Natural cycles for in-vitro fertilization: cost-effectiveness analysis and factors influencing outcome

Decrease in preovulatory serum estradiol is a valuable marker for predicting premature ovulation in natural/unstimulated in vitro fertilization cycle

Background

Premature ovulation occurs at a high rate in natural-cycle in vitro fertilization (IVF), and cycle cancellation further hampers the overall efficiency of the procedure. While lower levels of estradiol (E2) are observed in preovulatory follicles, it is unclear whether declines in E2 can be used as an effective marker of premature ovulation.

Methods

This retrospective analysis includes 801 natural/unstimulated IVF/ICSI cycles undergoing scheduled ovum pick-up (OPU) and 153 natural/unstimulated IVF/ICSI cycles undergoing emergency OPU at a university IVF center from May 2014 to February 2017.

Results

Among the 801 IVF/ICSI cycles undergoing scheduled OPU, preovulatory E2 levels increased by more than 10% in 403 (50.31%) cycles of the sample (Group A), while 192 (23.97%) cycles experienced a plateau (increased or decreased by 10%; Group B), and 206 (25.72%) cycles decreased by more than 10% (Group C). Group C had more patients who experienced premature LH surges, premature ovulation, as well as the fewest oocytes retrieved, frozen embryos, and top-quality embryos. A multivariate logistic regression analysis indicated that premature ovulation was associated with preovulatory E2/−1E2 ratio and premature LH surge. Moreover, preovulatory E2/−1E2 ratio served as a valuable marker for differentiating premature ovulation, with an AUC (area under the receiver operating curve) of 0.708 and 0.772 in cycles with premature LH surges and cycles without premature LH surges, respectively. Emergency OPU resulted in a significantly decreased rate of premature ovulation and increased number of frozen embryos.

Conclusion

Decreases in preovulatory serum E2 was a valuable marker for premature ovulation in natural/unstimulated IVF cycle. Emergency OPU based on the preovulatory E2/−1E2 ratio decreased the rate of premature ovulation in cycles that experienced E2 decreases.

Electronic supplementary material

The online version of this article (10.1186/s13048-018-0469-x) contains supplementary material, which is available to authorized users.

Early embryo mortality in natural human reproduction: What the data say

How many human embryos die between fertilisation and birth under natural conditions? It is widely accepted that natural human embryo mortality is high, particularly during the first weeks after fertilisation, with total prenatal losses of 70% and higher frequently claimed. However, the first external sign of pregnancy occurs two weeks after fertilisation with a missed menstrual period, and establishing the fate of embryos before this is challenging. Calculations are additionally hampered by a lack of data on the efficiency of fertilisation under natural conditions. Four distinct sources are used to justify quantitative claims regarding embryo loss: (i) a hypothesis published by Roberts & Lowe in TheLancet  is widely cited but has no practical quantitative value; (ii) life table analyses give consistent assessments of clinical pregnancy loss, but cannot illuminate losses at earlier stages of development; (iii) studies that measure human chorionic gonadotrophin (hCG) reveal losses in the second week of development and beyond, but not before; and (iv) the classic studies of Hertig and Rock offer the only direct insight into the fate of human embryos from fertilisation under natural conditions. Re-examination of Hertig's data demonstrates that his estimates for fertilisation rate and early embryo loss are highly imprecise and casts doubt on the validity of his numerical analysis. A recent re-analysis of hCG study data concluded that approximately 40-60% of embryos may be lost between fertilisation and birth, although this will vary substantially between individual women. In conclusion, natural human embryo mortality is lower than often claimed and widely accepted. Estimates for total prenatal mortality of 70% or higher are exaggerated and not supported by the available data.

Early embryo mortality in natural human reproduction: What the data say

It is generally accepted that natural human embryo mortality during pregnancy is high - losses of 70% and higher from fertilisation to birth are frequently claimed. The first external sign of pregnancy occurs two weeks after fertilisation with a missed menstrual period. Establishing the fate of embryos before this is challenging, and hampered by a lack of data on the efficiency of fertilisation under natural conditions. Four distinct sources are cited to justify quantitative claims regarding embryo loss: (i) a hypothesis published by Roberts & Lowe in TheLancet  is widely cited but has no quantitative value; (ii) life table analyses give consistent assessments of clinical pregnancy loss, but cannot illuminate losses at earlier stages of development; (iii) studies that measure human chorionic gonadotrophin (hCG) reveal losses in the second week of development and beyond, but not before; and (iv) the classic studies of Hertig and Rock offer the only direct insight into the fate of human embryos from fertilisation under natural conditions. Re-examination of Hertig's data demonstrates that his estimates for fertilisation rate and early embryo loss are highly imprecise and casts doubt on the validity of his numerical analysis. A recent re-analysis of hCG study data suggests that approximately 40-60% of embryos may be lost between fertilisation and birth, although this will vary substantially between individual women. In conclusion, it is clear that some published estimates of natural embryo mortality are exaggerated. Although available data do not provide a precise estimate, natural human embryo mortality is lower than is often claimed.

Natural cycle IVF: evaluation of 463 cycles and summary of the current literature

PURPOSE

Natural cycle (NC) IVF/ICSI has proven to be an alternative to conventional IVF/ICSI cycles.

METHODS

Within our retrospective, observational study (n = 159) infertile couples underwent (n = 463) cycles of NC-IVF/ICSI from May 2007 until December 2011. Oocyte pick-up was performed within a pure natural cycle excluding any hormonal stimulation except of hCG for ovulation induction. Oocytes were fertilized by IVF/ICSI and embryo transfer took place 2 or 3 days later. In addition, the current literature was analysed concerning pregnancy rates in NC-IVF/ICSI cycles.

RESULTS

Oocyte pick-up was performed in n = 463 NC and was successful in n = 342 cases (IVF n = 135, ICSI n = 207). 203 oocytes were fertilized (IVF n = 87, ICSI n = 116, FR 59.4 %) and lead to 192 embryo transfers. Finally, 25 pregnancies were reached (PR 13.0 % per transfer) resulting in four biochemical pregnancies, 7 (33.3 %) miscarriages, one pregnancy of unknown outcome and 13 live births. Within the current literature (n = 27 studies), PR in NC-IVF/ICSI cycles varied between 10.2 and 50 %.

CONCLUSIONS

Within our study, pregnancy rates in pure NC-IVF/ICSI remained below 15 %. Although this may be linked to unfavourable preconditions like patients' age >40 years, low ovarian reserve or long duration of infertility, further improvement is necessary to increase pregnancy rates.

GnRH antagonists: do they open new pathways to safer treatment in assisted reproductive techniques?

GnRH antagonists (GnRHnt) induce a rapid decrease in LH and FSH, preventing and interrupting LH surges. Their properties do not require a desensitization period and allow their use in the late follicular phase. GnRHnt could replace GnRH agonists (GnRHa) in ovarian stimulation without their side-effects and their long period of desensitivity. Both protocols using GnRHnt were associated with a smaller amount of gonadotrophin, a shorter stimulation period and a lower incidence of ovarian hyperstimulation syndrome (OHSS) with statistically comparable pregnancy rates. There is room for improvement of both protocols concerning the programming, the antagonist dose and the timing of antagonist administration. Luteal support should be maintained until the results of further studies. The perinatal outcome appears to be similar to that of other stimulation regimens. Triggering of ovulation can be facilitated by GnRHa for patients at risk of OHSS. Provided that pregnancy rates equivalent to those obtained with GnRHa are confirmed in larger series, GnRHnt will clearly represent a safer alternative to GnRHa protocols in IVF.

Empty follicle syndrome

Empty follicle syndrome (EFS) is a condition in which no oocytes are retrieved after an apparently adequate ovarian response to stimulation and meticulous follicular aspiration. EFS can be classified into 'genuine' and 'false' types according to hCG levels. It is a rare condition of obscure etiology. The existence of genuine EFS has been questioned and is still controversial. The limitation around EFS is that the definition of EFS is obscure. Management of patients with EFS is a challenge to physicians. No single treatment is known to be universally effective. However, patients should be adequately informed regarding the importance of correct hCG administration because improper hCG administration is a common and preventable cause of EFS. EFS is a syndrome that deserves additional study because such investigation could lead to a further understanding of ovarian biology and infertility.

Follicular flushing during oocyte retrieval: a systematic review and meta-analysis

PURPOSE

The purpose of this systematic review and meta-analysis was to examine the literature and identify randomized controlled trials (RCTs), in order to answer if performing follicular flushing during the oocyte retrieval may improve the assisted reproductive technologies (ART) outcomes.

METHODS

An exhaustive electronic search was performed using MEDLINE and EMBASE databases. Only RCTs comparing follicular flushing to aspiration only during ART, were included. We included 5 trials, with a total of 482 patients randomized, with median ages ranging from 30.5 to 37.1.

RESULTS

The data analyses did not show significant differences regarding live birth rate, clinical pregnancies rates, and the number of oocytes retrieved. The duration of oocyte retrieval was significantly increased in the follicular flushing group.

CONCLUSIONS

The results from this systematic review and meta-analysis suggest that there is no advantage to use of routine follicular flushing during OR in an unselected group of patients.

Natural cycle IVF/IVM may be more desirable for poor responder patients after failure of stimulated cycles

OBJECTIVE

To describe pregnancies and live births resulted from natural cycle IVF combined with in-vitro maturation (natural-cycle IVF/IVM) for three poor responder women after failure of stimulated cycles.

METHODS

For case 1 and 2, the mature oocytes from aspirated follicles were inseminated by intracytoplasmic sperm injection (ICSI) immediately; immature oocytes were matured in vitro, and the embryos from mature and immature oocytes transferred on day 3 after oocyte retrieval. For case 3, 3 consecutive natural cycles were performed, in which the matured oocytes from in vivo or in vitro were vitrified in the first and second cycle, and warmed on the retrieval day of the third fresh cycle. Then the embryos resulted from vitrified-warmed and fresh oocytes were transferred.

RESULTS

A total of 15 oocytes were obtained from the 7 retrieval cycles for the three cases. The case 1 was successfully pregnant at her first natural cycle, and case 2 was pregnant after two consecutive cycles. The two cases had successfully delivered and case 3 was in her ongoing pregnancy at the time of submission.

CONCLUSION

These results demonstrate that natural-cycle IVF/IVM might be a reasonable and efficient treatment alternative for poor responder patients when stimulated cycle has failed.

Successful pregnancy in an ovarian agenesis patient after modified natural cycle IVF oocyte donation

The recovery of a mature oocyte from a modified natural cycle followed by in-vitro fertilization (nIVF) is an attractive alternative to conventional IVF, involving ovarian stimulation, in the treatment of female infertility. Ovarian agenesis is a rare disorder resulting in primary amenorrhoea and infertility in affected females. A couple sought help for infertility due to ovarian agenesis of the female partner and decided to pursue treatment utilizing oocyte donation. Modified natural-cycle egg retrieval was carried out on the donor; one mature oocyte was retrieved and underwent IVF using a sperm sample from the male partner. A good-quality embryo was transferred, A viable pregnancy was confirmed by ultrasound scan and resulted in the delivery of a healthy baby boy at 36 weeks' gestation. This is the second published report of an ongoing clinical pregnancy and subsequent birth resulting from oocyte donation recovered during a modified natural cycle. The use of less invasive assisted reproduction techniques such as nIVF can be used in oocyte donation cycles successfully.

Reproductive healthcare systems should include accessible infertility diagnosis and treatment: an important challenge for resource-poor countries

Infertility is a central issue in the lives of many couples who suffer from it. In resource-poor countries the problem of childlessness is even more pronounced compared with Western societies owing to different sociocultural circumstances. It often leads to severe psychological, social, and economic suffering, and access to infertility treatment is often limited to certain procedures and certain costumers. The issue of infertility in resource-poor countries is underestimated and neglected, not only by local governments but also by the international nonprofit organizations. Simplification of the diagnostic and therapeutic procedures, minimizing the complication rate, and incorporating fertility centers into existing reproductive healthcare programs are essential measures to take in resource-poor countries if infertility treatment is to be accessible for a large part of the population. For reasons of social justice, a search for strategies to implement simplified methods of infertility diagnosis and treatment in resource-poor countries is urgently warranted.

Embryo implantation rates in natural and stimulated assisted reproduction treatment cycles in poor responders

Controlled ovarian stimulation with exogenous gonadotrophins and gonadotrophin-releasing hormone (GnRH) analogues enables the collection of multiple oocytes and subsequent development of multiple embryos. However, interfering with the natural hormonal milieu may decrease the probability of successful embryo implantation due to effects on oocytes and/or endometrium. In order to provide a fair comparison of embryo implantation rates between natural cycles and stimulated cycles, bias caused by the presence of multiple embryos available for transfer in stimulated cycles should be avoided. This retrospective study analysed embryo implantation rates in cycles in which only a single embryo was available for transfer in 304 women who had poorly responded to ovarian stimulation in the previous cycle. Embryo implantation rates with different stimulation protocols were as follows: natural cycle, 20% (6/30); gonadotrophin only, 5.6% (3/54); long GnRH protocol, 3.8% (2/52); co-flare protocol, 1.9% (1/52); microdose flare-up, 15.4% (4/26); GnRH antagonists, 14.4% (13/90). Although the difference was not statistically significant there was a trend towards higher implantation rates with natural cycles in this group of women. Natural cycle IVF may be a reasonable and patient-friendly treatment choice yielding an acceptable outcome for women who are known or anticipated poor responders to ovarian stimulation.

Infertility and the provision of infertility medical services in developing countries

BACKGROUND

Worldwide more than 70 million couples suffer from infertility, the majority being residents of developing countries. Negative consequences of childlessness are experienced to a greater degree in developing countries when compared with Western societies. Bilateral tubal occlusion due to sexually transmitted diseases and pregnancy-related infections is the most common cause of infertility in developing countries, a condition that is potentially treatable with assisted reproductive technologies (ART). New reproductive technologies are either unavailable or very costly in developing countries. This review provides a comprehensive survey of all important papers on the issue of infertility in developing countries.

METHODS

Medline, PubMed, Excerpta Medica and EMBASE searches identified relevant papers published between 1978 and 2007 and the keywords used were the combinations of 'affordable, assisted reproduction, ART, developing countries, health services, infertility, IVF, simplified methods, traditional health care'.

RESULTS

The exact prevalence of infertility in developing countries is unknown due to a lack of registration and well-performed studies. On the other hand, the implementation of appropriate infertility treatment is currently not a main goal for most international non-profit organizations. Keystones in the successful implementation of infertility care in low-resource settings include simplification of diagnostic and ART procedures, minimizing the complication rate of interventions, providing training-courses for health-care workers and incorporating infertility treatment into sexual and reproductive health-care programmes.

CONCLUSIONS

Although recognizing the importance of education and prevention, we believe that for the reasons of social justice, infertility treatment in developing countries requires greater attention at National and International levels.

Natural-cycle in vitro fertilization in poor responder patients: a survey of 500 consecutive cycles

OBJECTIVE

To determine the role of the natural cycle for in vitro fertilization (IVF) in poor responder patients.

DESIGN

Retrospective survey.

SETTING

Private center for assisted reproduction.

PATIENT(S)

294 women who were poor responders in a previous IVF cycle.

INTERVENTION(S)

Analysis of 500 consecutive natural cycles IVF.

MAIN OUTCOME MEASURE(S)

Number of cycles with oocytes, pregnancy rate per cycle, per transfer, and implantation rate.

RESULT(S)

Oocytes were found in 391 cases (78.1%), and cleaving embryos suitable for transfer were obtained in 285 cycles (57.0%). Pregnancy was observed in 49 cases, with a pregnancy rate of 9.8% per cycle, 17.1% per transfer, and 16.7% per patient. The patients were subdivided arbitrarily by the women's age into three groups. Patients 35 years old or younger showed a pregnancy rate of 18.1% per cycle, 29.2% per transfer, and 31.7% per patient. Women aged between 36 and 39 years showed a pregnancy rate of 11.7% per cycle, 20.6% per transfer, and 20.3% per patient. Women 40 years old or older showed a pregnancy rate of 5.8% per cycle, 10.5% per transfer, and 9.7% per patient. No differences were found for any of the evaluated parameters, independent of which cycle was the first, the second, third, fourth, or fifth, or further consecutive cycle.

CONCLUSION(S)

In poor responder patients, natural-cycle IVF is an effective treatment, especially in younger women.

Age, oestradiol and blastocysts can predict success in natural cycle IVF-embryo transfer

The aim of this study was to evaluate the influence of maternal age and oestradiol concentrations on blastocyst development and live birth rates in natural cycle IVF-embryo transfer. This observational study included 397 natural cycles with IVF embryo transfer for female infertility with embryo transfer on day 5. The cycles were divided into two groups according to the woman's age (<39 and > or = 39 years of age), and into two groups according to oestradiol concentrations on the day of human chorionic gonadotrophin (HCG) administration (0.4-0.49 nmol/l and 0.5-1.2 nmol/l). Comparison between the cycles in younger versus older age groups showed significant differences in blastocyst development rate, live birth rate per embryo transfer and live birth rate per cycle (55 versus 29%, 23 versus 3% and 13 versus 2% respectively) (P < 0.001). Comparison between cycles with lower versus higher oestradiol concentrations showed no significant differences in blastocyst development rate, live birth rate per embryo transfer and live birth rate per cycle (47 versus 49%, 18 versus 18%, and 11 versus 10% respectively). Advanced maternal age negatively predicts the success of natural cycle IVF, while low oestradiol concentrations on the day of HCG administration (ultrasound criteria fulfilled) do not negatively predict blastocyst development and success of natural cycle IVF.

Natural cycle IVF with and without terminal HCG: learning from failed cycles

Natural cycle IVF, without the use of LH down-regulation, is difficult because women start spontaneous LH surges at any time of the day and on any day of the week. This is not readily compatible with delivery of a routine IVF service and so historically the natural cycle has been modified by the use of human chorionic gonadotrophin (HCG) to make the natural cycle fit convenient clinical practice. This report re-evaluates data collected some years ago and seeks to determine whether the use of HCG is ultimately beneficial. Two large series of natural cycle IVF where only LH monitoring was performed (534 cycles) or where this was combined with HCG as necessary (241 cycles) were analysed. In essence, the use of HCG introduced as many problems as it overcame: there was no net benefit with respect to the number of eggs collected or clinical pregnancies generated. In fact there was an overall deterioration in all indices. The principle difficulties with natural cycle IVF are those associated with the prediction of follicle maturity and hence timing egg collection, and the conflict between costly and intrusively frequent monitoring with simpler but far less effective approaches.

En fécondation in vitro (FIV): pourquoi je ne stimule pas?

In vitro fertilization without stimulation, in natural or semi-natural cycles ("FIV-NAT") offers an interesting alternative to controlled ovarian hyperstimulation (COH) for some patients. This protocol may be proposed to patients suffering from altered ovarian status (AOS) with encouraging results. The second indication might be patients presenting repeated implantation failure (IMF). FIV-NAT allows avoiding possible adverse effects of HOC on the endometrium. Results are respectively 15.4 and 16.6% clinical pregnancy rate per oocyte retrieval for AOS and IMF, and 25.5 and 26.3% over 3 cumulative cycles. This treatment is less expensive and patient friendly.

Hopes and facts about mild ovarian stimulation

Over the last two decades, easier and less expensive stimulation treatments have been largely replaced by more complex and more demanding protocols. Since the mid-nineties, long-term gonadotrophin-releasing hormone agonist stimulation protocols have been widely used. Such lengthy expensive regimens are not free from short- and long-term risks and complications. Mild stimulation protocols reduce the mean number of days of stimulation, the total amount of gonadotrophins used and the mean number of oocytes retrieved. The proportion of high quality and euploid embryos seems to be higher compared with conventional stimulation protocols and the pregnancy rate per embryo transfer is comparable. Moreover, the reduced costs, the better tolerability for patients and the less time needed to complete an IVF cycle make mild approaches clinically and cost-effective over a given period of time. However, further prospective randomized studies are needed to compare cumulative pregnancy rates between the two protocols. Natural cycle IVF, with minimal stimulation, has been recently proposed as an alternative to conventional stimulation protocols in normo- and poor responder patients. Although acceptable results have been reported, further large prospective randomized studies are needed to better evaluate the efficacy of these minimal regimens compared with conventional stimulation approaches.

[The follicular flushing duplicate the pregnancy rate on semi natural cycle IVF]

OBJECTIVE

To evaluate the importance of follicular flushing on semi natural cycle IVF.

MATERIAL AND METHODS

We have compared prospectively the reproductive potential of oocytes obtained from follicular fluid (LF, N = 79) to those obtained from follicular flushing (R, N = 47) in 146 oocyte pick ups.

RESULTS

The group LF and R were similar with regard to fertilization rate (79.7 versus 88.1%, respectively), percentage of superior grade embryos (28.8 versus 37.8%) and implantation rate (24.1 versus 44.1%).

CONCLUSION

The practice of follicular flushing on semi natural IVF cycle improves the pregnancy rate. The oocytes obtained by follicular flushing had the same reproductive potential than those obtained on follicular fluid.

New alternative to infertility treatment for women without ovarian stimulation

Natural cycle IVF produced the world first successful live birth, but slowly this treatment has been replaced by ovarian stimulated cycle IVF, because it has been believed ovarian stimulated cycle IVF will increase the number of available embryos for transfer. Therefore, it directly increases the chance of pregnancy from the treatment cycle. However, ovarian stimulation is always associated with side effects. The recovery of immature oocytes followed by in-vitro maturation (IVM) and IVF is an attractive alternative to stimulated cycle IVF. IVM treatment provides a successful option to infertile women with polycystic ovaries and polycystic ovary syndrome. It is now possible to combine natural cycle IVF with IVM as an alternative for a selected group of women with various causes of infertility without recourse to ovarian stimulation.

Embryo transfer and luteal support in natural cycles

Embryo transfer policy and luteal supplementation was reviewed, comparing literature data and the results from the Maribor IVF Centre. A retrospective analysis of 1024 cycles in patients undergoing IVF, intracytoplasmic sperm injection (ICSI) or testicular sperm aspiration in unstimulated cycles was carried out using four different approaches for cycle monitoring. This showed that the most successful protocol for monitoring was administration of human chorionic gonadotrophin (HCG) when serum oestradiol was >0.49 nmol/l and follicle diameter was at least 15 mm. The implantation rate per transferred embryo was higher when a blastocyst was transferred (42.8%) rather than a day-2 embryo (23.5%) in the same monitoring protocol. Analysis of the influence of patient age on the success of oocyte retrieval, oocyte fertilization, embryo transfer rate and delivery rate demonstrates that patient age does not influence the rate of positive oocyte retrieval or fertilization rate as much as it influences pregnancy rate per embryo transfer. The delivery rate per cycle was dramatically influenced by age in patients over 38 years. There is no clear evidence in the literature as to whether luteal phase support is necessary in natural cycles for IVF/ICSI. Comparing the data, a higher pregnancy rate was observed if HCG was administered after embryo transfer.

Affordable IVF for developing countries

Worldwide, more than 80 million couples suffer from infertility; the majority are residents of developing countries. Residents of developing countries encounter a lack of facilities at all levels of health care, but especially infertility diagnosis and treatment. Infertility defined as a disease has a much stronger negative consequence in developing countries compared with Western societies. Social isolation, economic deprivation and violence are commonly observed. Tubal infertility due to sexually transmitted diseases, unsafe abortion and post-partum pelvic infections are the main causes of infertility in developing countries. Very often those conditions are only treatable by assisted reproductive technologies. Although preventative measures are undoubtedly the most cost-effective approach, not offering assisted reproduction is not an alternative. This study proposes a specially designed infertility care programme leading to cost-effective simplified assisted reproduction as a valid treatment protocol in developing countries when prevention or alternative methods have failed. Special attention should be given to avoid adverse outcomes such as ovarian hyperstimulation and multiple embryo pregnancy.

Controlled natural cycle IVF: a novel approach for a dominant follicle during an in-vitro maturation cycle

The objective of this retrospective analysis is to evaluate whether patients developing a dominant follicle in an in-vitro maturation (IVM) programme can be included in a natural cycle IVF (nIVF) programme. In a university teaching hospital, a total of 38 patients with polycystic ovarian syndrome were treated by metformin before undergoing an IVM cycle. Controlled nIVF was performed on seven patients with a dominant follicle. This paper reports three ongoing pregnancies from five embryo transfers in the latter group. Hence, nIVF can be a novel approach for women developing a dominant follicle during an IVM cycle.

In vitro maturation of human oocytes for assisted reproduction

OBJECTIVE

To describe and evaluate the current practice of in vitro maturation of oocytes for assisted reproduction.

DESIGN

Review of the available and relevant literature regarding in vitro maturation of oocytes.

CONCLUSION(S)

In vitro maturation of human oocytes retrieved from antral ovarian follicles is an emerging procedure quickly being incorporated into the realm of assisted reproductive technologies. This new technology has several potential advantages over traditional controlled ovarian hyperstimulation for IVF, such as reduction of costs by minimizing gonadotropin and GnRH analogue use, elimination of ovarian hyperstimulation syndrome, and simplicity of protocol. In vitro maturation of oocytes for assisted reproduction in human beings still is undergoing refinement but currently is providing efficacy and safety outcome comparable to that of traditional IVF in recent selected studies. Implementing in vitro maturation into an established IVF practice is feasible and requires only a few simple adjustments. Crucial to the advancement and optimization of the technology is a better understanding of how to maximize immature oocyte developmental competence and endometrial receptivity.

Cost-effective approaches to in vitro fertilization: Means to improve access

Many childless couples would like to have access to in vitro fertilization (IVF) through public-sector programs, but such programs are scant because of the high costs that IVF entails today. A solution for health departments worldwide might be to leave IVF methods requiring expensive equipment and ovarian stimulating hormones - such as human recombinant gonadotropins, plus gonadotropin-releasing hormone analogues to prevent a surge of luteinizing hormone - to the private sector. Rather, health departments could focus on methods using less equipment and no ovarian stimulating agent at all if possible. If not possible, inexpensive clomiphene citrate could be used, combined with human menopausal gonadotropin if needed. Before embryo transfer, oocyte maturation could occur in vitro or in a makeshift incubator: a tube closed, wrapped, and left in the woman's vagina for 24 h. To prevent short- and long-term costs as well as possible lifelong problems, the transfer of multiple embryos should not be performed.

Oocytes in the empty follicle: a controversial syndrome

OBJECTIVE

To assess the prevalence and etiology of the empty follicle syndrome (EFS).

DESIGN

Observational longitudinal study.

SETTING

Tertiary fertility centers.

PATIENT(S)

All patients beginning in vitro fertilization (IVF) treatment from December 2002 to November 2004 were included. Couples undergoing IVF with donor oocytes or participating in an experimental IVF study were excluded from analysis.

INTERVENTION(S)

Identification of EFS cycles. Comparing ovarian hyperstimulation strategy, follicle count, and timing of human chorionic gonadotropin (hCG) for final oocyte maturation of the EFS cycles with normal IVF cycles.

MAIN OUTCOME MEASURE(S)

Number of follicles punctured, number of oocytes recovered, previous and future IVF attempts, and serum hormone levels.

RESULT(S)

Twenty-five of a total of 1,849 patients were identified with an EFS cycle. Reasons for occurrence of EFS cycles were mistiming of hCG for final oocyte maturation, premature ovulation, and poor ovarian response. None of the affected patients had experienced EFS cycles in earlier IVF attempts nor were there any recurrence in subsequent treatments.

CONCLUSION(S)

Accurate timing of induction of final oocyte maturation, properly scheduled ovarian hyperstimulation, instruction of patients and doctors, and full workup for IVF are essential for the successful recovery of oocytes. Occurrence of EFS in IVF can normally be attributed to a failure of at least one of these factors and probably rarely or never occurs otherwise.

Outcome of in vitro fertilization treatment in patients who electively inseminate a limited number of oocytes to avoid creating surplus human embryos for cryopreservation

OBJECTIVE

To determine whether the outcome of IVF treatment in patients who electively inseminate a limited number of oocytes is comparable to that in a group of good-prognostic or poor-prognostic patients.

DESIGN

Retrospective clinical study.

SETTING

University-based tertiary fertility center.

PATIENT(S)

Two hundred three women under the age of 40 years.

INTERVENTION(S)

Patients undergoing their first cycle of IVF who elected to have no more than four oocytes inseminated (study group) or who produced only four or fewer oocytes (poor-prognostic group) or who had excess embryos cryopreserved (good-prognostic group).

MAIN OUTCOME MEASURE(S)

Implantation rate, clinical pregnancy rate, and ongoing pregnancy rate.

RESULT(S)

There were no significant differences in the implantation rate for the study group when compared with the good-prognostic group or the poor-prognostic group. The clinical pregnancy rate (62.5% vs. 64%) and ongoing-pregnancy or birth rate (56.3% vs. 60.7%) were similar between the study group and the good-prognostic group. However, the clinical pregnancy rate (62.5% vs. 29.7%) and ongoing-pregnancy rate (56.3% vs. 24.3%) were higher in the study group compared with the poor-prognostic group.

CONCLUSION(S)

Inseminating fewer oocytes in patients who elect not to cryopreserve excess embryos does not adversely affect their probability of conception.

Ongoing pregnancy after ICSI of frozen–thawed PESA-retrieved spermatozoa and IVF in a controlled natural cycle

The recovery of a mature oocyte from a natural cycle followed by IVF (nIVF) is an attractive alternative to conventional IVF, involving ovarian stimulation, in the treatment of female infertility. Similarly, surgical recovery of spermatozoa from the epididymis by percutaneous sperm aspiration (PESA) has simplified the treatment of men with obstructive azoospermia. A couple sought treatment for diminished ovarian reserve and male factor infertility using IVF. A mature oocyte was retrieved and was inseminated by intracytoplasmic sperm injection (ICSI), following recovery of spermatozoa by PESA. A good quality embryo was transferred. A viable pregnancy was confirmed by ultrasound scan. A healthy baby boy was delivered naturally at 37 weeks gestation. This study reports the first ongoing clinical pregnancy and subsequent birth resulting from ICSI of spermatozoa retrieved by PESA into an oocyte recovered during a natural cycle. The use of a combination of less invasive assisted reproductive techniques (PESA and nIVF) can overcome barriers to fertility.

Controlled natural cycle IVF with antagonist use and blastocyst transfer

A method of controlled natural cycle IVF (CONCIVF) was sought to provide simpler and shorter treatment without the risks of ovarian hyperstimulation syndrome and multiple pregnancies. A total of 138 couples with normal ovulation and normal sperm parameters, in whom the women were <40 years old, were the candidates for this study. Gonadotrophin-releasing hormone antagonist was used before human chorionic gonadotrophin (HCG) administration if LH increased to a concentration of 10 mIU/ml before HCG injection. Treatment was initiated at > or =16 mm follicular growth and at oestradiol concentrations > or =400 pmol/l with 5000 IU HCG induction. All the embryos were cultured to the blastocyst stage and transferred only if they reached early or advanced blastulation. A total of 126 patients underwent oocyte retrieval. In 102 cases, one oocyte was retrieved; 95% of the oocytes fertilized, 99% cleaved and 47.9% achieved the blastocyst stage. The implantation rate per blastocyst transfer was 53.3% and the live-birth rate per embryo transfer was 40%. Therefore, CONCIVF with blastocyst transfer gives acceptable blastocyst development and implantation rates without the long- or short-term side effects of ovulation induction.

Minimal stimulation IVF with late follicular phase administration of the GnRH antagonist cetrorelix and concomitant substitution with recombinant FSH: a pilot study

BACKGROUND

The use of the natural cycle for IVF offers the advantage of a patient-friendly and low-risk protocol. Its effectiveness is limited, but may be improved by using a GnRH antagonist to prevent untimely LH surges.

METHODS

In this pilot study, minimal stimulation IVF with late follicular phase administration of the GnRH antagonist cetrorelix and simultaneous substitution with recombinant FSH was applied for a maximum of three cycles per patient. Main outcome measures were pregnancy rates per started cycle and cumulative pregnancy rates after three cycles.

RESULTS

A total of 50 patients completed 119 cycles (2.4 per patient). Fifty-two embryo transfers resulted in 17 ongoing pregnancies [14.3% per started cycle; 32.7% per embryo transfer; 95% confidence interval (CI) 7.9-20.7% and 19.7-45.7%, respectively]. One dizygotic twin pregnancy occurred after transfer of two embryos, the other pregnancies were singletons. The cumulative ongoing pregnancy rate after three cycles was 34% (95% CI 20.6-47.4%). Live birth rate was 32% per patient (95% CI 18.8-45.2%).

CONCLUSIONS

Pregnancy rates after IVF with minimal, late follicular phase stimulation are encouraging. Considering the low-risk and patient-friendly nature of this protocol, it may be a feasible alternative to IVF with ovarian hyperstimulation.

NaturalIn VitroFertilization Cycles

Although the first in vitro fertilization (IVF) baby was born after a natural IVF cycle, very soon this procedure was almost abandoned mainly because of the very high cancellation rates, and controlled pharmacological ovarian hyperstimulation became the standard treatment in IVF cycles of normoresponder patients. However, in poor-responder patients, where only very few follicles can be recruited and very few oocytes, if any, can be retrieved after controlled ovarian hyperstimulation, natural IVF cycles may offer a comparable number of follicles, reduced costs, and less discomfort for the patients. In this group of patients, natural IVF cycle is a cost-effective approach.

A controlled trial of natural cycle versus microdose gonadotropin-releasing hormone analog flare cycles in poor responders undergoing in vitro fertilization

OBJECTIVE

To determine the efficacy of natural-cycle IVF compared with controlled ovarian hyperstimulation in poor responders.

DESIGN

Randomized, controlled study.

SETTING

Private center for assisted reproduction.

PATIENT(S)

One hundred twenty-nine women who were poor responders in a previous IVF cycle.

INTERVENTION(S)

Fifty-nine women underwent 114 attempts of natural-cycle IVF, and 70 women underwent 101 attempts of IVF with controlled ovarian hyperstimulation with microdose GnRH analog flare.

MAIN OUTCOME MEASURE(S)

Number of oocytes retrieved, pregnancy rate (PR) per cycle, PR per transfer, and implantation rate.

RESULT(S)

The poor responders treated with natural-cycle IVF and those treated with micro-GnRH analog flare showed similar PRs per cycle and per transfer. The women treated with natural-cycle IVF showed a statistically significant higher implantation rate (14.9%) compared with controls (5.5%). When subdivided into three groups according to age (<or=35 years, >or=36-39 years, >or=40 years), younger patients had a better PR than the other two groups.

CONCLUSION(S)

In poor responders, natural-cycle IVF is at least as effective as controlled ovarian hyperstimulation, especially in younger patients, with a better implantation rate.

State of the art in in-vitro oocyte maturation

PURPOSE OF REVIEW

The recovery of immature oocytes followed by in-vitro maturation (IVM) and in-vitro fertilization is an attractive alternative to conventional in-vitro fertilization treatment in which controlled ovarian stimulation with gonadotropins is used to increase the number of available oocytes and embryos. Significant progress has been made to improve pregnancy and implantation rates from in-vitro matured oocytes. This review summarizes current knowledge and achievements in human oocyte in-vitro maturation for clinical application, and will highlight recent advances reported in in-vitro maturation treatment.

RECENT FINDINGS

It has been demonstrated that priming of ovarian immature oocytes with follicle-stimulating hormone or human chorionic gonadotropin prior to immature oocyte retrieval improves oocyte maturation rates and embryo quality as well as pregnancy rates in infertile women with polycystic ovaries or polycystic ovary syndrome. The size of follicles may be important for the subsequent embryonic development, but the developmental competence of oocytes derived from the small antral follicles is not adversely affected by the presence of a dominant follicle. However oocyte maturation in vitro is profoundly affected by culture conditions. Currently more than 300 healthy infants have been born following immature oocyte retrieval and in-vitro maturation. In general, the clinical pregnancy and implantation rates have reached 30-35% and 10-15% respectively in infertile women with polycystic ovaries or polycystic ovary syndrome.

SUMMARY

In-vitro maturation treatment can now be offered as a successful option to infertile women with polycystic ovaries or polycystic ovary syndrome. It is possible to combine natural cycle in-vitro fertilization with immature oocyte retrieval followed by in-vitro maturation, and thus offer women with various causes of infertility reasonable pregnancy and implantation rates without recourse to ovarian stimulation. Further research remains to be done to address the mechanism of oocyte maturation in order to refine culture conditions and improve the implantation rate of oocytes matured in vitro.

Patient-friendly ovarian stimulation

The ultimate goal of successful IVF is the birth of a healthy child with no maternal complications. Advances in ovarian stimulation protocols using gonadotrophin-releasing hormone agonists (GnRHa) and high doses of gonadotrophins have resulted in increased oocyte numbers with improved pregnancy and birth rates. However, the efficacy of such therapy is controversial when measured against the potential side effects. These side effects include those arising from oestrogen deprivation during desensitization, complications associated with an increased risk of ovarian hyperstimulation syndrome (OHSS), and an increased possibility of multiple births. Additionally, the increased cost due to more frequent monitoring and increased drug dosage negatively impacts on patient care. Thus, refinements in drug regimens are needed not only to address these side effects, but also to target the quality, not the quantity, of oocytes. In studies comparing GnRH antagonist (GnRHnt) to GnRHa, patients receiving GnRHnt underwent a shorter induction using less gonadotrophin, the incidence of OHSS was reduced and they reported a better quality of life. While larger studies are needed to confirm these promising findings, it appears that milder stimulation protocols could represent an interesting option, at least for selected patients.

In vitro fertilization in spontaneous cycles--our experience

OBJECTIVE

To study the efficacy of a simple protocol of natural cycle in vitro fertilization.

METHOD

A retrospective study of 59 natural treatment cycles in 37 infertile couples with previous unsuccessful attempts of conventional in vitro fertilization.

RESULTS

In 24% of cycles, the aspiration was cancelled because of inadequate visualization of follicles or because of preterm ovulation. Aspiration was performed in 45 cycles with oocyte retrieval of 82% per aspiration. Embryo transfer was performed in 30 cycles, pregnancy rate per pick-up was 15%.

CONCLUSION

In vitro fertilization in a natural cycle is a simple, relatively cheap and comfortable procedure with reasonable results and can be offered to patients scheduled not only for in vitro fertilization because of tubal factor but also to patients with endometriosis or unexplained infertility.

Results of intracytoplasmic sperm injection of single oocyte in 362 unstimulated cycles

PURPOSE

The purpose was to test the adequacy of unstimulated cycles for intracytoplasmic sperm injection (ICSI) and to evaluate implantation and pregnancy rates in three different age groups.

METHODS

ICSI was performed in 362 unstimulated cycles in women up to 45 years old. All cycles were monitored by serum estradiol, urinary LH, and ultrasound.

RESULTS

The delivery rate per started cycle was higher in patients younger than 36 (9.4%) than in cycles with patient's age between 36 and 39 years (4.8%) or older than 40 (4.6%) but the difference was not statistically significant. In all groups, the fertilization rate was similar (70.4, 77.6, and 84.8%, respectively). The pregnancy rate per cycle and the pregnancy rate per puncture was similar in the group of patients in age between 36 and 39 years (8.3 and 9.7%) and those older than 40 (7.7 and 9.3%).

CONCLUSIONS

Unstimulated cycles monitored by serum estradiol, urinary LH, and ultrasound can produce an acceptable pregnancy rate after ICSI procedure only in patients younger than 36.

Transfer of two embryos instead of three will not compromise pregnancy rate but will reduce multiple pregnancy rate in an assisted reproduction unit

OBJECTIVE

To compare the pregnancy rates and multiple pregnancy rates of cycles initiated in 1998 and in 1999, during which 3 and 2 embryos were advised to be replaced, respectively.

STUDY DESIGN

A retrospective study

RESULTS

There were no differences between 1998 and 1999 in the pregnancy rate per cycle started or per transfer, implantation rate and the multiple pregnancy rates, despite a significantly lower number of embryos replaced in 1999. A significantly higher implantation rate was found in cycles with frozen embryos than those without. Using logistic regression analysis, the chance of pregnancy was significantly improved only by the presence of frozen embryos in the fresh cycles with an odds ratio of 2.0 (95% confidence interval: 1.3-3.0) whereas the chance of multiple pregnancy was significantly increased by replacing 3 embryos instead of 2 (odds ratio: 2.1, 95% confidence interval: 1.1-4.2).

CONCLUSION

Patients should be advised to have 2 embryos replaced without jeopardizing the pregnancy rates in the fresh cycles. The risk of multiple pregnancy is significantly increased when 3 embryos are transferred instead of 2.

Natural cycle IVF in unexplained, endometriosis-associated and tubal factor infertility

BACKGROUND

To elucidate possible differences between unexplained and minimal peritoneal endometriosis-associated infertility, we studied their outcome in natural cycle IVF (NIVF).

METHODS

A prospective cohort study was carried out on unexplained (33 couples), minimal peritoneal endometriosis-associated (30 couples) and tubal factor (24 couples) infertility in 223 NIVF cycles, using human chorionic gonadotrophin (HCG) for ovulation induction.

RESULTS

During the first NIVF attempt, follicular and luteal phase oestradiol, FSH, LH and progesterone concentrations, as well as endometrial thickness and follicular diameter were similar among the three groups. Periovulatory follicular growth monitored from day of HCG administration to oocyte aspiration was significantly lowered in unexplained infertility compared with minimal endometriosis-associated and tubal factor infertility. The fertilization rate, clinical pregnancy rate per initiated cycle, per successful oocyte retrieval and per embryo transfer, in minimal endometriosis (80.0, 10.4, 16.0 and 23.5% respectively) were similar to that in tubal factor infertility patients (68.6, 5.8, 11.4 and 16.0%) but significantly higher (P < 0.05) than that of the unexplained infertility group (62.2, 2.6, 5.4 and 8.7%).

CONCLUSIONS

The significant reduction in follicular periovulatory growth, fertilization and pregnancy rates in unexplained infertility compared with minimal peritoneal endometriosis patients may be explained by sub-optimal follicular development with possibly reduced oocyte quality, intrinsic embryo quality factors or by impaired implantation. From a clinical point of view, NIVF is less suited to unexplained infertility treatment, but might represent an interesting treatment option for minimal peritoneal endometriosis-associated infertility.

A randomized study comparing IVF in the unstimulated cycle with IVF following clomiphene citrate

The efficiency of IVF in unstimulated cycles was compared with that following ovarian stimulation with clomiphene citrate in a simple protocol with ultrasound monitoring only. A total of 132 couples with no previous IVF attempts, selected by female age <35 years, indication for intracytoplasmic sperm injection or infertility caused by tubal factor or unexplained infertility were randomized to the two protocols. Randomization yielded two comparable groups. The clomiphene group (68 couples) performed significantly better than the unstimulated group (64 couples) in terms of number of cycles with oocyte harvest (90/111 or 81% versus 65/114 or 57%; chi(2) = 9.21, P < 0.002), embryo transfers per started cycle (59/111 or 53% versus 29/114 or 25%; chi(2) = 18.14, P < 0.0001), live intrauterine pregnancy rate per started cycle (20/111 or 18% versus 4/114 or 4%; chi(2) = 12.42, P < 0.0001), live intrauterine pregnancy rate per embryo transfer (20/59 or 34% versus 4/29 or 14%; chi(2) = 3.96, P = 0.047), but not in terms of implantation rate (22/85 or 26% versus 4/29 or 14%; chi(2) = 1.65). Only two twin pregnancies occurred. Modest side-effects were recorded following clomiphene. Accordingly, a simple clomiphene citrate protocol, but not IVF in unstimulated cycles, seems compatible with the concept of 'friendly IVF', yielding a fair pregnancy rate both per cycle started and per embryo transfer in selected patients. The results do not substantiate any important negative anti-oestrogenic effects of clomiphene.

Avoiding multiple pregnancies: sailing uncharted seas

Single embryo transfer is being proposed as the solution to avoid multiple pregnancies in IVF. Nevertheless, in my opinion, although this is the right solution, it is still not the correct one at the present time. Mainly, it is unfair to the majority of infertile couples and it will also severely limit the physician's capacity to resolve unfavourable IVF cases. Furthermore, current IVF technology is far from perfect and the impact of single embryo transfer needs to be evaluated in patients over 38 years of age, poor responders, and also in regard to blastocyst transfer and the development of pre-implantation genetic diagnosis.

Value of the serum estradiol level on the day of human chorionic gonadotropin injection and on the day after in predicting the outcome in natural in vitro fertilization/intracytoplasmic sperm injection cycles

OBJECTIVE

To predict the risk of premature ovulation and possibility of pregnancy in natural IVF/ICSI cycles on the basis of the estradiol (E2) level on the day of hCG injection and on the day after.

DESIGN

A prospective study.

SETTING

Hospital research program.

PATIENT(S)

One hundred sixty-four women undergoing 305 IVF/ICSI natural cycles.

INTERVENTION(S)

Serum E2 levels were measured approximately 12 h before (day 0) and 12-17 h after hCG administration (day 1).

MAIN OUTCOME MEASURE(S)

E2 levels on day 0 and day 1, the ratio of the day 1 to day 0 levels, and cycle outcome.

RESULT(S)

In cycles with premature ovulation and in conception cycles, the average E2 level on day 0 was statistically significantly higher than in other cycles, whereas the E2 ratio was statistically significantly lower. Multiple logistic regression was used to determine the connection of the E2 level on day 0 (B0 = -0.742, B = 2.147, P =.01) and the E2 ratio (B0 = -0.742, B = -3.135, P<.001) with premature ovulation. Only the E2 ratio (B0 = 0.659, B = -2.209, P =.0068) was significantly connected with conception.

CONCLUSION(S)

In predicting the outcome of natural IVF/ICSI cycles, the importance lies not in the E2 level on the day of hCG administration or on the day after, but rather in the E2 ratio.

Optimal pregnancy outcome in a minimal-stimulation in vitro fertilization program

OBJECTIVE

We sought to provide a cost-beneficial approach to in vitro fertilization for infertile patients who could not afford the standard treatment with in vitro fertilization and to determine the optimal level of minimal ovarian stimulation to achieve acceptable pregnancy rates.

STUDY DESIGN

We performed a retrospective cohort study of 216 patients who underwent "minimal stimulation" in vitro fertilization between January 1994 and December 1998. During the first half of this study, various minimal ovarian stimulation protocols were performed in our private, free-standing center for in vitro fertilization. More recently, more ovarian stimulation, including a 4-day protocol featuring gonadotropin-releasing hormone agonist flare (ultrashort flare), was used. Clinical pregnancy outcome, multiple gestation, complications, and maternal age were compared between the first and second halves of this study.

RESULTS

The average ages of patients in the first half (phase 1) and the second half (phase 2) were similar, 32.4 +/- 0.3 versus 32.6 +/- 0.3 years, respectively. An average of 3.5 oocytes per retrieval was obtained in phase 1 versus 5.9 oocytes in phase 2. Failure to retrieve oocytes occurred in 3% of all cases. The mean number of embryos transferred per patient was 2.0 in phase 1 versus 2.4 in phase 2. In phase 1, 16.1% of patients failed to have viable embryos for transfer, in comparison with 9.7% in phase 2. The overall clinical pregnancy rate per retrieval was 16.9% in phase 1 versus 36. 6% in phase 2. Multiple gestation occurred in 5.0% of clinical pregnancies in phase 1 but increased to 33% in phase 2, with 9 sets of twins and 6 sets of triplets. The implantation rate was 9.3% for phase 1 versus 23.3% for phase 2. The clinical pregnancy rates per retrieval for phase 2 patients were 41.6% in women < or =34 years old and 25.6% for those > or =35 years old. No case of ovarian hyperstimulation syndrome was noted.

CONCLUSIONS

Minimal ovarian stimulation in the setting of in vitro fertilization offers a cost-beneficial alternative to standard treatment with in vitro fertilization in infertile patients who are <35 years old and in women <40 years old who have adequate oocyte reserve. More stimulation improves outcome. Minimalstimulation in vitro fertilization provides an alternative for those patients who cannot afford standard in vitro fertilization or who are concerned with exposure to high dosages of fertility medications.

The preovulatory serum estradiol pattern in natural IVF/ICSI cycles

PURPOSE

The aim of the study was to find whether inferences to the possible success of natural IVF/ICSI cycles could be drawn from the estradiol (E2) pattern.

METHODS

Sixty-eight women who underwent oocyte recovery in 98 natural cycles were recruited for the study. Daily serum E2 was measured in the preovulatory phase (-3 to +2 day). The E2 pattern was compared among four groups: Group A, unsuccessful egg retrieval; Group B, no fertilization; Group C, no implantation; and Group D, implantation.

RESULTS

There was no difference in mean E2 levels between groups. Only the ratio of E2 on day +1/E2 on day 0 was significantly lower in conception cycles in comparison with nonconception cycles. In cycles with a decreased E2 level on day +1, only the implantation rate was significantly higher in comparison with cycles with an increasing E2 level.

CONCLUSIONS

From the E2 pattern it is possible to make inferences about the likelihood of implantation but not the fertilization or oocyte recovery success.

Methodologic principles of cost analyses in the nursing, medical, and health services literature, 1990-1996

BACKGROUND

Cost analyses are needed to inform resource decisions. Oftentimes, however cost-benefit analysis (CBA), cost-effectiveness analysis (CEA), cost-minimization analysis (CMA), and cost-utility analysis (CUA) are performed using untested techniques and adhering to a variety of questionable principles.

OBJECTIVES

To analyze, compare, and present a set of useful principles for the main types and methods of cost analyses through a synthesis of current information in the published literature.

METHODS

The area of interest included all reports of cost research published as full articles in professional journals from January 1990 to August 1996 in the nursing, medical, and health services fields. In all, 88 sampled articles met the criteria for inclusion. A four-page data collection guide with 28 items grouped as demographics, cost-analysis types, methods, and principles was designed for the review. Incremental testing for interrater reliability using the kappa statistic for two raters was performed. Sampling, process-oriented, construct, and correlational validity were assessed.

RESULTS

The 88 articles included 4 from nursing, 59 from medical, and 25 from health services journals. Of these articles, 45 (51%) reported CBA, 36 (41%) CEA, 2 CMA, 4 CUA, and 1 both CBA and CEA. Three nursing studies were authored only by nurses. Three fourths of the medical and four fifths of the health services publications had interdisciplinary authorship. Existing databases were the primary source of data in 61 (69%) publications. Adherence to six main methodologic principles was apparent in 19 (22%) articles. None of the nursing studies adhered to all six principles, whereas 16% of the health services and 25% of the medical studies did.

CONCLUSIONS

Funded cost analyses of nursing interventions that adhere to the six known methodologic principles are needed to inform policy-level health care decisions. Because of the complexity of cost analysis methodology, including sensitivity analysis, future interdisciplinary efforts using existing databases may prove most effective. The six methodologic principles presented in this article can be useful for future nursing education and cost-analysis research designed to control cost and increase the quality of health care.