Scimitar syndrome patients birth month and surface water pesticide usage

Scimitar syndrome is a rare congenital heart disease. Recently I read of the following research and thought of some possible connection between this disease and surface water pesticide usage in the US.

http://www.sciencedaily.com/releases/2009/03/090330130235.htm
Month Of Conception Linked To Birth Defects In United States

"the researchers found a strong association between the increased number of birth defects in children of women whose last menstrual period occurred in April, May, June or July and elevated levels of nitrates, atrazine and other pesticides in surface water during the same months."

For those that need more academic details, read
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2667895/

So I thought it would be very interesting to see what month a Scimitar syndrome patient was born in. To that end, I set up a poll at Yahoo Scimitar syndrome group (health.groups.yahoo.com/group/scimitarsupport/surveys?id=2263924).

As of today there're 13 data points. (One person told me the child was prematurely born so the actual number of valid points is 12.) The data are as follows

Month - Count of Patients - Percentage
January - 1 - 7%
February - 3 - 23%
March - 1 - 7%
April - 1 - 7%
May - 2 - 15%
June - 0 - 0%
July - 1 - 7%
August - 2 - 15%
September - 0 - 0%
October - 0 - 0%
November - 2 - 15%
December - 0 - 0

I wish I had more data points. But it looks like there's a trend: more scimitar syndrome patients are born early in a year. Let's say it's February. That means the mother's conception time is May. That fits well with the US surface water high pollution period in a year.