Outcome of patients with one ovary in an in vitro fertilization program

Two is not always greater than one: patients with one ovary have similar assisted reproductive technology (ART) outcomes compared to patients with two ovaries

PURPOSE

To assess assisted reproductive technology (ART) outcomes in patients with one ovary compared to two ovaries.

METHODS

We performed a retrospective cohort study of all patients with one ovary who underwent ≥ 1 ART cycle between 2012 and 2020 at a large university-affiliated fertility center. Patients were 3-to-1 matched with two ovary controls during the same period. Primary outcome was metaphase II oocytes (MIIs) retrieved per cycle. Secondary outcomes included ovarian reserve markers, laboratory outcomes, and live birth rates (LBRs).

RESULTS

A total of 104 one ovary patients (158 cycles; median age 35.5 years) were matched to 312 two ovary patients (474 cycles; median age 35.0 years). In one ovary patients, anti-Mullerian hormone was lower (median 1.1 vs. 2.2, p < 0.01) and day 2 follicle-stimulating hormone was higher (median 7.4 vs. 6.2, p < 0.01). One ovary patients yielded median 7.5 MIIs and 10 oocytes per cycle, fewer than two ovary patients (11.0 and 14.5, respectively; p < 0.01). However, one ovary patients had ≥ 50% the MII and oocyte yield of two ovary patients (Z > 5.8, p < 0.01). Fertilization and blastocyst formation rates, euploidy rate, and rate of ≥ 1 embryo for transfer were equivalent between groups (p > 0.40). Among the one and two ovary groups, LBRs per transfer (45.8% vs. 46.6%, p = 1.00) and per patient who underwent transfer (68.3% vs. 73.9%, p = 0.55) were equivalent.

CONCLUSION

One ovary patients yielded fewer MIIs and oocytes than two ovary patients, but had ≥ 50% the yield of two ovary patients, suggesting a compensatory mechanism in oocyte yield in the solitary ovary. One and two ovary patients had equivalent LBRs.

Live birth and pregnancy rates after in vitro fertilization/intracytoplasmic sperm injection in women with previous unilateral oophorectomy: a systematic review and meta-analysis

OBJECTIVE

To quantify the effect of unilateral oophorectomy (UO) on the rates of live birth and pregnancy in women undergoing in vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI).

DESIGN

Systematic review and meta-analysis.

SETTING

Search of databases of published articles.

PATIENT(S)

The final analytical cohort encompassed 1,057 IVF/ICSI cycles in women with previous UO and 45,813 IVF/ICSI cycles in control women. Eighteen studies were identified by database searches of MEDLINE, Embase, Web of Science, and cited references. The review encompassed studies published up to June 1, 2021.

INTERVENTION(S)

UO prior to IVF/ICSI.

MAIN OUTCOME MEASURE(S)

The primary outcomes were the rates of live birth and pregnancy following IVF/ICSI. The secondary outcomes included the amount of gonadotropins administered for ovarian stimulation and the number of retrieved oocytes.

RESULT(S)

The studies were rated from medium to high quality (from 5 to 8) according to the Newcastle-Ottawa Quality Assessment Scale. All studies were observational, with inherent bias, and heterogeneity was high. The primary outcome of live birth had a significantly lower odds ratio (OR) in women with previous UO compared with controls (OR = 0.72, 95% confidence interval [CI] 0.57 to 0.91, z = -2.72). The OR for pregnancy rate per initiated treatment cycle was also significantly lower in women with previous UO compared with controls (OR = 0.70, 95% CI 0.57 to 0.86, z = -3.35). Additionally, the dose of administered gonadotropins was significantly higher and the number of retrieved oocytes was significantly lower in women with UO.

CONCLUSION(S)

The meta-analysis showed a significant detrimental effect of UO on the rates of live birth and pregnancy. The analysis further supports previous data showing a decreased sensitivity to gonadotropins and a lower number of recovered oocytes in women with previous UO.

STUDY REGISTRATION NUMBER

PROSPERO 2020, CRD42020160313.

Biological Impact of Unilateral Oophorectomy: Does the Number of Ovaries Really Matter?

Although unilateral oophorectomies are performed more often than bilateral ones in women of reproductive age, their clinical consequences have been less intensively investigated. Experimental models in animals have shown that compensatory mechanisms occur after a unilateral oophorectomy (UO). This review aims to summarize the available evidence on the biological effects of unilateral oophorectomy on women. Evaluated outcomes include age at onset of menopause, risk of cardiovascular and neurological disease, risk of mortality and fertility outcome after spontaneous conception or in vitro fertilization (IVF). Results were compared with findings reported after bilateral oophorectomy and/or ovarian excision and/or women with intact ovaries. An electronic database search was performed using PubMed and Scopus, followed by a manual search to identify controlled studies that compared women after UO with women with two intact ovaries. In particular, a systematic review of fertility outcomes after IVF was performed, and the data were summarized in a table. Women who underwent UO had a similar age at menopause and similar clinical pregnancy rate compared to women with two ovaries. However, decreased ovarian reserve affecting the quantity but not the quality of the ovarian pool after IVF was observed in the UO group. Furthermore, an increased risk of neurological disease and even an increased risk of mortality was observed in women with single ovary. These data need to be confirmed by further studies, and a plausible mechanism of action must be identified. At present, patients who undergo UO can be reassured with regard to their reproductive potential and their age at onset of menopause.

Reduced live-birth rates after IVF/ICSI in women with previous unilateral oophorectomy: results of a multicentre cohort study

STUDY QUESTION

Is there a reduced live-birth rate (LBR) after IVF/ICSI treatment in women with a previous unilateral oophorectomy (UO)?

SUMMARY ANSWER

A significantly reduced LBR after IVF/ICSI was found in women with previous UO when compared with women with intact ovaries in this large multicentre cohort, both crudely and after adjustment for age, BMI, fertility centre and calendar period and regardless of whether the analysis was based on transfer of embryos in the fresh cycle only or on cumulative results including transfers using frozen-thawed embryos.

WHAT IS KNOWN ALREADY

Similar pregnancy rates after IVF/ICSI have been previously reported in case-control studies and small cohort studies of women with previous UO versus women without ovarian surgery. In all previous studies multiple embryos were transferred. No study has previously evaluated LBR in a large cohort of women with a history of UO.

STUDY DESIGN, SIZE, DURATION

This research was a multicentre cohort study, including five reproductive medicine centres in Sweden: Carl von Linné Clinic (A), Karolinska University Hospital (B), Uppsala University Hospital (C), Linköping University Hospital (D) and Örebro University Hospital (E). The women underwent IVF/ICSI between January 1999 and November 2015. Single embryo transfer (SET) was performed in approximately 70% of all treatments, without any significant difference between UO exposed women versus controls (68% versus 71%), respectively (P = 0.32), and a maximum of two embryos were transferred in the remaining cases. The dataset included all consecutive treatments and fresh and frozen-thawed cycles.

PARTICIPANTS/MATERIALS, SETTING, METHODS

The exposed cohort included 154 women with UO who underwent 301 IVF/ICSI cycles and the unexposed control cohort consisted of 22 693 women who underwent 41 545 IVF/ICSI cycles. Overall, at the five centres (A-E), the exposed cohort underwent 151, 34, 35, 41 and 40 treatments, respectively, and they were compared with controls of the same centre (18 484, 8371, 5575, 4670 and 4445, respectively). The primary outcome was LBR, which was analysed per started cycle, per ovum pick-up (OPU) and per embryo transfer (ET). Secondary outcomes included the numbers of oocytes retrieved and supernumerary embryos obtained, the Ovarian Sensitivity Index (OSI), embryo quality scores and cumulative pregnancy rates. We used a Generalized Estimating Equation (GEE) model for statistical analysis in order to account for repeated treatments.

MAIN RESULTS AND THE ROLE OF CHANCE

The exposed (UO) and control women's groups were comparable with regard to age and performance of IVF or ICSI. Significant differences in LBR, both crude and age-adjusted, were observed between the UO and control groups: LBR per started cycle (18.6% versus 25.4%, P = 0.007 and P = 0.014, respectively), LBR/OPU (20.3% versus 27.1%, P = 0.012 and P = 0.015, respectively) and LBR/ET (23.0% versus 29.7%, P = 0.022 and P = 0.025, respectively). The differences in LBR remained significant after inclusion of both fresh and frozen-thawed transfers (both crude and age-adjusted data): LBR/OPU (26.1% versus 34.4%, P = 0.005 and P = 0.006, respectively) and LBR/ET (28.3% versus 37.1%, P = 0.006 and P = 0.006, respectively). The crude cancellation rate was significantly higher among women with a history of UO than in controls (18.9% versus 14.5%, P = 0.034 and age-adjusted, P = 0.178). In a multivariate GEE model, the cumulative odds ratios for LBR (fresh and frozen-thawed)/OPU (OR 0.70, 95% CI 0.52-0.94, P = 0.016) and LBR (fresh and frozen-thawed)/ET (OR 0.68, 95% CI 0.51-0.92, P = 0.012) were approximately 30% lower in the group of women with UO when adjusted for age, BMI, reproductive centre, calendar period and number of embryos transferred when appropriate. The OSI was significantly lower in women with a history of UO than in controls (3.6 versus 6.0) and the difference was significant for both crude and age-adjusted data (P = <0.001 for both). Significantly fewer oocytes were retrieved in treatments of women with UO than in controls (7.2 versus 9.9, P = <0.001, respectively).

LIMITATIONS, REASONS FOR CAUTION

Due to the nature of the topic, this is a retrospective analysis, with all its inherent limitations. Furthermore, the cause for UO was not possible to obtain in all cases. A diagnosis of endometriosis was also more common in the UO group, i.e. a selection bias in terms of poorer patient characteristics in the UO group cannot be completely ruled out. However, adjustment for all known confounders did not affect the general results.

WIDER IMPLICATIONS OF THE FINDINGS

To date, this is the largest cohort investigated and the first study indicating an association of achieving reduced live birth after IVF/ICSI in women with previous UO. These findings are novel and contradict the earlier notion that IVF/ICSI treatment is not affected, or is only marginally affected by previous UO.

STUDY FUNDING/COMPETING INTEREST(S)

None.

TRIAL REGISTRATION NUMBER

Not applicable.

Unilateral oophorectomy results in compensatory follicular recruitment in the remaining ovary at time of ovarian stimulation for in vitro fertilization

OBJECTIVE

To assess the effect of unilateral oophorectomy (UO) by assessing ovarian reserve (OVR) and the response to gonadotropin stimulation in women with UO undergoing in vitro fertilization (IVF) compared with the response of the ipsilateral ovary of women without UO.

DESIGN

Historical cohort study.

SETTING

Academic fertility clinic.

PATIENT(S)

Fifty-one women with single ovary compared with a referent group with both ovaries in a 1:2 fashion.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Day-3 follicle-stimulating hormone (FSH), estradiol, and antral follicle counts as measures of OVR, and IVF outcomes including number of follicles aspirated and oocytes retrieved.

RESULT(S)

The baseline demographics and serum markers of OVR were not different. Referent women had greater follicular yield and oocyte numbers when compared with women with UO; however, when compared with the ipsilateral ovary of the referents, women with UO had a higher antral follicle count and greater follicle and oocyte numbers. In multivariate analyses, the ovary from women with UO was more likely to yield more than the median number of follicles and oocytes than the ipsilateral ovary in referent women. Live-birth rates in both groups were similar.

CONCLUSION(S)

Our results suggest that the remaining ovary appears to compensate in follicular yield after UO in women, confirming the animal data. Women with UO can be reassured and appropriately counseled regarding IVF.

Women with one ovary in assisted reproduction technologies: a review of the literature

BACKGROUND

A number of patients who have undergone assisted reproductive technology (ART) have only one ovary.

PURPOSE

This article reviews the clinical implications of the absence of an ovary on the reproductive potential and the outcome in ART cycle.

DATA SOURCES

MEDLINE, Pubmed, the Cochrane Controlled Trials Register, and Cochrane Database of Systematic Reviews from the 1980s through April 2010.

STUDY SELECTION

Randomized, controlled trials; systematic reviews of trials; and observational studies; all restricted to English-language articles.

DATA SYNTHESIS

This review includes 58 articles. Women with a single ovary did not, in general, respond as well to ovulation induction treatment than women with two ovaries in ART cycles. It appears however, that once women with a single ovary achieve the stage of embryo transfer, they can be reassured that their chances of having a child are the same as women with two ovaries. Whether the right or left ovary responds better to superovulation is a question which remains unanswered in the literature.

LIMITATIONS

The authors could not address all management questions, and excluded non-English-language literature.