Eutopic or Ectopic Pregnancy: A Competition between Signals Derived from the Endometrium and the Fallopian Tube for Blastocyst Implantation

Expression of E-Cadherin and Ber-EP4 in the Trophoblastic Tissues of Intrauterine and Ectopic Tubal Pregnancies

Introduction: We investigated the role of E-cadherin and Ber-EP4 in tubal pregnancy by comparing their expressions in epithelial and trophoblastic cells both in ectopic tubal and intrauterine pregnancies. Methods: The Formalin-fixed paraffin embedded blocks of 17 intrauterine and 17 tubal pregnancies were immunohistochemically stained with E-cadherin and Ber-EP4. Results: E-cadherin was expressed in the epithelium, villous and extravillous trophoblast in tubal and intrauterine pregnancies but not in the syncytiotrophoblast. The staining intensity was lower in the extra-villous trophoblast in tubal ectopic pregnancies compared with intrauterine pregnancies. Ber-EP4 was expressed in the epithelium of tubal and intrauterine pregnancies and only in villous cytotrophoblast. The intensity of staining in tubal pregnancy was higher than in intrauterine pregnancy. Discussion: The loss of E-cadherin expression in extra-villous trophoblast and increased expression of Ber-EP4 in the villous cytotrophoblast may play a role in the formation of tubal pregnancy by allowing the blastocyst to attach to the tubal epithelium.

A delayed spontaneous second-trimester tubo-abdominal pregnancy diagnosed and managed by laparotomy in a "self-identified" infertile woman, a case report and literature review

BACKGROUND

Abdominal pregnancy, a rare form of ectopic pregnancy, is associated with high morbidity and adverse consequences for future fertility. Early recognition and management reduce mortality and allow minimal invasive and conservative treatment. In modern medicine, primitive prevention to unexpected fatal pregnancies is crucial.

CASE PRESENTATION

A divorced 33-year-old "self-identified" infertile polycystic ovary woman diagnosed as repeated implantation failure in previous in vitro fertilization with her ex-husband ever presented in surgery department with a history of 15-day abdominal pain, nausea, and vomiting and 3-h worsening abdominal pain. The serum beta-human chorionic gonadotropin value was more than 10,000 m-international units per milliliter. Sonogram findings were significant for the absence of intrauterine gestation; a placenta and well-formed living fetus of second-trimester gestation were seen in the abdomen, accompanied by hemoperitoneum. A unique spontaneously second-trimester tubo-abdominal pregnancy was confirmed in emergent laparotomy by gynecologists, she received a removing of the living fetus, a right total salpingectomy, resection of partial omentum and blood transfusion. The patient recovered uneventfully and her serum beta-human chorionic gonadotropin returned to normal range on the 30th postoperative day, till now, she has weak fertility awareness because of her catastrophic experiences in the unexpected abdominal pregnancy.

CONCLUSIONS

This case highlights woman with a previous in vitro fertilization history may be in is a high risk to be delayed or missed in diagnosis in an intended ectopic pregnancy due to a fixed belief in infertility. Educational interventions and contraceptive care should be provided by fertility and healthcare practitioner. The possibility of abdominal pregnancy must always be suspected and dealt with promptly and appropriately by the astute clinician.

Autologous Human Mesenchymal Stem Cell-Based Therapy in Infertility: New Strategies and Future Perspectives

Infertility could be associated with a few factors including problems with physical and mental health, hormonal imbalances, lifestyles, and genetic factors. Given that there is a concern about the rise of infertility globally, increased focus has been given to its treatment for the last several decades. Traditional assisted reproductive technology (ART) has been the prime option for many years in solving various cases of infertility; however, it contains significant risks and does not solve the fundamental problem of infertility such as genetic disorders. Attention toward the utilization of MSCs has been widely regarded as a promising option in the development of stem-cell-based infertility treatments. This narrative review briefly presents the challenges in the current ART treatment of infertility and the various potential applications of autologous MSCs in the treatment of these reproductive diseases.

Abdominal heterotopic pregnancy after in vitro fertilization and embryo transfer following bilateral salpingectomy: A case report and literature review

Background

Risk of heterotopic pregnancy following bilateral salpingectomy has increased considerably due to the widespread use of assisted reproductive technology. Poor understanding of this condition often causes delayed or missed diagnosis.

Objective

In this report, we describe the case of a 30-year-old pregnant woman with lower abdominal pain lasting for half a day and a history of bilateral salpingectomy. Two embryos had been transferred 21 days preceding her presentation.

Methods

Case report.

Results

Laparoscopic surgery revealed intraperitoneal hemorrhage and proper ovarian ligament pregnancy confirmed by histopathology. Viable intrauterine pregnancy was verified 3 days later by ultrasound examination.

Conclusion

Heterotopic pregnancy is a serious condition that may be life-threatening. Clinicians should be aware of the potential for heterotopic pregnancy in patients receiving in vitro fertilization and embryo transfer after bilateral salpingectomy.

Molecular Mechanisms Underlying the Association between Endometriosis and Ectopic Pregnancy

Endometriosis is a common inflammatory disease characterized by the presence of endometrial cells outside the uterine cavity. It is estimated that it affects 10% of women of reproductive age. Its pathogenesis covers a wide range of abnormalities, including adhesion, proliferation, and cell signaling disturbances. It is associated with a significant deterioration in quality of life as a result of chronic pelvic pain and may also lead to infertility. One of the most serious complications of endometriosis is an ectopic pregnancy (EP). Currently, the exact mechanism explaining this phenomenon is unknown; therefore, there are no effective methods of prevention. It is assumed that the pathogenesis of EP is influenced by abnormalities in the contraction of the fallopian tube muscles, the mobility of the cilia, and in the fallopian microenvironment. Endometriosis can disrupt function on all three levels and thus contribute to the implantation of the embryo beyond the physiological site. This review takes into account aspects of the molecular mechanisms involved in the pathophysiology of endometriosis and EP, with particular emphasis on the similarities between them.

The Circ-CYP24A1-miR-224-PRLR Axis Impairs Cell Proliferation and Apoptosis in Recurrent Miscarriage

Aim

Recurrent miscarriage (RM) is associated with numerous clinical factors. However, some RM occurred without specific factors. It has been revealed that some molecules such as hormones, miRNAs, and transcription factors are involved in RM by regulating proliferation, apoptosis, etc. However, the mechanism of RM has yet to be identified clearly. Circular RNAs (circRNAs) are a class of endogenous non-coding RNAs that often act as sponges for miRNAs or binds to proteins involved in biological processes. However, the functional role of circRNAs in the uterine decidua of patients with early RM is still unclear. In this study, we aimed to investigate the mechanisms of circ-CYP24A1 in RM.

Methods

The Dual-Luciferase Activity Assay was designed to analyze the bonding between circ-CYP24A1 and miR-224, and miR-224 and prolactin receptor (PRLR) mRNA 3′UTR. In situ hybridization (ISH) and immunohistochemistry (IHC) were used to observe the expression of circ-CYP24A1 and PRLR in the decidua. Rescue experiments were performed to investigate the regulating effects of circ-CYP24A1, miR-224, and PRLR. Western blotting was conducted to test the expression level of PRLR. The proliferation and apoptosis-related markers in Ishikawa cells were analyzed using CCK8, immunofluorescence staining, and the terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL) assay.

Results

In this study, based on the microarray analysis data, we identified a high level of circ-CYP24A1 and PRLR in the decidua of patients with early RM. Based on the bioinformatics prediction, the binding relationship between circ-CYP24A1 and miR-224, as well as miR-224 and PRLR, were verified. Functional experiments demonstrated that circ-CYP24A1 regulated proliferation and apoptosis by binding to and inhibiting miR-224, resulting in increased PRLR expression. Taken together, this study provides new insights into the mechanism of RM.

Conclusion

In this study, we found that circ-CYP24A1 plays a role in RM by impairing the balance of cell proliferation and apoptosis by sponging miR-224, thereby regulating PRLR.

The incidence of ectopic/heterotopic pregnancies after blastocyst-stage frozen-thawed embryo transfers compared with that after cleavage-stage: a Society for Assisted Reproductive Technologies Clinical Outcomes Reporting System study

OBJECTIVE

To investigate whether there is a difference in the ectopic/heterotopic pregnancy rate of blastocyst-stage frozen-thawed embryo transfers (FETs) compared with that of cleavage-stage FETs.

DESIGN

A retrospective cohort study.

SETTING

Not applicable.

PATIENTS

Women undergoing autologous FETs at either the blastocyst stage (n = 118,572) or the cleavage stage (n = 117,619), as reported to the Society for Assisted Reproductive Technology from 2004 to 2013.

INTERVENTIONS

None.

MAIN OUTCOME MEASURES

Pregnancy outcomes, specifically ectopic pregnancy rates and heterotopic pregnancy rates.

RESULTS

Among those who became pregnant, there was a significantly lower incidence of ectopic/heterotopic pregnancies in blastocyst-stage FETs versus that in cleavage-stage FETs (0.8% vs. 1.1%). The differences in ectopic/heterotopic pregnancy rates remained statistically significant after controlling for confounders such as tubal factor infertility and number of embryos transferred.

CONCLUSIONS

Blastocyst-stage FET was associated with a lower ectopic/heterotopic pregnancy rate compared with cleavage-stage FET.

Factors associated with the incidence of ectopic pregnancy in women undergoing assisted reproductive treatment

Background

Ectopic pregnancy (EP) is a common complication in women undergoing assisted reproductive treatment, but the underlying causes for this remain unclear. This study aimed to explore factors affecting the incidence of EP in in vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI).

Methods

This was a retrospective study on the incidence of EP in IVF/ICSI cycles between January 1, 2013 and December 31, 2017. Patient age, infertility diagnosis (tubal factor or not), primary or secondary infertility, type of cycle (frozen-thawed or fresh), type of embryo(s) transferred (cleavage embryo or blastocyst), number of embryos transferred (one, two, or three), previous history of EP, and endometrial combined thickness were analyzed to explore their relationships with the incidence of EP. Based on clinical typing results, the patients were divided into an EP group or a non-EP group. Categorical variables were analyzed using Chi-squared test or Fisher exact test. Logistic regression analysis was performed to explore their associations with the incidence of EP.

Results

The percentage of patients with primary infertility in EP group was significantly lower than that in non-EP group (31.3% vs. 46.7%, χ² = 26.032, P < 0.001). The percentage of patients with tubal infertility in EP group was also significantly higher than that in non-EP group (89.2% vs. 63.6%, χ² = 77.410, P < 0.001). The percentages of patients with transfer of cleavage-stage embryo or blastocyst (91.4% vs. 84.4%, χ² = 10.132, P = 0.001) and different endometrial combined thickness (ECT) (χ² = 18.373, P < 0.001) differed significantly between EP and non-EP groups. For patients who had a previous history of one to four EPs, the percentage of patients undergoing transfer of a cleavage-stage embryo was significantly higher in EP group than that in non-EP group (92.2% vs. 77.6%, χ² = 13.737, P < 0.001). In multivariate logistic regression analysis, tubal infertility was strongly associated with EP (adjusted odds ratio: 3.995, 95% confidence interval: 2.706–5.897, P < 0.001).

Conclusions

In IVF/ICSI cycles, transfer of a blastocyst-stage embryo, especially for patients with a previous history of EP, reduced the rate of EP. Tubal infertility was strongly associated with EP.

Effect of endometrial thickness on ectopic pregnancy in frozen embryo transfer cycles: an analysis including 17,244 pregnancy cycles

OBJECTIVE

To investigate whether endometrial thickness (EMT) influences the incidence of ectopic pregnancy (EP) in frozen embryo transfer (FET) cycles.

DESIGN

Retrospective cohort study.

SETTING

Academic tertiary-care medical center.

PATIENT(S)

A total of 16,556 patients were enrolled between January 2010 and December 2017, comprising 16,701 intrauterine, 488 ectopic, and 45 heterotopic pregnancy cycles after FET.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

EP was the primary outcome. EMT was the main measured variable. Data were analyzed with the binary logistic general estimating equations model to calculate the adjusted odds ratio (aOR) for EP.

RESULT(S)

After adjusting for confounders, EMT remained statistically significant as an independent risk factor for EP. Compared with women with an EMT of ≥14 mm, the aORs for women with EMT in the ranges 7-7.9, 8-9.9, and 10-11.9 mm were 2.70 (95% confidence interval [CI], 1.65-4.40), 2.06 (95% CI, 1.33-3.20), and 1.66 (95% CI, 1.07-2.58), respectively. Hormone replacement treatment for endometrial preparation during FET increased the risk of EP after adjustment for confounding variables.

CONCLUSION(S)

EMT is inversely proportional to EP rate in FET cycles and is therefore a potential quantitative marker of endometrial receptivity and uterine contractibility in an FET cycle. The predictive validity of EMT value must be evaluated in further studies.

Networks of E-cadherin, β1 integrin, and focal adhesion kinase in the pathogenesis of tubal pregnancy

E-cadherin, β1 integrin, and focal adhesion kinase (FAK) are reported to involved in eutopic implantation by mediating cell adhesion. However, less is documented about their roles in ectopic implantation. This study was undertaken to evaluate the roles and networks of E-cadherin, β1 integrin, and FAK in tubal pregnancy. A total of 31 Fallopian tube specimens were obtained from tubal pregnant women. Immunohistochemistry and western blot were used to analyze the distributions and levels of E-cadherin, β1 integrin and phosphorylated-FAK (Pho-FAK) in the Fallopian tube epithelium. Normal Fallopian tube samples derived from non-pregnant women with benign genital diseases were used for comparison. E-cadherin presented in the cytomembrane of tubal epithelial cells and β1 integrin mainly expressed in the cytoplasm. A lowest-level of E-cadherin was detected in the implantation site (0.63 ± 0.29) when compared with the non-implantation site (0.95 ± 0.37) and the controls (0.89 ± 0.33) (P < 0.05). β1 integrin, as well as Pho-FAK in the implantation site (0.81 ± 0.35; 0.72 ± 0.24), showed a higher-level than that in the non-implantation site (0.59 ± 0.26; 0.48 ± 0.27) or the control group (0.38 ± 0.19; 0.36 ± 0.25) (p < .05). The decreased E-cadherin and increased β1 integrin are implicated in tubal pregnancy. The involvement of β1 integrin maybe depends on β1 integrin/FAK signaling.

Dysregulated erythropoietin-producing hepatocellular receptor A2 (EphA2) is involved in tubal pregnancy via regulating cell adhesion of the Fallopian tube epithelial cells

BACKGROUND

Tyrosine kinase receptor erythropoietin-producing hepatocellular receptor A2 (EphA2) is abundant in the endometrium and plays a role in the establishment of eutopic implantation. A similar molecular mechanism may exist between uterine implantation and tubal implantation, therefore EphA2 involvement in tubal pregnancy is suspected. Due to the limited availability of human Fallopian tube specimens, EphA2 expression in human Fallopian tube epithelium remains largely unknown.

METHODS

A total of 31 women with tubal pregnancy and 41 non-pregnant women with benign uterine diseases were enrolled in this study. Immunohistochemistry was used to investigate the expression pattern of EphA2 in the Fallopian tube epithelium of non-pregnant women (n = 29) and women with tubal pregnancy (n = 17). The changes of EphA2 and its activated form, phosphorylated-EphA2 (Pho-EphA2), in the Fallopian tube epithelium from non-pregnant women (n = 12) and women with tubal pregnancy (n = 14) were compared by quantitative RT-PCR and western blot assay.

RESULTS

EphA2 was expressed throughout the Fallopian tube epithelium, including the isthmus, the ampulla and the infundibulum. EphA2 concentration remained unchanged throughout the whole menstrual cycle, irrespective of menstrual phases and tubal regions. EphA2 mRNA in the Fallopian tube epithelium did not differ between normal women and women with tubal pregnancy (P > 0.05). With respect to the protein level, a significantly higher ratio of EphA2 over Pho-EphA2 was shown in women with tubal pregnancy (P < 0.05).

CONCLUSIONS

EphA2 is widely expressed in human Fallopian tube epithelium in a temporospatial-independent manner. Dysregulated EphA2 and its phosphorylation-dependent regulatory mechanism may unexpectedly enhance the cell adhesion activity of the Fallopian tube epithelial cells, leading to a mis-contact between the Fallopian tube epithelium and the embryo.

Thawed embryo transfer and ectopic pregnancy: a meta-analysis

PURPOSE

To examine whether thawed embryo transfers can reduce the rate of EP.

METHODS

The PubMed, EMBASE, Cochrane Library databases and two randomized controlled trials registration centers were thoroughly searched until March 2017. The clinical outcomes of IVF/ICSI cycles were compared between thawed and fresh embryo transfer.

RESULTS

Twenty-one articles were included in this meta-analysis. There were 801,464 pregnancies totally (thawed-ET: n = 158,967, fresh-ET: n = 642,497). The ectopic pregnancy rate was significantly lower in the group of thawed-ET than that in the group of fresh-ET (OR 0.69, 95% CI 0.57-0.82; I² = 83%). We subdivided the data into subgroups for D3 embryo transfer and D5 embryo transfer. We also found that the ectopic pregnancy rate was significantly lower with thawed-ET on D3 than that with fresh-ET (OR 0.67, 95% CI 0.53-0.85; I² = 0%). The risk of ectopic pregnancy was significantly decreased with thawed-ET on D5 than that with fresh-ET (OR 0.57, 95% CI 0.50-0.64; I² = 45%).

CONCLUSION

Our results indicate that in contrast to fresh embryo transfers, thawed D3 or D5 embryo transfers can reduce the rate of EP.

Unilateral Salpingectomy and Methotrexate Are Associated With a Similar Recurrence Rate of Ectopic Pregnancy in Patients Undergoing In Vitro Fertilization

STUDY OBJECTIVE

To determine whether different treatment approaches of ectopic pregnancy (EP), particularly unilateral salpingectomy and methotrexate, affect its recurrence rate in patients undergoing in vitro fertilization (IVF).

DESIGN

A retrospective cohort study (Canadian Task Force classification II-2).

SETTING

An academic medical center.

PATIENTS

Patients with a history of a previous EP who achieved pregnancy after IVF cycles between January 2004 and August 2015 were included. The recurrence rate of EP was compared between patients who underwent different treatment approaches for a previous EP.

INTERVENTIONS

IVF.

MEASUREMENTS AND MAIN RESULTS

A total of 594 patients were included. Seventeen patients had a recurrence of EP (2.9%). Patients with a history of ≥2 EPs were associated with a significantly higher recurrence rate of EP than those with 1 previous EP (8.5% vs. 1.8%; p = .01; odds ratio [OR] = 2.2; 95% confidence interval [CI], 1.2-4.4). Patients who underwent unilateral salpingectomy (n = 245) had a comparable recurrence rate of EP after IVF with those who received methotrexate (n = 283) (3.6% vs. 2.8%; p = .5; OR = 1.3; 95% CI, 0.4-3.4). This OR remained unchanged after adjusting for patient's age, number of previous EPs, number of transferred embryos, and peak estradiol level during stimulation (adjusted OR = 1.4; 95% CI, 0.5-3.8). None of the patients who underwent bilateral salpingectomy (n = 45) or salpingostomy (n = 21) had a recurrence of EP after IVF.

CONCLUSION

The recurrence rate of EP significantly correlates with the number of previous EPs. Treatment of EP with methotrexate has a comparable recurrence rate of EP after IVF with unilateral salpingectomy. Therefore, the risk of recurrence should not be a reason to favor salpingectomy over methotrexate in this population.

Elevated serum interleukin-1β levels and interleukin-1β-to-interleukin-1 receptor antagonist ratio 1 week after embryo transfer are associated with ectopic pregnancy

OBJECTIVE

To investigate whether interleukin-1β (IL-1β) and interleukin-1 receptor antagonist (IL-1RA) serum levels in the early luteal phase differ in IVF cycles that result in an ectopic pregnancy (EP) when compared with other outcomes.

DESIGN

Retrospective cohort.

SETTING

Not applicable.

PATIENT(S)

A total of 307 women whose serum samples were available, with the following IVF outcomes: 103 live births, 80 negative pregnancy tests, 52 biochemical pregnancies, 47 EPs, and 25 miscarriages.

INTERVENTION(S)

Serum samples were obtained on cycle days 24 and 28 (cycle day 14 = day of egg retrieval). Levels of IL-1β and IL-1RA were determined by quantitative ELISA performed by blinded personnel.

MAIN OUTCOME MEASURE(S)

IL-1β and IL-1RA levels, IL-1β-to-IL-1RA ratio versus cycle outcome.

RESULT(S)

The IL-1β levels were predictive of an EP. At cycle days 24 and 28 the mean IL-1β levels were higher in patients with an EP (127.1 pg/mL and 166.9 pg/mL, respectively) than in women with any other IVF outcome (15.8-55.3 pg/mL and 14.8-75.5 pg/mL, respectively). At cycle day 24 the IL-1β-to-IL-1RA ratio was 0.18 in the ectopic group versus 0.01-0.09 in the other groups.

CONCLUSION(S)

Elevated IL-1β levels and IL-1β-to-IL-1RA ratio as early as 4 days before the first pregnancy test are associated with an EP. If confirmed by prospective studies, clinical application of these findings could potentially improve EP detection.

Ectopic pregnancy secondary to in vitro fertilisation-embryo transfer: pathogenic mechanisms and management strategies

BACKGROUND

Ectopic pregnancy (EP) is the leading cause of maternal morbidity and mortality during the first trimester and the incidence increases dramatically with in vitro fertilisation and embryo transfer (IVF-ET). The co-existence of an EP with a viable intrauterine pregnancy (IUP) is known as heterotopic pregnancy (HP) affecting about 1% of patients during assisted conception. EP/HP can cause significant morbidity and occasional mortality and represent diagnostic and therapeutic challenges, particularly during fertility treatment. Many risk factors related to IVF-ET techniques and the cause of infertility have been documented. The combination of transvaginal ultrasound (TVS) and serum human chorionic gonadotrophin (hCG) is the most reliable diagnostic tool, with early diagnosis of EP/HP permitting conservative management. This review describes the risk factors, diagnostic modalities and treatment approaches of EP/HP during IVF-ET and also their impact on subsequent fertility treatment.

METHODS

The scientific literature was searched for studies investigating EP/HP during IVF-ET. Publications in English and within the past 6 years were mostly selected.

RESULTS

A history of tubal infertility, pelvic inflammatory disease and specific aspects of embryo transfer technique are the most significant risk factors for later EP. Early measurement of serum hCG and performance of TVS by an expert operator as early as gestational week 5 can identify cases of possible EP. These women should be closely monitored with repeated ultrasound and hCG measurement until a diagnosis is reached. Treatment must be customised to the clinical condition and future fertility requirements of the patient. In cases of HP, the viable IUP can be preserved in the majority of cases but requires early detection of HP. No apparent negative impact of the different treatment approaches for EP/HP on subsequent IVF-ET, except for risk of recurrence.

CONCLUSIONS

EP/HP are tragic events in a couple's reproductive life, and the earlier the diagnosis the better the prognosis. Due to the increase incidence following IVF-ET, there is a compelling need to develop a diagnostic biomarker/algorithm that can predict pregnancy outcome with high sensitivity and specificity before IVF-ET to prevent and/or properly manage those who are at higher risk of EP/HP.

Role of activins in embryo implantation and diagnosis of ectopic pregnancy: a review

Embryo implantation is a major prerequisite for the successful establishment of pregnancy. Ectopic implantation outside the intrauterine cavity and the development of ectopic pregnancy (EP) is a major cause of maternal morbidity and occasionally mortality during the first trimester. EP may be induced by failure of tubal transport and/or increased tubal receptivity. Activins, their type II receptors and follistatin have been localised in the human endometrial and tubal epithelium and they are major regulators of endometrial and tubal physiology during the menstrual cycle. Pathological expression of activins and their binding protein, follistatin, was observed in tissue and serum samples collected from EP. Several studies with different designs investigated the diagnostic value of a single measurement of serum activin-A in the differentiation between normal intrauterine and failing early pregnancy and the results are controversial. Nevertheless, the diagnostic value of activins in EP, including the other activin isoforms (activin-B and -AB) and follistatin, merits further research. This review appraises the data to date researching the role of activins in the establishment of normal pregnancy and, pathogenesis and diagnosis of tubal EP.

L-selectin ligands expression in human fallopian tube epithelia of tubal pregnancies

The objective of the study was to evaluate the expression of L-selectin ligands in tubal epithelia during tubal ectopic pregnancy. Sixteen fallopian tube samples from ectopic pregnancies and four normal control fallopian tubes from women undergoing sterilization were obtained for the study. Oviduct tissues from ectopic pregnancies were separated into implantation sites and matched nonimplantation sites. Expression of L-selectin ligands was evaluated by immunohistochemistry with antibodies against HECA-452 and MECA-79 and by real-time PCR. Immunoreactivity levels against HECA-452 and MECA-79 were significantly higher at the implantation site than at the paired nonimplantation site or at the normal oviducts. Moreover, compared with MECA-79 staining, stronger HECA-452 staining was observed in the implantation and nonimplantation groups. HECA-452 histologic scores at implantation sites correlated with serum human chorionic gonadotropin levels. Increased expression of L-selectin ligands may be involved in the implantation process in tubal pregnancy.

Risk of ectopic pregnancy following day-5 embryo transfer compared with day-3 transfer

The incidence of ectopic pregnancy after IVF is increased approximately 2.5-5-fold compared with natural conceptions; however, the aetiology for this increased risk remains unclear. One proposed practice change to decrease the incidence of ectopic pregnancy is blastocyst embryo transfer on day 5 rather than cleavage-stage embryo transfer on day 3. A retrospective cohort study was conducted to compare the risk of ectopic pregnancy following fresh day-5 embryo transfer with day-3 embryo transfer among women who underwent IVF and achieved pregnancy from 1998 to 2011. There were 13,654 eligible pregnancies; 277 were ectopic. The incidence of ectopic pregnancy was 2.1% among day-3 pregnancies and 1.6% among day-5 pregnancies. The adjusted risk ratio for ectopic pregnancy from day-5 compared with day-3 transfer was 0.71 (95% confidence interval 0.46-1.10). Although this analysis included 13,654 cycles, with a two-sided significance level of 0.05, it had only 21.9% power to detect a difference between the low incidence of ectopic pregnancy among both day-3 and day-5 transfers. In conclusion, this study was not able to demonstrate a difference in the risk of ectopic pregnancy among day-3 compared with day-5 transfers.