The home pregnancy testing kit that you just brought home from the drug store has shown a positive result.
You're pregnant.
Now you're wondering when you will begin to have nausea and vomiting.
Because this is your first pregnancy, like many other first time mothers to be you're awaiting its start as Mother Nature's verification of your condition.
Statistically, it should happen soon, but then again, you could be one of the rare few who never experience it.
Yes, there is a minority of women who never experience nausea or any other symptoms normally associated with morning sickness.
Most likely though, you'll fall into the mainstream of women, over two-thirds in fact, who experience morning sickness with the first signs of nausea occurring during the first trimester of their pregnancy.
If you're statistically average, you'll probably experience the first signs of nausea and morning sickness between the fourth and sixth week of your pregnancy, although it is not unheard of to start as late as the tenth week.
You can make a fairly accurate estimate of your start date by adding about six weeks to the date that you started your last menstrual period.
Don't forget that that date is only a statistical probability.
It's no guarantee.
Every pregnant woman reacts uniquely, and each pregnancy is different.
You may begin to experience nausea somewhat earlier than the estimated date, or, as indicated above, you may not experience it at all.
Calculating an estimated date for the beginning of nausea and vomiting can be an entertaining exercise, and may be correct within a liberal range of error.
The fact is, however, that the actual start date depends not upon your calculation, but upon certain changes that are taking place in your body and it chemical and hormonal makeup, as the body tries to adapt to your developing condition.
No one, including the experts, is certain about why morning sickness occurs.
The majority of studies identify changes in the levels of two hormones: progesterone and estrogen, along with other biological and nutritional changes that lower blood sugar levels, raise the level of progesterone in the muscles of the uterus, or cause a negative response to certain vegetable toxins.
Having a history of nausea when taking birth control pills, and showing a tendency toward motion sickness, can also be factors.
Should you turn out to be one of those rare women who never experience nausea or other morning sickness symptoms, ignore the pessimists who insist that morning sickness and nausea are important to ensuring delivery of a healthy child.
Sure, it's true that the lessening of morning sickness symptoms is observed in women who eventually miscarry, no medical evidence supports the claim that the baby's health is in any manner affected by nausea and vomiting or the lack thereof.
The information given above tells you a great deal about nausea and vomiting, but still fails to answer the question of how early the onset of morning sickness and nausea can be expected to occur.
The best answer that anyone can give is that "it depends.
" With the rare exceptions noted above, you are likely to notice the symptoms of morning sickness and nausea early in your first trimester and experience a normal period of annoying nausea - events that you can reminisce about with your children in the distant future.