Impact of stage III–IV endometriosis onrecipients of sibling oocytes: matchedcase-control study

Israel Dıaz, M.D.,a Jose Navarro, M.D.,a,b Luis Blasco, M.D.,a,c Carlos Simon, M.D.,a,d

Antonio Pellicer, M.D.,a,d and Jose Remohı, M.D.a,d

Instituto Valenciano de Infertilidad, Valencia, Spain

Objective: To evaluate the impact of severe endometriosis on IVF-ET outcome in women receiving oocytesfrom the same donor.

Design: A matched case-control study.

Setting: Oocyte donation program at the Instituto Valenciano de Infertilidad.

Patient(s): Fifty-eight recipients were included in a matched case-control study of IVF-ET in our oocytedonation program. Twenty-five patients were diagnosed by laparoscopy with stage III–IV endometriosis(group I), while the remaining 33 were free of the disease (group II). On the day of retrieval, oocytes froma single donor were donated to recipients from both groups. Some of the donors supplied oocytes for morethan 2 patients. Recipients received steroid replacement therapy for endometrial preparation.

Intervention(s): Ovarian stimulation and oocyte retrieval in donors. Uterine embryo transfer (ET) inrecipients after appropriate exogenous hormone replacement therapy (HRT).

Main Outcome Measure(s): Pregnancy, implantation, miscarriage, and live birth rates.

Result(s): The number of oocytes donated and fertilized, as well as the number of available and transferredembryos, was not statistically different between the two groups. Pregnancy, implantation, and miscarriagerates were not affected by stage III–IV endometriosis when compared with the control group. The live birthrate was 28.0% in the group with endometriosis and 27.2% in the control group.

Conclusion(s): These results show that implantation is not affected by stage III–IV endometriosis. Given thecontemporary methods of endometrial preparation for transfer of embryos derived from donor oocytes, anypotential negative effect of severe endometriosis on the uterine environment is undetectable. (Fertil Sterilt2000;74:31–4. ©2000 by American Society for Reproductive Medicine.)

Key Words: Oocyte donation, endometriosis, pregnancy, implantation rate

Although numerous mechanisms have beenproposed to explain how endometriosis mayinterfere with normal reproduction, to datethere is no conclusive evidence as to how thisdisease affects fertility.

Assisted reproduction techniques allow theexclusion of many factors that have been sug-gested as playing a role in the infertility as-sociated with endometriosis, such as ovulatorydysfunction, pelvic adhesions, altered tubal mo-tility, distortion of tuboovarian relations, oviductdysfunction, and impaired oocyte retrieval.

Lower implantation rates have been report-ed in patients with endometriosis undergoingIVF and ET cycles (1). Some investigators sug-gest an altered embryo quality (2, 3), maybe

due to aberrant events in morphological em-bryogenesis (4) or a higher in vitro embryoblockage in patients with endometriosis (5).Other investigators have focused on the endo-metrial participation, using uterine receptivitymarkers such as integrins, which are a potentialmethod for the evaluation of a receptive endo-metrial state in patients with endometriosis.The disruption of the integrins expression with-in the cycling endometrium and its associationwith a decreased uterine receptivity and infer-tility are controversial (6, 7).

Oocyte donation is a therapeutic option forpatients with premature ovarian failure (POF),low response to conventional ovarian stimula-tion for IVF, and severe endometriosis withrepeated IVF failures. Reproductive outcome

Received August 24, 1999;revised and acceptedJanuary 20, 2000.Reprint requests: JoseRemohı, M.D., InstitutoValenciano de Infertilidad,Guardia Civil 23, 46020,Valencia, Spain (FAX: 34(96) 369-4735; E-mail:jmnavarrop@yahoo.com).Presented in part at the15th annual meeting of theEuropean Society ofHuman Reproduction andEmbryology (ESHRE),Tours, France, June 27–30,1999.a Instituto Valenciano deInfertilidad.b The Center forReproductive Medicine andInfertility, Department ofObstetrics andGynecology, The New YorkHospital-Cornell MedicalCenter, New York,New York.c Hospital of the Universityof Pennsylvania,Department of Obstetricsand Gynecology, Universityof Pennsylvania School ofMedicine, Philadelphia,Pennsylvania.d Department of Pediatrics,Obstetrics andGynecology, ValenciaUniversity School ofMedicine, Valencia, Spain.

FERTILITY AND STERILITY tVOL. 74, NO. 1, JULY 2000Copyright ©2000 American Society for Reproductive MedicinePublished by Elsevier Science Inc.Printed on acid-free paper in U.S.A.

0015-0282/00/$20.00PII S0015-0282(00)00570-7

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comparison between patients with severe endometriosis whoreceive donor oocytes and patients without endometriosisprovides an appropriate setup to address how this diseaseaffects fertility. Previous studies have shown that endome-triosis is not detrimental to implantation (3, 8). However,these studies were retrospective and were not controlled forthe origin of the oocytes. In our experience, the quality of theoocytes in donors is not a variable that strongly affects theresults of ovum donation. However, it is also true that thereare differences between patients. Thus, a good prospectivecomparative study focusing on implantation should rule outthe possibility of assigning oocytes of different quality to theestablished groups.

This study was designed to allocate sibling oocytes torecipients with and without severe endometriosis to confirmor reject the hypothesis that the endometrial environmentdoes not affect fertility in women with severe endometriosis.

MATERIALS AND METHODS

Twenty-five oocyte recipients with stage III–IV endome-triosis and 33 without the disease were compared. The clin-ical study was approved by our institutional review board.The oocytes were randomly donated to recipients on the dayof retrieval according to the number of recovered oocytesfrom a single donor free of known endometriosis. Initially, aminimum number of 8 oocytes was donated to a women withendometriosis and another without endometriosis. If thenumber of oocytes recovered was.16, this allowed for asecond donation, which was sorted among the women in thewaiting list who did not have endometriosis. This is why thefinal number of controls is higher than in the group withsevere endometriosis.

DonorsDonors were 10 women undergoing IVF and 15 young

fertile women who voluntarily donated oocytes. The meanage of the donors was 25.66 4.8 years, and the infertilityetiologies in those undergoing therapeutic IVF were maleinfertility (n 5 3), tubal infertility (n5 6), and unexplainedinfertility (n 5 1).

The protocol for controlled ovarian stimulation, oocyteretrieval, and gamete handling in the IVF laboratory in-cluded pituitary desensitization with daily subcutaneous(SC) administration of 1 mg of leuprolide acetate (Procrin;Abbott S.A., Madrid, Spain) beginning in the luteal phase ofthe previous menstrual cycle. This dose was continued untilthe estrogen levels were less than 60 pg/mL (220 pmol/L),and negative vaginal ultrasounds were used to define ovarianquiescence. The dose of leuprolide acetate was then de-creased to 0.5 mg until the day of human chorionic gonad-otropin (hCG) administration.

On days 1 and 2 of ovarian stimulation, 150 IU/d ofhighly purified follicle-stimulating hormone (FSH; Neo-Fertinorm; Serono Laboratories, Madrid, Spain) were intra-

muscularly administered together with 150 IU/d of humanmenopausal gonadotropin (hMG; Lepori, Farma Laborato-ries, Barcelona, Spain). On days 3, 4, and 5 of ovarianstimulation, 75 IU of FSH and 75 IU of hMG were admin-istered to each woman. Beginning on day 6, hMG wasindividualized according to serum estradiol and transvaginalovarian ultrasound scans.

Human chorionic gonadotropin (10,000 IU; Profasi; Se-rono Laboratories, Madrid, Spain) was administered intra-muscularly when at least two leading follicles reached adiameter of between 20 and 21 mm and the serum E2 con-centration was.800 pg/mL. Leuprolide acetate and gonado-tropin injections were discontinued on the day of hCG ad-ministration. Transvaginal oocyte retrieval was scheduled36–38 hours after hCG injection.

RecipientsGroup I was made up of 25 recipients with documented

stage III–IV endometriosis, all of whom had undergonediagnostic laparoscopy before ET. Endometriosis was eval-uated according to the revised AFS classification (9).

The control group (n5 33) included one or more recip-ients not known to have endometriosis who received eggsfrom the same donor (group II). All the controls were as-sessed by a clinical history, physical examination, and trans-vaginal ultrasonography, as well as diagnostic laparoscopy,all of which show no evidence of endometriosis. The indi-cations for oocyte donation were failed IVF (n5 8), lowresponse to conventional IVF ovarian stimulation (n5 10),and ovarian failure (n5 15). Patients with severe male factorinfertility were excluded.

Transvaginal ultrasonographic findings revealed no evi-dence of abnormal uterine cavities in either of the two groups.All recipients underwent a trial of HRT cycle with endome-trial biopsies control before therapy. All biopsies were in theadequate luteal phase in both groups, and no dose adjust-ments of the HRT regimen were necessary. The protocol ofsteroid replacement included pituitary desensitization withone IM ampoule administration of 3.75 mg of leuprorelineacetate (Ginecrin Depot, Abbott S.A., Madrid, Spain) begin-ning in the secretory phase of the previous cycle for patientswith ovarian function. HRT was administered to all patientsstarting on day 1 of the cycle; 2 mg of E2 valerate (Progy-nova; Schering Spain, Madrid, Spain) was administereddaily from days 1 to 8, 4 mg was administered daily fromdays 9 to 11, and 6 mg was administered daily on day 12.

After 13 days of E2 valerate administration, recipientswere ready to receive oocytes and waited until a donationbecame available. On the day of the donated oocytes re-trieval, 800 mg/d of micronized intravaginal progesterone(P4) (Progeffik; Laboratories Effik S.A., Madrid, Spain) wasadministered. Embryo transfer was performed 48 hours afteroocyte recovery using the vaginal route. The transfer offrozen-thawed embryos was not included in this study. The

32 Diaz et al. Severe endometriosis in oocyte donation Vol. 74, No. 1, July 2000

replacement with 6 mg of E2 valerate daily and 800 mg of P4daily was maintained for 15 days, after which a urinaryb-hCG analysis was performed. In case of positive results,E2 valerate and P4 were continued at the same dosage untilday 80 of pregnancy, which was confirmed by fetal heartactivity.

Statistical AnalysisData are expressed as the mean6 SD. All statistical

calculations were performed with the Statistical Package forSocial Science version 8.0 (SPSS Inc., Chicago, IL). Signif-icant differences were determined usingx2, Fisher’s exacttest, Yates correctedx2, or Student’st-test when appropriate.Statistical significance was defined asP,0.5.

RESULTS

The mean age of patients with endometriosis and of thecontrol group was 35.06 3.4 years and 38.56 4.9 years,respectively (P,.05). The mean age of the donors was25.66 4.8 years. The number of oocytes donated, fertiliza-tion rate, number of embryos available, number of embryostransferred, and the average number of good quality embryostransferred were not statistically significant between the twogroups. IVF outcomes in oocyte recipients with and withoutstage III–IV endometriosis are shown in Table 1.

Pregnancy, implantation, and miscarriage rates were notaffected by stage III–IV endometriosis when compared withthe control group. The live birth rate in the group withendometriosis and the control group was 28.0% and 27.2%,respectively; the difference was not significant.

DISCUSSION

Patients with endometriosis have a poor IVF outcome interms of reduced pregnancy rate per cycle, reduced preg-nancy rate per transfer, and reduced implantation rate (1, 3, 5).However, Geber (10) showed that the severity of the diseasedoes not affect the IVF outcome. In agreement with findingspublished by Sung et al. (8), Simo´n et al. (3) showed thatpatients with endometriosis had the same chances of implan-tation and pregnancy as other recipients when the oocytescame from donors without known endometriosis. In thesestudies, the oocytes came from different donors and fromdifferent cycles, and therefore it could be argued that otherfactors might have obscured the possible existing differ-ences. The present study obviates this criticism and supportsthe observations of Simo´n et al. (3) since recipients wereallocated oocytes provided by the same donor.

We have shown that implantation is not affected in pa-tients with advanced stages of endometriosis, suggesting thatinfertility in these patients is not related to an unsuitableperitoneal and/or endometrial environment affecting endo-metrial receptivity. Integrins were proposed to be sensitiveindicators of the endometrial receptive state because theirexpression is modified around the time of implantation. Thismethod was used to evaluate the possibility that endometri-osis could adversely affect the endometrial environment innatural cycles comparing women with and without endome-triosis (6, 7). However, the differences detected in integrinexpression and its association with endometriosis as a pre-dictor of uterine receptivity in these patients remain contro-versial.

Our results show that women with severe endometriosisundergoing steroid replacement therapy are as likely to con-ceive as women in the control group, suggesting that uterinereceptivity is not impaired. The question still to be answeredis whether this situation applies for natural cycles or whetherthe fact that we are employing GnRH analogs and HRTmakes a difference in the endometrial milieu of these cycles,and whether this is why recipient’s endometriosis does notaffect outcome.

The study presented herein had an original design, but thefinal number of individuals included and embryos obtainedand replaced may not have sufficient statistical power (0.57)to draw final conclusions. However, our results accumulatedover the years (3, 5) and the results of the present designclearly suggest that severe endometriosis does not affectimplantation in ovum donation.

The poor IVF outcome in cases of advanced stages ofendometriosis may be related to a reduced number of re-trieved oocytes, leading to a reduced number of selectedembryos available to be transferred. There is a strong bodyof evidence that embryo morphology correlates with implan-tation rates and IVF success. Thus, the better the embryoselection, the better the IVF outcome, despite the presence of

T A B L E 1

IVF outcomes in recipients of sibling oocytes with andwithout stage III–IV endometriosis (rAFS classification ofendometriosis, 1997 (9)).

Study group

P valueEndometriosis

(III–IV) Control

No. of patients 25 33No. of cycles 25 33Agea 35.06 3.4 38.56 4.9 0.004No. of oocytes donateda 7.86 1.6 7.76 1.9 NSNo. of embryos transferreda 4.06 0.7 4.16 1.2 NSNo. of good quality embryos

transferreda 3.66 0.2 3.76 0.1 NSImplantation (%) 15/101 (14.8) 22/137 (16.0) NSNo. of pregnancies (%) 10 (40.0) 15 (45.5) NSMiscarriage (%) 3 (30.0) 4 (26.0) NSLive birth (%) 7 (28.0) 9 (27.2) NS

Note: NS 5 not significant.a Values are mean6 SD.

Dıaz. Stage III–IV endometriosis. Fertil Steril 2000.

FERTILITY & STERILITY t 33

endometriosis. This adds credibility to our hypothesis thatendometriosis, even when severe, does not affect implanta-tion, and the poor outcomes observed in these patients aremore likely due to oocyte and embryo alternatives.

Whether this is the result of a direct effect of endometri-osis on folliculogenesis or not remains unanswered. Giventhe contemporary methods of endometrial preparation for thetransfer of embryos derived from donor eggs, any potentialnegative effect of severe endometriosis on the uterine envi-ronment is undetectable.

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34 Diaz et al. Severe endometriosis in oocyte donation Vol. 74, No. 1, July 2000