Handbook of Current and Novel Protocols for the Treatment of Infertility

Handbook of Current and Novel Protocols for the Treatment of Infertility is a valuable resource of well-organized, comprehensive scientific data with practical guides and step-by-step protocols for infertility management. Written by contributors located worldwide, this book discusses different practice patterns and approaches used internationally, along with innovative topics including preimplantation genetic testing, time lapse imaging and the role of artificial intelligence in ART. This book provides up-to-date, evidence-based guidance on daily practice and is a valuable resource for infertility providers, including trainees in the field of reproductive endocrinology and infertility, embryologists, specialists in reproductive medicine and gynecologists.The field of Assisted Reproductive Technology (ART) is rapidly evolving and stimulation protocols, fertility strategies and aspects of infertility treatments are constantly being updated as advances and new discoveries are made.

• Presents protocols for infertility management and new developments in practical techniques and understanding, including discussions on in vitro maturation, in vitro fertilization and ovarian stimulation
• Discusses innovative topics such as the role of artificial intelligence in infertility management, protocols using progesterone to prevent ovulation, dual-stim protocols, random start protocols, complications in IVF, and management of these complications
• Chapter written by well-known experts on infertility management from different parts of the world, thus providing a worldwide perspective

• Language: English
• Publisher: Academic Press
• Release date: Sep 6, 2023
• ISBN: 9780323901062

Book preview

Preface

Juan Garcia Velasco, Human Fatemi, Nikolaos Polyzos, and I undertook this endeavor to develop an up-to-date textbook of fertility care for both the trainee in need of instruction and the experienced clinician who wants to refresh and update their knowledge. It includes information on how to perform modern care as well as exposure to uncommon albeit contemporaneous subjects in the realm of fertility care.

We included basic chapters such as the male and female infertility evaluation, ovarian stimulation and insemination, and several chapters on managing different types of in vitro fertilization (IVF) cycles. How women with polycystic ovary syndrome (PCOS) require tailored care. We went over different types of ovarian trigger for oocyte collection. Using progestins to prevent ovulation, sperm DNA fragmentation, and its role on fertility outcomes. We discussed the mild stimulation protocol and the dual stim protocol, for which a recent prospective randomized trial demonstrated the advantage of as compared to two sequential follicular phase start cycles.

We discussed the management of recurrent pregnancy loss, and we critically reviewed care for recurrent implantation failure, endometrial receptivity, and the microbiome.

We even have chapters on how to set up an IVF and an andrology laboratory, which are not typically available in textbooks. We provide a schematic on how to troubleshoot an IVF laboratory when success rates suddenly decrease unexpectedly, knowledge which is both important for the clinicians and the embryologists responsible for the patients and the laboratory.

We made sure to include information about in vitro maturation (IVM) of human oocytes, likely the future of our field. We selected chapters to be included from both: a group which believes in stimulation and triggering for an IVM and another group which would almost never perform such procedures in their IVM cycles. This was done so that the reader could be exposed to both points of view. This concept goes back to the basis of fertility care. That there are many different ways to perform fertility care, with most believing that their way is the best, while most of these different ways work perfectly fine.

This book will address how to manage the complications from IVF and how to minimize their occurrence.

We selected international experts in the field as the authors, who are both contemporaneous and represent the diverse methods of fertility care around the world. We were very fortunate that many of the best academic fertility experts in the field today participate by contributing chapters.

We hope that you find this book both educational and novel.

We wish to thank Elsevier for undertaking this endeavor and all the assistants who have helped this title progress.

Sincerely,

The Editors

Michael H. Dahan, Human M. Fatemi, Nikolaos P. Polyzos, and Juan A. Garcia Velasco

Chapter 1: The evaluation of the female infertility patient

Ezgi Demirtas, and Michael H. Dahan     Division of Reproductive Endocrinology and Infertility, McGill University Health Care Center, Montreal, QC, Canada

Abstract

Infertility is the failure to conceive for a period of 1 year. However, in older women an evaluation may be undertaken after six months of attempting conception. The evaluation of infertility in the female is crucial to determine the treatment required. It is complex, with a logic but is easily mastered by practitioners of fertility care. In this chapter we will explain in the depth the standard tests used to evaluate the female member of a couple with infertility. This is the first step towards the mastery of fertility care.

Keywords

Age related decline; Fecundity; Female; Infertility; Medical history; Ovulation

The World Health Organization (WHO) categorizes infertility as a disease (WHO, 1). It affects both genders and causes considerable personal suffering and disruption of family life.

When heterosexual couples try to conceive, we talk about functional fertility. This would translate into how easy or how difficult it is for a couple to conceive. Even in absence of a factor affecting fertility, the probability of conception declines with increasing female age. This is attributed to the decrease in ovarian reserve depicted by a quantitative and a qualitative decline in the follicular pool [1,2].

Fecundability is a term used when referring to the probability of a spontaneous conception in one menstrual cycle in couples having regular sexual intercourse. Fecundability varies from 11% to 33% in reproductive-age women (where >90% of women studied were <35 years of age and without known infertility factors being present when they initiated attempted conception) [3–5]. Cumulative pregnancy rates at 12 months of regular unprotected intercourse were traditionally reported as being about 80%–85% in the age group 25–27 years. Recently, the American Society of Reproductive Medicine reassessed cumulative pregnancy rates in young couples without infertility and determined that 85% of couples conceived after six months of regular unprotected intercourse. Of women 40–45 years of age, 55% are pregnant by one year [6]. Fecundability declines, as the female age gets older, even if there is no known infertility factor.

The time from the start of unprotected sexual intercourse to pregnancy is called time to pregnancy and is reported in months. As the female ages, time to pregnancy increases. The median time to pregnancy was reported to be three months for women under 38 years of age, four months for women 38–39, eight months for women 40–41, and longer than 12 months for women 42–44 years of age, in a population at least 30 years old, with no known infertility factors [7].

If the duration of time to pregnancy is long enough that it passes a predetermined threshold, then the fertility investigation for both partners is recommended. The term infertility is historically described as not conceiving for one year despite regular unprotected sexual intercourse, two to three times a week, in a heterosexual relationship. The infertility investigation is often recommended to start earlier, after six months of subfertility, if the female age is older than 35 years or if there is an obvious problem like menstrual irregularity, a previous diagnosis of endometriosis, or a known moderate male factor [8]. The reason to set the age cut off at 35 years for initiation of an evaluation at six months of infertility is that the quantitative and qualitative follicular pool depletion accelerates with age, the decline in monthly fecundity rate is faster, and the time to pregnancy becomes longer after age 35. For women, over 40 years of age, the investigations need to be completed more immediately, and the treatment needs to be expedited.

The WHO published a technical report in 1992, titled Recent Advances in Medically Assisted Conception following the WHO Scientific Group Meeting in April 1990, in Geneva [9]. In that report, the prevalence of female factors was reported as higher than the prevalence of male factors. The most common female infertility causes were ovulatory disorders and tubal factors even though the prevalence of causes varied according to the various geographical regions (Tables 1.1 and 1.2).

Female fertility often needs to be evaluated in women and nonbinary individuals (with female karyotype) who do not fit the classical definition of failure to conceive in 6–12 consecutive months despite regular unprotected sexual intercourse where a male partner is contributing. These are women and sometimes nonbinary individuals planning oocyte preservation, women in homosexual relationships planning reciprocal in vitro fertilization (IVF), and women who desire conception using donor sperm with or without a partner. Trans-males may also need evaluation for both conception and fertility preservation with testosterone suplementation having no effect on outcomes in IVF cycles.

Having both male and female evaluated concomitantly is recommended in all cases where applicable, since 20%–35% of the time, there are factors affecting fertility in both partners in couples. Further testing may be planned for a woman where the man's test results are found to be in the normal range. Or, for instance, tubal evaluation may be deferred if a man is known to have severe sperm factor, and the couple is recommended to undergo IVF where tubal patency is not needed to be tested. In these cases, an evaluation of the uterine cavity may be indicated to rule out polyps, fibroids or Asherman's syndrome.

Table 1.1

Table 1.2

History assessment

The fertility investigation starts with a comprehensive history (ideally to be complemented with a thorough physical exam in a setup where an in-person clinic visit takes place). History and through the physical exam alone will reveal vast information for planning further tests and treatment options and will also guide the preconceptional counseling. The significant parameters to ask in history are listed and explained in Table 1.3.

Physical exam

Height and weight measurements, BMI calculation, and appearance

Extremes of body mass index (BMI) on both ends and fat distribution need to be noted. Very low BMI is also associated with reduced fertility. Eating disorders leading to very low BMI are associated with hypothalamic amenorrhea (WHO group 1) by decreasing hypothalamic gonadotropin-releasing hormone secretion [12].

Together with high BMI, central obesity may suggest insulin resistance; abdominal circumference should be measured. As these women are often given dietary and exercise advice, and sometimes prescribed metformin, the resultant change in weight, BMI, abdominal circumference or fat distribution, and change in menstrual cycle length need to be noted during care. Patients with high or low BMI should ideally be referred to a nutritionist.

Not only the BMI but also the patient's weight alone is also important, particularly in the selection of gonadotropin dose in ovulation induction and controlled ovarian stimulation for IVF. Higher doses are usually required above 170 lbs (77 kg) even if the ovarian reserve is good.

A short stature (less than 5 feet in height, 152.4 cm) with or without primary amenorrhea may suggest Turner syndrome (TS). Other phenotypic features, such as the webbed neck, low-set ears, shield chest, pigmented nevi, cubitus valgus, and low hairline, may be recognized when the patient is seen in the clinic. Pure 45,X cases are mostly diagnosed during childhood whether due to phenotypic appearance or due to nondevelopment of secondary sexual characteristics. Before pregnancy, all women with classic or mosaic Turner's syndrome should undergo evaluation of aortic root dilation and congenital urinary system abnormalities. TS may be mosaic with varying degrees of 46XX cell lines present, as well. In this case, the women may have menses and are at risk for premature ovarian failure. In the case of TS mosaic with a Y chromosome present (45X/46XY or other combinations), the gonads need to be removed due to future malignity risk.

Table 1.3

In the presence of primary amenorrhea, secondary sex characters need to be observed. Underdeveloped secondary sex characteristics may refer to hypothalamic causes (hypogonadotropic hypogonadism—low or normal serum follicle-stimulating hormone [FSH] and luteinizing hormone [LH]) or gonadal failure where hypothalamo–pituitary axis works well (high serum FSH an LH) [14]. A karyotype test for these patients will likely be needed. Other genetic and sex development disorders, Swyer syndrome (46XY), which is pure gonadal dysgenesis, androgen insensitivity syndrome (testicular feminization, 46, XY), and Leydig cell agenesis commonly have a female phenotype with primary amenorrhea. There is no uterus and no Fallopian tubes in androgen insensitivity syndrome and complete Leydig cell agenesis; however, there may exist a uterus in Swyer syndrome, and gonads are underdeveloped streak gonads. All gonads in phenotypic females with Y chromosomes need surgical removal to prevent malignancy.

Mullerian agenesis, complete transverse vaginal septum, or imperforate hymen are other causes of primary amenorrhea with normal 46, XX karyotype.

A recent concept, idiopathic hirsutism, may be seen in women who are hirsute but having regular cycles. Circulating androgens are also found to be in normal levels. However, this does not guarantee a normal ovulation; up to 40% of these women may be anovulatory [15].

Body hair distribution is another finding that needs to be examined. Hirsutism refers to the presence of male-like pattern of terminal hairs in women. This may indicate elevated serum androgens. It should be differentiated from hypertrichosis as hypertrichosis is excessive hair anywhere on the body, while hirsutism is only on the androgen-sensitive areas, that is, chin, upper lip, chest, upper back, etc. Hirsutism is traditionally evaluated according to Ferriman–Gallwey (FG) scoring system [16], and this system was modified by multiple investigators and is called the modified FG system [17–20]. A score of 8 or higher is considered hirsutism. However, today, visual assessment of terminal body hair on the androgen-sensitive areas being >5 mm in length has become the most widely used method to evaluate hirsutism [21].

Thyroid and breast

The thyroid gland needs to be examined for goiter or thyroid nodules in all patients. A breast exam may uniformly be performed in all patients or only in the presence of a history of oligomenorrhea to investigate galactorrhea, when breast secretion is reported by women and when there are concerns about underdeveloped secondary sex characteristics (and anyone with suspicion of a breast mass). While evaluating galactorrhea, current medication use and recent pregnancy/delivery history need to be kept in mind. Consideration should be given to the testing of serum thyroid-stimulating hormone (TSH) and prolactin levels in all patients with ovulatory problems and irregular menstruations. Hyper- or hypothyroidism may cause menstrual abnormalities, and subclinical levels should likely be corrected prior to pregnancy to prevent any complications, particularly in the presence of antithyroid antibodies [22–24].

Pelvic exam

The pelvic exam revealing a fixed uterus brings about questions regarding adhesions caused by endometriosis or pelvic adhesions due to previous PID, peritonitis, tuberculosis, or previous surgery. It may also reveal vaginismus preventing sexual intercourse. Detection of a large uterus may suggest uterine fibroids, or a bulky uterus may suggest the presence of adenomyosis. Again, pain and/or rectovaginal sensitivity or nodules during pelvic exam may suggest endometriosis.

Pelvic ultrasound

The pelvic ultrasound examination when integrated with history and physical exam provides valuable further information and/or clarification to the fertility evaluation. Although an examination by a transvaginal transducer often provides sharper images of the uterus and ovaries in most cases, a transabdominal ultrasound exam is also performed when image optimization is not conceivable by the transvaginal route due to patient habitus (often high BMI), large uterus and/or fibroids, ovaries located high in the pelvis, and when the structure of interest falls out of the depth of penetration of the transvaginal transducer. A transabdominal ultrasound exam is particularly instrumental in obtaining a clear image in selected cases where the ovaries are anteriorly located and far from the vaginal vault. The ultrasound exam can provide accurate information about ovarian morphology, antral follicle count (AFC), presence of uterine fibroid(s) and their locations, uterine anomalies, and adenomyosis.

Pelvic ultrasound examination provides information not only on pelvic anatomy but also on ovarian reserve through ovarian volume and AFC.

The quality of the pelvic ultrasound exam is highly machine-, operator-, and subject-dependent. Therefore, information obtained from poor-quality ultrasound images needs to be interpreted cautiously, and if the AFC estimation is not believed to be accurate, ovarian reserve evaluation needs to be completed by blood tests.

Evaluation of ovarian reserve

Declining fecundability rates with increasing female age are well documented. Female age is an important parameter of the ovarian reserve evaluation. It is often used as a post hoc test as the ovarian reserve of younger women is expected to be higher compared to older females and with oocytes from younger women having the greatest potential for euploidy [25]. The most often used ovarian reserve tests (ORTs) are the AFC, serum anti-Mullerian hormone (AMH), and early follicular phase serum FSH (to be interpreted with the concomitant serum estradiol level). Another biomarker for ovarian reserve, more rarely used as compared to AFC, AMH, and FSH, is serum inhibin B levels.

Ovarian reserve evaluation not only helps diagnosing the underlying pathology in cases of menstrual irregularity/amenorrhea but also helps determine the FSH dose to be administered in ovulation induction for timed intercourse or insemination and ovarian stimulation for IVF treatment.

AFC: The presence of 12–20 or more follicles, 2–9 mm in diameter, in an ovary, and/or ovarian volume >10 mL qualifies the ovary as polycystic ovary (PCO) [26]. These women may or may not have regular menstrual cycles, may or may not have polycystic ovarian syndrome (PCOS). However, they are expected to respond well or overrespond to the ovarian stimulation during IVF treatment. On the other hand, women with total AFC of 12 or less are at risk for decreased ovarian reserve and suboptimal cumulative pregnancy rates at IVF. An AFC less than six is indicative of poor ovarian reserve [25].

AMH: AMH is a glycoprotein produced by antral and preantral follicles. It can be measured anytime throughout the menstrual cycle as it is predominantly FSH-independent and it has low intra- and intermenstrual cycle variability [27,28]. It is arguably the most accurate predictor of ovarian reserve and treatment outcome [29–32]. In the past, there was no consensus regarding the AMH levels referring to normal ovarian reserve due to poor assay reproducibility [33,34]. However, the Beckman–Coulter assay for AMH has provided high levels of reproducibility. With other assays, levels between 1 and 4 ng/mL may be considered as cut offs for normal ovarian reserve [35]. Lower values refer to poorer ovarian reserve. With the Beckman–Coulter assay, serum levels of less than 1.2 ng/mL are considered a poor prognosis group.

FSH: Basal (cycle day 2–5 of a spontaneous or induced menstrual cycle) serum FSH and estradiol levels are used in ovarian reserve evaluation. In women with oligomenorrhea or amenorrhea, these tests (FSH and estradiol) can be performed at random and may detect diminished ovarian reserve (serum FSH levels above 12–15 IU/L and normal serum estradiol levels), menopause (high FSH typically above 40 IU/L and very low estradiol levels), or hypothalamic amenorrhea (FSH low [30% of subjects, <2.0 IU/L] or normal [70% or subjects, 2–10 IU/L] and low or undetectable serum estradiol levels). This occurs because the assay often measures immunizable and not bioactive FSH that is released in hypothalamic amenorrhea. Rarely serum LH levels can help evaluate primary amenorrhea.

Suboptimal cumulative pregnancy rates are reported in women with lower ovarian reserve in IVF treatments. However, in women without infertility and low ovarian reserve, spontaneous pregnancy rates may be similar to women with normal ovarian reserve. For example, infertile patients had similar AMH levels compared with controls with no history of infertility in an age-adjusted regression analysis [36]. In multiple other studies, the biomarkers (not age) of ovarian reserve are not convincingly shown to have correlation neither with chances of spontaneous pregnancy nor with miscarriage rates [37–40]. Women with poorer ovarian reserve, compared with same age group women with normal ovarian reserve, have similar spontaneous pregnancy chances and similar miscarriage rates. Therefore, interpretation of test results and patient counseling should be done with caution.

Inhibin-B: Inhibin-B declines with dwindling ovarian reserve in most studies [41,42], however not in all of them [43,44]. It is mostly used in research settings rather than being commonly employed as an ovarian reserve biomarker. It is argued that there may be a delay in decline of inhibin-B compared to the actual decline in ovarian reserve [44].

Ovulation assessment

Ovulation status needs to be assessed in all women evaluated for infertility.

The majority of women with a history of menstrual cycles between 24 and 35 days in duration have ovulatory cycles [45,46], especially if they have molimina symptoms. Molimina symptoms are feelings in women associated with progesterone production or withdrawals which include breast tenderness, sleep difficulties, a sense of bloating, mood changes and irritability, headache, fatigue, acnea, increased appetite in the luteal phase, etc. However, in a moderate-sized study, 89% of women with regular cycles and molimina were ovulating according to progesterone measurements [47].

In addition to menstruation cycle history, women may present their basal body temperature records as a tool of retrospective identificator of their ovulatory status. In combination with menstrual history, the presence of molimina symptoms and basal body temperature charts can help identify the ovulatory women without further testing [48]. For prospective identification of ovulation, urinary LH kits (ovulation predictors) can reliably be used particularly in women with regular cycles [49]. However, it must be kept in mind that women in menopause, perimenopause, or having PCOS syndrome may have elevated LH levels above the cut off of 20 IU/L and not be ovulating.

It's reported that over one-third of women with regular menstrual cycles may not have ovulation [50]. Therefore, a midluteal serum progesterone measurement can be used as a reliable test; >5 ng/mL serum progesterone concentration suggests a specificity of 98.4 (95% CI 96.0–99.5) and with a sensitivity of 89.6 (95% CI 85.2–92.9) for ovulation [51].

Women with menstrual cycle intervals longer than 35 days are considered anovulatory; however, among them up to 50% may be ovulating where the study group included women with cycles 36–45 days [52]. Therefore, oligo-ovulatory may be a more accurate term for them rather than anovulatory. Ovulation can be assessed with serial pelvic ultrasound exams and urinary ovulation predictors (urinary LH test kits) as in this study, and it may further be combined with serum progesterone measurement one week after the ovulation for a more accurate assessment. However, this is neither practical nor cost-effective for a general use. Yet, when intended, to clarify ovulation status, weekly serum progesterone measurement starting from cycle day 21 or weekly ultrasound monitoring to observe follicular development and presence of a corpus luteum may be used to clarify the situation in these women when necessary.

For women who do not have regular cycles, whether amenorrheic or oligomenorrheic, and/or where serum progesterone level indicates anovulation, serum FSH and estradiol levels together with or without other parameters (AFC and AMH) of ovarian reserve are used to establish the differential diagnosis of anovulation (Table 1.4). Serum prolactin and TSH assays need to be included in the tests. In routine, daily practice these tests; in case of oligo- or amenorrhea, these are mostly requested together instead of a stepwise approach. When PCOS is diagnosed, a metabolic screening is also warranted, especially in women with high BMI. Testing serum lipid levels, renal function (blood urea nitrogen and creatinine), and diabetes via hemoglobin HbA1c, ideally less than 6% or 42 mmol/mol is desired prior to treatment, must be less than 7% to conceive in diabetic women; otherwise, risks of fetal anomalies increase. Diabetes is suspected when HbA1c is >6.5% or >48 mmol/mol. Liver function tests should be considered where HbA1c is high.

Hyperprolactinemia prevents ovulation through LH suppression. It may or may not cause galactorrhea and therefore needs to be tested in women with anovulation. Mild hyperprolactinemia (20–50 mIU/L) may impair fertility without causing amenorrhea by causing inadequate progesterone secretion.

To keep in mind, if the amenorrhea (investigated as anovulation) follows a delivery, curettage, myomectomy, and rarely PID, it may be mistaken for anovulation while the etiology is mechanic (Asherman's syndrome or cervical stenosis).

Table 1.4

Tubal patency evaluation

Tubal patency should be evaluated in all women unless ovulatory dysfunction is present. However, it may be deferred in a severe male factor infertility necessitating IVF where the woman does not have any history of prior sexually transmissible disease. Similarly, women without history of infertility planning donor sperm insemination can defer the tubal evaluation and try insemination for an initial three to six cycles. In anovulatory infertility, failure to conceive within three to six months of ovulation induction should then result in evaluations of tubal patency.

The gold standard of tubal function evaluation is exploratory laparoscopy and chromotubation. However, this is not recommended for routine use for women who do not have endometriosis symptoms, prior pelvic surgery, and unsatisfactory hysterosalpingography. An exploratory laparoscopy would enable diagnoses of peritubal adhesions, which could result in a patent but nonfunctional Fallopian tube.

Both hysterosalpingogram (HSG) and hysterosalpingo-contrast sonography (HyCoSy) are common methods to evaluate fallopian tube patency. In the presence of a single patent fallopian tube, pregnancy rates are like those of women with both tubes patent per the current metaanalyses. The fallopian tubes are being evaluated using saline instillation sonography (SIS), ultrasound visible foam solutions, or HyCoSy. SIS provides an excellent view of the uterine cavity for both congenital anomalies (especially when combined with 3D ultrasound) and acquired pathologies (polyp, submucosal fibroid, and synechiae). However, it is difficult to diagnose a hydrosalpinx with SIS as compared to HSG. Tubal patency may also be present and not seen with SIS. With HyCoSy, using 3D ultrasonography and intrauterine foam installation, fallopian tube patency evaluations are comparable to outcomes seen with HSG and laparoscopy but with less discomfort.

Other investigations

Serum testosterone (free or total), DHEAS (dehydroepiandrosterone sulfate), and early morning fasting 17-hydroxyprogesterone levels can aid in evaluating women with hirsutism. (17-hydroxyprogesterone should be done in the early or mid-follicular phases in ovulatory women).

Tests for hepatitis B, hepatitis C, syphilis, and human immunodeficiency virus are helpful since gametes and sperm will be handled.

Rubella and varicella immunity can be evaluated prepregnancy, and vaccination is offered to women who are nonimmune given the potential to protect the fetus.

Serum prolactin levels should be tested in women with galactorrhea and menstrual disturbances.

A hemoglobin hematocrit and platelet count should be obtained before any surgical procedures including IVF.

Genetic screening for carrier status is often offered before conception to couples with large panels available today based on ethnic origin. Although this is not required in many countries, it is prudent to have documents offering it to the couple before conception.

Screening for thalassemia and sickle cell carrier status in women or couples of Asian, Mediterranean, and African descents may also be indicated preconception.

Many laboratories offer comprehensive genetic carrier screening that can be tailored to ethnic origin and may be helpful for certain couples to prevent rare recessive disease. The payment for such may or may not be covered by insurance.

Conclusion

All women need a thorough history and physical exam. They should undergo transvaginal ultrasonography, ovulation assessment, ORT, and tubal patency evaluation in most cases. Documentation of ovulation by blood test may not be required in all cases. A tailored screening before initiating fertility care for each patient is recommended regarding their needs.

References

1. Recent advances in medically assisted conception. Report of a WHO Scientific Group. World Health Organ Tech Rep Ser. 1992;820:1–111.

2. Shrem G, et al. Influence of maternal age and ovarian reserve on the decision to continue or to cancel IVF cycles in patients with one or two large follicles: a dual effect. Reprod