**4. Treatment of endometritis**

The purpose of the treatment protocol is always to prepare the endometrium for embryo descent, which happens about 6 days after-mating, but the choice of the exact management depends on the specific etiological diagnosis [56]. The main objective is to resolve endometrial inflammation by restricting the bacterial contamination and by improving uterine physical clearance. This goal is reached through the control of post-mating inflammation length and degree, and/or through the identification and the elimination of the microorganism involved in the uterine infection [67]. Resolution of underlying problems is necessary to succeed in endometritis treatment.

Any anatomical defects, which may contribute to development of infections and impairs the post-insemination fluid drainage, should be corrected with surgery, e. g. , Caslick's vulvo‐ plasty or urethral extension [79]. Traditional therapy to improve physical clearance of uterine fluid is uterine irrigation, associated to the administration of ecbolic, either oxytocin (10–25 UI i. v. or i. m. ) or cloprostenol (250 μg i. m. ), 4 to 8 hours after breeding [44, 80–86]. In case of infectious endometritis, the key to resolve the pathology is the antimicrobial therapy, either with systemic or intrauterine administration. Mucolytic irrigations have been recommended before the antimicrobial infusion, in order to eliminate bacterial biofilm and to improve drugs absorption by the uterine mucosa [17].

New treatment strategies are being developed, thanks to the growth of knowledge about persistent uterine infection pathophysiology. For example, immunomodulatory therapy has been proven effective in modulating the impaired uterine inflammatory response in suscep‐ tible mares. Different biological products such asheterologous or autologous plasma, plateletrich plasma infusions, autologous conditioned serum and mesenchymal stem cells have been tested [87–92]. Corticoids and *Mycobacterium* cell wall extract or *Propionibacterium acnes* have been confirmed to be useful to treat endometritis [93]. At the end of the treatment, its efficacy should be controlled. A clinic examination should always be performed and culture swab and/ or a biopsy sample should be collected at 3–4 weeks from the beginning of the treatment.

#### **4. 1. Uterine flushing**

myeloperoxidase concentration. It has been noted that its concentration is high in mares affected by endometritis, showing a positive correlation both with positive cytological results and with the presence of intrauterine fluid [59]. Further studies to establish the threshold between normal and pathologic uterine concentrations of myeloperoxidase are needed.

Another intriguing biomarker is NO, a smooth muscle relaxant able to compromise the uterine contractility and, consequently, its clearance [60]. A higher amount of NO and a higher NOS expression in uterine biopsies were found in susceptible mares 13 hours after insemination, compared with resistant ones [26]. Although it is not clear whether the higher NO concentra‐ tion in susceptible mares is the cause or the result of a delayed uterine clearance, the difference between the susceptible and the resistant mares suggests a possible role for it either directly

The purpose of the treatment protocol is always to prepare the endometrium for embryo descent, which happens about 6 days after-mating, but the choice of the exact management depends on the specific etiological diagnosis [56]. The main objective is to resolve endometrial inflammation by restricting the bacterial contamination and by improving uterine physical clearance. This goal is reached through the control of post-mating inflammation length and degree, and/or through the identification and the elimination of the microorganism involved in the uterine infection [67]. Resolution of underlying problems is necessary to succeed in

Any anatomical defects, which may contribute to development of infections and impairs the post-insemination fluid drainage, should be corrected with surgery, e. g. , Caslick's vulvo‐ plasty or urethral extension [79]. Traditional therapy to improve physical clearance of uterine fluid is uterine irrigation, associated to the administration of ecbolic, either oxytocin (10–25 UI i. v. or i. m. ) or cloprostenol (250 μg i. m. ), 4 to 8 hours after breeding [44, 80–86]. In case of infectious endometritis, the key to resolve the pathology is the antimicrobial therapy, either with systemic or intrauterine administration. Mucolytic irrigations have been recommended before the antimicrobial infusion, in order to eliminate bacterial biofilm and to improve drugs

New treatment strategies are being developed, thanks to the growth of knowledge about persistent uterine infection pathophysiology. For example, immunomodulatory therapy has been proven effective in modulating the impaired uterine inflammatory response in suscep‐ tible mares. Different biological products such asheterologous or autologous plasma, plateletrich plasma infusions, autologous conditioned serum and mesenchymal stem cells have been tested [87–92]. Corticoids and *Mycobacterium* cell wall extract or *Propionibacterium acnes* have been confirmed to be useful to treat endometritis [93]. At the end of the treatment, its efficacy should be controlled. A clinic examination should always be performed and culture swab and/ or a biopsy sample should be collected at 3–4 weeks from the beginning of the treatment.

or through a NO-associated pathway [26].

**4. Treatment of endometritis**

absorption by the uterine mucosa [17].

endometritis treatment.

304 Genital Infections and Infertility

The uterine lavage is helpful to remove debris, microbes, neutrophils and other substances that interfere with the mucosal absorption of antimicrobial and with neutrophils action. This also improves the clearance by stimulating uterine contractility. The lavage contrasts infectious agents by mechanical irritation of endometrium, which helps recruitment of neutrophils and opsonins [17].

The choice to treat or not a mare with uterine lavage relies on the presence of post-mating intrauterine fluid and on the degree of edema. An US examination is performed 4 to 8 hours post-mating: when no or little edema or slight accumulation of fluid is detected, the lavage is not performed. Otherwise, when the intrauterine fluid is more than 2 cm in depth, the mare is treated with immediate uterine irrigation [17]. To avoid the interference with conception, the best timing for uterine flushing is 4 hours post-breeding [94]. Thus, a further US exami‐ nation is advisable 24 hours post-breeding to evaluate if additional uterine irrigations are needed. Whenever US results are impracticable, a preventive uterine lavage between 4 and 12 hours after breeding should be performed [47].

The procedure for a therapeutic uterine lavage is identical to that described for the low volume uterine flush, except for that a large-bore (e. g. , 8 mm inner diameter × 11 mm outside diameter) Bivona catheter with a balloon cuff is used, and that a volume of 1 to 2 liters of warm solution is typically infused and then removed by gravity [95]. The warm uterine flushing should be combined with uterine massage per rectum to uniformly diffuse the fluid and to stimulate the myometrium contraction. Lavage is generally repeated until the effluent results are clear or not too turbid.

Uterine infusions are performed with isotonic saline solution or other balanced electrolytes solutions, such as lactated Ringer's solution. A low volume, 5–10 ml, of povidone-iodine solution can be added to 1 L of saline as preventive antimicrobial and antifungal treatment. This management is cost-effective and easy to be prepared, stored and delivered. However, it has been reported that intrauterine administration of1% povidone-iodine solution during days 0 and 2 post-ovulation in healthy mares did not induce the histological changes of endometritis, but altered progesterone concentrations and reduced the expression of endometrial proges‐ terone receptors, without affecting estrogen receptors. It was suggested that these changes could reduce embryo survival [96]. Ecbolics are administered as described to eliminate completely the infused fluids [17].

#### **4. 2. Antibiotic treatment**

Identifying and destroying bacterial infections might be the key to resolve some chronic reproductive problems. On the other hand, the decision to use antibiotics should rely on clear diagnostic evidences, which is not always the case. Hence, the key factor in treating endome‐ tritis with antibiotics is to confirm the presence of a true bacterial infection [97]. In endometritis, the infection is frequently limited to the endometrium and intrauterine infusion of antimicro‐ bials is the most common approach treatment. However, the analysis of uterine biopsies showed that *Streptococcus zooepidemicus* was present deep within the endometrial tissue in infertile mares [98]. In these cases, treatments limited to intra-uterine infusions may be unsuccessful, especially if the antibiotic did not achieve deep-tissue concentrations, adequate to kill the microorganism [97]. Infectious endometritis must be treated by intrauterine infusion, during estrus, with the appropriate antimicrobial administered daily for 3 to 7 days and after uterine irrigations, which eliminate organic material that may interfere with the antibiotic function. Intrauterine infusion volumes of antibiotics from 30 to 200 ml have been suggested to achieve distribution throughout the uterine lumen [99]. The infusion of small volumes is advisable, since larger volume infusions result in reflux through the cervix and inadequate distribution over the endometrium. Anyhow, the solution should be water-soluble and nonirritant.

Due to the increased spread of antimicrobial resistance, the choice of the antibiotic should be made considering the susceptibility pattern obtained from uterine culture [67]. Sometimes it is not possible to obtain a culture, either because the owners refuse the procedure or because there is no time to wait for results. In these cases, broad-spectrum antibiotics are the first choice to treat endometritis. Criteria for the choice are based on the consideration of the most common bacteria isolated from mares' reproductive tract: *S. equi* subsp. *zooepidemicus* (Gram positive), *E. coli* (Gram negative), *K. pneumoniae* (Gram negative), *P. aeruginosa* (Gram negative), *S. aureus* (Gram positive), and *Bacteroides* spp. (Gram negative, anaerobe) [19, 71, 100–103].

The effect of various antibiotics has been evaluated with controversial results. Gentamicin (1-2 g) or Amikacin (1-2 g) Gram-negative coveragehave both been demonstrated to significantly reduce the activity of neutrophils [17]. On the basis of the results of an online survey of veterinarians concerning antibiotic use in equine reproduction, the most common antimicro‐ bials used for intrauterine infusions in the mare before receiving culture/ antibiotic sensitivity results were ceftiofur (21%), followed by gentamicin (19%), ticarcillin with clavulanic acid (13%), ampicillin (12%), other (12%), procaine penicillin (5%), amikacin (5%), potassium penicillin (3%) and ticarcillin (3%). The category "other" included combination of penicillin and gentamicin (2%), penicillin and neomycin (2%), ampicillin and gentamicin (1%), oxyte‐ tracycline, framomycin, framycetin, cefquinome, cefazolin or chloramphenicol [97]. Dosages for antibiotics and antimicotics commonly administered either systemically or through intrauterine irrigation to treat endometritis are summarizedin Table 2.

Antibiotic intrauterine infusion in the estrus cycle may be realized either before or after breeding, preferably after ovulation is confirmed. The use of antimicrobial that may potentially have spermicidal properties onthe day of insemination/mating generates controversial opinions. The uterine lavage or infusion is executed at least 4 hours after the insemination, so that the oviduct colonization with the sperm is not compromised. Then, 2 days after ovulation the progesterone levels increase, and the uterine defense mechanisms efficiency consequently decrease. For this reason, performing the infusion between 4 hours after insemination and 2 days after ovulation is considered to be harmless for the conception [104]. On the other hand, the antimicrobial uterine infusion in progesterone phase has been associated with increased incidence of resistant bacterial and fungal infection [105–106].

During acute endometritis, the time length of the antimicrobial treatment should depend on the degree of endometritis, according to endometrial biopsy. In slightly endometritis 3 days, in moderate one 5 days and in severe endometritis 7 days are necessary [99]. Concerns about inducing secondary fungal infections and/or antibiotic resistance are some of the reasons why the intrauterine antibiotic infusions have been reduced. Indeed, uterine lavages with saline associated to the use of ecbolics are now commonly accepted, and antibiotic therapies are more targeted at specific isolated organisms, in conjunction with methods to disrupt biofilms [97].

infertile mares [98]. In these cases, treatments limited to intra-uterine infusions may be unsuccessful, especially if the antibiotic did not achieve deep-tissue concentrations, adequate to kill the microorganism [97]. Infectious endometritis must be treated by intrauterine infusion, during estrus, with the appropriate antimicrobial administered daily for 3 to 7 days and after uterine irrigations, which eliminate organic material that may interfere with the antibiotic function. Intrauterine infusion volumes of antibiotics from 30 to 200 ml have been suggested to achieve distribution throughout the uterine lumen [99]. The infusion of small volumes is advisable, since larger volume infusions result in reflux through the cervix and inadequate distribution over the endometrium. Anyhow, the solution should be water-soluble and non-

Due to the increased spread of antimicrobial resistance, the choice of the antibiotic should be made considering the susceptibility pattern obtained from uterine culture [67]. Sometimes it is not possible to obtain a culture, either because the owners refuse the procedure or because there is no time to wait for results. In these cases, broad-spectrum antibiotics are the first choice to treat endometritis. Criteria for the choice are based on the consideration of the most common bacteria isolated from mares' reproductive tract: *S. equi* subsp. *zooepidemicus* (Gram positive), *E. coli* (Gram negative), *K. pneumoniae* (Gram negative), *P. aeruginosa* (Gram negative), *S. aureus* (Gram positive), and *Bacteroides* spp. (Gram negative, anaerobe) [19, 71, 100–103].

The effect of various antibiotics has been evaluated with controversial results. Gentamicin (1-2 g) or Amikacin (1-2 g) Gram-negative coveragehave both been demonstrated to significantly reduce the activity of neutrophils [17]. On the basis of the results of an online survey of veterinarians concerning antibiotic use in equine reproduction, the most common antimicro‐ bials used for intrauterine infusions in the mare before receiving culture/ antibiotic sensitivity results were ceftiofur (21%), followed by gentamicin (19%), ticarcillin with clavulanic acid (13%), ampicillin (12%), other (12%), procaine penicillin (5%), amikacin (5%), potassium penicillin (3%) and ticarcillin (3%). The category "other" included combination of penicillin and gentamicin (2%), penicillin and neomycin (2%), ampicillin and gentamicin (1%), oxyte‐ tracycline, framomycin, framycetin, cefquinome, cefazolin or chloramphenicol [97]. Dosages for antibiotics and antimicotics commonly administered either systemically or through

Antibiotic intrauterine infusion in the estrus cycle may be realized either before or after breeding, preferably after ovulation is confirmed. The use of antimicrobial that may potentially have spermicidal properties onthe day of insemination/mating generates controversial opinions. The uterine lavage or infusion is executed at least 4 hours after the insemination, so that the oviduct colonization with the sperm is not compromised. Then, 2 days after ovulation the progesterone levels increase, and the uterine defense mechanisms efficiency consequently decrease. For this reason, performing the infusion between 4 hours after insemination and 2 days after ovulation is considered to be harmless for the conception [104]. On the other hand, the antimicrobial uterine infusion in progesterone phase has been associated with increased

During acute endometritis, the time length of the antimicrobial treatment should depend on the degree of endometritis, according to endometrial biopsy. In slightly endometritis 3 days,

intrauterine irrigation to treat endometritis are summarizedin Table 2.

incidence of resistant bacterial and fungal infection [105–106].

irritant.

306 Genital Infections and Infertility

The combination of local and systemic antimicrobial treatment must be performed when clinical examination results in evident general illness, in case of infection or inflammation involving the deeper layers of the uterus, when repeated antimicrobial intrauterine infusions fail to cure, and when the recontamination is alarming. Systemic therapy during diestrus is preferable, since it is associated to lower fluctuation in antibiotic tissue levels and further contamination of the uterus should not happen. Trimethoprim-sulfa, ampicillin, penicillin and gentamicin are commonly used as systemic therapy. Oral administration of enrofloxacin at 5 mg/kg is recommended twice daily, to reach endometrial levels above the minimum inhibitory concentration of many endometritis-associatedbacteria. In adequate doses repetition or drug interaction may create resistant microorganism and superinfections, such as yeasts or fungal overgrowth, which makes it particularly difficult to treat.



**Table 2.** Most commonly used antibiotics and antimicotics to treat equine endometritis, dosages for either systemic or intrauterine use, and bacterial susceptibility

#### **4. 3. Mucolytics and chelating agents**

Persistent endometritis could be associated with hypersecretion of mucus by endometrial epithelium and the presence of exudate renders aminoglycosides chemically inert and generally interferes with antibiotic penetration. Some Gram-negative and positive bacteria or fungi produce biofilm that confers antibiotic resistance [107–108]. The pathogens confirmed to produce biofilm include *S. epidermis, E. coli, E. cloacae* and the most potent biofilm producer *P. aeruginosa*.

Administration of mucolytic drugs is used to eliminate excessive mucus and exudates for the negative effect of the latters both on intrauterine antibiotics and on sperm transport to the oviduct. Despite controversial viewpoints, intrauterine effects of mucolytic oral administration have not been confirmed. However, it was stated that oral N-acetylcysteine (NAC) treatment, even if it does not reduce the viscosity of uterine mucus, has an anti-inflammatory effect on the equine endometrium [109]. Different kinds of intrauterine mucolytics are used and include NAC, dimethyl sulfoxide (DMSO) and kerosene.

The NAC is a mucolytic agent that disrupts disulfide bonds between mucin polymers, thereby reducing mucus viscosity, and in addition possesses antioxidant and possibly antimicrobial properties [110–112]. Furthermore, its properties help the sperm transport to the oviduct. Intrauterine post-breeding infusion of 3. 3% solution of NAC did not result to be harmful to mares' endometrium, and it decreased the extracellular mucus thickness and staining intensity in healthy mares, but not in mares with active bacterial endometritis. The same NAC protocol applied in mares repeatedly bred and with a history of mucus hypersecretion, combined with post-mating uterine lavage, oxytocin, and infusion of an antibiotic, was correlated to good pregnancy rates [113]. The safety of NAC on mucosal surfaces is clear, based on its use as a mucolytic for respiratory disease in humans and treatment for meconium impaction in foals [113]. Interestingly, some recent findings demonstrate that intrauterine application of NAC in healthy mares in estrus may reduce the endometrial response to irritants [114]. The intrauterine administration of 0. 6% NAC solution, prepared by adding30 ml of 20% NAC to 150 ml of sterile saline, performed 48 hours before breeding, improves the pregnancy rates [110]. The effect of post-breeding intrauterine infusion of 30% DMSO solution showed to be effective in improving the endometrial biopsy score, and it lead to higher pregnancy rates compared with mares infused with saline [115]. The improvement of the pregnancy rate, following the infusion of 50 ml of commercial kerosene, operates differently from the other mucolytics. The mecha‐ nisms hypothesized were that kerosene activates endometrial glands and reduces the mucus through the destruction of the uterine epithelium. A moderate to severe endometritis results from kerosene uterine administration, with severe edema and production of serum-like exudates. Half of the treated mares manifest necrosis of the endometrium [116].

Advanced strategies include uterine infusion of buffered chelating agents. Their mechanism of action is not completely clear, but they alter the integrity and permeability of the bacterial cell wall by chelation of the calcium and/or magnesium on the outer membrane. To explicate this action, the chelating agents have to be indirect contact with the bacterial cell wall [67]. Recommended treatment is the infusion of 200 to 500 ml of the first-generation *Tris-EDTA* (ethylenediaminetetraacetic acid 3. 5 M plus tromethamine 50 mM) or third-generation *Tricide* (8 mM disodium EDTA dehydrate plus 20 mM 2-amino-2-hydroxymethyl-1, 2-propanediol) [117–120]. After 12–24 hours, the uterus should be flushed to remove debris and accumulated dead cells. The efflux should be examined; and if it is cloudy or mucus is present, the chelating treatment should be repeated one more time [58].

#### **4. 4. Ecbolics**

**Molecule Dosage**

308 Genital Infections and Infertility

Procaine penicillin 22,000 IU/kg

Fluconazole 14 loading

intrauterine use, and bacterial susceptibility

**4. 3. Mucolytics and chelating agents**

Ticarcillin + clavulanic

Amphotericin B

*P. aeruginosa*.

**(mg/kg)**

q12h

acid 3–6 g /200 mg

Trimethoprim sulfa 30 q12h OS

0.3–0.9 q24-48h

then 5 q24h

Nystatin 0.5–2.5 × 106

NAC, dimethyl sulfoxide (DMSO) and kerosene.

**Route**

Ticarcillin 3–6 g Gram positive,

**Intrauterine**

IM 4.5–6 × 106

Clotrimazole 400–700 mg q24h Yeast [128]

Itraconazole 5 q12–24h IV/OS Broad spectrum [128] Ketokonazole 20 q12h Via Nasogastric intubation in 1–2 h Broad spectrum [128] Miconazole 500–700 mg q24h Broad spectrum [128]

**Table 2.** Most commonly used antibiotics and antimicotics to treat equine endometritis, dosages for either systemic or

Persistent endometritis could be associated with hypersecretion of mucus by endometrial epithelium and the presence of exudate renders aminoglycosides chemically inert and generally interferes with antibiotic penetration. Some Gram-negative and positive bacteria or fungi produce biofilm that confers antibiotic resistance [107–108]. The pathogens confirmed to produce biofilm include *S. epidermis, E. coli, E. cloacae* and the most potent biofilm producer

Administration of mucolytic drugs is used to eliminate excessive mucus and exudates for the negative effect of the latters both on intrauterine antibiotics and on sperm transport to the oviduct. Despite controversial viewpoints, intrauterine effects of mucolytic oral administration have not been confirmed. However, it was stated that oral N-acetylcysteine (NAC) treatment, even if it does not reduce the viscosity of uterine mucus, has an anti-inflammatory effect on the equine endometrium [109]. Different kinds of intrauterine mucolytics are used and include

**Dosage Bacterial Susceptibility Ref.**

UI Gram positive [128]

Broad spectrum [*Staphylococcus, Enterobacter, Bacillus*]

*S. aureus, E. coli, Klebsiella* spp*., Proteus,* some *Nocardia* spp.

UI q24h Yeast [128]

IV 100–200 mg q24h Broad spectrum [128]

IV/OS 100 mg q24h Yeast [128]

*Pseudomonas* [97]

[97]

[128]

Uterine irrigation should be associated with systemic administration of ecbolic drugs, which increase clearance of the fluid through cervix, stimulate myometrial contraction and impair lymphatic drainage from the uterus. Oxytocin is an equine uterine ecbolic commonly utilized in doses ranging from 10 to 25 IU i. v. or i. m. Higher doses should be avoided, since it may impair pregnancy rates [86]. The administration of oxytocin, in estrus and 48 hours postbreeding, induces high-amplitude uterine contractions lasting from 30 minutes to 1 hour. However, oxytocin half-life is very short and repeated administrations enhance treatment effectiveness [81, 121–122].

These drugs may be ineffective in aged maiden mares in which the cervix often fails to dilate. In such cases, oxytocin therapy should be associated with topical application to the cervical epithelium of misoprostol, a synthetic PGE1 analogue, before breeding, or substituted by cloprostenol administration to sustain low-amplitude uterine contraction for 2 to 4 hours. Intramuscular administration of cloprostenol or PGF2α at a dosage of 250μgis recommended, before the ovulation or within 12 hours. However, administration post-ovulation is not advisable, since it decreases serum progesterone concentration and consequently the preg‐ nancy rates. The cloprostenol-induced contractions last longer; therefore, cloprostenol is more suitable for mares with lymphatic stasis. Side effects, such as sweating and abdominal cramping, are minimal, transient, inconstant and dose-dependent [123].

The best timing for ecbolic administration after uterine lavage associated to the antimicrobi‐ al infusion has not been established, yet. When treating anxious or excitable mares, seda‐ tives with α2-adrenergic agonist action, such as xylazine or detomidine, should be used. These sedatives optimize oxytocin effect and increase the intrauterine pressure, where as acepromazine, aα1-adrenergic antagonist, can cause a reduction of uterine contractions after oxytocin treatment [47].

#### **4. 5. Immunomodulators**

Higher levels of anti-inflammatory cytokines were observed in resistant mares compared with susceptible ones. The rationale for using immunomodulators is to equilibrate the expression of pro- and anti-inflammatory cytokines in susceptible mares and to rehabilitate the homeo‐ stasis of the local inflammatory response.

Glucocorticoids have been demonstrated to suppress the immune response, decreasing gene expressions of the pro-inflammatory cytokines, IL-1α, IL-6, IL-8, while enhancing defense mechanisms and stimulating a higher anti-inflammatory response. Thus, short-term steroid therapy maybe beneficial for treating post-mating endometritis in the mare [124]. An increase of pregnancy rates after single injection of dexamethasone within 1 hour post-mating, approximately 0. 1 mg⁄kgi. v. , associated with routine therapy, has been demonstrated in mares with history of fluid accumulation after breeding. Oral administration of 9-alphaprednisolone acetate at 0. 1 mg⁄kg twice daily for 4 days, beginning 48 hours before breed‐ ing, and the association of dexamethasone, administered within 1hour after mating, and prednisolone, administered once daily before and after mating, were confirmed to be efficacious only in susceptible mares, decreasing uterine edema, and reducing and clarify‐ ing intra-uterine fluid [125–126].

Other immunomodulatory treatments have been tested to elicit a general increase in immune system activity by means of non-specific cell-mediated response and modulating the release of cytokines [127]. *Mycobacterium phlei* wall extractand *Propionibacterium acnes* were reported to be efficient in uterine infectioncaused by *S. equi* and *S. zooepidemicus* and in chronic endo‐ metritis, respectively [17, 93]. In 2014, mesenchymal stem cells and autologous conditioned serum were used to modulate successfully the uterine inflammatory response to spermatozoa in healthy mares [90]. However, the former seems to be more reliable than the latter, and additional studies are ongoing to determinate the effects of mesenchymal stem cells on "problem" mares. Preliminary data on small volume intrauterine infusion of platelet-rich plasma, either before or after insemination, suggest an improvement in conception rate, probably due to a more appropriate uterine environment for embryo survival. Both the efficacy and the exact mechanisms of action of these treatments need further elucidation, but they seem to be triggered through activating platelets, cytokines and growth factors, and they seem to regulate cell migration, attachment, proliferation and differentiation, and to promote extrac‐ ellular matrix accumulation [89, 91–92, 128].
