Association of uterine artery Doppler, follicle-stimulating hormone, and anti-Müllerian hormone with post-chemotherapy ovarian reserve in reproductive-age colorectal cancer patients

Abstract

BACKGROUND

Colorectal cancer (CRC) incidence is rising among reproductive-age women, yet chemotherapy frequently compromises ovarian reserve, impairing fertility. Ovarian reserve assessment traditionally relies on serum follicle-stimulating hormone (FSH) and anti-Müllerian hormone (AMH), while uterine artery Doppler parameters - pulsatility index (PI), resistance index (RI), and peak systolic velocity (PSV) - reflect ovarian perfusion. However, their combined correlation with post-chemotherapy ovarian reserve remains underexplored. We hypothesize that integrating these parameters will enhance predictive accuracy for diminished ovarian reserve, informing fertility preservation strategies.

AIM

To investigate correlations of uterine artery blood flow, FSH, and AMH with ovarian reserve post-chemotherapy in reproductive-aged CRC patients.

METHODS

This study included 110 reproductive-aged women with CRC who received chemotherapy from March 2021 to September 2024. Based on criteria assessed three months post-chemotherapy, they were divided into diminished (n = 50) and normal (n = 60) ovarian reserve groups. Uterine artery PI, RI, PSV, serum FSH, and AMH were compared. Correlations and predictive efficacy were analyzed using Pearson correlation and receiver operating characteristic (ROC) curves.

RESULTS

The diminished ovarian reserve group exhibited significantly higher uterine artery PI, RI, and serum FSH levels, but lower PSV and serum AMH levels than the normal ovarian reserve group (P < 0.05). Correlation analysis showed PI, RI, and FSH were positively correlated with ovarian reserve decline (r = 0.395, 0.420, 0.378; P < 0.05), whereas PSV and AMH were negatively correlated (r = -0.506, -0.614; P < 0.05). ROC curve analysis revealed AMH had the best predictive value among single markers [area under the curve (AUC) = 0.895], with AUCs of 0.726, 0.733, 0.791, and 0.723 for PI, RI, PSV, and FSH, respectively. Combined detection of all five indicators increased the AUC to 0.950, with 94% sensitivity and 90% specificity, significantly outperforming any single indicator (P < 0.05).

CONCLUSION

In post-chemotherapy reproductive-age CRC patients, elevated PI, RI, FSH and reduced PSV, AMH correlate with diminished ovarian reserve. Combined testing at three months aids risk identification and fertility preservation.

Key Words: Colorectal neoplasms; Ovarian reserve function; Ultrasonography; Blood flow parameters; Follicle-stimulating hormone; Anti-Müllerian hormone; Women

Core Tip: Combined assessment of uterine artery Doppler parameters [pulsatility index (PI), resistance index (RI), and peak systolic velocity (PSV)] with serum follicle-stimulating hormone (FSH) and anti-Müllerian hormone (AMH) levels demonstrates superior predictive value for diminished ovarian reserve in reproductive-aged colorectal cancer patients after chemotherapy. The combined detection achieved an area under the curve of 0.950, significantly outperforming any single indicator, with PI, RI, and FSH positively correlated, while PSV and AMH negatively correlated with ovarian reserve decline. This multimodal approach provides a non-invasive, comprehensive strategy for early identification of chemotherapy-induced ovarian damage.

INTRODUCTION

Over 1.8 million new instances of colorectal cancer (CRC) are recorded each year, making it the third most frequent disease worldwide[1]. The incidence of early-onset CRC (EOCRC) in those under 50 increased by around 12.9% between 1990 and 2021, indicating a trend toward earlier beginning of CRC[2]. The World Health Organization defines the reproductive age for women as 15-49 years[3]. As the average age of marriage and childbearing continues to rise in China, women diagnosed with EOCRC may face the challenge of a cancer diagnosis during their childbearing years, often prior to completing their families. Ovarian reserve is a crucial measure of a woman’s ability for reproduction. It is defined as the number and quality of primordial follicles that are still present in the ovaries, indicating the capacity for follicular development and oocyte generation[4]. Impaired ovarian reserve following chemotherapy in reproductive-aged women with CRC represents a significant issue in treatment-related reproductive toxicity[5].

In recent years, given the rising cancer prevalence in younger populations and the widespread use of chemotherapy, this problem has become more prominent. It can affect women of all reproductive ages and often manifests as menstrual disorders and abnormal hormone levels. Without early monitoring and intervention, patients may experience persistent amenorrhea, infertility, and earlier onset of menopausal symptoms[6], severely impacting quality of life and fertility aspirations. Currently, the treatment of CRC primarily relies on chemotherapy. However, chemotherapeutic agents have well-established reproductive toxicity on ovarian tissue, which can lead to depletion of primordial follicles, damage to ovarian microvasculature, and subsequently result in diminished ovarian function or even premature ovarian insufficiency[7]. Therefore, timely and accurate assessment of ovarian reserve before and after chemotherapy is of great clinical significance for guiding individualized fertility preservation strategies[8].

Currently, basal hormone levels such as follicle-stimulating hormone (FSH) and estradiol are commonly used in clinical practice to evaluate ovarian function. However, these indicators are significantly influenced by the menstrual cycle, exhibit wide fluctuations, are susceptible to endocrine interference, and have limitations in sensitivity and stability[9]. Studies have shown that anti-Müllerian hormone (AMH), released by preantral and tiny antral follicles’ granulosa cells, shows minimal cyclical variation and can provide a more stable reflection of ovarian reserve[10]. Furthermore, uterine artery blood flow metrics, such as peak systolic velocity (PSV), resistance index (RI), and pulsatility index (PI), can indirectly reflect ovarian blood perfusion, which is closely related to follicular development and ovarian function[11]. To date, research on the relationship between uterine artery Doppler parameters (PI, RI, PSV) and serum levels of FSH and AMH in female CRC patients of reproductive age following chemotherapy remains relatively limited, as well as their predictive value for ovarian reserve.

This study aims to monitor these parameters and explore their correlation with post-chemotherapy ovarian reserve, with the goal of providing a reference for the early identification of declining ovarian function and the implementation of fertility preservation measures in clinical practice.

MATERIALS AND METHODS

General information

Methods from March 2021 to September 2024, 110 women of childbearing age with CRC who received chemotherapy in our hospital were selected. Three months after chemotherapy, all patients were divided into two groups according to the preset evaluation criteria of ovarian reserve function: The ovarian reserve function decreased group (50 cases) and the ovarian reserve function normal group (60 cases). This study was reviewed and approved by the medical ethics committee of Yuyao Maternal and Child Health Hospital (approval number: YFYLS-2026-001), and met the ethical review requirements for exemption from signing informed consent.

Exclusion and inclusion criteria

Inclusion criteria: (1) Age between 15 years and 49 years; (2) Female sex; (3) Diagnosis of CRC according to the Chinese Protocol for Diagnosis and Treatment of Colorectal Cancer (2023 edition)[12]; (4) Having undergone surgical treatment, with postoperative physical condition deemed suitable for adjuvant chemotherapy as assessed by the physician; and (5) Giving informed permission in writing.

Exclusion criteria: (1) Concurrent pregnancy; (2) Presence of complications in other organs such as the liver or kidneys; (3) History of malignancy at other sites; and (4) Presence of psychiatric disorders or mental disabilities.

Methods

Selection of follow-up time point and collection of clinical data: Based on the metabolic cycle of chemotherapy drugs in the body and the recovery law of ovarian function, patients usually have passed the acute bone marrow suppression period 3 months after the end of chemotherapy, the menstrual cycle tends to be stable or presents characteristic changes after chemotherapy, and it takes about 85 days for follicles to mature from initial recruitment. This time point can stably reflect the real damage degree of chemotherapy to the original follicle pool. At baseline, clinical information was gathered, such as age and body mass index (BMI). Serum FSH and AMH levels were measured three months after chemotherapy.

Measurement of uterine artery ultrasound blood flow parameters: Transvaginal color Doppler ultrasonography was performed on all patients using a GE Voluson E8 color Doppler ultrasound system with a probe frequency range of 5-8 MHz. Examinations were conducted three months post-chemotherapy on day 14 of the menstrual cycle. Patients were instructed to empty their bladders and assume the lithotomy position. A sterile sheath was placed over the probe, which was then inserted into the vagina. Routine two-dimensional ultrasound examination of the uterus, adnexa, and pelvis was performed. With the uterine sagittal section displayed and the measurement plane perpendicular to the long axis of the uterus, blood flow parameters were assessed. The uterine artery was identified by color imaging, and sampling was performed bilaterally at the cervix, the junction of the myometrium and endometrium, and the uterine body. After obtaining five consecutive stable waveforms, relevant parameters were measured. Parameters of uterine artery blood flow, including RI, PI, and PSV, were read using the ultrasound machine’s built-in software. PSV was also measured manually. The average of three measurements for each parameter was used as the final study data.

Post-chemotherapy ovarian function assessment: Ovarian function three months after surgery was comprehensively evaluated based on serum AMH, antral follicle count (AFC), and FSH levels. Diminished ovarian reserve was defined by meeting any one of the following four criteria[13]: (1) AMH < 1.1 ng/mL; (2) AFC < 5-7 follicles in both ovaries; (3) Basal FSH > 10 IU/L during two consecutive menstrual cycles; and (4) Women over the age of 35 who have not been pregnant successfully for more than 6 months.

Sample size calculation

According to the principle of sample size calculation of correlation research, the sample size is 5-10 times of the number of variables. There are 17 variables in this study. Considering the 10% loss of follow-up, 94-189 samples are calculated. Finally, 110 samples are included in this study, meeting the minimum sample size requirements.

Statistical analysis

SPSS software (version 21.0) was used to analyze the data. The t test was used to compare the measurement results, which are displayed as mean ± SD. The χ² test was used to compare count data, which are displayed as n (%). Pearson correlation analysis was used to examine the relationship between ovarian reserve function and the levels of PI, RI, PSV, FSH, and AMH. The predictive value of PI, RI, PSV, FSH, and AMH for diminished ovarian reserve in reproductive-age female CRC patients after chemotherapy was evaluated by constructing receiver operating characteristic (ROC) curves. A P value < 0.05 was considered statistically significant.

RESULTS

Comparison of general characteristics between the two groups

The age of the patients in the two groups BMI, menarche age, pregnancy times, menstrual cycle, course of disease, tumor diameter, type of chemotherapy, tumor stage and history of ovarian surgery had no significant difference, which was comparable, as shown in Table 1 for specific data.

Table 1 Comparison of general characteristics between the two groups, n (%)/mean ± SD.

Indicator	Diminished ovarian reserve group (n = 50)	Normal ovarian reserve group (n = 60)	χ2/t	P value
Age, years			0.478	0.489
< 35	16 (32.00)	23 (38.33)
≥ 35	34 (68.00)	37 (61.67)
BMI (kg/m2)	23.26 ± 2.17	23.54 ± 2.36	0.638	0.525
Menarche age, years	12.94 ± 2.56	13.28 ± 2.55	0.703	0.484
Gravidity, times	1.28 ± 0.70	1.53 ± 0.70	1.888	0.062
Menstrual cycle, days	30.30 ± 1.63	29.88 ± 2.10	-1.144	0.255
History of ovarian surgery			-	0.687
No	47 (94.00)	56 (93.33)
Yes	3 (6.00)	4 (6.67)
Disease duration, years	2.12 ± 0.44	2.22 ± 0.52	1.057	0.293
Tumor diameter, cm	2.98 ± 0.57	3.06 ± 0.80	0.629	0.531
Type of chemotherapy			0.178	0.673
Non platinum containing scheme	10 (20.00)	14 (23.33)
Platinum containing scheme	40 (80.00)	46 (76.67)
Tumor staging			0.079	0.779
I-II	27 (54.00)	34 (56.67)
III-IV	23 (46.00)	26 (43.33)
Smoking or not			-	0.753
No	46 (92.00)	54 (90.00)
Yes	4 (8.00)	6 (10.00)
Drinking or not			-	0.726
No	47 (94.00)	55 (91.67)
Yes	3 (6.00)	5 (8.33)

BMI: Body mass index.

Assessment of ovarian reserve function

Two types of post-chemotherapy female CRC patients of reproductive age were identified by the Expert Consensus on the Clinical Diagnosis and Treatment of Diminished Ovarian Reserve: The diminished ovarian reserve function group [50 cases, accounting for 45.45% (50/110)] and the normal ovarian reserve function group [60 cases, accounting for 54.55% (60/110)].

Comparison of uterine artery ultrasound hemodynamic parameters between the two groups after chemotherapy

As shown in Table 2, the PI and RI values of the uterine artery in the diminished ovarian reserve function group were higher than those in the normal ovarian reserve function group, while the PSV value was lower. The differences were statistically significant (P < 0.05).

Table 2 Comparison of uterine artery ultrasound hemodynamic parameters between the two groups after chemotherapy, n (%)/mean ± SD.

Group	n	PI	RI	PSV (cm/second)
Diminished ovarian reserve group	50	2.56 ± 0.28	0.91 ± 0.06	33.62 ± 3.26
Normal ovarian reserve group	60	2.28 ± 0.36	0.83 ± 0.11	37.45 ± 3.29
t value		-4.469	-5.061	6.101
P value		< 0.001	< 0.001	< 0.001

PI: Pulsatility index; RI: Resistance index; PSV: Peak systolic velocity.

Comparison of FSH and AMH levels between the two groups after chemotherapy

According to Table 3, there were statistically significant differences (P < 0.05) in blood FSH and AMH levels between the impaired ovarian reserve function group and the normal ovarian reserve function group.

Table 3 Comparison of follicle-stimulating hormone and anti-Müllerian hormone levels between the two groups after chemotherapy (mean ± SD).

Group	n	FSH (mIU/mL)	AMH (ng/mL)
Diminished ovarian reserve group	50	10.27 ± 2.95	1.92 ± 0.24
Normal ovarian reserve group	60	8.20 ± 2.13	3.29 ± 1.18
t value		-4.128	8.798
P value		< 0.001	< 0.001

FSH: Follicle-stimulating hormone; AMH: Anti-Müllerian hormone.

Correlation between uterine artery ultrasound hemodynamic parameters, FSH and AMH levels, and ovarian reserve function

Pearson correlation analysis showed that PI, RI, and FSH levels showed a favorable correlation with the decline in ovarian reserve function (r = 0.395, 0.420, 0.378, P < 0.05), while PSV and AMH expression were negatively correlated with the decline in ovarian reserve function (r = -0.506, -0.614, P < 0.05).

Predictive value of uterine artery ultrasound hemodynamic parameters, FSH and AMH levels for diminished ovarian reserve function

The AUC values for PI, RI, PSV, FSH, and AMH in predicting diminished ovarian reserve function were 0.726, 0.733, 0.791, 0.723, and 0.895, respectively. Compared with individual detection of PI, RI, PSV, FSH, and AMH, combined detection showed higher diagnostic value for diminished ovarian reserve function (P < 0.05), with an AUC of 0.950. The predictive value of PI, RI, PSV, FSH, and AMH for diminished ovarian reserve function is shown in Table 4, and the ROC curve is presented in Figure 1.

Figure 1 Combined receiver operating characteristic curve analysis of uterine artery ultrasound blood flow parameters, follicle-stimulating hormone and anti-Müllerian hormone levels for predicting diminished ovarian reserve. AUC: Area under the curve.

Table 4 Predictive value of uterine artery ultrasound hemodynamic parameters, follicle-stimulating hormone and anti-Müllerian hormone levels for diminished ovarian reserve function.

Indicator	AUC	P value	Sensitivity (%)	Specificity (%)	Accuracy (%)	95%CI
PI	0.726	< 0.001	0.88 (44/50)	0.50 (30/60)	67.27 (74/110)	0.632-0.819
RI	0.733	< 0.001	0.90 (45/50)	0.52 (31/60)	69.09 (76/110)	0.640-0.825
PSV	0.791	< 0.001	0.92 (46/50)	0.52 (31/60)	70.00 (77/110)	0.708-0.873
FSH	0.723	< 0.001	0.62 (31/50)	0.82 (49/60)	72.73 (80/110)	0.622-0.824
AMH	0.895	< 0.001	0.94 (47/50)	0.85 (51/60)	89.09 (98/110)	0.823-0.966
Combined detection	0.950	< 0.001	0.94 (47/50)	0.90 (54/60)	91.82 (101/110)	0.911-0.989

FSH: Follicle-stimulating hormone; AMH: Anti-Müllerian hormone; PI: Pulsatility index; RI: Resistance index; PSV: Peak systolic velocity; AUC: Area under the curve.

DISCUSSION

With the trend of younger onset age of CRC, fertility preservation in female patients of reproductive age has garnered increasing attention. Chemotherapy is a crucial component of comprehensive treatment for CRC; however, its damaging effects on ovarian function cannot be overlooked. It can lead to diminished ovarian reserve and premature ovarian insufficiency, thereby severely impacting patients’ quality of life and reproductive potential[14]. Therefore, identifying sensitive and accurate biological and imaging indicators to assess post-chemotherapy ovarian reserve in such patients holds significant clinical importance. This study focuses on uterine artery hemodynamic parameters and serum endocrine hormones to explore their correlation with ovarian reserve among women of reproductive age with CRC following chemotherapy.

Normal ovarian function is fundamental for maintaining female fertility, encompassing two main aspects: Endocrine regulation and cyclical ovulation. Endocrinologically, the ovaries are responsible for synthesizing and releasing sex hormones, which play vital physiological roles in maintaining typical female body morphology and appearance, as well as promoting the development and manifestation of secondary sexual characteristics[15]. Stable levels of sex hormones not only help sustain the physiological state of secondary sexual characteristics but also facilitate the maturation and development of the female reproductive system[16]. Furthermore, an appropriate hormonal environment is a key condition for achieving successful pregnancy and ensuring offspring reproduction[17]. Ovarian reserve function is closely linked to ovarian perfusion status[18], with the ovarian artery playing a crucial physiological role in follicular growth and maturation[19]. Studies have shown that the ovaries rely on the ovarian and uterine artery for blood supply, and normal follicular development requires adequate nourishment. Increased blood supply enhances the transport efficiency of gonadotropins to target cells within the local circulation, thereby supporting healthy follicular development[20]. The study’s findings showed that, compared to the group with normal ovarian reserve, individuals with reduced ovarian reserve exhibited significantly higher PI and RI, while PSV was significantly lower. This suggests that post-chemotherapy decline in ovarian reserve may be closely related to increased uterine artery vascular resistance and reduced perfusion. A high-resistance, low-perfusion hemodynamic pattern may restrict nutrient and oxygen supply to the ovarian parenchyma, affecting normal follicular development and survival, ultimately leading to depletion of the ovarian reserve[21]. This perspective finds support in the study by Luo et al[22]. Ultrasonic hemodynamic parameters, as a non-invasive and repeatable examination method, provide intuitive evidence for assessing the macroscopic perfusion environment of the ovaries.

Regarding serum endocrine hormones, FSH and AMH are core clinical indicators for assessing ovarian reserve[23]. The hypothalamus’s gonadotropin-releasing hormone and ovarian-derived estrogen provide both positive and negative feedback that controls its production and release[24]. In female physiology, this hormone primarily acts on follicular growth, development, and maturation. It works in synergy with luteinizing hormone (LH) to promote the ovulation process and estrogen synthesis, thereby participating in the regulation of the menstrual cycle[25]. In the menstrual cycle’s follicular phase, its serum concentration typically ranges between 1.7-8.5 mIU/mL, decreasing to lower levels in the luteal phase. Clinically, FSH measurement holds significant diagnostic value. Conditions including reduced ovarian reserve, primary amenorrhea, or early puberty brought on by hyperpituitarism frequently result in elevated levels[26]. Conversely, decreased levels may be associated with factors like polycystic ovary syndrome, long-term use of combined oral contraceptives, or excessive exogenous sex hormone intake[27].

AMH is a member of the superfamily of transforming growth factors-beta. It is primarily synthesized and secreted by ovarian granulosa cells and shows significant expression in the female reproductive system. This hormone can control antral follicle maturation and prevent primordial follicles from developing into expanding follicles, postponing the follicular pool’s early depletion[28]. AMH can show an age-related reduction in ovarian reserve earlier than more conventional markers like FSH, estradiol, inhibin B, and AFC. Although minimal cyclic fluctuations in AMH, especially in young women, have been reported, its variability is considerably lower compared to other reproductive hormones such as FSH and estradiol[29]. Therefore, it is widely considered a stable marker. Owing to its numerous significant advantages in evaluating ovarian reserve, AMH is considered the most precise biomarker for reflecting ovarian aging. Consequently, using AMH for ovarian function screening is deemed to have important clinical application prospects.

The study’s findings showed that women with reduced ovarian reserve following chemotherapy had considerably higher blood FSH concentrations and significantly lower AMH levels than those with normal ovarian function. The elevation in FSH suggests reduced ovarian sensitivity to gonadotropin feedback, implying that higher FSH concentrations are required to initiate follicular development in the context of diminished ovarian reserve. The substantial decline in AMH directly reflects the damaging effect of chemotherapy on the follicular quantity within the ovaries. It should be noted that factors such as age, BMI, and different chemotherapy regimens may all impact ovarian function[30]. In order to eliminate the possible interference of the above factors on the results of this study and ensure that the two groups of patients are balanced and comparable before entering the final analysis, this study first examined baseline data including age, BMI, age at menarche, and chemotherapy regimen. The baseline data of menarche age and chemotherapy regimen were compared. The results showed that there was no significant difference in the above indicators between the two groups, which laid a solid foundation for the subsequent comparison of uterine artery blood flow parameters and serum markers between the two groups. Additionally, FSH itself is susceptible to fluctuations across the physiological cycle. Therefore, comprehensive assessment using multiple indicators holds significant clinical importance.

This investigation further examined the association between uterine artery hemodynamic parameters, serum markers, and diminished ovarian reserve. It found that PI, RI, and serum FSH levels were positively correlated with diminished ovarian reserve, while PSV and AMH levels were negatively correlated. This suggests that the decline in ovarian reserve after chemotherapy is not the result of a single mechanism but likely involves a dual pathophysiological process encompassing impaired ovarian microcirculation perfusion and depletion of the primordial follicular pool. As the uterine artery is a primary vessel supplying blood to the uterus and partially to the ovaries, increased vascular resistance and decreased flow velocity may directly reduce blood perfusion to the ovarian parenchyma, affecting the follicular microenvironment and consequently accelerating follicular atresia. Simultaneously, the compensatory rise in serum FSH levels and the direct decline in AMH levels collectively corroborate the substantial reduction in ovarian reserve from two dimensions: The feedback regulation of the hypothalamic-pituitary-ovarian axis and the quantity of remaining follicles within the ovary. Therefore, the combined application of PI, RI, PSV, FSH, and AMH can provide a more comprehensive and multidimensional assessment of ovarian damage and reserve status after chemotherapy, with predictive value surpassing that of any single indicator.

This study not only verified the correlation between uterine artery ultrasound blood flow parameters combined with serum FSH, AMH and ovarian reserve dysfunction in women of childbearing age with CRC after chemotherapy, but also provided an objective basis for the construction of hierarchical and accurate ovarian function monitoring and management strategies. Based on the results of this study, it is suggested that for women of childbearing age who need adjuvant chemotherapy after CRC surgery, the above combined detection should be routinely carried out at the critical time point of 3 months after the end of chemotherapy. In terms of specific clinical decision-making path, if the joint test results of patients indicate that the decline of ovarian reserve function is at high risk, clinicians should identify them as high-risk groups of premature ovarian failure, and timely take comprehensive intervention measures, including referring them to the reproductive medicine center for systematic fertility assessment and consultation by specialists, discussing and formulating individualized fertility protection scheme in combination with the patient’s fertility desire, and strengthening long-term health management, focusing on the starting time of hormone replacement therapy, bone health maintenance and cardiovascular risk monitoring, in order to alleviate the long-term complications of iatrogenic menopause. On the contrary, for patients assessed as low-risk, the time window of family planning can be appropriately relaxed, and the conventional follow-up strategy can be continued.

This study still has some limitations. First of all, this study conducted an inter group equilibrium test on the confounding factors such as chemotherapy type, tumor stage, ovarian surgery history, smoking history and drinking history. The results showed that the two groups were comparable, which controlled the interference of the above factors to the results to a certain extent. However, ovarian reserve function is affected by many factors. This study failed to include the cumulative dose of chemotherapy drugs, individual genetic differences and other factors, which may still have some limitations on the research conclusion. Secondly, this study adopted a cross-sectional design, and all indicators were collected at a single time point after chemotherapy. Although this design can effectively identify the correlation between uterine artery blood flow parameters, FSH, AMH and the decline of ovarian reserve function, it cannot establish a clear causal relationship. This study could not distinguish whether the continuous decrease of blood perfusion after chemotherapy directly led to follicular depletion or the secondary changes after ovarian parenchyma damage negatively affected the hemodynamic parameters. Thirdly, this study only selected 3 months after chemotherapy as a single observation node. Although this time point can reflect the early ovarian reserve after chemotherapy, it failed to cover the dynamic evolution of ovarian function over time. The ovarian injury caused by chemotherapy may be acute exhaustion, delayed injury or self limited recovery. With the extension of follow-up time to 6 months, 1 year or even longer, the uterine artery blood flow parameters and serum hormone levels of patients may have new trends. Therefore, the conclusion of this study is mainly applicable to the early evaluation after chemotherapy, and the prediction ability of long-term ovarian function outcome needs to be verified by longitudinal follow-up study. Moreover, this study is a retrospective design, without blind method for ultrasonic operators and laboratory testers. Although the detection index is an objective quantitative parameter, there may still be potential measurement bias. Finally, the comparison and correlation analysis of multiple indicators involved in this study are based on clear clinical assumptions, but the significance level correction of multiple comparisons is not carried out, which may increase the risk of type I errors to a certain extent, so that the significance of some statistical results is highly estimated. Therefore, prospective longitudinal studies should be carried out in the future in terms of research design. The changes of uterine artery blood flow parameters and serum hormone levels should be dynamically monitored at multiple preset time points before, during and after chemotherapy. Combined with the cumulative dose of chemotherapy drugs, multivariate analysis should be carried out. Through the construction of longitudinal data analysis model, the sequence of changes of each index and its predictive role in the process of ovarian function injury should be more clearly revealed, so as to provide stronger evidence for the inference of causality. At the same time, the follow-up time should be extended to 6 months, 1 year or even longer, in order to comprehensively observe the dynamic evolution of ovarian function, and clarify the different patterns and clinical outcomes of ovarian injury after chemotherapy. At the research implementation level, the follow-up study should implement strict blind operation, and expand the sample size to carry out a multi center prospective cohort study to further verify the reliability of the conclusions of this study. In terms of statistical methods, the main outcome indicators should be set in advance, and Bonferroni and other correction methods should be used to control class I errors, so as to enhance the preciseness of statistical inference.

CONCLUSION

In conclusion, for reproductive-age women with CRC after chemotherapy, the combination of ultrasonic hemodynamic parameters with FSH and AMH can more comprehensively and earlier reflect the extent of chemotherapy-induced damage to ovarian reserve. This provides multidimensional and objective imaging and biochemical evidence for clinically assessing ovarian function status in reproductive-age CRC patients post-chemotherapy. Comprehensive analysis of these indicators aids in the individualized prediction of ovarian function decline risk and offers important references for formulating fertility preservation strategies and timely implementation of assisted reproductive interventions.