Goal of non-ART infertility therapy should be to produce a single child.
The goal of infertility treatment is for each patient to have one healthy child at a time, according to a new Practice Committee Opinion from the American Society for Reproductive Medicine (ASRM).
In women who experience oligoovulation or anovulation, ovulation induction is typically offered. For ovulatory women who have unexplained or age-related infertility, the treatment often is controlled ovarian stimulation. Either intervention can lead to ovulation from multiple follicles and, ultimately, increase the risk of multiple gestation.
Multiple gestation increases maternal morbidity and both fetal and neonatal morbidity and mortality. Most of the poor perinatal outcomes relate directly to preterm birth. Treatment of women who have infertility, therefore, requires achieving a balance between two competing needs:
* maximizing the probability of pregnancy
* minimizing the risk of multiple (two fetuses or more) or high-order multiple (more than two fetuses) gestation.
Many multiple births are iatrogenic
Approximately 60% of twin births result from natural conception, 30% from ovulation induction and controlled ovarian stimulation, and 10% from assisted reproductive technologies (ART). For high-order multiple gestation, the figures are 20% for natural conception, 50% for ovulation induction and controlled ovarian stimulation, and 30% for ART. These statistics reveal that a very large percentage of multiple births are iatrogenic, with fertility treatment increasing the risk of twins by a factor of approximately 20 and the risk of high-order multiples by a factor of more than 100. The risk of monozygotic twinning also increases by a factor of 2 or 3 after ovulation induction, compared with natural conception.
Multiple gestation is expensive
The economic costs associated with excess perinatal and maternal morbidity are substantial. They include the immediate costs associated with maternal hospitalization and neonatal intensive care and lifetime costs associated with care for chronic illness, rehabilitation, and special education. Although these costs might be offset by the productivity of individuals, the overall benefit to society is clearly greater when a singleton is born. Personal and familial nonfinancial costs of morbidity and mortality can also be significant.
A sense of urgency on the part of the patient may contribute to an increased risk of multiple gestation by prompting more aggressive treatment. Other contributors include limited health coverage, which creates a personal financial burden, and inadequate patient education about the risks of multiple gestation.
Strategies for limiting the risk of multiple gestation
Appropriate treatment goals are the foundation of risk-reducing strategies. For example, ovulation induction in women who have oligo-ovulation or anovulation should aim toward producing a single oocyte. These women tend to respond to lower dosages of ovarian-stimulation drugs than are typically given. Therefore, women undergoing ovulation induction should receive a lower dosage of gonadotropins and be monitored very carefully for the number of developing follicles and ovarian hyperstimulation syndrome.
In contrast, the goal of controlled ovarian stimulation in ovulatory women who have unexplained or age-related subfertility is to stimulate the development and ovulation of more than one mature follicle to increase cycle fecundity.
Regrettably, efforts have failed to identify estradiol levels and the specific size and number of follicles that prevent multiple gestation. The most likely reason is that follicular size cannot accurately predict the maturity of the oocyte within--follicles as small as 10 mm sometimes yield mature and fertilizable oocytes. Moreover, the population that undergoes ovulation induction or controlled ovarian stimulation is very heterogenous. Therefore, it is not possible to propose valid guidelines to reduce the rate of multiple gestation.
Nevertheless, multiple gestation is sufficiently problematic that we recommend some strategies to reduce its incidence:
* Use low-dosage gonadotropin stimulation with careful monitoring, and limit the number of follicles that are roughly 15 mm or larger to two in patients 37 years of age or younger; three in patient 38 to 40 years old; and more in patients older than 40
* Develop specific cancellation criteria, which should be explained to and accepted by patients undergoing controlled ovarian stimulation. Gonadotropin-releasing hormone (GnRH) antagonists may be of benefit. (1)
* When clomiphene citrate stimulates the development of two or more mature follicles, outcomes do not differ from those obtained with controlled ovarian stimulation using gonadotropins and intrauterine insemination (IUI). (2) Therefore, a reasonable strategy in many patients is to consider initiating treatment with clomiphene citrate and IUI and to proceed directly to in vitro fertilization (IVF) when treatment fails, thereby avoiding controlled ovarian stimulation altogether. (3)
* Pre-ovulatory ultrasonography-guided aspiration of excess follicles to reduce the risk of multiple gestation has potential benefit but needs further study.
Overall, regardless of the medication or regimen employed, it may not be possible to entirely eliminate the risk of multiple gestation associated with ovulation induction or controlled ovarian stimulation.
When to consider gestation reduction
High-order multifetal gestation reduction has been utilized as a strategy to reduce complications associated with ovulation induction and controlled ovarian stimulation, but use of this technology must be regarded as an adverse outcome of infertility treatment. Overall, data suggest that multifetal gestation reduction is associated with a reduced risk of prematurity, although its true benefit is difficult to elucidate due to potential bias in the interpretation of data. A small percentage of patients lose the entire pregnancy, and the procedure can present patients with a profound ethical dilemma and psychological trauma. Thorough counseling is imperative.
Despite feelings of loss and guilt that persist for a year or longer, most patients report that they would make the decision to undergo gestation reduction again if a similar situation arose in the future. (4)
The procedure should be performed only in a specialized center by an experienced practitioner.
WHAT THIS EVIDENCE MEANS FOR PRACTICE
When performing ovulation induction and controlled ovarian stimulation, use the lowest dose of drug necessary to obtain a single mature follicle in anovulatory women, two follicles in young ovulatory women, and three follicles in women 38 to 40 years old. Because of the high risk of multiple gestation associated with controlled ovarian stimulation followed by IUI, consider moving directly to IVF after use of clomiphene citrate and IUI.
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|Title Annotation:||assisted reproductive technologies; UPDATE|
|Date:||Feb 1, 2012|
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