On 2014 Feb 14, Bruno Ramalho Carvalho commented:

Since the association between assisted reproductive techniques (ART) and birth defects was firstly raised, controversies have been frequently presented in literature. This is an interesting study, but, in my opinion, no definite conclusions can be taken with current knowledge.

It is a fact: large studies with robust methodologies have suggested that children born after ART have an increased risk of birth defects compared with naturally conceived ones. According to literature, risk of major malformations (conditions that cause functional impairment or require surgical correction) may be increased in up to 40% after IVF/ICSI.

In a recent meta-analysis, Wen et al (2012) compared 124,468 children conceived by ART with spontaneously conceived children, and suggested a significantly increased risk of birth defects in the first group. However, the relative risk (RR=1.37, 95%CI 1.26-1.48) was lower than the suggestion of this study, with no increased risk for ICSI when compared with conventional IVF.

As a matter of fact, the recent evaluation of more than 15,000 children born after ART demonstrated similar birth defect rates comparing with naturally conceived children (Yan et al, 2011). A large population study in Denmark compared congenital abnormality rates among naturally conceived and fertility treatment offspring from subfertile couples, and found no differences in overall prevalence of congenital malformations. Also, this study indicated that parental factors, like increasing time to pregnancy, should be considerably associated with a greater risk of birth defects (Zhu et al, 2006), which is at least plausible and has been proposed by other authors (Seggers et al, 2012).

Finally, mounting evidence suggests that parental infertility may be an important independent risk factor for birth defects. It is noticeable that, in majority of studies, naturally conceiving mothers are significantly younger, more likely to be parous and more ethnically diverse than ART mothers, and attempts to stratify patients according to infertility history or paternal age, for example, are infrequent. Then, as suggested by Basatemur & Sutcliffe (2008), this is why it would not be wrong to consider the risk of birth defects more associated with heredity that with ART themselves.

It would be great to read authors' and other researchers' comments on what I've mentioned above.

On 2014 Feb 14, Bruno Ramalho Carvalho commented:

Since the association between assisted reproductive techniques (ART) and birth defects was firstly raised, controversies have been frequently presented in literature. This is an interesting study, but, in my opinion, no definite conclusions can be taken with current knowledge.

It is a fact: large studies with robust methodologies have suggested that children born after ART have an increased risk of birth defects compared with naturally conceived ones. According to literature, risk of major malformations (conditions that cause functional impairment or require surgical correction) may be increased in up to 40% after IVF/ICSI.

In a recent meta-analysis, Wen et al (2012) compared 124,468 children conceived by ART with spontaneously conceived children, and suggested a significantly increased risk of birth defects in the first group. However, the relative risk (RR=1.37, 95%CI 1.26-1.48) was lower than the suggestion of this study, with no increased risk for ICSI when compared with conventional IVF.

As a matter of fact, the recent evaluation of more than 15,000 children born after ART demonstrated similar birth defect rates comparing with naturally conceived children (Yan et al, 2011). A large population study in Denmark compared congenital abnormality rates among naturally conceived and fertility treatment offspring from subfertile couples, and found no differences in overall prevalence of congenital malformations. Also, this study indicated that parental factors, like increasing time to pregnancy, should be considerably associated with a greater risk of birth defects (Zhu et al, 2006), which is at least plausible and has been proposed by other authors (Seggers et al, 2012).

Finally, mounting evidence suggests that parental infertility may be an important independent risk factor for birth defects. It is noticeable that, in majority of studies, naturally conceiving mothers are significantly younger, more likely to be parous and more ethnically diverse than ART mothers, and attempts to stratify patients according to infertility history or paternal age, for example, are infrequent. Then, as suggested by Basatemur & Sutcliffe (2008), this is why it would not be wrong to consider the risk of birth defects more associated with heredity that with ART themselves.

It would be great to read authors' and other researchers' comments on what I've mentioned above.