Ezgi Demirtas, Hananel Holzer, Weon-Young Son, Shai Elizur, Dan Levin, Ri-Cheng Chian and Seang Lin Tant
Author for correspondence Royal Victoria Hospital,
Women’s Pavilion F4, 687 Pine Avenue West, Montreal, QC, H3A 1A1, Canada
Tel.: +1 514 934 1934
Fax: +1 514 843 1496 seanglin.tan@muhc.mcgill.ca

In vitro maturation of human oocytes obtained from unstimulated ovaries offers a more ‘patient friendly’ treatment option than conventional IVF treatment with ovarian stimulation to the couples undergoing assisted reproductive technologies. It has classically been offered to women who are considered high risk for ovarian hyperstimulation syndrome. Since significant progress has been made to improve the implantation and pregnancy rates using in vitro matured oocytes, the patient spectrum for in vitro maturation treatment has become wider. However, implantation and pregnancy rates of conventional IVF are still higher than those of unstimulated cycles followed by in vitro maturation. To improve the in vitro maturation outcomes, some studies have focused on improving in vitro culture conditions, whereas others have tried to improve the quality and quantity of oocytes retrieved by modifications in the follow-up of treatment cycles.

Keywords: in vitro maturation • IVF • oocyte • ovarian hyperstimulation syndrome

More than 4 million babies have been born following treatment with assisted reproductive technologies (ART) since the first IVF baby in 1978 [1]. The first ART baby was obtained by a natural cycle IVF treatment. Soon after this achievement, natural cycle IVF was replaced by ovarian stimulation followed by IVF. Although obtaining many mature oocytes remarkably increased the pregnancy and live-birth rates, it has also brought the disadvantages of mul- tiple pregnancies with their associated risks and the risk of ovarian hyperstimulation syndrome (OHSS) [2]. While multiple pregnancy rates show great variation with regard to the number of embryos transferred, the risk of severe OHSS is generally 1% but may be as high as 10% in high-risk groups, particularly in young women with polycystic ovaries (PCO) or polycystic ovary syndrome (PCOS) [3].

Development of in vitro maturation

The possibility of maturing oocytes in vitro opened an era of a new treatment method for infertile couples. In 1935, Pincus and Enzmann first demonstrated that immature oocytes have the ability to resume meiosis spontaneously when removed from the fol- licle [4]. Later, Edwards et al. demonstrated that in vitro-matured human oocytes could be fertilized [5]. Cha et al. used immature human oocytes retrieved during gynecologic surgeries

in an oocyte donation program and obtained the first in vitro maturation (IVM) pregnancy in 1991 [6]. The first IVM pregnancy with a patient’s own oocytes was obtained in 1994 by Trounson et al. [7]. Soon after, the same group reported another pregnancy in a PCOS patient with IVM and intracytoplasmic sperm injection (ICSI) and assisted hatching [8].

The first animal derived from an oocyte matured in vitro was a mouse in 1996 [9]. IVM of oocytes from unstimulated ovaries has also been used for domestic animal production and also for the protection and salvation of endangered species facing extinction [10]. Animal models are also good resource for the research in this field.

Throughout most of the 1990s, results from IVM remained low. A major breakthrough occurred when Chian et al. introduced human chorionic gonadotropin (hCG) priming for IVM for human oocytes 36 h prior to the oocyte retrieval, and reported a 32% implantation rate and 40% clinical pregnancy rate in a series of 25 cycles in patients with PCOS [11]. Subsequently, other reports followed with up to 54% clinical pregnancy rates using in vitro-matured oocytes from unstimulated cycles [12].

Although IVM success rates have consistently been lower than IVF success rates, IVM has several important advantages over IVF. Since there is no ovarian stimulation, the risk of OHSS is essentially eliminated in IVM treatment. The immediate side effects of the stimulation drugs (i.e., nausea, vom- iting, breast tenderness, mood swings and injection-site reactions) are avoided. It requires less meticulous follow-up and reduces the number of visits during the treatment cycle. Furthermore, it is preferable for some patients who are concerned about the long- term risks of hormonal ovarian stimulation and prefer not to receive it. Besides, IVM is more affordable for the patients, since they do not pay for the medication. All these factors make IVM more ‘patient friendly’.

It was demonstrated that immature human oocytes could be matured and fertilized in vitro but early reports showed low implantation rates when compared with conventional stimulated cycles. The lower success rate might be attributed to asynchrony in the cytoplasmic and nuclear maturation of the oocyte, as well as asynchrony in the endometrium. Another possible explana- tion could be that the final number of matured oocytes obtained in unstimulated cycles followed by IVM is relatively low compared with conventional stimulated cycles. Although the number of centers that offer IVM to their patients as an alternative over stimulated IVF cycles has been increasing, patients have to choose between a more patient friendly but less successful treat- ment or a more successful but also more aggressive approach. Therefore, increasing the pregnancy and the live-birth rates in IVM treatment has become crucial. For this reason, some studies have focused on improving culture media in vitro, whereas others have tried to improve the quality and quantity of oocytes, as well as endometrial synchrony, by in vivo stimulation with gonadotropins, as well as adjusting the optimal retrieval time with regard to follicular size at hCG administration.

Strategies to overcome low implantation rates in IVM Improving in vitro culture techniques

Successful oocyte maturation requires nuclear maturation through meiosis I and II (M-I/M-II), and cytoplasmic matura- tion. The nuclear maturation appears to be controlled by cytoplasmic maturation, which includes relocation of organelles, synthesis and modification of proteins and mRNAs, proper storage and timely reactivation of molecules and biochemical processes that are necessary for supplying the required materi- als for the subsequent developmental steps for the oocytes [13]. These subsequent developmental steps refer not only to the steps until M-II stage oocyte but also to successful fertilization and developing a competent embryo.

Regulation of oocyte maturation in vivo is a complex procedure and various hormonal signals and transcription factors regulating gene expression are involved in the microenvironment of the maturing oocyte. The oocyte is surrounded by the cumulus cells and there are gap junctions between the oocyte and cumulus cells [12]. These gap junctions allow the regulatory molecules, such as ions, cAMP, purines and growth factors, to pass through the cytoplasm of the oocyte and cumulus cells. The oocyte is in meiotic arrest until maturation is triggered. IVM is an induced process, triggered by a luteinizing hormone (LH) surge and mediated by growth factors. Park et al. dem- onstrated that LH stimulation induces the transient and sequential expression of the EGF family members: amphiregulin, epiregulin and

β-cellulin in vivo [14]. However, IVM occurs spontaneously when the oocyte is removed from the follicle [15]. If immature oocytes are removed from the various size antral follicles, meiotic resumption will be resumed very rapidly before the necessary cytoplasmic preparation is completed. It is suggested that untimely removal of the oocyte from its dynamic environment interrupts the in vivo capacitation of the oocyte [16] and the oocyte matures without completing the necessary preparation. Therefore, the timing of resumption of meiosis is important in oocyte maturation. To solve this problem for IVM systems, some scientists suggest delaying spontaneous nuclear maturation while simultaneously promoting development of the cytoplasm [16]. cAMP was reported to be a useful mediator for this aim. Intraoocyte cAMP levels are mediated by cumulus cells, and high levels of cAMP and cAMP analogs prevent meiotic resump- tion [17]. An approach suggested to inhibit or delay spontaneous oocyte maturation in vitro to give the oocyte a chance to complete its preparation is increasing the cAMP of the environment by add- ing phosphodiesterase-type-3-inhibitor in the maturation medium; this in turn reversibly arrests the nuclear development of human oocytes in vitro [18]. The cytoplasm during this time is prepared for the subsequent developmental steps.

The in vivo system is a complex mechanism that is very well orchestrated. Reinitiation of meiosis in vitro is entirely differ- ent. Premature interruption of the gap junction communication between the cumulus cells and the oocyte seems to compromise the developmental competence of the oocyte. Although the IVM rate to M-II stage and progression to 2–8-cell embryo stage fol- lowing insemination may not be affected by the absence of cumulus cells during maturation, development beyond the blastocyst stage appears to be significantly lower in cumulus-free oocytes compared with cumulus-intact counterparts [19].

Kinase/phosphatase systems play major roles in the reinitiation of meiosis. Intraoocyte cAMP levels increase in response to the LH surge in vivo [17] and this increment in cAMP level increases protein kinase A activity in vivo that is believed to interrupt gap junction communications between the oocyte and cumulus cells by phosphorylation of the gap junction protein connexin 43, and this leads to reinitiation of meiosis [20]. Protein kinase C and isoforms suppress meiotic resumption in the oocyte; however, its stimula- tion in cumulus cells triggers germinal vesicle breakdown [21,22]. Maturation-promoting factor is another regulator molecule with kinase activity [23]. There are other molecules of the protein kinase/ phosphatase group, such as aurora A kinase, protein phosphatase-1 and cdc25 phosphatase, that have been reported to play roles in oocyte maturation, particularly in meiotic resumption [24–26]. Various kinase inhibitors were used to delay meiotic reinitiation in vitro with and without improvement and sometimes with adverse effects on embryo development [27,28].

It has recently been shown that there are oocyte-secreted factors that are critical regulators of normal cumulus cell function [16,29].

The oocyte has a paracrine control over the cumulus cells via these oocyte-secreted factors. These are soluble growth factors that have a paracrine effect on both cumulus and granulosa cells. Oocyte- secreted factors are relatively new for the field and the studies to explain the dynamic relation between the oocyte and cumulus cells in vivo, and their possible use in IVM of human oocytes, are yet to be conducted. However, IVM techniques are likely to be improved by further studies to enhance oocyte developmental competence in vitro.

Human chorionic gonadotropin

The first major breakthrough in IVM treatment was the administration of hCG prior to immature oocyte retrieval; with maturation, fertilization and pregnancy rates reported to be 84, 87 and 40%, respectively, in a series of 25 cycles [11]. Following this first report of hCG priming, the first prospective randomized study comparing hCG primed and nonprimed cycles showed hastened oocyte maturation and higher clinical pregnancy rates in IVM cycles primed with hCG 10,000 IU subcutaneously, 36 h prior to oocyte retrieval [30]. This finding was confirmed by Son et al. where the IVM rate was faster in oocytes obtained from hCG-primed IVM cycles (hCG 10,000 IU, 36 h prior to oocyte retrieval) than the ones obtained from nonprimed cycles [31]. Nevertheless, there were also reports that did not find any beneficial effect of hCG priming with regards to the number of oocytes retrieved, matu- ration, fertilization or cleavage rates [32]. Pretreatment with hCG before the immature oocyte retrieval theoretically promotes IVM and therefore improves pregnancy rates. The exact mechanism of hCG effect on small follicles remains unclear; however, it has been shown that granulosa cells in small follicles from anovulatory (but not ovulatory) women with polycystic ovaries responded prema- turely to LH [33]. This finding may be important in the mecha- nism of anovulation in PCOS and may help to explain how hCG priming hastens oocyte maturation in vitro. Although, there are still conflicting results concerning the use of hCG priming, there may be a technical advantage to it; the cumulus cell expansion of the oocytes caused by the high dose of hCG facilitates detachment and expulsion of the cumulus–oocyte complex from the follicle during aspiration and makes the oocyte retrieval easier compared with unstimulated, non-hCG-primed IVM cycles.

The advantages of hCG administration have also been con- firmed by the treatment outcomes. Priming with hCG may help to obtain in vivo-matured oocytes at retrieval. It has been shown that fertilization, cleavage and blastocyst development rates in IVM cycles that yield mature oocyte(s) on the day of retrieval are higher compared with the cycles that did not produce any mature oocytes on the day of retrieval [34]. The number of good-quality blastocysts generated from in vivo matured oocytes is also significantly higher than that of in vitro matured oocytes [35]. The embryo quality and clinical pregnancy rates are higher (40 vs 23.3%) in these IVM cycles with in vivo-matured oocytes at retrieval compared with the cycles without in vivo-matured oocytes on the day of retrieval [36]. Furthermore, the oocytes that matured within 24 h during the culture produce better quality embryos than those derived from oocytes that matured after 48 h.

Follicle-stimulating hormone priming

Wynn et al. were the first to demonstrate a beneficial effect of follicle-stimulating hormone (FSH) priming on the number of oocytes retrieved and maturational competence of the oocytes [37].

Although results of studies on FSH priming are controversial, it may have potential benefits; larger ovarian size and easier retrieval, higher E2 levels and higher maturational competence of the oocytes. This approach may also lead to improved endo- metrial priming. Mikkelsen found improved implantation and clinical pregnancy rates in FSH-primed cycles, 21.6 and 29%, respectively, without additional hCG administration in anovu- latory women [38]. Lin et al., in a prospective study, compared FSH plus hCG premedication versus hCG alone and found no additional benefit of FSH in cases where FSH and hCG were both administered [39]. According to our experience at McGill Reproductive Center, low-dose FSH pretreatment appears to be favorable over 17β-estradiol priming in terms of implantation and pregnancy rates in the selected group of patients when endometrial thickness is less than 6 mm in the midfollicular phase of the IVM cycle [40].

Timing of oocyte retrieval

As a general assumption, the dominant follicle suppresses the development of small follicles. Immature oocytes retrieved from conventional stimulated cycles, in the presence of large dominant follicles, are capable of undergoing IVM, fertilization and cleav- age [41–43]. However, the clinical pregnancy outcomes of these immature oocytes obtained from stimulated cycles are disappoint- ingly low. It has been suggested that morphological and molecular differences exist between the immature oocytes retrieved from stimulated and unstimulated ovaries [44]. The in vitro developmental competence of the immature oocytes obtained from unstimulated cycles appears to be superior to those obtained from stimulated ovaries.

In unstimulated ovaries, Russell et al. showed that when the leading follicle was larger than 13 mm, fewer oocytes are retrieved, the fertilization rate was lower and fewer embryos were generated [45]. Cobo reported higher blastocyst formation when the leading follicle was smaller than 10 mm [46]. While these reports suggested that the large follicles might compromise the devel- opmental potential of oocytes in the small antral follicles, some other reports have suggested that the competence of the oocytes retrieved from the small antral follicles were not adversely affected by a growing dominant follicle in unstimulated cycles [47,48]. Some authors, on the other hand, have demonstrated the advantage of the presence of in vivo-matured oocyte(s) in hCG-primed IVM cycles [35,36]. Retrieval of in vivo-matured oocytes is more likely to occur in cycles where follicles are allowed to grow to 10–12 mm before oocyte retrieval. It seems that obtaining at least one mature oocyte on the day of retrieval contributes to better clinical out- come in unstimulated cycles and in practice we give hCG when the largest follicle has a diameter of 10–12 mm.

Another issue for the best timing of oocyte retrieval is the dura- tion between hCG administration and oocyte retrieval. We believe that prolonging the duration between hCG administration and oocyte retrieval in IVM cycles is a beneficial approach to retrieve higher number of oocytes stimulated in vivo. When the dura- tions of 35 versus 38 h between hCG administration and oocyte retrieval were compared, the 38-h group yielded a significantly higher number of mature oocytes [49]. In addition, the IVM rate after 24-h in culture was significantly higher and the clinical preg- nancy rate in the 38 h group was higher compared with the 35-h group in the unstimulated cycles, at 40.9 versus 25% [49].

Metformin

A study evaluated the effect of metformin pretreatment on IVM outcomes in the patients with clomiphene citrate-resistant PCOS [50]. A total of 56 women underwent 70 cycles of IVM treatment. Metformin was administered to patients at a dose of 500 mg twice a day for 12 weeks before IVM treatment. The women were administered human menopausal gonadotropin (HMG) for 5 days and hCG 10,000 IU, 36 h prior to the oocyte collection. Although the number of immature oocytes, oocyte maturation, fertilization and cleavage rates in the metformin- treated group were comparable to the control group, significantly higher implantation and clinical pregnancy rates were obtained in the metformin-treated group (15.3 and 38.2%, respectively) com- pared with the controls (6.2 and 16.7%, respectively), suggesting that pretreatment with metformin may improve IVM outcome.

Patient selection for IVM

Pregnancy rates following IVM treatment correlate with the total number of oocytes retrieved [51]. This is best predicted by ultrasonographic assessment of the antral follicle count (AFC). Therefore, the prime candidates of the IVM treatment are women with PCO or PCOS, regardless of whether they are ovulatory or anovulatory [52]. The number of immature oocytes retrieved can be predicted by the number of 2–8 mm antral follicles, ovarian volume and peak ovarian stromal velocity measured by Doppler ultrasound during the early follicular phase. Since the AFC decreases with increasing age [53], lower implantation and clinical pregnancy rates are expected in older age groups in IVM treat- ment due to the decreasing AFC in addition to the age factor itself leading to poorer oocyte quality. Therefore, the majority of IVM pregnancies in the literature have been reported in women with PCOS and in a relatively younger age group (below 35 years of age) and pregnancy rates in women with normal ovaries appear to be lower [54]. Since the number of oocytes retrieved is important, a high-resolution ultrasound transducer is required to aspirate the oocytes from small follicles. Nevertheless, it is technically difficult to aspirate follicles smaller than 2–4 mm.

Immature oocyte retrieval followed by IVM is a particularly promising alternative to stimulated cycles for oocyte donors who have high AFC. Even if oocyte donors do not have PCO, their AFC tends to be relatively higher owing to their younger age. This makes IVM a favorable choice for these donors, particularly those who have concerns regarding the short-term side effects of hormonal ovarian stimulation or long-term health implications of the stimulatory hormones. Endometrial asynchrony is not a dis- advantage for the recipient either. The clinical pregnancy rate was 50% (six out of 12) in our first report of an IVM oocyte donation program where the donors had PCO/PCOS [55]. We believe IVM could be offered as the treatment of choice to oocyte donors who have an AFC of 15–20 but do not necessarily have PCO.

Immature oocyte retrieval in an unstimulated cycle followed by IVM and oocyte/embryo cryopreservation is proposed to be the preferred method for fertility preservation for cancer patients who will undergo imminent cytotoxic treatment and do not have sufficient time for planning a stimulated cycle and/or who have a tumor that does not allow them to receive hormonal ovar- ian stimulation. The first baby born following this method in a study patient has been announced and a 20% pregnancy rate was reported in 20 women younger than 35 years [56].

Repeated poor ovarian response [57] and repeated poor oocyte quality in conventional stimulated cycles, and the need for pre- implantation genetic diagnosis/screening are other indications of IVM [58].

In vitro maturation as a rescue

Occasionally, treatment begins as a stimulated cycle for subsequent IVF but is cancelled due to the high risk of OHSS. In this regard, Lim et al. suggested switching conventional IVF cycle into an IVM cycle in those PCO(S) patients who were at risk of developing OHSS during ovarian stimulation [59]. In a series of patients undergoing IVF, early administration of hCG 10,000 IU subcutaneously was undertaken when the number of follicles recruited was greater than 20 and the leading follicle reached 12–14 mm in diameter, followed by retrieval of the immature oocytes, IVM, subsequent fertilization by ICSI and then embryo transfer. The trial resulted in an overall pregnancy rate of 47.1% per embryo transfer. Although hCG was administered, no cases of OHSS were reported.

Similar rationale may be applied to cases of poor ovarian response to hormonal ovarian stimulation. Liu reported that oocyte retrieval and subsequent IVM was offered to 19 patients who were administered gonadotropins for more than 7 days and did not have a dominant follicle larger than 10 mm [60]. Oocyte retrieval was performed following administration of hCG 10,000 IU subcutaneously. The implantation and clinical pregnancy rates were reported as 15.8 and 40.4%. Interestingly, the mature oocyte rate at retrieval was found to be 15%, which was higher than expected in a typical IVM cycle.

In vitro maturation outcome

In vitro maturation is patient friendly and success rates have been increasing over the past decade. In general, the implantation and clinical pregnancy rates are reported to be 10–15 and 30–35%, respectively, by IVM treatment in women with PCO/PCOS and the clinical pregnancy rate increases to 54% in cases of blastocyst transfer [12]. However, almost all centers have more favorable IVF outcomes compared with their own IVM outcomes. However, IVM results from some centers may reach and even surpass the general IVF results (Tables 1 & 2). These results have made IVM a plausible treatment option that; in fact, it has comparable outcomes with conventional stimulated cycles for IVF/ICSI.

All ART pregnancies are associated with an increased risk of multiple pregnancy, cesarean delivery and congenital abnormality. Babies born to date following IVM treatment show no increased risk of congenital abnormality or adverse perinatal outcome over that already accepted for IVF or ICSI [61]. Nevertheless, we observed a higher rate of clinical miscarriage following IVM compared with IVF and ICSI [62]. This appears to be related to the patient characteristics of the treatment group (i.e., PCOS) rather than the IVM procedure itself, since the miscarriage rates following IVM and IVF/ICSI were comparable in patients with PCOS [62].

Conclusion

The IVM technique should be widely available in all ART centers for appropriate patients. Prime candidates of the method are women with high AFC regardless of cycle regularity. The success rate of IVM in women with normal ovaries remains to be studied before offering the method universally as a replacement for conventional hormonal ovarian stimulation followed by IVF/ICSI.

Expert commentary

Current knowledge demonstrates that in vivo-matured oocytes have more favorable fertilization, cleavage and pregnancy out- comes than IVM ones, and there is a benefit for treatment out- come in retrieving at least one mature oocyte even in unstimu- lated cycles for IVM. We believe that hCG pretreatment should be undertaken in IVM cycles. Although there is no consensus on hCG timing with respect to the leading follicle size, retrieval of in vivo-matured oocytes are more likely to occur in cycles where follicles are allowed to grow to 10–12 mm before the retrieval. Since the leading follicle size at the time of retrieval is smaller compared with the conventional stimulated cycles, prolonging the duration between hCG administration and the oocyte retrieval to 38 h is recommended. These approaches are employed to retrieve at least one mature oocyte as well as the immature ones. While the modifications in clinical fol- low-up are attempting to determine the best timing for oocyte retrieval, the laboratory technique needs to be optimized for IVM of oocytes to improve the developmental competence of the embryos generated following immature oocyte retrieval.

Five-year view

The current literature is lacking IVM treatment outcomes from large series, particularly for women with regular cycles. Our knowledge of FSH/HMG pretreatment or hCG timing with regard to the largest follicle diameter and the time interval between hCG administration and oocyte retrieval are limited. Although it was reported by several studies that the develop- mental competence of immature oocytes was not compromised in the presence of a dominant follicle, larger studies are yet to be performed to establish the optimal leading follicle size before retrieval. It appears that not only hCG but also FSH/HMG pretreatment may offer good treatment outcomes, particularly for cases that have poor endometrial development and in cases of very small follicle sizes. The duration of FSH/HMG administration also remains to be further investigated. Ongoing challenges for the near future can be summarized as:

• Further improving implantation and clinical pregnancy rates

• Best timing of hCG with regard to largest follicle diameter and the time interval between hCG administration and oocyte retrieval

• Whether or not recombinant hCG could replace urinary hCG

• The role of FSH/HMG pretreatment if follicles are very small

• How to choose the best embryos to transfer since there is an asynchrony among embryos

Financial & competing interests disclosure

Ri-Cheng Chian and Seang Lin Tan receive royalties from Medicult (Cryoleaf). Ri-Cheng Chian also receives royalties from Cooper Surgical (IVM media). The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

Key issues

  • Antral follicle count is the best indicator of treatment outcome: the higher the better.
  • High-resolution ultrasonography is required to identify and successfully retrieve the oocytes from the small antral follicles.
  • Retrieval of at least one mature oocyte appears to improve treatment outcomes.
  • Retrieval of in vivo matured oocytes is more likely to occur in cycles where follicles are allowed to grow to 10–12 mm before retrieval.
  • Human chorionic gonadotropin administration prior to oocyte retrieval improves pregnancy rates.
  • Center experience appears to be a key factor for treatment outcomes.

References

Papers of special note have been highlighted as:

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Affiliations

  • Ezgi Demirtas, MD
    Royal Victoria Hospital, Women’s Pavilion F6, 687 Pine Avenue West, Montreal, QC, H3A 1A1, Canada
    Tel.: +1 514 934 1934
    Fax: +1 514 843 1496 ezgi.demirtas@muhc.mcgill.ca

  • Hananel Holzer, MD
    Royal Victoria Hospital, Women’s Pavilion F6, 687 Pine Avenue West, Montreal, QC, H3A 1A1, Canada
    Tel.: +1 514 934 1934
    Fax: +1 514 843 1496 hananel.holzer@muhc.mcgill.ca

  • Weon-Young Son, PhD
    Royal Victoria Hospital, Women’s Pavilion F6, 687 Pine Avenue West, Montreal, QC, H3A 1A1, Canada
    Tel.: +1 514 934 1934
    Fax: +1 514 843 1496 weon-young.son@muhc.mcgill.ca

  • Shai Elizur, MD
    Royal Victoria Hospital, Women’s Pavilion F6, 687 Pine Avenue West, Montreal, QC, H3A 1A1, Canada
    Tel.: +1 514 934 1934
    Fax: +1 514 843 1496 shai.elizur@muhc.mcgill.ca

  • Dan Levin, MD
    Royal Victoria Hospital, Women’s Pavilion F6, 687 Pine Avenue West, Montreal, QC, H3A 1A1, Canada
    Tel.: +1 514 934 1934
    Fax: +1 514 843 1496 dan.levin@muhc.mcgill.ca

  • Ri-Cheng Chian, PhD
    Royal Victoria Hospital, Women’s Pavilion F6, 687 Pine Avenue West, Montreal, QC, H3A 1A1, Canada
    Tel.: +1 514 934 1934
    Fax: +1 514 843 1496 ri-cheng.chian@muhc.mcgill.ca

  • Seang Lin Tan, MD, MBA
    Royal Victoria Hospital, Women’s Pavilion F4, 687 Pine Avenue West, Montreal, QC, H3A 1A1, Canada
    Tel.: +1 514 934 1934
    Fax: +1 514 843 1496 seanglin.tan@muhc.mcgill.ca