Fertility Topics Explained from the Experts at SFS
Ovarian hyperstimulation syndrome (OHSS) is a life-endangering condition that occurs following ovarian stimulation for the treatment of infertility. It occurs due to overstimulation of the ovaries with the development of numerous follicles in susceptible women. Systemic effects can be very serious and can lead to life-endangering complications. Thus every effort must be made to avoid the condition and when it does threaten, to take the necessary steps to mitigate its effects, and at the same time attempt to protect egg quality which often is adversely affected as well. Prevention starts with recognizing those women who are at the greatest risk of developing OHSS. They include:
In such cases, it is prudent to minimize the dosage of gonadotropins administered, but alas, this often will not eliminate risk of OHSS developing anyway. Aside from the risk that OHSS places the woman at, it can also have a devastating effect on egg quality/competency. Thus, all too often, the measures taken (see below) to reduce maternal risk come at a price. PRESENTATION AND MANAGEMENT OF OHSS: The onset of OHSS, heralded by the presence of large numbers (>25) of developing ovarian follicles and rapidly rising plasma estradiol levels, often exceeding 3000pg/ml within 7 or 9 days of stimulation, and rapidly peaking above 6,000 pg/ml prior to hCG administration. When this happens, the risk of OHSS developing is above 80%. The fear of this escalating often leads physicians to prematurely administer hCG in an attempt to abruptly arrest the process and prevent escalation of risk to the patient. However, the premature administration of the “trigger” shot arrests egg development and adds to the problem of poor egg/embryo quality in such cases. Symptoms and signs of OHSS include: abdominal distention due to fluid collection (ascites), fluid in the chest cavity (hydrothorax), rapid weight gain (of a pound or more per day) due to tissue fluid retention, abdominal pain, lower back ache, nausea, diarrhea, vomiting, visual disturbances such as blurred vision and spots in front of the eyes (scotomata), a rapidly declining urine output, cardiovascular collapse and failure of blood to clot which sometimes results in severe bruising (ecchymosis) and frank bleeding. These symptoms and signs may appear before pregnancy can be diagnosed. If pregnancy occurs, the condition is likely to worsen progressively over a period of 3-5 weeks whereupon it rapidly resolves spontaneously over a few days. If no pregnancy occurs, the symptoms and signs all disappear spontaneously within 10-12 days of the hCG injection. When increasing fluid collection in the abdominal cavity (ascites) starts to compromise breathing raising the head of the bed rose slightly by placing a 4-6 inch block at the base of each head post and using a few additional pillows, will sometimes help ameliorate the problem. In cases where this does not help or symptoms become severe, all or most of the fluid can readily and safely be drained through t transvaginal sterile needle aspiration (vaginal paracentesis-performed once or sometimes twice a week) can be performed once or twice weekly . The problem will usually self corrects within 10-12 days of the hCG shot if pregnancy does not occur or, by the 8th week of pregnancy. Urine output should be monitored daily to see if it drops below about 500ml a day (about two cups and a half). A chest X-ray, to evaluate for fluid collection in the chest and around the heart should be done weekly along with blood tests for hematocrit, BUN, electrolytes, creatinine, platelet count and fibrin split products (FSP). If indicated on the basis of a deteriorating clinical situation, hospitalization might be needed for close observation and if necessary, to provide intensive care. In all case of OHSS, the ovaries and contain numerous theca-lutein cysts and will invariably be considerably enlarged. This is irrelevant to the final outcome, unless ovarian torsion (twisting of the ovary on its axis), an extremely rare complication occurs. The latter would usually require surgical emergency surgical intervention. Human chorionic gonadotropin (hCG) “Fans the flames “ of OHSS. That is why the occurrence of pregnancy worsens the condition. In women who do not conceive, the clinical severity of OHSS will usually peak 7-10 days after the hCG “trigger”, plateaus for another 3-4 days and thereupon rapidly improves within the ensuing week. Thus in the absence of hCG the condition is “self-limited”. Sometimes severe symptoms due ascites make it imperative to drain the fluid transvaginally (often repeatedly). This brings immediate relief but it can be short-lived requiring repeated drainage a few days later until the condition resolves. If the woman conceives following a fresh embryo transfer, the rising hCG blood levels can exacerbate the OHSS for several weeks, but either way, it usually disappears spontaneously by the 8th to 9th harrowing week of pregnancy. This is why there is a growing tendency to avoid fresh embryo transfers, preferring to do FET’s later once the woman is out of risk. It is also the reason for a move to avoid using 10,000U of hCG for the “trigger shot” or to avoid to supplant hCG with an “agonist” trigger. But this comes at a price – see below. OHSS AND POOR EGG/EMBRYO QUALITY/COMPETENCY: OHSS is also associated with poor egg/embryo quality. This is especially so in women with high ovarian LH-induced testosterone (e.g. those with PCOS). These often present with poorly developed (“dysmorphic”) eggs, with reduced fertilization potential and yielding “poor quality embryos”. However, in the author’s opinion (which admittedly runs contrary to popular opinion), this is unlikely to be due to an intrinsic deficit in egg quality. Rather, it more likely relates to intra-ovarian hormonal changes brought about by hyperstimulation and which compromise egg development. This effect, in my opinion, can often be significantly reduced through implementation of an individualized or customized ovarian stimulation protocols that minimize exposure of the developing follicles and eggs to excessive LH-induced ovarian androgens. This can be best achieved by limiting the use of LH-containing gonadotropins such as Menopur through selective institution of “prolonged coasting" (see below). Approaches to preventing OHSS include:
A word of caution: I do not use long term administration of antagonists (Ganirelix/Cetrotide/Orgalutron), such as with the agonist/antagonist conversion protocol (A/ACP) in high responders whom are at risk of developing OHSS prolonged in-cycle administration of because it can interferes with the E2 assay (often causing the value to be understated), and serial measurement of E2 is a vital part of monitoring patients undergoing “coasting”
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