Effect of Low-Dose Aspirin on Midluteal Phase Uterine Artery Blood Flow in Patients With Recurrent Pregnancy Loss

A nomogram and risk stratification to predict subsequent pregnancy loss in patients with recurrent pregnancy loss

STUDY QUESTION

Could the risk of subsequent pregnancy loss be predicted based on the risk factors of recurrent pregnancy loss (RPL) patients?

SUMMARY ANSWER

A nomogram, constructed from independent risk factors identified through multivariate logistic regression, serves as a reliable tool for predicting the likelihood of subsequent pregnancy loss in RPL patients.

WHAT IS KNOWN ALREADY

Approximately 1-3% of fertile couples experience RPL, with over half lacking a clear etiological factor. Assessing the subsequent pregnancy loss rate in RPL patients and identifying high-risk groups for early intervention is essential for pregnancy counseling. Previous prediction models have mainly focused on unexplained RPL, incorporating baseline characteristics such as age and the number of previous pregnancy losses, with limited inclusion of laboratory and ultrasound indicators.

STUDY DESIGN, SIZE, DURATION

The retrospective study involved 3387 RPL patients who initially sought treatment at the Reproductive Immunology Clinic of Renji Hospital, Shanghai Jiao Tong University School of Medicine, between 1 January 2020 and 31 December 2022. Of these, 1153 RPL patients met the inclusion criteria and were included in the analysis.

PARTICIPANTS/MATERIALS, SETTING, METHODS

RPL was defined as two or more pregnancy losses (including biochemical pregnancy loss) with the same partner before 28 weeks of gestation. Data encompassing basic demographics, laboratory indicators (autoantibodies, peripheral immunity coagulation, and endocrine factors), uterine and endometrial ultrasound results, and subsequent pregnancy outcomes were collected from enrolled patients through initial questionnaires, post-pregnancy visits fortnightly, medical data retrieval, and telephone follow-up for lost patients. R software was utilized for data cleaning, dividing the data into a training cohort (n = 808) and a validation cohort (n = 345) in a 7:3 ratio according to pregnancy success and pregnancy loss. Independent predictors were identified through multivariate logistic regression. A nomogram was developed, evaluated by 10-fold cross-validation, and compared with the model incorporating solely age and the number of previous pregnancy losses. The constructed nomogram was evaluated using the AUC, calibration curve, decision curve analysis (DCA), and clinical impact curve analysis (CICA). Patients were then categorized into low- and high-risk subgroups.

MAIN RESULTS AND THE ROLE OF CHANCE

We included age, number of previous pregnancy losses, lupus anticoagulant, anticardiolipin IgM, anti-phosphatidylserine/prothrombin complex IgM, anti-double-stranded DNA antibody, arachidonic acid-induced platelet aggregation, thrombin time and the sum of bilateral uterine artery systolic/diastolic ratios in the nomogram. The AUCs of the nomogram were 0.808 (95% CI: 0.770-0.846) in the training cohort and 0.731 (95% CI: 0.660-0.802) in the validation cohort, respectively. The 10-fold cross-validated AUC ranged from 0.714 to 0.925, with a mean AUC of 0.795 (95% CI: 0.750-0.839). The AUC of the nomogram was superior compared to the model incorporating solely age and the number of previous pregnancy losses. Calibration curves, DCAs, and CICAs showed good concordance and clinical applicability. Significant differences in pregnancy loss rates were observed between the low- and high-risk groups (P < 0.001).

LIMITATIONS, REASONS FOR CAUTION

This study was retrospective and focused on patients from a single reproductive immunology clinic, lacking external validation data. The potential impact of embryonic chromosomal abnormalities on pregnancy loss could not be excluded, and the administration of medication to all cases impacted the investigation of risk factors for pregnancy loss and the model's predictive efficacy.

WIDER IMPLICATIONS OF THE FINDINGS

This study signifies a pioneering effort in developing and validating a risk prediction nomogram for subsequent pregnancy loss in RPL patients to effectively stratify their risk. We have integrated the nomogram into an online web tool for clinical applications.

STUDY FUNDING/COMPETING INTEREST(S)

This study was supported by the National Natural Science Foundation of China (82071725). All authors have no competing interests to declare.

TRIAL REGISTRATION NUMBER

N/A.

Low Molecular Weight Heparin-Aspirin-Prednisolone Combination Does Not Increase the Live Birth Rate in Recurrent Implantation Failure: A Retrospective Cohort Study

This study investigates the triple combination of adjuvants (low molecular weight heparin (LMWH)-aspirin-prednisolone) whether it improves the live birth rates of IVF&ICSI patients with previous implantation failure. This retrospective study included 1095 patients with >2 failed either fresh or frozen single embryo transfer cycles between 2014 Jan and 2021 Jan. Patients were divided into two subgroups. Group A consisted of patients with only vaginal progesterone for luteal phase support. Group B consisted of patients with triple (daily subcutaneous LMWH, daily 150 mg aspirin, and daily 16 mg prednisolone) luteal phase supplementation to vaginal progesterone. Demographic parameters, cycle characteristics, embryology, and pregnancy outcomes were compared, and the study's primary outcome was the live birth rate. Demographic parameters were similar between the groups. Positive b-hCG, miscarriage, and live birth rates were similar between groups as Group A vs. Group B, positive b-hCG 30.8% (190/617) vs. 35.4% (169/478), miscarriage rates 4.4% (27/617) vs. 6.7% (32/478), and live birth rates 20.4% (126/617) vs. 23.8% (114/478), respectively. When patients were stratified according to previous failures, live birth rates were still similar. Pregnancy outcomes were significantly improved in only patients with diminished ovarian reserve (Group A vs. Group B, positive b-hCG 24.2% vs. 34.3%, live birth rate 12.1% vs. 21.9%, p < 0.01). Whether the embryo transfer was fresh or frozen-thawed did not affect the results. A combined supplementation of LMWH, aspirin, and prednisolone in the luteal phase does not improve live birth rates of IVF&ICSI patients with previous implantation failure except potentially for patients with diminished ovarian reserve.

Homocysteine increases uterine artery blood flow resistance in women with pregnancy loss

OBJECTIVE

Uterine arterial blood flow is an important factor in embryonic development. Increased uterine artery blood flow resistance may be related to vascular damage. Homocysteine (HCY) can induce injury of endothelial through various pathways. Therefore, we investigate the association between serum HCY levels and uterine artery blood flow in the non-pregnant state in women who have experienced pregnancy loss (PL).

METHODS

364 women eligible for PL were included in the study. The detection of HCY was completed by the Laboratory of Lanzhou University Second Hospital. We divided the patients into three groups: Low-HCY (HCY<10 umol/L, n = 144), Medium-HCY (HCY 10∼15 umol/L, n = 174) and High-HCY (HCY>15 umol/L, n = 46). The patients were subjected to vaginal color Doppler ultrasonography to measure bilateral uterine artery resistance index (RI), pulsatility index (PI) and peak systolic velocity/end diastolic velocity (S/D).

RESULT

Among 364 women, the right uterine artery RI in L-HCY, M-HCY, and H-HCY groups were 0.78±0.08, 0.79±0.07 and 0.81±0.07, respectively (P = 0.04). The left uterine artery RI in L-HCY, M-HCY, and H-HCY groups were 0.78±0.08, 0.81±0.07 and 0.81±0.07, respectively (P = 0.01). The right uterine artery RI level and the left uterine artery RI was significantly associated with HCY level (r = 0.103, P = 0.050; r = 0.104, P = 0.047, respectively). Of these, 177 women experienced their next pregnancy, and 33 patients experienced PL again. The pregnancy rate in l-HCY, M-HCY, and HHCY groups were 47.92% (69/144), 49.43% (86/174) and 47.83% (22/46), respectively (P = 0.95). In next pregnancy, the PL rate in l-HCY, M-HCY, and HHCY groups were 8.70% (6/69), 22.58% (22/86) and 22.73% (5/22), respectively (P = 0.03).

CONCLUSION

HCY can increase the uterine artery resistance in the non-pregnant state and is associated with the abortion rate of next pregnancy.

Low-dose aspirin improves blood perfusion of endometrium of unexplained recurrent biochemical pregnancy loss

OBJECTIVE

To assess the differences in Doppler parameters of endometrial receptivity in unexplained recurrent biochemical pregnancy loss (URBPL) and the therapeutic effect of low-dose aspirin (LDA).

METHODS

A retrospective study was conducted at Ren Ji Hospital, Shanghai, PR China, from January 2017 to January 2019. Doppler parameters of endometrium and uterus were recorded as the evaluation of the endometrial receptivity. Receiver operating characteristic (ROC) curve was managed to predict the risk of URBPL. Ultrasonography tests were repeated after 2 months of treatment with LDA.

RESULTS

Biochemical pregnancies did not correlate with maternal age. The resistance of endometrial perfusion (pulsatility index, resistive index, and systolic-to-diastolic ratio) was significantly higher in URBPLs (P < 0.001) and had predictive values (0.739, 0.779, and 0.760, respectively). Endometrial thickness and impedance to uterine blood flow showed no statistically significant difference (P > 0.05). After treatment with LDA, patients with URBPL improved the blood perfusion of endometrium significantly (P < 0.01).

CONCLUSION

There was no relation between BPL and maternal age. Patients with URBPL had inappropriate endometrial blood velocity. Doppler indices are capable of predicting the risk of URBPL. LDA exerts the therapeutic effect on improving blood perfusion of endometrium in URBPL.

Low-dose aspirin treatment improves endometrial receptivity in the midluteal phase in unexplained recurrent implantation failure

OBJECTIVE

To compare endometrial receptivity in patients with and without unexplained recurrent implantation failure (URIF) and the benefits of low-dose aspirin treatment in women with URIF.

METHODS

A retrospective study was conducted at Ren Ji Hospital, Shanghai, from January 2014 to January 2017. Endometrial thickness, pulsatility index (PI), resistive index (RI), and systolic-to-diastolic ratio (S/D) values of endometrial and uterine perfusion were recorded and compared between women with and without URIF. Receiver operating characteristic (ROC) curve analysis was used to evaluate the predictive accuracy of the risk of URIF. Ultrasonography examination was repeated after 2 months of treatment with low-dose aspirin.

RESULTS

PI, RI, and S/D values for endometrial blood flow were significantly higher in URIF patients than the control group (P < 0.001). The predictive indexes were 0.833, 0.857, and 0.839, respectively. Differences between the groups for endometrial thickness and impedance of uterine perfusion were not significant (P > 0.05). After low-dose aspirin treatment, endometrial and uterine arterial blood flow resistance in URIF patients was significantly lower than before treatment (P < 0.05).

CONCLUSION

URIF patients had inappropriate endometrial blood flow. Doppler parameters are promising for predicting women at high risk of URIF. Low-dose aspirin treatment can improve endometrial receptivity.

Aspirin enhances trophoblast invasion and represses soluble fms-like tyrosine kinase 1 production: a putative mechanism for preventing preeclampsia

OBJECTIVE

Recent studies suggested that prophylactic aspirin prior to 16 weeks of gestation in high-risk patients may reduce the risk of developing preeclampsia; however, the exact mechanism of aspirin's effect on the pathophysiology of preeclampsia is not clear. This study was designed to investigate the effect of aspirin on trophoblast cell function and its effect on soluble fms-like tyrosine kinase 1 (sFlt-1) production to elucidate the preventive mechanisms for preeclampsia.

METHODS AND RESULTS

We used two human trophoblastic cell lines (HTR-8/SVneo and JAR) and freshly isolated cytotrophoblasts from normal and preeclamptic placenta at term to determine the effect of aspirin on trophoblast cell function. Trophoblasts were pretreated with aspirin, and then cell functions and sFlt-1 expression were assessed. Our results showed that aspirin promoted trophoblast invasion not only in HTR-8/SVneo and JAR cells, but also in isolated cytotrophoblasts. sFlt-1 production was repressed by aspirin in a dose-dependent manner. By adding Flt-1 recombinant protein, the trophoblast invasion ability was inhibited in HTR-8/SVneo cells, which was reversed by Flt-1 small interfering ribonucleic acid knockdown. In addition, metalloproteinase 2/9 expression and activity were activated by aspirin but inhibited by sFlt-1. Aspirin also downregulated Akt phosphorylation, and trophoblast invasiveness was facilitated under Akt inhibitor treatment.

CONCLUSION

Aspirin enhances cell invasiveness and inhibits sFlt-1 production in trophoblasts. Moreover, sFlt-1 itself also inhibits trophoblast invasion. Our novel findings suggest that the preeclampsia prevention effect of aspirin may be exerted through these two mechanisms.

Characteristics of midluteal phase uterine artery hemodynamics in patients with recurrent pregnancy loss

AIM

To study the association in resistance to uterine artery blood flow and recurrent pregnancy loss (RPL) and find its potential influencing factors.

METHODS

A retrospective study was conducted in 870 RPL and 237 non-RPL patients visiting to the Clinic from January 2014 to February 2018. All participants underwent comprehensive examinations and were scanned by transvaginal Doppler ultrasonography during the midluteal phase to measure the pulsatility index (PI), resistance index (RI) and systolic/diastolic ratio (S/D) values of the left and right main uterine arteries. P value less than 0.05 was considered statistically significant.

RESULTS

The mean PI, RI and S/D values for uterine arteries were significantly higher in RPL patients than in non-RPL patients (P < 0.001). When subjects were grouped according to the different etiologies of RPL, significant higher indices of uterine arteries were found in RPL patients with antiphospholipid syndrome (P < 0.001), autoimmune diseases (P < 0.001), endocrinological abnormalities (P < 0.05), thrombophilia (P < 0.001), uterine anomalies (P < 0.01) and unexplained RPL (P < 0.001). No differences were found between patients with chromosomal anomalies and uterine arteries blood flow (P > 0.05). In RPL patients, mean PI, mean RI and mean S/D values shows no difference among groups (P > 0.05). The Similar results were observed in age and number of spontaneous abortion (P > 0.05).

CONCLUSION

Impaired uterine artery blood perfusion may be an underlying pathology to RPL, and it can be used as an independent risk factor for pregnancy failure.

Minimally invasive spinal anesthesia for cesarean section in maternal anticoagulation therapy: a randomized controlled trial

BACKGROUND

Anticoagulant therapy during pregnancy is widely used due to the increasing awareness of maternal hypercoagulability. Few studies have reported the use of minimally invasive spinal anesthesia in these parturients. The objective of this study was to evaluate the safety and feasibility of minimally invasive spinal anesthesia in parturients with anticoagulation therapy undergoing cesarean section.

METHODS

This was a randomized, controlled study conducted in 239 parturients using anticoagulants and undergoing selective cesarean section. 37 parturients withdrew, and finally parturients received spinal anesthesia using 27gauge pen type fine spinal needles (experimental group, n = 110) and 22gauge traditional spinal needles (control group, n = 92). The primary efficacy outcomes included low back pain (LBP) and postdural puncture headache (PDPH) after delivery. Secondary efficacy outcomes included visual analogue scale during subarachnoid puncture (VASdural), difference between visual analogue scale (VAS) during peripheral venipuncture and VASdural (∆VAS), VAS of back puncture point 24, 48 and 72 h after operation (VASdural-24 h, VASdural-48 h and VASdural-72 h, respectively), maternal satisfaction and hospitalization stay.

RESULTS

No parturient had PDPH and was suspected with spinal or intracranial haematoma in two groups. There was no significant difference in VASlbp-24 h, VASlbp-48 h and VASlbp-72 h (P = 0.056; P = 0.813; P = 0.189, respectively) between two groups. In experimental group, VASdural (P = 0.017), ∆VAS (P = 0.001) and VASdural-24 h (P < 0.0001) were lower, whereas maternal satisfaction was higher (P = 0.046). There was no significant difference in VASdural-48 h, VASdural-72 h, urination function, strength recovery and hospitalization stay (P = 0.069; P = 0.667; P = 0.105; P = 0.133; P = 0.754, respectively) between the two groups.

CONCLUSIONS

Minimally invasive spinal anesthesia provided lower VASdural, VASdrual-24 h and a higher maternal satisfaction. Hence, it is considered as a safe, reliable and reasonable option for cesarean section parturients during maternal anticoagulation therapy with normal platelet count and coagulation time.

TRIAL REGISTRATION

This study was registered at www.ClinicalTrials.gov at November 11th, 2016 ( NCT02987192 ).

Transdermal estrogen gel and oral aspirin combination therapy improves fertility prognosis via the promotion of endometrial receptivity in moderate to severe intrauterine adhesion

Intrauterine adhesion (IUA) is one of the most common gynecological diseases in women of reproductive age. IUA, particularlyin moderate to severe forms, accounts for a large percentage of infertility cases. Clinically, the first-line treatment strategy for IUA is transcervical resection of adhesion (TCRA), followed by adjuvant postoperative treatment. Estrogen is one of the classic chemotherapies used following TCRA and contributes to preventing re-adhesion following surgery. However, estrogen has limited effects in promoting pregnancy, which is the ultimate goal for IUA management. In the present study, a transdermal estrogen gel and oral aspirin combination therapy was used in patients with IUA following TCRA. Compared with in the control group (transdermal estrogen only therapy), the combination therapy significantly increased endometrial receptivity marker (αvβ٣ and laminin) expression in endometrium tissues. Additionally, ultrasonic examination revealed the pulsatility index and resistant index of the uterine artery were lower in the combination therapy group. Combination therapy promoted angiogenesis and prevented fibrosis following TCRA more effectively than estrogen-only therapy. Collectively, the evaluation indices, including American Fertility Society score, endometrial parameters and pregnancy rate, indicated that patients with combination therapy had better prognoses in endometrial repair and pregnancy. In conclusion, postoperative combination therapy with transdermal estrogen gel and oral aspirin may be more efficacious in enhancing endometrial receptivity by increasing uterine blood and angiogenesis, contributing to improved fertility prognosis. The findings of the present study may provide novel guidance to the clinical treatment of IUA.