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Pregnancy

Third Trimester

Introduction
Third Trimester Month By Month
Physical Changes and Symptoms

Introduction

The third trimester begins at the 28th week of pregnancy and lasts until birth. This is usually a time of growing excitement and anticipation of the baby's arrival. After all, you are coming down the home stretch!

There is probably much thought about when labor will start and how your delivery will go. A growing sense of tension during this time is understandable, as are worries and fears about whether your baby will be healthy. Like many women during late pregnancy, you may be tired of being pregnant. You may find yourself wishing for the time to pass quickly until the birth so that you can begin to enjoy your new baby.

Third Trimester Month by Month

Seventh Month (Week 28-32)
Your baby is now about 15 inches long and weighs about 2 ¼ to 3 ¾ pounds. The baby exercises by kicking and stretching, and changing position from side to side. You might even be able to see the movement when one of the tiny heels pokes you.

You may gain another 3 or 4 pounds this month, and may also notice some slight swelling in your ankles. A slight amount of swelling is normal. You may feel better if you lie down or prop your feet up during the day.

Eighth Month (Week 33-37)
Your baby has grown to about 17 inches long and weighs about 6 pounds by the end of this month. The eyes are open and the baby changes position in the uterus. This position is maintained until the baby is born. During this month, you may gain 3 to 5 pounds. Continue your daily activities, with rest periods, but stop doing any heavy lifting or work that causes strain.

Ninth Month (Week 38-delivery)
At 40 weeks, the baby is "full-term" and weighs from 6 to 9 pounds. Your baby settles further down into your pelvis and people will say that your baby has "dropped." You may feel more comfortable and your breathing will be easier, although you may need to urinate more frequently. You will be visiting your doctor every week until your baby is born.

It is natural for your thoughts to turn to the plans that need to be made. Now is the time, for instance, to start thinking about whether you will breast feed. You will also need to choose a doctor or other health care provider for your child. You may want to meet with this caregiver before your baby's birth to get acquainted and discuss any questions you might have.

Physical Changes and Symptoms

Like the rest of your pregnancy, you will experience the third trimester in your own unique way. Some of the common signs and symptoms experienced by many women are described in this section, along with potential problems and what to expect during office visits in late pregnancy.

Before pregnancy, your uterus, a small, almost-solid organ, weighed only about 2 ounces (56 grams) and could hold a volume of less than half an ounce (about 15 milliliters). At full- term, it will weigh about 2 1/2 pounds (a little over one kilogram) and will have stretched to hold your baby, the placenta and about a quart (about a liter) of amniotic fluid. Nearly all of the physical symptoms of late pregnancy arise from this increase in the size of the uterus.

Weight Gain
Gaining an adequate amount of weight during pregnancy helps to insure an adequate birth weight for the baby. An infant whose birth weight is 7 to 8 pounds is generally much healthier than one whose weight is 5.5 lbs or less.

Because your baby's birth weight is affected by the amount of weight you gain, you should never try to lose weight during your pregnancy. Get advice from your doctor or nurse if you have questions about how much weight you should gain. With proper eating and exercise, most women return to near their prepregnancy weight at 6 months after delivery if they maintain the same diet and exercise regimen they had before pregnancy. You will usually lose weight more quickly if you breast-feed your baby.

By the end of pregnancy, the "average" woman has gained 25 to 35 pounds (11 to 16 kilograms). How much you gain will depend greatly on your weight before pregnancy. The Institute of Medicine recommends that underweight women gain 28 to 40 pounds (12 1/2 to 18 kilograms), normal-weight women gain 25 to 35 pounds (11 to 16 kilograms) and overweight women gain 15 to 25 pounds (7 to 11 kilograms). During the third trimester, most women gain an average of 11 pounds (about 5 kilograms). Your own weight gain may vary somewhat from this amount yet still be normal.

Shortness of Breath
If you are like many women in late pregnancy, you may be feeling as though you cannot get enough air. This is because your diaphragm - the broad, flat muscle that lies under your lungs - is being pushed up out of its normal place by the expanding uterus. The diaphragm rises about 1 1/2 inches (about 4 centimeters) from its usual position during pregnancy. This may seem like a small amount, but it's enough to decrease your lung capacity (the amount of air your lungs are able to take in). At the same time, the hormone progesterone acts on the respiratory center in the brain, causing you to breathe more deeply. As a result, although your total lung capacity is decreased, the volume of air you are taking in with each breath is actually increased during pregnancy.

Despite your own discomfort, you do not need to worry about your baby. Your expanded respiratory and circulatory systems are providing the baby plenty of oxygen. Your body is now carrying more blood and more oxygen-rich blood. These increases cause the oxygen level in your blood to increase, ensuring an adequate supply to your growing baby.

Improving your posture will help you to breathe better, both during and after pregnancy. Practice sitting and standing with your back straight and your shoulders back, relaxed and down. Aerobic exercise is also beneficial throughout pregnancy because it will improve breathing and lower your pulse rate. , Be careful not to overexert yourself. Consult your doctor about a safe exercise program for late pregnancy. When sleeping, lying propped up on pillows or on your side may help lessen the pressure on your diaphragm.

If none of these measures seem to help, do not be discouraged. Your breathlessness will subside during the last few weeks of pregnancy, when the baby drops farther down into your pelvis and takes the pressure off your diaphragm.

Although mild shortness of breath is common in pregnancy, more severe breathing problems may be a sign of a more serious problem, such as a blood clot in the lung. If you develop severe shortness of breath along with chest pain, discomfort while taking a deep breath, rapid pulse or rapid breathing, contact your doctor right away or go to an emergency room promptly.

Other Minor Discomforts

Hip pain
The increased hormones of pregnancy tend to cause the connective tissue in your body to soften and loosen up. One result is that the joints between the bones of your pelvis become more relaxed. The greater flexibility of these bones makes it easier for the baby to pass through them during birth. Unfortunately, it can also have the added effect of producing hip pain. Hip pain in late pregnancy usually occurs on one side. The changes in your posture, along with lower back pain that result from the heavier uterus can add to your discomfort. Exercises to strengthen your lower back and abdominal muscles may ease hip pain. Warm baths and compresses may also be helpful.

Sciatica
Pain, tingling or numbness running down the buttock, hip and thigh is called sciatica. The pressure of the pregnant uterus on the sciatic nerve can cause sciatica. Two sciatic nerves run from your lower back down your legs to your feet. Sciatic nerve pain during pregnancy is usually not a cause for concern. However, you should still tell your doctor about it because there are other, more rare causes of sciatica that could be more serious. When your baby changes position closer to the time of delivery, sciatic pain is likely to ease. Warm baths, a heating pad and sleeping on the opposite side may help until then.

Vaginal pain
Some women occasionally feel a sharp, stabbing pain inside the vagina during late pregnancy. This is probably linked to the cervix starting to dilate, which can happen weeks, days or hours before labor begins. It is usually nothing to be concerned about, but tell your doctor if it causes a great deal of discomfort. Any severe pain in the lower abdomen or associated vaginal bleeding should be reported to your doctor right away.

Sleeping Problems
As you get closer to delivery, you may find it more difficult to sleep through the night. There could be several reasons for this. One is the size of your abdomen, which may make it seem impossible for you to find a comfortable position. Another is the natural anticipation, or even anxiety, which you may be feeling about your baby's arrival. Insomnia can be troublesome for you, but there is no need to worry about it harming your baby.

As is the case during the second trimester, the best position for sleeping in late pregnancy is on your side, with your legs and knees bent. Lying on your side is better than on your back because it takes pressure off the large vein that carries blood from your legs and feet back to your heart. The side position is also good for taking pressure off your lower back.

Try using a pillow to support your abdomen and another one to support your upper leg. Also try leaning against a bunched-up pillow or rolled-up blanket placed at the small of your back. This can help take some of the pressure off the hip you are lying on. The relaxation exercises you learned in childbirth classes can help you cope with anxiety well before labor begins. If you are feeling restless and anxious at night instead of getting proper sleep, try some of these relaxation techniques to calm your mind and allow your body to rest.

Skin Changes

Itchy abdomen
The stretching and tightening of the skin across your abdomen during late pregnancy tends to leave it dry, making you want to scratch. Do this as little as possible. Keep your abdomen lubricated with a good moisturizing cream to help alleviate the discomfort. You may also want to try an anti-itch cream, such as one with 0.5 percent hydrocortisone in it.

Varicose veins
Varicose veins are more common in women than in men, and they often tend to be inherited. Caused by a weakness in the small veins that carry blood back to the heart, they show up as fine bluish, reddish or purplish lines under the skin, most often on the legs and ankles.

The circulatory changes of pregnancy that are designed to support the growing fetus can produce this unfortunate but common side effect. Varicose veins may surface for the first time or may worsen during late pregnancy, when the uterus exerts greater pressure on the veins in the legs. Varicose veins may cause no symptoms or may be accompanied by mild to severe pain. Measures to help prevent them, keep them from getting worse, or ease their discomforts include the following:

  1. Avoid standing for long periods. Don't sit with your legs crossed. This position can aggravate circulatory problems.
  2. Elevate your legs whenever you can and when sitting, rest them on another chair or a stool.
  3. When lying down, raise your legs and feet on a pillow.
  4. Exercise regularly to improve your overall circulation.
  5. Use specially measured and fitted compression stockings to help improve the circulation in your legs. Ask your healthcare provider to recommend a good brand.

Although varicose veins do not go away by themselves, they generally improve greatly after delivery. In severe cases they can be removed surgically. This procedure is not normally done during pregnancy.

Vascular spiders
Spider nevi, or vascular spiders, usually arise only during pregnancy. Their name comes from the way they look - tiny, red, raised lines that branch out from the center, like a spider. They appear most often on the upper body, face and neck and are due to the effects of hormones on the circulatory system. Unlike varicose veins, spider nevi do not cause pain or discomfort, and they usually go away after delivery.

Stretch marks
The reddish or whitish streaks you may notice on your breasts, abdomen and upper thighs are common to about half of pregnant women. These are known as stretch marks, and women who aren't pregnant also get them.

Stretch marks are not necessarily related to gaining weight. In some women they can be severe even when little weight has been gained during pregnancy. Heredity is thought to play the biggest role in their development. There is no proven treatment for stretch marks. Because they develop from deep within the connective tissue underneath the skin, they cannot be prevented by anything applied externally. Contrary to some beliefs, there are no "miracle" creams or ointments that will make them magically vanish. They will, however, tend to fade slowly after delivery.

PUPPP
The term "PUPPP" refers to a condition called pruritic urticarial papules and plaques of pregnancy. Occurring in about one of every 150 pregnancies, PUPPP is characterized by itchy, reddish, raised patches on the skin. These usually show up first on the abdomen and often spread to the arms and legs. In some women, the itching can be extreme.

Although PUPPP can be quite uncomfortable for the mother, it does not cause a risk for the baby. It is not known for certain what causes PUPPP, but there appears to be a genetic factor involved because it tends to run in families. Unlike so many of the other symptoms of pregnancy, PUPPP does not seem to be linked to increased hormone levels. When it occurs, it is nearly always in first pregnancies, and it rarely recurs in subsequent ones. Treatment of PUPPP consists of oral medications or anti-itching creams that are applied to the skin. Oatmeal baths or baking soda baths may also provide some relief. The rash-like symptoms of PUPPP will go away after delivery.

Hemorrhoids
Hemorrhoids are firm, swollen pouches formed underneath the mucous membranes inside or outside the rectum. A form of varicose veins, hemorrhoids are more common during pregnancy because of increased pressure on the rectal veins. They may occur for the first time or may become more frequent or severe during pregnancy. Bleeding, itching and pain in and around the anus are among the uncomfortable symptoms of hemorrhoids. Although they sometimes require surgical treatment, they usually eventually shrink and go away on their own after delivery.

As with so many other conditions, the best way to deal with hemorrhoids is prevention. If you have had this problem before pregnancy, taking preventive measures is especially important from early pregnancy onward. Avoid becoming constipated by including high-fiber foods, fruit and vegetables and plenty of fluids in your diet. Straining during bowel movements puts pressure on the rectal veins and can cause or aggravate hemorrhoids. To treat hemorrhoids and ease their symptoms, try the following:

  1. Keep the area around your anus clean. Gently wash the area after each bowel movement. This can be done with hygienic witch hazel pads (sold over the counter) or in a warm sitz bath (a shallow basin that fits over the toilet and in which the buttocks and hips are submerged). Use only soft, non-dyed, unscented toilet paper.
  2. Warm soaks - in a tub or a sitz bath - will help shrink hemorrhoids and provide soothing relief. Add an oatmeal bath formula or baking soda to the water to relieve itching.
  3. Apply compresses with an ice pack or hygienic pads.
  4. Avoid sitting for long periods, especially on hard chairs. Consult your doctor before using any over-the-counter remedy for hemorrhoids.

Occasionally, a hemorrhoid may become thrombosed (filled with blood clots). A thrombosed hemorrhoid can be very painful and may require surgical excision to alleviate the pressure.

Leaking Urine
The increased pressure of your pregnant uterus on your bladder may cause you to occasionally leak urine. You may notice this symptom when you laugh, cough or sneeze. It will most likely disappear 3-6 months after delivery.

Try to completely empty your bladder whenever you have the urge to urinate - and do not hold urine in. Frequent emptying will keep your bladder from becoming over-full, which contributes to leakage. Wear panty liners to help keep you dry. Kegel exercises can help strengthen the muscles that control urination. You do these exercises by contracting the muscles of the pelvic floor.

Kegel Exercises:
Tighten the muscles of the pelvic floor as if you are stopping a stream of urine. Try this at frequent intervals for ten seconds at a time, four or five times in a row. Performing these exercises may help cut down on urine leakage.

You can actually feel these muscles contract during urination by stopping the flow of urine. The exercises themselves, however, should not be done regularly during urination, or when the bladder is full - since this practice could train the muscles to behave inappropriately when they are needed to empty the bladder.

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Last Reviewed: Mar 03, 2006

Thomas  A deHoop, MD Thomas A deHoop, MD
Formerly Associate Professor of Clinical Obstetrics and Gynecology
Director, Medical Student Education
No longer associated

Arthur T Ollendorff, MD Arthur T Ollendorff, MD
Associate Professor of Obstetrics and Gynecology
College of Medicine
University of Cincinnati