Friday, April 25, 2008

More fertility questions

Q: "Is there anything else to test a husband for if his count is excellent and they're "strong swimmers"?"

A: Basically, no. You would think that evaluation of male fertility would be very straightforward, since the male gametes are readily available for examination, but this is not so. Just because a sperm has a normal shape and is moving doesn't mean it can fertilize an egg. Many tests have been developed to try to answer this question, and while some advanced sperm tests show a correlation with fertilization capacity in research studies, none of them wind up being clinically useful. Here are some male fertility tests that, in my opinion, fall into this category: hamster egg sperm penetration assay, hemizona assay, strict morphology testing, DNA fragmentation studies. I have seen men who have failed these tests but whose sperm could fertilize a human egg without difficulty. I don't think the tests are worth the expense, and they are seldom covered by insurance.

It turns out that a simple semen analysis is about as good as anything for predicting male fertility. If there are more than 20 million motile sperm in a man's ejaculate, he is probably fertile. If there are less than 10 million, he probably isn't.

Q: "I underwent IVF with ICSI at age 35 after trying for my first pregnancy for 2 years. My husband had a slightly abnormal SA that may be from his previous exposure to chemotherapy (you can comment on that if you'd like). They wanted me to have PGD since I was 35. No thanks, I said. Especially since they were charging $4000 out of pocket.... I knew my chances for an abnormality based on our history and I also trusted nature to take care of any abnormalities they could have picked up with PGD, accepting the consequences if nature didnt....

I got pregnant the first attempt and have a wonderful son after a very traumatic pregnancy (threatened miscarriage, chronic abruption, fetal abnormalities). The genetic testing on my son is all completely normal, however, he does have a syndrome, there is just no test for it....

Are there any abnormalities or genetic syndromes related to IVF with ICSI, or with chemo exposure to the dad?"

A: Whether fertility treatment causes birth defects has been debated for many years. People are still arguing about whether clomiphene causes birth defects, even though the drug has been on the market for more than 30 years. The development of in vitro fertilization has renewed interest in this matter. Several studies have shown that children conceived with IVF have a higher incidence of birth defects, but the defect found is not consistent among all the studies. More recently, it was suggested that IVF caused certain "imprinting" disorders by altering methylation of DNA due to culture of the embryos outside of the body. However, a larger study failed to confirm this.

Why all the conflicting results? I think a lot of it has to do with the nature of the IVF patients, and how a control population is chosen for study. Infertile women are different from the general population of pregnant women: they are older, of different ethnicity and socio-economic status, and their infertility problem is often associated with other problems that may affect pregnancy outcome (for example, the association betweeen polycystic ovary syndrome and diabetes). In my opinion, there is no convincing evidence showing that IVF (or clomiphene, or any other fertility treatment) causes birth defects.

There are two exceptions to this. (1) IVF for male factor infertility is more likely to yield a child (if male) that will be infertile himself. (2) The incidence of cystic fibrosis is higher in children of men with congenital absence of the vas deferens who conceive by IVF. In both of these cases, it isn't the fertility procedure that causes the defect, but rather the underlying problem.