Dakota seabolt Prenatal Development Timeline By dakotaseabolt Dec 22, 1994 conception Conception is when the male inserts the sprem and the sprem meats the a egg in side the female Period: Dec 22, 1994 to Mar 23, 1995 First Trimester Dec 23, 1994 Zygpte A ferilized ovum Dec 26, 1994 Embryle Period: Mar 24, 1995 to Jun 22, 1995 2nd Trimester Period: Jun 23, 1995 to Sep 28, 1995 Third Trimester Sep 28, 1995 Birth birth is when a women has a baby and there is a new cheniration in the family