One Case of Transvaginal and Transabdominal Oocyte Retrieval Guided by Ultrasound Probe: A Case Report

The patient was a 39 year‐old woman with an 11 year marital history. In 2016, she underwent full‐term cesarean section owing to placenta previa and delivered a healthy neonate. She had been attempting to conceive a second child, but failed to achieve pregnancy despite ceasing contraception for more than 1 year. Her menstrual cycles were generally regular, with a cycle length of 28 days and menstrual duration of 7 days. Additionally, after giving birth, she suffered from moderate‐to‐severe dysmenorrhea, requiring oral analgesics during menstruation. Transvaginal ultrasound findings: The uterus was retroverted and markedly enlarged, measuring approximately 92 × 90 × 80 mm, with an irregular contour and clear boundary. Several hypoechoic lesions were detected in the myometrium, the largest measuring 58 × 42 mm and located in the posterior uterine wall, with indistinct margins. Both ovaries were normal in size. A cystic dark area measuring 16 × 11 mm was observed in the right ovary, with poor acoustic transmission and punctate internal echoes. Antral follicle counts (AFC) were 4–5 in both ovaries. On day 2 of the menstrual cycle, serum hormone levels were as follows: follicle‐stimulating hormone (FSH) 7.49 mIU/mL, estradiol (E2) 55 pmol/mL, luteinizing hormone (LH) 2.41 mIU/mL, anti‐Müllerian hormone (AMH) 2.94 ng/mL, and cancer antigen 125 (CA125) 167.88 U/mL. Chromosomal karyotype analysis revealed a normal female karyotype (46, XX). The patient was 160 cm tall and weighed 60 kg, with a body mass index (BMI) of 23.4 kg/m 2 . The male partner had no significant past medical history; semen analysis and physical examination showed no obvious abnormalities, and his chromosomal karyotype was 46, XY. The patient was diagnosed with secondary infertility, uterine adenomyosis and post‐cesarean section scarred uterus. After comprehensive written informed consent was obtained for assisted reproductive technology treatment, a GnRH antagonist protocol was initiated for controlled ovarian hyperstimulation (COH) in December 2025. On day 2 of the menstrual cycle, ovulation induction was commenced with 225 U recombinant human follicle‐stimulating hormone (Gonal‐f, Merck, France) administered subcutaneously once daily. On day 6 of COH, 0.25 mg ganirelix (Qingle, Chia Tai Tianqing) was added subcutaneously once daily for pituitary downregulation. On day 8 of stimulation, ultrasound revealed 4 follicles ≥ 17 mm in diameter in the left ovary and 5 follicles ≥ 16 mm in diameter in the right ovary, with serum E2 levels reaching 4321.32 pmol/L. Subsequently, 6500 U human chorionic gonadotropin (hCG, Eze, Merck, USA) was administered subcutaneously for oocyte maturation trigger, and oocyte retrieval was scheduled 36 h later. During ovarian stimulation, the left ovary was found to be deeply positioned; although clearly visualized by transvaginal ultrasound, it was anteriorly obstructed by a transversely positioned, abnormally enlarged uterus. Despite attempts to adjust its position via combined abdominal pressure, the left ovary remained immobile. Transabdominal ultrasound subsequently showed that the left ovary was superficially located with clearly visible follicles. Oocyte retrieval was performed under intravenous general anesthesia, induced by intravenous bolus injection of propofol medium/long‐chain lipid emulsion at the initiation of the procedure. All ultrasound assessments and interventions were conducted using a ProSound 6 real‐time ultrasound diagnostic system (Aloka, Japan): transvaginal ultrasound was performed with a 7.5 MHz endocavitary probe, while transabdominal ultrasound utilized a 3.5 MHz convex array probe; color Doppler flow imaging was selectively applied to identify pelvic vascular structures and avoid vascular injury during needle trajectory planning. Pre‐procedural ultrasound measurements revealed abdominal wall thickness at the planned puncture site was 18 mm, and the depth of the left ovary from the abdominal skin surface was 32 mm, facilitating accurate preoperative technical planning. Initially, transvaginal ultrasound‐guided oocyte retrieval was performed for the right ovary uneventfully. The needle trajectory was meticulously planned via transvaginal ultrasound to bypass the cervical stroma and large pelvic vessels, with real‐time monitoring to ensure accurate follicular aspiration. A single transvaginal puncture was conducted to aspirate 5 mature follicles, and 5 oocytes were successfully harvested without procedural complications. Following completion of right ovarian retrieval, the patient remained in the lithotomy position with an empty bladder. Repeated transvaginal ultrasound confirmed that the enlarged uterine body still anteriorly obstructed the left ovary, and manual abdominal compression failed to reposition the ovary to a transvaginally accessible location (Figure  1 ). Transvaginal ultrasound image. Arrow: The abnormally enlarged and transversely positioned uterus is located anterior to the left ovary, completely obscuring the left ovary and blocking the transvaginal puncture access for oocyte retrieval; the left ovary is in a deep pelvic position. Given the technical difficulty of transvaginal retrieval for the left ovary, the procedure was promptly converted to transabdominal ultrasound‐guided puncture. The patient was repositioned supine, and the lower abdominal skin was disinfected with povidone‐iodine and draped using sterile surgical drapes. The abdominal probe was covered with a sterile protective sheath, with sterile ultrasonic coupling gel applied internally. Color Doppler guidance was used to map the inferior epigastric vessels and pelvic vascular arcade, ensuring the planned needle trajectory was free of major vascular structures to minimize bleeding risk. The left ovary was localized in the left lower abdomen, and gentle probe pressure was applied to approximate the ovarian tissue to the abdominal wall for optimal puncture access. The left ovary was superficially positioned with clear follicular delineation, and the ideal puncture site was marked accordingly (Figure  2 ). Transabdomina ultrasound‐guided follicle aspiration image. Arrow 1: Abdominal ultrasound probe; Safe transabdominal puncture path that avoids the uterus for oocyte retrieval. Arrow 2: Left ovary, which is in a superficial position without uterine obstruction; Clearly visible ovarian follicles. The ultrasound probe was stabilized with the left hand, and a 17G single‐chamber puncture needle (WEGO, China) was held in the right hand. The needle was advanced adjacent to the probe through the skin and subcutaneous tissue into the left ovary, with the needle hub connected to a negative pressure suction device. Dominant follicles aligned along the puncture path were aspirated sequentially, with minor probe adjustments to ensure clear visualization of aspiration. The needle remained close to the probe throughout the procedure, with only one abdominal wall puncture performed. A total of 4 follicles were aspirated, yielding 4 oocytes. The total operative duration was approximately 20 min, and the procedure was completed smoothly. Postoperatively, the patient recovered uneventfully with no fever, abdominal distension, localized pain, or puncture site bleeding. Intraoperative and postoperative blood loss was meticulously quantified, with total blood loss less than 10 mL; no active bleeding, subcutaneous hematoma, or abnormal vaginal bleeding was detected. Concurrent transvaginal and transabdominal ultrasound at the 2 h follow‐up confirmed no obvious free fluid in the pelvic or abdominal cavities. Perioperative infection prophylaxis was administered in accordance with standardized clinical guidelines: oral cefuroxime axetil (500 mg, twice daily) was prescribed postoperatively for 3 consecutive days to prevent surgical site and pelvic infectious complications. After standard IVF insemination and embryo culture, a total of 7 2PN embryos were identified on day 1. On day 3, all 7 embryos were high‐quality cleavage‐stage embryos and were subjected to extended blastocyst culture. On day 5, 5 blastocysts (graded 4BA, 4BA, 4BB, 3BB, 3CB) were successfully cryopreserved. Given the presence of adenomyosis and a markedly enlarged uterus, fresh embryo transfer was canceled in this cycle. Currently, we plan to administer 3 to 6 months of pretreatment with gonadotropin‐releasing hormone agonists (GnRHa), followed by hormone replacement therapy and subsequent frozen embryo transfer (FET), with the timing tailored to the regression of uterine size and serum hormone levels. Long‐term reproductive outcomes including clinical pregnancy and live birth rates remain under prospective follow‐up. Outcome Reporting Limitation: This case report is currently restricted to reporting procedural success, embryo development and blastocyst cryopreservation, as the scheduled FET and subsequent clinical pregnancy outcomes have not yet been completed. Follow‐up data will be supplemented promptly once FET and subsequent pregnancy outcomes are available to strengthen the clinical evidence of this individualized oocyte retrieval approach.

Qiaoqiao Lu: conceptualization, data curation, funding acquisition, investigation, methodology, project administration, resources, supervision, validation, writing – original draft, writing – review and editing. Jianying He: conceptualization, investigation, methodology, visualization, writing – review and editing. Ning Zheng: conceptualization, formal analysis, project administration, validation, writing – review and editing.

As a single‐case report with the patient's signed consent, no other ethical review was required.

The authors have nothing to report.

Transvaginal ultrasound‐guided oocyte retrieval is the gold‐standard procedural core of assisted reproductive technology, favored for its clear visualization and minimal invasiveness, making it the routine clinical approach for safe and efficient oocyte harvest [ 6 ]. Nevertheless, this technique is not universally applicable; it may be technically unfeasible or excessively high‐risk in specific scenarios, such as severe pelvic‐abdominal adhesions, congenital reproductive malformations, extreme obesity, or ovarian transposition for fertility preservation, all of which can cause abnormal ovarian positioning or transvaginal access obstruction. In such refractory cases, transabdominal ultrasound‐guided oocyte retrieval serves as a reliable and practical salvage approach [ 7 , 8 ]. This discussion integrates high‐quality published data, conducting a concise analytical comparison of complication rates, oocyte yield, procedural time and pregnancy outcomes to contextualize safety profiles and clarify the unique value of this case. Previous studies have shown that standard transvaginal oocyte retrieval carries a major complication rate (severe bleeding, infection, visceral injury) of 0.3%–0.5%, while transuterine puncture through hypervascular adenomyotic tissue raises this risk to 2%–3% due to heightened bleeding and infection hazards [ 9 , 10 ]. In contrast, transabdominal oocyte retrieval has a major complication rate of 0.4%–0.6% [ 11 ], comparable to routine transvaginal retrieval and far safer than high‐risk transuterine puncture. This case had no perioperative or postoperative complications, aligning with transabdominal retrieval safety data in key literature and verifying its risk‐reduction benefit for adenomyosis‐related ovarian obstruction. Published studies confirm transabdominal retrieval yields non‐inferior oocyte counts compared with conventional transvaginal retrieval, while transuterine puncture carries a 20%–30% oocyte yield reduction risk and potential needle deformation—critical for patients with limited follicle reserve [ 12 ]. This case achieved 100% oocyte yield (9 oocytes from 9 follicles, 4 mature), far exceeding the expected outcomes of transuterine puncture and consistent with transabdominal retrieval yield data in prior reports, proving the simplified technique preserves oocyte acquisition efficacy while ensuring safety. Sönmezer et al. [ 13 ] reported a mean procedural time of (12.4 ± 1.2) minutes for vaginal probe‐guided transabdominal retrieval in 64 patients, while Pereira et al. [ 14 ] noted longer durations for combined transvaginal‐transabdominal retrieval due to complex anatomy. Starting from the induction of intravenous anesthesia, the present case had a 15 min procedural time, slightly longer than the cohort average but clinically negligible; the extension stemmed from precise anatomical localization and risk assessment to avoid transuterine puncture, prioritizing safety. This duration is reasonable for complex single‐case procedures, confirming the simplified technique does not compromise operational efficiency compared with published data. Key literature confirms transabdominal oocyte retrieval does not impair subsequent embryo implantation or pregnancy outcomes; Pereira et al. and Sönmezer et al. [ 13 , 14 ] both documented successful full‐term pregnancies post‐procedure. While this is a single‐case report, the uncomplicated retrieval and high‐quality oocytes lay a solid foundation for subsequent fertility treatment, aligning with published conclusions that transabdominal retrieval does not compromise reproductive outcomes for patients with transvaginal/transuterine puncture contraindications. Current transabdominal oocyte retrieval techniques are mainly categorized into abdominal probe‐guided and transvaginal probe‐guided approaches, and the majority of previous studies adopted specialized puncture guides combined with transvaginal ultrasound assistance [ 15 , 16 ]. In recent years, Yang et al. [ 17 ] proposed a novel modified transabdominal ovarian puncture technique for oocyte retrieval, which is guided by a conventional vaginal ultrasound probe. This approach utilizes a towel clip to grasp and press the abdominal skin, mimicking the anatomical structure of the vaginal fornix, thereby enabling flexible placement of the vaginal ultrasound probe on the smooth abdominal wall and simplifying the entire oocyte retrieval operation. This case carries distinct novelty and clinical advancement compared with existing transabdominal oocyte retrieval reports. Most literature focuses on transabdominal retrieval for complete transvaginal inaccessibility, such as congenital ovarian ectopia, severe pelvic adhesions, or post‐surgical ovarian transposition. In contrast, this case involves adenomyosis‐induced mechanical ovarian obstruction—where the ovary was clearly visualized transvaginally but safe puncture was impossible, a rarely documented indication that expands the clinical applicability of transabdominal oocyte retrieval. Additionally, this case utilizes a simplified technique with a conventional abdominal convex array probe (no specialized puncture guides), differing from modified equipment or vaginal probe‐guided methods in prior studies, boasting stronger operability and wider suitability for routine reproductive centers. This case verifies the safety and efficacy of simplified transabdominal oocyte retrieval for adenomyosis‐induced ovarian obstruction, providing a replicable clinical protocol for anatomically challenging cases. As a single‐case report, conclusions are limited to this specific patient population, and large‐sample cohort studies are needed to validate broader applicability and optimize procedural details.

Written informed consent was obtained from the patient for the publication of this case report.

Prior to the emergence of in vitro fertilization (IVF) technology, harvesting human oocytes for research or clinical applications posed substantial challenges. The world's first IVF‐ET infant, Louise Brown, born in 1978, was conceived via laparoscopic oocyte retrieval. Oocyte retrieval through cesarean section or laparoscopic surgery is not only costly and highly invasive but also lacks repeatability, making it inappropriate for multiple oocyte retrieval cycles. With progressive advancements in medical imaging, ultrasound has been gradually integrated into oocyte retrieval procedures. Early ultrasound‐guided oocyte retrieval was performed via a transabdominal‐transvesical approach, which was frequently associated with complications including urinary tract infections and hematuria [ 1 ]. At present, transvaginal ultrasound‐guided oocyte retrieval is a simple, minimally invasive routine technique that is essential for all reproductive medicine centers [ 2 ]. However, transabdominal oocyte retrieval remains a necessary alternative in specific clinical scenarios, such as difficult transvaginal access due to abnormal ovarian positioning, fertility preservation in specialized patient populations, and medical contraindications to transvaginal puncture [ 3 , 4 , 5 ]. Herein, we present an elderly infertile patient diagnosed with adenomyosis, whose left ovary was deeply positioned and anteriorly obstructed by an abnormally enlarged uterus. Although transvaginal ultrasound clearly localized the left ovary, transvaginal oocyte retrieval would require needle penetration through the uterine body, carrying considerable procedural risks. Accordingly, the procedure was intraoperatively converted to transabdominal puncture retrieval, and mature oocytes were successfully obtained. This case report aims to provide clinical reference for individualized oocyte retrieval strategies in special clinical scenarios among patients undergoing assisted reproductive technology.

The authors declare no conflicts of interest.