Ovarian Hyperstimulation Syndrome

Ovarian hyperstimulation syndrome (OHSS) is the most serious complication of controlled ovarian stimulation (COS) as part of assisted reproductive technologies (ART). While the safety and efficacy of ART is well established, physicians should always be aware of the risk of OHSS in patients undergoing COS, as it can be fatal. This article will briefly present the pathophysiology of OHSS, including the key role of vascular endothelial growth factor (VEGF), to provide the foundation for an overview of current techniques for the prevention of OHSS. Risk factors and predictive factors for OHSS will be presented, as recognizing these risk factors and individualizing the COS protocol appropriately is the key to the primary prevention of OHSS, as the benefits and risks of each COS strategy vary among individuals. Individualized COS (iCOS) could effectively eradicate OHSS, and the identification of hormonal, functional and genetic markers of ovarian response will facilitate iCOS. However, if iCOS is not properly applied, various preventive measures can be instituted once COS has begun, including cancelling the cycle, coasting, individualizing the human chorionic gonadotropin trigger dose or using a gonadotropin-releasing hormone (GnRH) agonist (for those using a GnRH antagonist protocol), the use of intravenous fluids at the time of oocyte retrieval, and cryopreserving/vitrifying all embryos for subsequent transfer in an unstimulated cycle. Some of these techniques have been widely adopted, despite the scarcity of data from randomized clinical trials to support their use.

In vitro maturation (IVM) of human immature oocytes has been shown to be a viable option for patients at risk of ovarian hyperstimulation syndrome (OHSS), those seeking urgent fertility preservation and in circumstances where controlled ovarian stimulation is not feasible. Moreover, IVM techniques can be combined with ovarian tissue cryobanking to increase the chances of conception in cancer survivors. The clinical applications of IVM in the field of reproductive medicine are rapidly expanding and the technique is now classified as non-experimental. In contrast to conventional IVF (in vitro fertilization), IVM offers several advantages, such as reduced gonadotropin stimulation, minimal risk of ovarian hyperstimulation syndrome (OHSS), reduced treatment times and lower costs. However, the technical expertise involved in performing IVM and its lower success rates compared to traditional IVF cycles, still pose significant challenges. Despite recent advances, such as innovative biphasic IVM systems, IVM is still an evolving technique and research is ongoing to refine protocols and identify techniques to improve its efficiency and effectiveness. A comprehensive understanding of the distinct mechanisms of oocyte maturation is crucial for obtaining more viable oocytes through in vitro methods, which will in turn lead to significantly improved success rates. In this review, the present state of human IVM programs and future research directions will be discussed, aiming to promote a better understanding of IVM and identify potential strategies to improve the overall efficiency and success rates of IVM programs, which will in turn lead to better clinical outcomes.

Polycystic ovarian syndrome (PCOS) is a widespread syndrome that poses unique challenges and constraints to the field of assisted reproductive technology. This condition is the most common cause of anovulation among infertile couples. Debate exists over the best therapeutic course of action when patients with PCOS proceed to IVF. In this review, we evaluate the best-performing and safest methods of IVF preparation, ovarian stimulation, trigger method for maturation of stimulated egg growth, and planning for embryo transfer. Pre-IVF considerations include being aware of individual AMH and vitamin D levels as well as BMI prior to selecting an ovarian stimulation protocol. Numerous supplements such as myo-inositol complement the benefits of lifestyle change and may enhance IVF performance including oocyte yield and pregnancy rate. Concerning stimulation protocols, antagonist cycles with the judicious use of GnRH agonist trigger, pre-treatment with metformin and vitamin D repletion may help mitigate the accompanied risk of ovarian hyperstimulation syndrome (OHSS). Following ovarian stimulation, PCOS patients typically undergo programmed frozen embryo transfer (FET) cycles which are more conducive for women with irregular cycles, but likely carry a higher risk of hypertensive disorders of pregnancy. However, newer stimulated FET protocols using Letrozole may offer improved outcomes. Overall, patients with PCOS require careful individual tailoring of their IVF cycle to achieve optimal results.

ObjectiveTo evaluate clinical and laboratory parameters associated with the severity of ovarian hyperstimulation syndrome (OHSS) and to assess pregnancy outcomes in women hospitalized with moderate or severe OHSS. Several risk factors, including elevated antral follicle count (AFC), anti-Mullerian hormone (AMH), and serum estradiol (E2) levels, increase the risk of OHSS.MethodsWe studied 71 women with a median age of 32.7 years and a body mass index (BMI) of 22.8 kg/m2 with moderate (n=38) and severe (n=31) OHSS. We measured E2, hemoglobin (Hb), hematocrit (Hct), creatinine, albumin (Alb), total protein (TP), D-dimer (DD), and alanine aminotransferase (ALT) levels on the day of hospitalization and every second day until discharge. Data on the length of hospitalization, along with pregnancy outcomes, were recorded.ResultsThere were no intergroup differences between women with moderate and severe OHSS in terms of age and BMI. The total pregnancy rate in both moderate (18/38) and severe (9/31) OHSS was 27/69; however, in women with severe OHSS, the positive pregnancy outcome was approximately half that observed in the moderate OHSS group and was accompanied by longer hospitalization (2.9-fold). All women with OHSS had elevated initial E2 levels (>6910pg/mL). Women with severe OHSS had higher initial E2 (p=0.001) and Hct (p=0.006) levels, together with lower Alb and TP concentrations (both pConclusionElevated estradiol concentration is an associated factor for OHSS in women undergoing COH. Basal serum albumin concentration, together with total protein level and hematocrit, are predictive factors for OHSS severity.