Your Pregnancy Week-by-Week - 3 Weeks Pregnant

3 Weeks Pregnant

Conception and fertilization

This week you've ovulated, and the day you've been waiting for has come: you've conceived! In other words, the soon-to-be-fetus began its miraculous conversion from a solitary cell to a bouncing baby boy or girl. 

The single-cell fertilized egg, or zygote, automatically creates a shield to keep other sperm out until the winning sperm finds its way through the outer layer of the egg. 

Your zygote, though, doesn't remain single for long. It splits into two cells within hours, then four, and so on, until, only a few days after that critical first encounter between sperm and egg, the expanding cluster comprises about 100 cells. The embryo would be created by others, the placenta by others, but for now, T's only one microscopic ball of cells that at the end of this sentence is one-fifth the size of the time.

3 weeks pregnant is how many months?

If you're 3 weeks in, you're in the first month of pregnancy. There are just 8 months to go! 

Implantation

Hello, Tiny? Yeah. Yes. Don't underestimate its potential, though. The blastocyst, as it is now called, as it separates (don't worry, you'll eventually come up with a cuter name), moves from your fallopian tube to your uterus this week, a journey that lasts about five or six days.

It inserts itself in the uterine wall until it appears during week 4 and expands for the next nine months. Congratulations, in other words! You have a baby-in-the-making yourself, ready to begin the amazing ride that ends in your arms. 

Boy or girl?

But is your lone little cell going to miraculously turn into a girl or a boy? While it's going to be months before you can certainly find out, that incredible decision has already been made, believe it or not. 

Pared for a Biology Crash Course? There are 46 chromosomes in the fertilized egg — 23 from you, 23 from Dad. An X chromosome is often supplied by the mother, so either an X or a Y may be given by the father. If an X is borne by the semen that fertilizes your egg, the XX zygote would be a child. If the sperm is Y-bearing, a child would be the XY Zygote.

 

Your Body at Week 3

The corpus luteum and pregnancy hormones

For now, from the outside, it would look that this is happening, but only for the next few weeks. If your timing is accurate and you had intercourse during ovulation, one blessed sperm has fertilized your egg and your body is gearing up to host the blastocyst (which will eventually become your baby!) that is going for the next nine months to the uterus, its house.

But what's going this week indoors? Only after the egg is released, a new occupant, called the corpus luteum, gets the follicle it comes from, a yellowish body of cells that fills the space left by the egg. Progesterone and some estrogen continue to be formed by the corpus luteum, enough of these pregnancy hormones to nourish and sustain the future baby before the placenta takes over in around 10 weeks. 

In the meanwhile, the blastocyst (or soon-to-be embryo) inserts itself in the uterine lining about a week after fertilization and the placenta begins to take form. The cells of the newly developing placenta begin to produce human chorionic gonadotropin within six to 12 days of snuggling into the uterus (around week 4 of pregnancy) (hCG).

During the first trimester before falling in the second, HCG surges tell the ovaries to stop releasing eggs and cause the development of more progesterone and estrogen, which prevent shedding of the lining of the uterus and help placenta formation.

 As you'll see later, in your pregnancy, all these hormones play an important role and induce a whole host of body changes, including signs such as morning sickness. 

Both semen and blood, signs of hCG can be picked up, which is why home pregnancy tests make you pee on a stick and your OB/GYN does a blood check at your first appointment, but you will still not get a positive outcome for another week or two on a pregnancy test.

Pregnancy and sense of smell

Do scents unexpectedly feel better than ever before to you? That might be a hint of you being pregnant! A very real side effect of pregnancy caused by hormones such as estrogen and hCG is an enhanced sense of smell, which magnifies any little wafting around you in the air.

Your keener-than-ever nose might be picking it up, whether it's the food your neighbourhood restaurant is frying up, the trash on the street corner or your husband's cologne down the corridor.

The downside to this new powerhouse of yours? It will help turn up the morning sickness. If that's the case, keep away as far as possible from the kitchen and nearby eateries, make friends with the refrigerator and open the curtains. 

You should also try to wash the clothing more regularly and turn to unscented toiletries. And don't be coy about telling you family and friends to clean up after a workout, after chowing down on the garlicky pasta or onion-loaded burger, to go easy on the perfume and brush their teeth.