15 seconds and multiplying by 4. A rate below 180 bpm means placental perfusion is failing and the kitten has roughly 6 to 12 hours before it is lost. Below 150 bpm is an emergency: operate now, do not wait for progesterone.

Record each kitten separately. Litters are not uniform, and one rate of 170 among five rates of 220 is the finding that justifies surgery, not the average.

Radiographs: count, position, and head-pelvis fit

Take a lateral and a ventrodorsal view at day 55 to 58, when fetal bones are mineralized. Count skulls and spines; a mismatch means a kitten is hidden behind the pelvis or the count is wrong, and either way you need to know before surgery. Compare the widest part of each skull with the queen's pelvic inlet on the same film: a skull wider than the inlet, or a kitten sitting transversely in the pelvic canal, predicts dystocia.

Breech presentation alone is not an indication, since many queens deliver posterior presentation normally. Transverse lie, two kittens entering the canal together, and a kitten lodged with no progress for 30 minutes after strong contractions are.

The anesthetic plan

Premedicate with an opioid only, such as buprenorphine 0.01 to 0.02 mg/kg intramuscularly; avoid alpha-2 agonists and acepromazine, which depress the kittens and slow uterine recovery. Induce with alfaxalone 2 mg/kg or propofol 3 to 5 mg/kg intravenously to effect, intubate, and maintain on isoflurane or sevoflurane at the lowest concentration that holds the plane.

Monitor on a pulse oximeter and capnograph, and hold mean arterial pressure above 60 mmHg with crystalloids at 10 ml/kg per hour. Hypotension is the commonest reason a litter comes out flat, and uterine blood flow drops before the queen's own pressure looks alarming. Extubate only when she swallows, and keep her on oxygen for 5 minutes after the last kitten is out.

Clip and prep a wide field, because the incision may need to extend. Keep surgery time under 20 minutes from incision to last kitten out: every extra minute of uterine manipulation adds anesthetic exposure to the litter. Have two assistants, a warm box at 35 to 37 Celsius, a suction bulb, and towels ready before the first kitten appears.

The first 30 seconds of a kitten's life

1. 0-5 seconds: tear the sac, clamp and cut the cord 1 cm from the abdomen.
2. 5-15 seconds: clear the mouth and nose with the bulb, wipe fluid from the face.
3. 15-25 seconds: rub firmly with a dry towel, head down, to start breathing.
4. 25-30 seconds: assess heart rate and color; if no breathing, give 3 to 5 seconds of gentle chest compressions.
5. Then place in the warm box and repeat stimulation every 60 seconds until crying.

Costs and what to expect afterwards

Count the placentas as they come out and match the number to the kittens. A retained placenta is the leading cause of post-operative metritis, and it announces itself with a temperature above 39.5 Celsius and foul-smelling discharge within 48 hours.

Budget before the due date with the cost tool and confirm whether the clinic charges an emergency premium after midnight, which is usually 30 to 50 percent.

A planned cesarean in the United States runs USD 800 to 2,000, and an emergency at 2 a.m. with a compromised litter commonly reaches 2,500 to 4,000. The queen goes home on day 1 to 2 with analgesia for 3 to 5 days; the incision is checked at 10 to 14 days. Expect her to be a poor mother for the first 12 hours, which is normal after anesthesia, so plan to bottle-feed or use a foster queen for that window.

When to operate without waiting

Operate immediately for a fetal heart rate under 150 bpm, green or brown vulvar discharge before labor, more than 30 minutes of strong contractions with no kitten, a kitten visible in the canal for 10 minutes without progress, or a queen that is collapsed or bleeding. In those cases the progesterone result is academic. Have the litter's warming box and a bottle-feeding plan ready before surgery starts.

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