Emergency caesarean section and planned caesarean section, how? When? And why?
To be able to deal with the theme "caesarean section" it is necessary to first determine when the pregnancy ends, in a gestation of only 63 days even an advance or a delay of 2-3 days can be extremely detrimental to the state of health of the unborn. The pregnancy starts in the moment in which the ovulation takes place, and its duration will be 63 days, too often the calculations related to the identification birth’s day are made starting from the day in which the mating takes place, the error’s margin, in this case, it is very large and can range from a minimum duration of 58 up to a maximum of 70-71 days.
The reason for such a wide range is due, on the one hand, to the survival of post-ovulation ovules, which can remain in the uterine tubes for a long time before being fertilized, and on the other hand, to the documented survival of sperm in the female genital tract up to about 7 days after mating. It goes without saying that, if a mating is done well in advance of the date of actual fertility, the sperm can maintain its fertilizing capacity in the female genitalia and fertilize the oocytes even after lot of days (pregnancy that will last more than 63 days up to a maximum of 70-71 days).
The opposite situation, that of a pregnancy which, counted from mating’s date can last less than 63 days, because the female dog is the only animal species in which at follicles burst moment, are ovulated immature oocytes, the defined process of meiosis to ensure the maturation of oocytes, making them viable, takes in 48 hours. At this moment, the mature oocytes can maintain their fertility for about another 2-3 days. A mating that takes place 5 days after ovulation can be fruitful with the birth of puppies 58 days after mating.
The ovulation date’s importance detected thanks to the ovulation’s proper monitoring, through vaginal smears and progesterone’s dosage, will be an extremely reliable parameter to predict the delivery’s date. Lacking the ovulatory data, it is possible to postpone the gestation with the help of the ultrasound, the embryonic and subsequently foetal biometrics is the one that is exploited for this purpose (M. Beccaglia, M. Faustini and GC Luvoni, 2008). At diagnosis’ time of pregnancy between 24 and 30 days it will be possible to derive the average diameter of the embryonic vesicles, this number expressed in mm is inserted in a mathematical proportion that will result in the days remaining to childbirth, obviously with different mathematical proportions depending on the size of the female dog, the margin of error can be a +/- 1.
Foetus head diameter’s ultrasound measurement (BP)
After defining the pregnancy’s duration and how to establish its end it will be necessary to ensure adequate assistance to childbirth, if the pregnant belongs to a breed with a high degree of dystocia (Bulldog and chondrodystrophic breeds) or there is a previous history of difficulty in the ejective phase of childbirth, it will be good to plan a C-section to minimize the risk of loss of puppies.
In most of the cases, 18-24 hours before the delivery there is a female dog’s body temperature lowering under the 37,5°C, which corresponds to 10-14 hours after the blood rate’s fall of progesterone. The delivery cannot take place if the progesterone does not fall below 2 ng/ml.
It may be useful, therefore, to predict the delivery, to evaluate progesterone’s blood rate, if it is under 2 ng/ml the delivery will take place within the next 24 hours.
The most reliable parameter to consider knowing the puppies’ health’s condition or better their suffering’s state, at the end of pregnancy, is surely the relief of the foetal heart’s relief rate, by means of the mother’s abdominal ultrasound.
A normal heart rate should be higher than 200 bpm (beats per minute), a frequency of less than 200 indicates already foetal suffering and a frequency between 180-200 may be compatible with a birth occurring within the next 24 hours but a foetal heart rate below 180-160 bpm provides at most a wait of 12 hours for a possible natural birth otherwise caesarean section, A heart rate below 160 requires a caesarean section without waiting for further time.
It is good to consider that a foetal heart rate below 120, in most cases, does not leave much hope for the puppies’ survival, even with a C-section performed immediately.
Let’s see now what may be the conditions for which to think about a caesarean section, the difficulty in the expulsion of puppies or in the failure to start the delivery are defined as "dystopias" and the causes can be both maternal and foetal or both.
In case the dystonia is due to maternal causes the possibilities are:
-Primary uterine inertia.
-Secondary uterine inertia.
-Dystopia due to obstruction.
Primary uterine inertia is characterized by the inability to expel foetuses through the birth canal that has no abnormalities except for a cervix’s incomplete dilatation. The exact cause of this is not entirely clear and several factors seem to influence it: mechanical, hormonal, anatomical and genetic causes. We speak of complete primary uterine inertia if there aren’t second stages of childbirth’s signs, that is, the expulsion stage, there may be vaginal losses from lochiations (greenish) in excused uterine contractions’ absence.
The contractions are weak, infrequent, and unproductive. Atony can occur after the expulsion of some of them. It occurs with greater frequency in obese and/or old dogs as well as the uterus’ excessive distension for a high number of foetuses or a single microsomal foetus (of remarkable dimensions) could be the cause.
There are also pathologies or systemic conditions that can justify a birth with primary uterine inertia such as hypocalcaemia, obesity, uterine infection, septicaemia, inadequate nutrition, uterine torsion, or trauma. Serum calcium should always be evaluated in dogs affected by uterine inertia.
Secondary uterine inertia is due to obstruction, foetal or maternal origin, which leads to the loss of contractility of the uterine musculature. In the case of maternal obstruction, account shall be taken of:
Uterus’ torsion: If a foetus or all foetuses cannot be expelled (depending on the location of the torsion), it is a rare condition.
Inguinal or perineal hernia: inguinal muscles of perineum's failure, for which the pregnant uterus, or a portion of it, can herniate outside the pelvic cavity with impossibility of foetuses’ expulsion.
Uterine rupture: the rupture of the wall of the uterus with consequent passage of a foetus, or more than one, in abdominal cavity makes impossible the expulsion and associates itself with complications like peritonitis. Also, this is a rare and more frequent condition in elderly subjects and with a protracted uterine contractility without the possibility of expelling foetuses for various reasons.
Conformation abnormalities: An abnormality of the uterus has been described as a maternal cause of dystonia in which the body or the first sections of both horns form a thin fibrous tube about 1 cm in diameter.
Obstruction dystopia more frequent, but still rare, are abnormalities in the vagina or vulva such as fibrous septa that bipartite the birth canal or the presence of bands of fibrous tissue that constitute an impediment of foetus’ progression. (See the photo)
Usually, these conditions are diagnosed during the coupling as depending on the location can be an obstacle to the natural mounting. For this reason, dogs that are subjected to artificial insemination should always undergo an endoscopic examination to verify that the entire vaginal tract has a normal conformation.
Dystocia due to foetal causes:
The presentation, the position, and or the posture of the puppies during childbirth may predispose to dystocia. The 60% of the cubs are delivered in longitudinal cranial position and the remaining 40% in longitudinal caudal podalic position, however the caudal podalic position is considered "normal" in the accomplishment of the delivery in the dog even if objectively accompanied by a greater incidence of difficulties in the expulsion. Probably the greater duration of time with which it arrives at the expulsion phase of the podalic puppy is due to the lack of stimulation from the head of the puppy on the mother's pelvis in stimulating the uterine and abdominal contractions.
Transverse presentation is rather rare, and usually associated with a bicorne presentation of a single foetus, that is, a position at the level of uterus’ bifurcation with the head and the fore legs growing in a uterine horn and the hind legs and tail in the other uterine horn. The transverse position often results in an obstruction in the pelvic canal (see fig.n. G)
The foetus plays an important role in positioning itself correctly with the head and with the front legs extended, each on the side of the head: the foetal death, before having engaged the birth canal, predisposes to obstructive dystocia.
Abnormal foetal development is often associated with ejection difficulties. The abnormalities of foetal development may be the hydrocephalus, the oedematous cub or "anasarca", more frequent in some breeds due to a genetic predisposition as in the English Bulldog. Other developmental defects, often associated with dystocia in the dog, are additional legs or abdominal hernia, due to the failure to merge the alba line or thoracic hernia due to embryonic fusion of the two hemithorax.
Prolonged pregnancy beyond the end:
Failure to deliver more than 65 days after the ovulation day should give cause for concern and it will therefore be appropriate to carry out a check on the dam to assess the causes of this delay and the state of health of the unborn. The fall in the dog’s rectal temperature below 37.5° C indicates the occurrence of luteinises (pregnancy’s end) and the sudden fall in the blood rate of progesterone, from there to 24 hours the dog should start to give birth. It has been investigated that the monitoring fall of progesterone’ is useful as an indicator of the pregnancy’s end and especially as an indicator to proceed with a possible c-section but unfortunately the fall of the hormone rate can be extremely rapid even in 12 hours.
In two different studies, 59% and 48% of dogs with dystocia and prolonged pregnancy had gestations with a single foetus, it seems that the presence of a single foetus is not sufficient in stimulating adequately, from the hormonal point of view, the uterine contractions necessary for the accomplishment of a "normal" delivery in "normal" times.
The treatment for a prolonged pregnancy beyond the end, calculated from the day of ovulation, if from an ultrasound point of view the foetal beats are below 180 bpm/m' and with an amniotic fluid’s shortage is the caesarean section.
The success of a caesarean section is linked to several factors, the main ones are:
-Choice of time to perform surgery.
-Choice of medications for anaesthesia.
-Speed in the extraction of puppies.
-Appropriate resuscitation techniques.
It is necessary to clarify the concept that there are no medicines that can be used in anesthesiology protocols that are completely safe, the placental barrier is permeable to all the molecules, it is recommended to choose those medicines that have the fastest metabolism and pass as little as possible the placental barrier. There are several anaesthesiologica protocols, but the most valid concept is to use the protocol with which you are most familiar.
In a patient's preparation for surgery, it is good to ensure a good oxygenation and not lie down in dorsal decubitus before being ready for surgery, this is because the pregnant uterus would compress the large blood vessels creating low puppies’ oxygenation.
To guarantee puppies’ fast extraction it would be necessary to be in 3 or 4 operators, for the anaesthesia, and revive the puppies.
A valuable help during caesarean section is given by the "incubator" which can also be a non-professional type "nursery" (see photo) but suitable to keep the puppies at a right temperature and controlled humidity rate, as the puppies are revived, they will be placed inside the "nursery" to can help the next puppy.
(“nursery” available on www.dogmarket.it)
An extremely important fact is that the dog should not be left with the puppies without the control of the breeder. The post-awakening from the anaesthesia can justify mother’s obsessive-compulsive attitudes towards the "born", sometimes obsessive puppies’ lapping can lead to mutilation and/or cannibalism unintentionally. The advice is to make the dog breastfeed after anaesthesia, lying on side, and once the puppies fall asleep after the sucking, withdraw mother, and bring her back to the puppies, left warm in the birthing box, after 2-3 hours. These indications are valid for the first 24 hours after awakening from the anaesthesia. The puppies must be kept inside a birth box, possibly with a heated floor from the heating platform with an inside temperature of 28° C for the first week of life. Puppies born from caesarean section, if don’t have, in the first 4 hours of birth the possibility to feed naturally, should be supported by odourless and colourless liquid food that gives an energy intake that doesn’t lower blood sugar and gives the necessary vigour for proper and effective breastfeeding, for this purpose, I believe that the most effective product is the "ENERGY BOOSTER" (64% lipid, available on www.dogmarket.it), to be administered directly in the mouth with insulin syringe at a rate of 0.2-0.5 ml two or three times per day depending on the size of the breed in question. This supplement may be stopped when the daily weight increases by 10% during the 24 hours.