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Physicians can reduce the risk of OHSS by monitoring of FSH therapy to use this medication judiciously, and by withholding hCG medication.
Cabergoline confers a significant reduction in the risk of OHSS in high risk women according to a Cochrane review of randomized studies, but the included trials did not report the live birth rates or multiple pregnancy rates. Cabergoline, as well as other dopamine agonists, might reduce the severity of OHSS by interfering with the VEGF system. A systematic review and meta-analysis concluded that prophylactic treatment with cabergoline reduces the incidence, but not the severity of OHSS, without compromising pregnancy outcomes.
The risk of OHSS is smaller when using GnRH antagonist protocol instead of GnRH agonist protocol for suppression of ovulation during ovarian hyperstimulation. The underlying mechanism is that, with the GnRH antagonist protocol, initial follicular recruitment and selection is undertaken by endogenous endocrine factors prior to starting the exogenous hyperstimulation, resulting in a smaller number of growing follicles when compared with the standard long GnRH agonist protocol.
A Cochrane review found administration of hydroxyethyl starch decreases the incidence of severe OHSS. There was insufficient evidence to support routine cryopreservation and insufficient evidence for the relative merits of intravenous albumin versus cryopreservation. Also, "coasting", which is ovarian hyperstimulation without induction of final maturation, does not significantly decrease the risk of OHSS.
Sporadic OHSS is very rare, and may have a genetic component. Clomifene citrate therapy can occasionally lead to OHSS, but the vast majority of cases develop after use of gonadotropin therapy (with administration of FSH), such as Pergonal, and administration of hCG to induce final oocyte maturation and/or trigger oocyte release, often in conjunction with IVF. The frequency varies and depends on a woman's risk factors, management, and methods of surveillance. About 5% of treated women may encounter moderate to severe OHSS. Risk factors include young age, the development of many ovarian follicles under stimulation, extreme elevated serum estradiol concentrations, the use of hCG for final oocyte maturation and/or release, the continued use of hCG for luteal support, and the occurrence of a pregnancy (resulting in hCG production).
Mortality is low, but several fatal cases have been reported.
Clomifene citrate (or clomid) is the medication which is most commonly used to treat anovulation. It is a selective estrogen-receptor modulator, affecting the hypothalamic–pituitary–gonadal axis to respond as if there was an estrogen deficit in the body, in effect increasing the production of gonadotrophins. It is relatively easy and convenient to use. Clomifene appears to inhibit estrogen receptors in hypothalamus, thereby inhibiting negative feedback of estrogen on gonadotrophin production. It may also result in direct stimulation of the hypothalamic-pituitary axis. It also has an effect on cervical mucus quality and uterine mucosa, which might affect sperm penetration and survival, hence its early administration during the menstrual cycle. Clomifene citrate is a very efficient ovulation inductor, and has a success rate of 67%. Nevertheless, it only has a 37% success rate in inducing pregnancy. This difference may be due to the anti-estrogenic effect which clomifene citrate has on the endometrium, cervical mucus, uterine blood flow, as well as the resulting decrease in the motility of the fallopian tubes and the maturation of the oocytes.
The standard dosage for first-time takers is 50 or 100 mg of clomifene per day for five consecutive days, starting early in the menstrual cycle, usually on the third to fifth day counting from the beginning of the menstrual period. In case of amenorrhea, a period can be induced by intake of an oral progestin for 10 days. In absence of success, the dosage can be increased in subsequent cycles with increments of 50 mg. However, at a dosage of 200 mg, further increments are unlikely to increase pregnancy chances.
The gonadotropin-releasing hormone (GnRH) pump is used to release doses of GnRH in a pulsatile fashion. This hormone is synthesised by the hypothalamus and induces the secretion of LH and FSH by the pituitary. GnRH must be delivered in a pulsatile fashion to imitate the random secretion of the hypothalamus in order to fool the pituitary into secreting LH and FSH. The GnRH pump is the size of a cigarette box and has a small catheter. Unlike other treatments, using the GnRH pump doesn’t usually lead to multiple pregnancies. Filicori from the University of Bologna suggests that this might be because gonadotrophins are absent when the treatment is initiated, and therefore the hormones released by the pituitary (LH and FSH) can still take part in the retro-control of gonadotrophin secretion, mimicking the natural cycle. This treatment can also be used for underweight and/or anorexic patients; it has also been used in certain cases of hyperprolactimenia.
Tamoxifen affects estrogen receptors in a similar fashion as clomifene citrate. It is often used in the prevention and treatment of breast cancer. It can therefore also be used to treat patients that have a reaction to clomifene citrate.
Bromocriptine acts in a completely different manner to the other treatments mentioned above. It does not induce ovulation, but reduces the production of prolactin by the pituitary. Bromocriptine is only prescribed in cases of overproduction of prolactin (hyperprolactinemia).
Corticosteroids (usually found in anti-inflammatory drugs) can be used to treat anovulation if it is caused by an overproduction of male hormones by the adrenal glands. Corticosteroids are usually used to reduce the production of testosterone.
Several studies indicate that in some cases, a simple "change in lifestyle" could help patients suffering from anovulation. Consulting a nutritionist, for example, could help a young woman suffering from anorexia to put on some weight, which might restart her menstrual cycle. Conversely, a young overweight woman who manages to lose weight could also relieve the problem of anovulation (losing just 5% of body mass could be enough to restart ovulation). However, it is widely acknowledged by doctors that it is usually very difficult for PCOS patients to lose weight.
Previously, metformin was recommended as treatment for anovulation in polycystic ovary syndrome, but in the largest trial to date, comparing clomiphene with metformin, clomiphene was more effective than metformin alone. Following this study, the ESHRE/ASRM-sponsored Consensus workshop do not recommend metformin for ovulation stimulation. Subsequent randomized studies have confirmed the lack of evidence for adding metformin to clomiphene.
Potential methods in unexplained infertility include oral ovarian stimulation agents (such as clomifene citrate, anastrozole or letrozole) as well as intrauterine insemination (IUI), intracervical insemination (ICI) and in vitro fertilization (IVF).
In women who have not had previous treatment, ovarian stimulation combined with IUI achieves approximately the same live birth rate as IVF. On the other hand, in women who have had previous unsuccessful treatment, IVF achieves a live birth rate approximately 2-3 times greater than ovarian stimulation combined with IUI.
IUI and ICI has higher pregnancy rates when combined with ovarian stimulation in couples with unexplained infertility, for IUI being 13% unstimulated and 15% stimulated, and for ICI being 8% unstimulated and 15% stimulated. However, the rate of twin birth increases substantially with IUI or ICI combined with ovarian stimulation, for IUI being 6% unstimulated and 23% stimulated, and for ICI being 6% unstimulated and 23% stimulated.
According to NICE guidelines, oral ovarian stimulation agents should not be given to women with unexplained infertility. Rather, it is recommended that in vitro fertilization should be offered to women with unexplained infertility when they have not conceived after 2 years of regular unprotected sexual intercourse. IVF avails for embryo transfer of the appropriate number of embryos to give good chances of pregnancy with minimal risk of multiple birth.
A review of randomized studies came to the result that IVF in couples with a high chance of natural conception, as compared to IUI/ICI with or without ovarian stimulation, was "more" effective in three studies and "less" effective in two studies.
There is no evidence for an increased risk of ovarian hyperstimulation syndrome (OHSS) with IVF when compared with ovarian stimulation combined with IUI.
Prognosis in unexplained infertility depends on many factors, but can roughly be estimated by e.g. the
Hunault model, which takes into account female age, duration of infertility/subfertility, infertility/subfertility being primary or secondary, percentage of motile sperm and being referred by a general practitioner or gynecologist.