Week 4 of Pregnancy
Your Baby in Week 4 of Pregnancy
No bigger than a poppy seed, the ball of cells that will develop into your baby has completed its journey from your fallopian tube to your uterus. Once settled in its new home, it will undergo the great divide — splitting into two groups. Half will become your baby (or embryo), while the other half forms the placenta, your baby’s lifeline until delivery. The multilayered embryo then begins to grow into specialized parts of your baby’s body. The inner layer, known as the endoderm, will develop into your baby’s digestive system, liver, and lungs. The middle layer, called the mesoderm, will soon be your baby’s heart, sex organs, bones, kidneys, and muscles. The outer layer, or ectoderm, will eventually form your baby’s nervous system, hair, skin, and eyes.Learn more about your baby this week and development of the embryo and placenta.
Your Body in Week 4 of Pregnancy
While the tiny ball of cells that is your baby begins to undergo its magical transformation into a multilayered embryo, your body is going through a magical transformation of its own — from a reliable buddy to a weird and wacky science experiment. You may start exhibiting early pregnancy symptoms like bloating, cramping, and mood swings that feel similar to premenstrual symptoms. You might also experience implantation bleeding , a common (and harmless) light pink, red, or brown spotting that can occur when the egg settles into your uterus.You might feel a little pressure in your abdomen (nothing to worry about!) and your breasts may feel a little tender and become even bigger (but get ready for more growth spurts!).
Learn more about your pregnant body this week and how the egg implants
Week 4 Pregnancy Tip: Figuring Out Your Due Date
Think you need a Ph.D. in quantum physics to figure out your due date? Doing the math is actually a lot easier than you think (even if you slept through high school algebra): Your estimated due date is 40 weeks from the first day of your last period. Too easy? Here’s the slightly confusing part. If you do give birth on that day, your baby will have clocked in only 38 weeks in utero, not 40. That’s because pregnancy counting begins two weeks before your baby is even conceived (making you about 4 weeks pregnant before you can tell you’re expecting from a pregnancy test). Want to set your watch to that due date — or at least, plan your maternity leave to it? Not so fast. Remember, your estimated due date is just that — an estimate. Most babies are born between 38 and 42 weeks (with babies of first-time moms more likely to arrive on the later side); only a handful actually make their debut right on schedule.
Week 4 Pregnancy Symptoms
Implantation bleeding (possibly): If you find that you’re spotting this week (right around the time that you would have had your period or a little before), don’t be alarmed. This is usually a sign that the embryo has implanted itself into the uterine wall (and that’s good!). Don’t have any spotting at all? Don’t worry, either — only a small percentage of women experience implantation bleeding, so not having this symptom doesn’t mean that you’re not pregnant.
PMS-like symptoms (breast tenderness, bloating, mood swings) that might not go away: Sore, tender boobs? Check. Trouble buttoning your pants? Check. Feeling grumpy one minute, happy the next? Check and check. Early pregnancy symptoms are sort of like PMS symptoms but a little more exaggerated (think PMS on steroids). So your breasts may be tingly, sore, and feel a little full, thanks to the progesterone and estrogen coursing through your system (and getting your breasts ready — yes, even at this early stage — to feed your baby). And what’s up with the bloating? Well, blame progesterone for that one. It’s helping to slow down your digestion to allow more nutrients to enter the bloodstream and reach your baby. You can also blame your roller-coaster moods on hormones (go ahead — they’ll be a convenient excuse for the next nine months!).
Learn more about pregnancy symptoms and solutions.
Week 4 Pregnancy Articles
Think you can’t start your day without that morning cup of joe? Here’s how to cut caffeine during pregnancy and get by without the percolator perks.