Week Description
Around 1 week after conception
(Counting from first day of last menstrual period)
Please keep in mind that each pregnancy is different and the growth rates vary from individual to individual. This information is based on general development. If you have any questions, please check with your gynecologist.
Fetal Development
Several sperms penetrate the egg’s outer layer, however, one miracle sperm will manage to enter the ovum and fertilize it. The chromosomes of mother and father dash about and parts of both begin to form the chromosomes of your baby. At the moment of conception, your baby's gender is determined by the sex chromosomes in the father's sperm.
Multiples: If two eggs released from the ovary (either from the same ovary or one egg from each ovary) and are fertilized by two separate sperms, fraternal twins have been conceived. Fraternal twins can be the same sex or one of each and will look as much alike or as different as any siblings. If the fertilized egg later divides in two, identical twins will develop (or divides into three, identical triplets will develop, etc). As identical multiples originate from one egg, they have the same chromosomal makeup and the same gender, same hair and eye color, blood type, etc.
Maternal Changes
Around the 14th day from the start of your last menstrual cycle, one of the eggs is released from your ovary and is drawn into your fallopian tube where conception occurs.