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What is happening with my baby? Your baby is developing at an astonishing rate. As a matter of fact, this week begins what is known as the "embryonic period" because so much growth and development takes place. The embryonic period lasts from week 4 through week 8. Your baby is about the size of a split pea this week (that's 0.25 inches), and by the end of the week it will be curved into a C shape with a bump on one end that will become the head. In addition to the items explained in detail below, the liver, stomach, intestines, pancreas, gall bladder, and kidneys all begin to develop this week. Arm buds will also form, and by the end of the week, they look like little flippers.
Circulation: Last week we saw how blood vessels begin to form a large S-
Nervous System: As the embryo becomes longer, more somites will appear along the centralized neural tube. The neural tube itself will close this week, and the spinal cord will begin to form in the middle of the tube. The brain will also develop this week, giving rise to the forebrain, midbrain, and hindbrain. The brain will automatically coordinate the development of the senses, as we'll see next.
Senses: Several structures, called sensory placodes, begin to form near the developing brain. Just above the top pair of somites, the lens placodes emerge on the sides of the embryo. In time, this will evolve into the lens of the eye. Nearby, the nasal placodes develop. These will give rise to the nose. Finally, a tiny dimple on either side of the embryo marks the place where the otic placodes are developing. The otic placodes will form the baby's ears.
Pharyngeal Arches: Early in week 4, a series of paired and rounded ridges appear on either side of the neck region of the embryo. By the end of the week, 6 pairs of these pharyngeal arches are present, although only 3 are visible. (The word pharyngeal stems from the word pharynx, which refers to the area in the back of the throat.) These arches have been thought to resemble a fish's gills; however, it should be noted that they do not function as gills. A fish's gills act as a breathing mechanism. Pharyngeal arches, on the other hand, will develop into multiple separate structures. The 1st arch will develop into parts of the upper and lower jaw, the ear, the mouth, the teeth, and the nose. The 2nd arch will help to form the tongue, the neck, the tonsils, and the ear. The 3rd arch will help to form the tongue, the parathyroid gland, the thymus gland, and the neck. The 4th, 5th, and 6th arches will all work together to form parts of the larynx, commonly referred to as the "voicebox," which extends from the back of the throat leading to the lungs, as well as contributing to the parathyroid and thymus glands.
What is happening in my body? It has been 4 weeks since conception, and you are considered 6 weeks LMP by your obstetrician. Last week we learned how the embryo began to form many crucial systems that it will need throughout its life such as the heart and spine. You probably know you're pregnant by now, but if not, you'll make that discovery soon. As growth continues to occur within you, it's common to continue to feel all of the symptoms listed in prior weeks in addition to the following, and as always, every pregnancy is different, so even if you experience none of these symptoms, you are considered completely normal.
Nausea Increases Your nausea might actually increase this week, as hormones climb even higher in your blood stream. Try to take it easy, and use some of the common morning sickness remedies. Keep in mind that morning sickness usually tapers off as you head into the second trimester, and you're already half way there! (Remember that your OB considers you 6 weeks pregnant, since your last menstrual period was 6 weeks ago.)
Tight-
Weight Gain If you aren't too busy with nausea and vomiting, you might have put on a few pounds by now. This is normal, so don't worry about weight gain at this point. Keep in mind that you only need an additional 200 calories/day when you're pregnant (that's an apple a day), so if you've gained several pounds in one week, look back at what you've been eating and try to plan better for the next week. Usually a weight gain of 6 to 11 pounds in the first trimester is considered healthy.
Weight Loss Then again, if you are busy with nausea and vomiting, you might have actually lost a few pounds. This is okay, so long as you are able to hold in some nourishment. The baby will get what it needs from you through whatever you are able to take in, but if you find that you are constantly vomiting, consult your OB. You might have a condition called hyperemesis gravidarum.
Smell and Food Aversions You might find that you are absolutely repulsed by the
thought or smell of a certain food at this time in your pregnancy. This can change
daily for some women. Some even perceive odors that aren't really there -
What should I know about miscarriage? Miscarriage is defined as the loss of a pregnancy before 20 weeks of gestation. It is estimated that between 15 and 20% of pregnancies end in miscarriage, most of them occurring in the first 12 weeks. Miscarriages can be caused by many different things, but at least half are thought to occur because of chromosomal abnormalities in the embryo that happen by chance as cell division takes place. Miscarriages that occur later in pregnancy can be due to the health of the mother, such as infection, diabetes, high blood pressure, problems with the immune system, and abnormalities of the uterus or cervix. Miscarriages are not caused by exercise, sex, working, lifting heavy objects, nausea and vomiting, falling, getting hit, or being frightened, sad, or upset. It is unlikely that the baby will be harmed by any injury to you unless the injury is serious enough to threaten your own life.
Definitions A spontaneous abortion is the medical term for a miscarriage. All of the terms that refer to miscarriage are usually referred to by health care professionals as a type of "abortion," although they should not be confused with elective abortion procedures. A threatened abortion occurs when there is bleeding. The cervix may or may not be dilated upon inspection. A miscarriage will not necessarily happen, but there is a chance that it might. This is a common diagnosis, since any bleeding during pregnancy is usually termed a threatened abortion. An inevitable abortion occurs when there is bleeding, the cervix is dilated, and the membranes surrounding the baby have broken. A miscarriage is certain to occur at this point. An incomplete abortion occurs when a miscarriage has started, but a portion of the placenta remains in the uterus. Bleeding may be heavy, and it will continue until the uterus is empty. A missed abortion occurs when the baby is found to have no heartbeat on ultrasound but has not been passed out of your body. There may be no symptoms or bleeding. A D&C may be necessary to remove the baby in an incomplete or a missed abortion.
What are the symptoms? Almost all miscarriages start with vaginal bleeding. It should be noted, however, that up to 25% of all women have some sort of bleeding during pregnancy. Of this number, about half will have a miscarriage. The bleeding can be very scant or very heavy, and it may start and stop or be continuous. Additional symptoms that can occur are menstrual cramping, abdominal pain, and low backache. However, mild cramps, achiness, or pulling sensations on one or both sides of the abdomen are normal. Any time you have bleeding or severe pain, contact your physician, and if you have already made your physician aware of your bleeding, call back any time the bleeding increases or you begin to have cramps or pains with it.
What can be done? Your doctor will want to do a pelvic examination to see if your cervix has started to open. He or she may also check to see if the membranes surrounding the baby have been ruptured. An ultrasound can be done to determine whether the baby has a heartbeat. If any clots have been passed, your doctor may wish to examine them to see whether it contains tissue from the baby. Many doctors will prescribe pain medication and bedrest for any bleeding that occurs, but there is nothing that can be done once a miscarriage has begun. When due to health concerns that exist in the mother, sometimes a threatened miscarriage can be stopped by treating the underlying condition, for example, bringing down high blood pressure, treating infection, placing a stitch in the cervix, etc.
Week 4
(6 weeks since your last period)
Of Note This Week
How to Tell Someone You’re Pregnant
Get some ideas to help you break this important news to others. (COMING SOON)
Videos of Interest:
Month Two: via Discovery Health
The Embryo Takes Shape: via Nova Online
Embryonic Development: From Nova
