mechanism in reptiles is not as well understood as that of mammals.
It is suspected that a multitude of environmental and behavioral factors, as well as underlying diseases, contribute to an abnormal function of the endocrine system, which in turn leads to dystocia.
It is also possible that a lack of breeding and exposure to males may be contributing factors.
In addition to basic husbandry aspects, such as UVB light, temperature, humidity, and a proper diet, female reptiles also have a need for appropriate substrate and environment that is conductive for egg laying.
SIGNALMENT/HISTORY
Dystocia occurs in female chelonians of reproductive age or size.
Most animals have a history of inadequate nutrition and husbandry lacking an appropriate area for laying eggs.
CLINICAL PRESENTATION
Signs of dystocia may include straining with or without vocalization, decreased fecal production, cloacal prolapse, hind limb weakness/paresis, lethargy, and anorexia.
Some animals may also appear restless and may be observed attempting to dig.
In some instances, the eggs may be palpable through the prefemoral fossa during physical exam.
Physical exam should be done carefully to avoid rupturing the eggs.
In most cases, the owners are not aware of the fact that their chelonian is in dystocia.
Other abnormalities identified in physical exam may include dehydration, poor body condition score, and pliable bones.
RISK FACTORS
Husbandry
Inappropriate husbandry is likely a significant contributing factor to the occurrence of dystocia.
Beyond temperature and humidity, inadequate UVB light exposure and calcium supplementation is key in the development of NSHP, which in turn can have a significant impact in calcium availability, egg calcification, and contractions of the reproductive tract.
Chelonians presenting for dystocia may also have concurrent NSHP.
An often‐forgotten aspect of the husbandry of reproductive female chelonians is the provision of an adequate substrate for nesting.
Reptiles that may not perceive the environmental conditions are adequate for successful oviposition may not have the proper stimuli to lay their eggs.
Others
A less‐discussed topic is the effect that lack of exposure to males may have on the reproductive cycle of reptiles.
Many reptiles display courtship and breeding behaviors that likely influence the proper hormonal stimulation of prospective females.
Many female chelonians in captivity are kept alone without the benefit of behavioral cues from a male counterpart.
This possibility of a behavioral effect must be considered, especially when animals are maintained in proper husbandry and are otherwise healthy.
DIFFERENTIAL DIAGNOSIS
Follicular stasis
Neoplasia
Egg yolk coelomitis
Ovarian cysts
GI obstruction
DIAGNOSTICS
Radiography
The eggs of most species appear calcified, round to ovoid, but sea turtle eggs are minimally calcified.
Ultrasound
Appearance of calcified eggs is a well-delineated hyperechogenic eggshell membrane to significant acoustic shadowing.
In those with poorly calcified eggshell, ultrasound may be more sensitive than radiographs at diagnosing broken eggs, which may be associated with egg yolk coelomitis.
CT and MRI
Both these modalities are extremely sensitive at identifying eggs and can better assess their structure, integrity, and location.
Coelioscopy
Coelioscopic examination allows for confirmation of the presence of eggs and ruling out egg yolk coelomitis. However, the presence of eggs makes coelioscopy more difficult due to their space‐occupying nature. Coelioscopy can also be used to assess the viability of the oviduct based on appearance and coloration.
Hematology and Biochemistry
A chemistry panel is essential to help to identify other possible underlying disease processes such as dehydration and NSHP. In addition to Ca and P, Mg levels should be documented, as Mg also plays an important role in Ca homeostasis. Levels of Mg below 1 mg/dl and/or ionized Ca below 1 mmol/l should be considered deficient. Hypercalcemia and hyperphosphatemia are common findings in reproductively active females.
CBC: a leukocytosis indicates a significant inflammatory response, which may suggest an additional underlying disease like egg yolk coelomitis.
PATHOLOGICAL FINDINGS
Grossly, dystocia can be identified by the presence of eggs within the oviduct.
Pathologic findings may include variation in eggs size, calcification, malformations, broken eggshells, and oviduct torsions.
Healthy eggs should be smooth, uniform in shape and white in color.
A deviation from this appearance (i.e., dark, shriveled) is indicative of pathology.
APPROPRIATE HEALTH CARE
The treatment approach to dystocia
