December 16, 2009

More Research on Risks of Birth Impairments with Assisted Reproduction

The November issue of the journal Fertility & Sterility includes an article that attempts to determine whether assisted reproductive technology (ART, or AHR for “assisted human reproduction”) may be associated with a higher risk of birth impairments.

The authors reviewed data from records in an Ontario birth database for which information about reproductive assistance was reported, and compared outcomes for the 790 infants conceived via assisted means (including ovulation induction, intra-uterine insemination, in vitro fertilization, and intracytoplasmic sperm injection) to the outcomes of 43,462 infants conceived without assisted methods.

After adjusting for factors such as maternal age and smoking, the authors found that 2.91% of infants conceived by ART were diagnosed with a major birth impairment compared with 1.86% in the control group, with significantly greater odds of all anomalies and cardiovascular and gastrointestinal impairments; risks were highest for the IVF group as compared with other methods examined.

The authors explain that some other research has shown various levels of increased risk, but that it is not clear what might explain the findings. They speculate that “Elements that may contribute to increasing birth defects include the advanced age of one or both partners of the infertile couple, the essential cause of infertility, or the medications used to induce ovulation or to maintain the luteal phase.” They suggest that “The potential risk of anomalies associated with AHR may be considered in the counseling that is offered to infertile couples.”

In November of last year, the CDC released a study on the same topic and concluded, “Infants conceived with Assisted Reproductive Technology (ART) are two to four times more likely to have certain types of birth defects than children conceived naturally, according to a study by the CDC.”

The study found higher risks of some heart defects, cleft lip, and some gastrointestinal impairments associated with ART in singleton births as compared to babies conceived without fertility treatments.

The agency explained, however, that the absolute risk of any birth impairment is low, and provided the following example for context: “In the United States, cleft lip with or without palate affects approximately 1 in every 950 births; doubling the risk among infants conceived by ART would result in approximately 1 in every 425 infants being affected by cleft lip with or without palate.”

Reaching a similar conclusion as the current article, the authors of the CDC study state that “Although the mechanism is not clear, couples considering ART should be informed of all potential risks and benefits.”

A number of other studies have investigated this issue, although the body of literature on the topic has been criticized as being inadequate due to methodologic problems such as “inadequate population sizes, inappropriate control groups, missing adjustments, and unclear descriptions of the methods used to screen malformation,” according to one author.

However, most reviews of the topic seem to come to a similar conclusion: that further research is needed, and what is known should be discussed with those seeking ART so they may make informed choices about potential risks.


2 Responses to “More Research on Risks of Birth Impairments with Assisted Reproduction”

  1. mrs spock Says:

    Much like last year’s research concerning Clomid and uterine cancer, this research tells those of us living with infertility essentially nothing. It does not compare infertile women who conceived spontaneously (such as myself) with couples who conceived using interventions. Infertility encompasses such a wide variety of diagnoses, including male and female factors, genetic factors, recurrent miscarriage, and age-related factors. This study only analyzes the method needed to achieve a pregnancy, not the medical barrier that caused the infertility.

    Until these factors are explored, true risk can not be determined.

  2. Rachel Says:

    Mrs. Spock, you’re right, that seemed to be one major limitation of what is known on this topic right now – just about every paper I looked at said something similar to paragraph 4 above, that they’re detecting it but don’t know if it has more to do with the treatment, the various causes of infertility, etc. We’ll definitely try to keep an eye out for more definitive literature to be published.

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