Summary
Caring for premature kittens is challenging. Factors to consider include how prematurely they are born and their birth weight, as well as the knowledge and skill of the caregiver. Learn more about the causes of premature birth and how to recognize and care for premature kittens so you can give them their best chance for survival.
Caring for Premature Kittens
A premature kitten (aka preemie) is one born 61 days or younger than the average gestation period of ~63 days (+/- 2 days). The earlier a kitten is born, the less likely the chance of survival; if born two or more weeks early, survival is not expected. However, many slightly premature kittens can survive with proper care.
Understanding Premature Kitten Causes
Within a single litter of kittens, some may be born prematurely due to superfecundation. This situation occurs when a female cat mates with a male cat (or several different male cats) during her heat cycle. Each egg can be fertilized at a different time or by a different male’s sperm. Therefore, some eggs may be fertilized earlier, yet those kittens are born at the same time when the full-term kittens are born.
Other causes for premature birth include the queen experiencing an injury, illness, stress, malnutrition, hormonal imbalances, noninfectious uterine or vaginal disease, ovarian cysts or genetic predispositions.
As with kittens carried to term, premature kittens are born unable to see, hear or regulate their body temperature (See Daily Care of Bottle Kittens). Premature kittens have additional challenges as essential organs, including their lungs, kidneys, liver and digestive system, are not fully developed to function properly.
Lungs will lack surfactant and cannot exchange oxygen and carbon dioxide efficiently. Kidneys will be limited in their ability to maintain the correct electrolytes (elements in the blood that are critically important to life, including sodium, potassium, chloride, calcium, and phosphorous) and acid-base balances (pH) within the body. The liver will be less able to synthesize protein, remove toxins or produce chemicals needed for digestion. And the digestive system will be unable to absorb enough nutrition from the queen’s milk or kitten milk replacement formula.
Recognizing Premature Kittens
While birth weights of kittens of different breeds vary, premature kittens will have an even lower- than-expected body weight below ~85 grams. Full-term kitten birth weights are 85–110 grams or 2.9–3.9 ounces, with average weights of 98 grams or 3.5 ounces.
Premature kittens will also have visible differences, including the absence of fur, especially on extremities, and wrinkled-looking skin.
Finally, premature kittens are much weaker than full-term kittens and will likely lack the reflexes of righting, rooting, suckling and displaying the flexor reflex of pulling their back legs up to their body when scruffed. Scruffing by people is not generally recommended, but it may be done quickly and gently on very young kittens to assess this reflex. Premature kittens may also have difficulty holding their head and body in position to latch onto a nipple, making it difficult or impossible for them to nurse effectively.
Caring for Premature Kittens Immediately Following Birth
Assist the queen as necessary to ensure the fetal membrane is removed, the umbilical cord is severed, and the kitten is stimulated to breathe. See The Queen Birth Process article. If the kitten is having difficulty breathing, seek immediate veterinary intervention. If premature kittens are unable to inflate their lungs completely, hypoxia (low oxygen level in blood and tissues) ensues and will require immediate veterinary treatment before respiratory arrest occurs. Swinging or slinging kittens is not recommended to clear the airways because it can result in dropping the kitten and cerebral hemorrhage.
Be sure the kitten’s fur is licked dry by the queen or assist with dry, soft towels as needed. Keep the kitten warm with the assistance of an external heating device or preferably by keeping the kitten in an incubator with an ambient temperature of 90–95° F/32–35°C. Most incubators also have options for attaching external oxygen sources.
Once the kitten is stable, warm and breathing well, do a brief exam on the kitten, trim the umbilical cord if needed about 3 inches from the abdomen, being careful not to pull on it and treat the stump with povidone iodine. Allow the umbilical cord to dry and fall off on its own, which in premature kittens may take 7–10 days. Removing the cord can lead to hemorrhage and hernia or can introduce infection, which could prove fatal.
Caring for Premature Kittens Daily
Much of the daily care for premature kittens is the same as for bottle kittens. (See Daily Care of Bottle Kittens) However, premature kittens need frequent feeding and monitoring. They will likely not be able to suckle strongly or at all, so syringe or tube feeding of kitten milk replacement formula will probably be necessary in smaller amounts and on a more frequent schedule than a bottle- or syringe-fed kittens born at term.
Keeping Premature Kittens Warm
All kittens, including premature kittens, must be warm before being fed. Premature kittens are predisposed to hypothermia (low body temperature) and can feel cold, be limp, have low blood pressure, slowed circulation and appear pale (then blue) on the paws, abdomen, tongue and gums. These are particularly dangerous as they can result in decreased heart and respiratory rates and lead to cardiovascular failure.
Hypothermic premature kittens need to be slowly warmed to a rectal temperature of 97°–98°F/36.1°–36.6°C over a period of one to three hours. Rewarming them too rapidly increases their metabolic demand and can cause pulmonary and circulatory collapse. Hypothermic kittens fail to suckle effectively, which leads to hypoglycemia (low sugar level) and deprives the body of energy. This results in unconsciousness and, ultimately death.
Environmental warmth, a minimum nest ambient temperature of 90-95°F/32-35°C, an ambient room temperature of 75°F/24°C and proper humidity near 60% are essential for maintaining kittens’ temperature and hydration simultaneously. Increasing humidity can be accomplished using an inexpensive room humidifier or simply by placing open water-filled containers near a heat source or a window.
There are numerous ways to warm premature kittens. An incubator is ideal, however there are other options such as certain bird brooders and intensive care units.
Heating pads (without an automatic shut off), microwaved rice bags, warm-water-filled plastic bottles and SnuggleSafe® discs can also be used to warm kittens. The objects must be reheated frequently and covered with a towel, fleece or flannel to prevent burning the kittens. Infrared warmers can also be used, but extreme care is necessary to ensure that premature kittens do not become hyperthermic (overheated) or burned. It is imperative that kittens can move away from the heat source. Since many premature kittens lack adequate muscle development and strength to move onto and off of heating sources, it is imperative that the caregiver ensures that the heat source being used is at a safe temperature and that the kitten is checked frequently and changed to a different position. This is done to prevent one area of the kitten (facing toward the heat source) from becoming too warm while another part (facing away from the heat source) becomes too chilled.
Feeding Premature Kittens
During the first week to ten days of life, premature kittens require frequent feeding, about every 30 minutes to 1 hour. Kittens born 6 days or earlier than the due date and/or with a body temperature of 94°–95°F/34.4°–35°C should be tube fed. Body temperatures less than 94°F/34.4°C lead to bradycardia (low heart rate) and lack of gastrointestinal peristalsis (muscle contractions that move food through the digestive tract), and any fluids given orally cannot be adequately absorbed. Veterinary intervention at this juncture is indicated.
Premature kittens are exceedingly prone to dehydration because of immature renal (kidney) function. The usual skin tent test assessment is unreliable because of decreased fat content. Dehydration can be judged by evaluating the gums, which should be moist and not tacky or pale, assessing the ability to urinate and the color of the urine, which should be very pale yellow, and judging the overall condition of the kitten.
Initially, an electrolyte solution of Lactated Ringers mixed with 50% Dextrose at a 2:1 ratio or three tablespoons of unflavored Karo syrup (not the sugar-free variety) mixed with ½ cup of unflavored Pedialyte solution can be given via an oral syringe or dropper to kittens at 1 ml per 100 grams body weight every 20–30 minutes until the kitten is rehydrated and can urinate when stimulated. Fluids should be warmed to 95°–99°F/35°–37.2°C before they are given by any route to prevent hypothermia. Contact a veterinarian in cases of severe dehydration.
Kitten milk replacement formula can be started once premature kittens appear stable and have a body temperature greater than 95°F/35°C). Kitten milk replacement formula is mixed in graduating ratios of water-to-formula to ease the transition to bottle feeding and to prevent diarrhea, which commonly occurs whenever there is a change in diet. Because a premature kitten’s digestive system is still underdeveloped, the formula needs to be diluted to make it easier to digest and will also help provide additional hydration. It is recommended that the first four feedings be at a ratio of 8:1, eight parts water to one part formula. The second four feedings are at a ratio of 4:1, and all other bottle feedings are at a ratio of 2:1.
Remember that the maximum comfortable stomach capacity is 4 ml/100 grams in body weight. Avoid filling the stomach to capacity to help prevent any aspiration. Depending on the kitten’s condition (how premature, what the kitten weighs, etc.), feeding may need to happen in small amounts every hour or may be extended to every two to three hours as the kitten grows and becomes stronger. It is essential that the kitten receive frequent feedings to maintain necessary glucose levels. Do not wait for kittens to wake up to feed them. Newborn kittens, especially premature ones, will sleep almost all the time and waiting for them to wake up may cause their glucose levels to drop dangerously low. Also, since the eyes of newborn kittens are shut, and weak kittens may not be strong enough to move or vocalize, it is very difficult to tell whether the kitten is awake or not.
While there are measurements on the syringes to show how much formula is given to the kitten, some formula may dribble out of the syringe or from the kitten’s mouth. Therefore, weighing the kitten before and after feeding will help to track exactly how much formula (by weight) the kitten has taken in. See below for information about stimulating to urinate or defecate before feeding. Similarly, weighing kittens after urinating or defecating provides a more accurate measure of the kitten’s body weight as you are not also weighing urine and feces. In small kittens, a full bladder or colon can add a significant weight change.
Stimulating Premature Kittens to Urinate and Defecate
Premature kittens, like all kittens under 3–4 weeks of age, must be stimulated to urinate and defecate either by the queen or caregiver. Although urination occurs at each stimulation, a kitten typically defecates only once every 12–24 hours. Seek veterinary attention if the kitten hasn’t defecated by the third day. Stimulating orphan premature kittens to urinate and defecate and keeping them clean becomes a caregiver’s job. Each kitten is an individual and will respond differently to stimulation techniques, the most common being using soft tissue or toilet paper to gently massage the genital and perianal area in a circular motion and apply constant contact until elimination begins. Once urination or defecation starts, stimulation should continue until all the urine or feces has been expelled and the kitten is no longer ‘pushing’ to defecate. Note: when the kitten begins to defecate, you can stop rubbing and allow the feces to be expelled. Then, start rubbing again to ensure all the feces has been expelled. If the kitten does not push to expel more feces after 10 seconds or so, you can stop stimulating.
It is best practice to stimulate for urination and defecation before feeding and again after feeding. Applying warm water to the tissue immediately before stimulation can be useful for kittens who have difficulty eliminating urine or feces.
Comfort Items for Premature Kittens
Warmth and touch are especially important for the development of premature kittens. A product such as Snuggle Kitty may ease loneliness, fear and separation anxiety by mimicking maternal intimacy with warmth and a heartbeat.
Although premature birth represents a significant survival challenge for kittens, meticulous caregiver attention and management can increase the chance of their survival.
