HOME  •  HEALTH  •  LIBRARY  •  AREAS  •  CENTERS  •  BOARDS  •  CHATS  •  JOIN FREE

Week 20
MDAdvice.com Home > Health Library > Your Pregnancy: Week by Week > Previous Week > Contents > Next Week

How Big Is Your Baby?

At this point in development, the crown-to-rump length is 5.6 to 6.4 inches (14 to 16cm). Your baby weighs about 9 ounces (260g).

How Big Are You?

Congratulationsù20 weeks marks the midpoint. You're halfway through your pregnancy! Remember, the entire pregnancy is 40 weeks from the beginning of your last period if you go full term.

Your uterus is probably just about even with your bellybutton. Your doctor has been watching your growth and the enlargement of your uterus. Growth to this point may have been irregular but usually becomes more regular after the 20th week.

Measuring the Growth of Your Uterus

Your uterus is measured often to keep track of your baby's growth. Your doctor may use his or her fingers and measure by finger breadth, or a measuring tape may be used.

Your doctor needs a point of reference against which to measure your growth. Some doctors measure from your bellybutton. Many measure from the pubic symphysis. The pubic symphysis is the place where the pubic bones meet in the middle-lower part of your abdomen. This bony area is just above your urethra (where urine comes out), 6 to 10 inches (15.2 to 25.4cm) below the bellybutton, depending on how tall you are. It may be felt 1 or 2 inches (2.5 to 5cm) below your pubic hairline.

Measurements are made from the pubic symphysis to the top of the uterus. After 20 weeks of pregnancy, you should grow about 0.4 inch (1cm) each week. If you are 8 inches (20cm) at 20 weeks, at your next visit (4 weeks later), you should measure about 9.6 inches (24cm).

If you measure 11.2 inches (28cm) at this point in pregnancy, you may require further evaluation with ultrasound to determine if you are carrying twins or to see if your due date is correct. If you measure 6 inches (15 to 16cm) at this point, it may be a reason to do further evaluation by ultrasound. Your due date could be wrong, or there may be a concern about intrauterine-growth retardation or some other problem.

Not every doctor measures the same way, and not every woman is the same size. Babies vary in size. If pregnant friends ask, ôHow much did you measure?ö don't worry if their measurements are different. Measurements differ among women and may be different for a woman from one pregnancy to another.

If you see a doctor you don't normally see or if you see a new doctor, you'll probably measure differently. This does not indicate a problem or that someone is measuring incorrectly. It's just that everyone measures a little differently.

Having the same person measure you on a regular basis can be very helpful in following the growth of your baby. Within limits, changing measurements are a sign of fetal well-being and fetal growth. If they appear abnormal, it can be a warning sign.

If you're concerned about your size and the growth of your pregnancy, ask your doctor about it.

How Your Baby Is Growing and Developing

Your Baby's Skin

The skin covering your baby begins growing from two layers. These layers are the epidermis, which is on the surface, and the dermis, which is the deeper layer. By this point in your pregnancy, the epidermis is arranged in four layers. One of these layers contains epidermal ridges, which are responsible for patterns of surfaces on fingertips, palms and soles of the feet. They are genetically determined.

The dermis lies below the epidermis. It forms projections that push upward into the epidermis. Each projection contains a small blood vessel (capillary) or a nerve. This deeper layer also contains large amounts of fat.

When a baby is born, its skin is covered by a white substance that looks like paste. Called vernix, it is secreted by the glands in the skin beginning around 20 weeks of pregnancy. Vernix protects your growing baby's skin from amniotic fluid.

Hair appears at around 12 to 14 weeks of pregnancy. It grows from the epidermis; hair ends (hair papillae) push down into the dermis. Hair is first seen on the fetus on the upper lip and eyebrow. It is usually shed around the time of birth and is replaced by thicker hair from new follicles.

Ultrasound Pictures

The illustration on page 170 shows an ultrasound exam (and an interpretive illustration of the ultrasound) in a pregnant woman at about 20 weeks gestation. An ultrasound is often easier to understand when it is actually being done. The pictures you see are more like motion pictures.

If you look closely at the illustration, it may make sense to you. Read the labels and try to visualize the baby inside the uterus. An ultrasound picture is like looking at a slice of an object. The picture you see is 2-dimensional.

When Margaret had an ultrasound, she was disappointedùit didn't look like a baby to her. If you have an ultrasound exam and don't see everything or it doesn't make sense, don't feel bad. These images are difficult to interpret unless you've had extensive training and experience. Margaret was reassured to see the heart beat and to see her baby move.

An ultrasound done at this point in pregnancy is helpful for confirming or helping to establish your due date. If the ultrasound is done very early or very late (first or last 2 months), the accuracy of dating a pregnancy is not as good. If two or more fetuses are present, they can usually be seen. In many cases, fetal problems can also be seen at this time.

Percutaneous Umbilical Blood Sampling

Percutaneous umbilical blood sampling (PUBS), also called cordocentesis, is a test done on the fetus while it is still developing inside your uterus.

The advantage of the test is that results are available in a few days. The disadvantage is it carries a slightly higher risk of miscarriage than amniocentesis.

Guided by ultrasound, a fine needle is inserted through the mother's abdomen into a tiny vein in the umbilical cord. A small sample of the baby's blood is removed for analysis. PUBS detects blood disorders, infections and Rh-incompatability.

The baby's blood can be checked before birth, and the baby can be given a blood transfusion, if necessary. This procedure can help prevent life-threatening anemia that may develop if the mother is Rh-negative and has antibodies that are destroying her baby's blood.

Changes in You

Increased Vaginal Discharge

During pregnancy it is normal to have an increase in vaginal discharge or vaginal secretions called leukorrhea. This discharge is usually white or yellow and fairly thick. It is not an infection. We believe it is caused by the increased blood flow to the skin and muscles around the vagina, which causes a violet or blue coloration of the vagina. This symptom, visible to your doctor early in pregnancy, is called Chadwick's sign.

You may have to wear sanitary pads if you have a heavy discharge. Avoid wearing pantyhose and nylon underwear; choose underwear with a cotton crotch.

Vaginal infections can and do occur during pregnancy. The discharge that accompanies these infections is often foul-smelling, is yellow or green, and causes irritation or itching around or inside the vagina. If you suffer from any of these symptoms, call your doctor. Many creams and antibiotics that treat vaginal infections can be used safely during pregnancy.

Douching during Pregnancy

Most doctors agree you should not douche during pregnancy. Bulb-syringe douches are definitely out!

Using a douche may cause you to bleed or may cause more serious problems, such as an air embolus. An air embolus results when air gets into your bloodstream from the pressure of the douche. It is rare, but it can cause very serious problems for you.

Abdominal Itching

As your uterus has grown and filled your pelvis, your abdominal skin and muscles have stretched. Itchiness is a fairly natural consequence. Many women complain their abdomen itches with stretched skin. Lotions are OK to use to help reduce itching. Try not to scratch and irritate your skinùthat can make it worse!

Stretching Abdominal Muscles

Your abdominal muscles are also being stretched and pushed apart as your baby grows. Muscles are attached to the lower portion of your ribs and run vertically down to your pelvis. They may separate in the midline. These muscles are called the rectus muscles; when they separate, it is called a diastasis recti.

You will notice the separation most often when you are lying down and you raise your head, tightening abdominal muscles. It will look like there is a bulge in the middle of your abdomen. You might even feel the edge of the muscle on either side of the bulge. It isn't painful and doesn't harm you or your baby. What you feel in the gap between the muscles is the uterus. You may feel the baby's movement more easily here.

If this is your first baby, you may not notice the separation at all. With each pregnancy, separation may be more noticeable. Exercising can strengthen these muscles, but you may still have the bulge or gap.

Following pregnancy, these muscles fall back together. The separation won't be as noticeable, but it may still be present. A girdle probably won't help get rid of the bulge or gap.

How Your Actions Affect Your Baby's Development

Will You Get Varicose Veins?

Varicose veins, also called varicosities or varices, occur to some degree in most pregnant women. There appears to be an inherited predisposition to varicose veins that can be made more severe by pregnancy, increased age and from pressure caused by standing for long periods of time.

Varicose veins are blood vessels that are engorged with blood. They occur primarily in the legs but may also be present in the vulva. The change in blood flow and pressure from the uterus make varices worse, which causes discomfort.

In most instances, varicose veins become more noticeable and more painful as pregnancy progresses. With increasing weight (especially if you spend a lot of time standing), they will get worse.

Symptoms vary. For some, the main symptom is a blemish or purple-blue spot on the legs with little or no discomfort except perhaps in the evening. Other women have bulging veins that require elevation at the end of the day.

Treating Varicose Veins

Many women wear support hose; many types are available. They can be helpful. Wearing clothing that doesn't restrict circulation at the knee or the groin may also help. Spending only a little time on your feet and a lot of time lying on your side or elevating your legs can be beneficial. This enables the veins to drain more easily.

If you have varicose veins in your legs or vulva, stay off your feet as much as possible. Wear flat shoes when you can. When you're sitting down, don't cross your legs, which cuts off circulation and can make problems worse. Following these measures may help keep veins from swelling as much.

Following pregnancy, swelling in the veins should go down, but varicose veins probably won't disappear altogether. Surgery that can get rid of these veins is called vein stripping. It would be unusual to operate on varicose veins during pregnancy, although it is a treatment to consider when you are not pregnant.

You Should also Know

Hearing Your Baby's Heartbeat

It may be possible to hear your baby's heartbeat with a stethoscope at 20 weeks. Before doctors had doppler equipment that enabled them to hear the heartbeat and ultrasound to see the heart beating, a stethoscope helped the listener hear the baby's heartbeat. This usually occurred after quickening for most women.

Listening with a stethoscope gives a different sound than you might be used to hearing at the doctor's office. The sound isn't loud. If you've never listened through a stethoscope, it may be difficult to hear at first. It does get easier as the baby gets larger and sounds are louder.

If you can't hear your baby's heartbeat with a stethoscope, don't worry. It's not always easy for a doctor who does this on a regular basis!

If you hear a swishing sound (baby's heartbeat), you have to differentiate it from a beating sound (mother's heartbeat). A baby's heart beats very rapidly, usually 120 to 160 beats every minute. Your heartbeat or pulse rate is slower, in the range of 60 to 80 beats a minute. Don't be afraid to ask your doctor to help you distinguish the sounds.

Lyme Disease

Lyme disease refers to an infection transmitted to humans by ticks. I am often asked about it. There are several stages of the illness. In about 80% of those bitten, there is a skin lesion with a distinctive look, called a bull's eye. There may be flulike symptoms. After 4 to 6 weeks, symptoms may become more serious.

At the beginning of the illness, blood tests may not diagnose Lyme disease. A blood test done later in the illness can establish the diagnosis.

We know Lyme disease can cross the placenta. At this time, we don't know if it is dangerous to the baby. Researchers are studying it.

Treatment for Lyme disease requires long-term antibiotic therapy and sometimes intravenous antibiotic therapy. Many medications used to treat Lyme disease are safe to use during pregnancy.

Avoid exposure to Lyme disease, if possible. Stay out of areas known to have ticks, especially heavily wooded areas. If you can't avoid these areas, wear long-sleeved shirts, long pants, a hat or scarf, socks and boots or closed shoes. Be sure to check your hair when you come in; ticks often attach themselves there. Also, check your clothing to make sure no ticks remain in folds, cuffs or pockets.

Previous Week > Contents > Next Week

 Home  |  Help  |  Feedback  |  Privacy Policy  |  Register  |  Contact Us  |  Visitor Survey  |  Subscribe to HealthMail  |  Advertising  |  About MDAdvice.com

Copyright © The Online Medical Network Inc. All rights reserved. All material provided by MDAdvice.com is intended for informative purposes only and is not a substitute for professional medical advice. Please consult your physician with any questions or concerns you may have regarding your health. Use of this site indicates your agreement with the Terms of Use.