Right at the beginning of pregnancy week 3, the sperm is about to meet the egg. When the two meet for the first time, the sperm does all the work trying to break through the tough outer layer of the egg. Once successful, the egg shuts down so no more sperm can make it through. There is a small chance that more than two eggs each get fertilized by two different sperms, or that one fertilized egg and sperm split up, and the result would be twins.
Once conception occurs, the sperm and egg exchange chromosome and DNA information. A combination of 23 pairs of chromosomes from each parent will be required to make up the 46 chromosomes present in baby. Week 3 is also the time when baby’s sex is determined. Dad has two types of sperm in his body – X and Y. Mom always contributes one X chromosome. Dad, on the other hand, is responsible for another X (a girl) or a Y (a boy).
Mom‘s body first ripens the egg and then experiences implantation on average 9 days after ovulation/fertilization. Once implanted, which happens usually in pregnancy week 4 the body immediately takes over as if on autopilot. Hormone levels start to rise and mom may feel some telltale side effects of the new hormone levels. Common pregnancy symptoms include tender breasts, but week 3 is still early so the lack of breast tenderness does not mean baby is not there and growing.
Once the implanted egg is secured in the uterus, the uterus and the cervix will begin prepping for the pregnancy. When the time comes for the next menstrual cycle, the opening of the cervix that once allowed the uterine lining to flush out is now blocked. The uterus will not allow the lining to be shed because pregnancy hormones are already working to grow baby.
Dad has no idea when conception occurs. He does know, however, that he must continue to offer his part of the deal. Regular deposits are probably being made in hopes of conception. Rest assured that after pregnancy is confirmed, dad’s life will change.
Again, mom needs to continue eating well, exercising and taking those prenatal vitamins. The 3rd week of pregnancy is still too early to detect baby in most cases. Home pregnancy tests will not reveal a pregnancy until 3 to 5 days before a missed period — or better yet — 3 to 5 days after a missed period. Patience is key right now so calm down and keep having fun trying.