Your baby this week
3 weeks pregnant

Your pregnancy today

The placenta is already beginning to secrete the hormone human chorionic gonadotrophin (hCG). This hormone prolongs the lifespan of the corpus luteum as well as stimulates production of progesterone.

Drink up

Drink water

Water should be your number one beverage before  and during pregnancy. The human body is mostly composed of water, so consider it a vital nutrient. Drinking plenty of water, that is, a minimum of eight 8-ounce glasses each day, also helps flush your system of toxins.

Nutritionist Martha Belury, PhD, RD notes, "Water is a very important beverage to consume in ample amounts before, during, and after pregnancy." Read more about what to -- and what not to -- eat and drink before and during pregnancy here.

Testing testing

Commercially available pregnancy tests kits may not be accurate on the first day or so after a missed period because of natural variability in ovulation and when developing embryos attach themselves to the lining of the wombs. Attachment occurs roughly nine days after fertilization, but ranges from six to 12 days, Wilcox said. Pregnancy cannot be detected before implantation.

"The interesting thing we were able to look at was how the time of implantation varies among women in relation to their expected menstrual period," he said. "While on average, most people will implant before their expected menstrual cycle, the natural variability is something that doctors and pregnancy kit manufacturers haven't taken into account." Read our article, "Another reason to take a pregnancy test twice," here.

Twin odds

A study has found that the odds of having fraternal twins increases with maternal obesity and for those women who are the top twenty-fifth percentile for height. Women with a pre-pregnancy body mass index (BMI) of 30 or more are significantly more likely to have dizygotic twins (fraternal twins, each formed from a separate egg and sperm) than are women with lower BMIs.

The study also found an interesting relationship between maternal height and increased odds of fraternal twins. Women in the top 25th percentile of height had a significantly increased odds ratio for fraternal-twin pregnancies, although this association was not as strong as that for BMI. These results were reported in the March 2005 issue of medical journal Obstetrics & GynecologyRead more about this fascinating study here.

In the know

Do you know that you might experience a little vaginal bleeding -- but could still have a perfectly healthy pregnancy? It's called implantation bleeding. If you experience vaginal bleeding during the early part of your pregnancy, the first thing you probably feel is fear. There are, however, many reasons you might see blood. Find out about what causes it and if it is something to worry about here!

Keep in mind

Do you qualify for WIC? In the US, the Women, Infants, Children (or WIC, pronounced "wick") program provides low-income pregnant, postpartum and breastfeeding women as well as children under the age of five with supplemental, nutritious foods. They offer food, nutrition counseling along with access to health services to low-income pregnant, breastfeeding, and non-breastfeeding postpartum women, as well as to infants and children up to age five who are found to be at "nutritional risk." The program varies state by state so check with your local department of health for more information.

If money is tight, read here for more tips to make your prenatal care work for you and your personal situation.

Tip: A woman who participates in certain other government benefit programs (such as the Food Stamp Program or Medicaid) automatically meets the income eligibility requirement.

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