Daylight Savings Time begins on March 11 in 2018, so this day (for most locations in the U.S.) has only 23 hours.

Could there be other factors (such as seasonal variation in the birth rate) that would invalidate this argument? The U.S. birthrate during April, 1997, was 14.3 births per 1000 on an annual basis. The least rate was 13.9 for November, 2.8% less than April. Since a day with 23 hours is 4.2% shorter than one with 24 hours, it seems plausible that March 11 will achieve the minimum in 2018.