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The Third Trimester of Pregnancy

Lovely young pregnant woman at home in white room near window

You’re finally ready for the third act — your pregnancy’s final trimester. By now, you’re probably accustomed to having a protruding belly, your morning sickness is long gone, and you’ve come to expect and enjoy the feeling of your baby moving around and kicking inside you. In this trimester, your baby continues to grow, and your practitioner continues to monitor your and your baby’s health. You also begin making preparations for the new arrival, which may mean anything from getting ready to take a leave of absence from your job to taking childbirth classes (or otherwise finding out what to expect during labor and delivery). Third trimester lasts for about 40 weeks. During this time period, you will experience both physically and emotionally challenging.

What Changes Occur in the WOmen’s Body in the Third Trimester?

The fetus spends most of the third trimester growing, adding fat, and continuing to develop various organs, especially the central nervous system. The arms and legs get chubbier, and the skin becomes thicker and smooth.
Events that occur in the third trimester includes:

  • Fetal movements (Movement of the baby)
  • Pregnancy rashes and itches
  • Fatigue
  • Insomnia
  • Hemorrhoids
  • Tender Breasts that may leak watery milk
  • Feeling the baby “drop”
  • Shortness of breath
  • Stretch marks
  • Swelling
  • Varicose veins

Tips to Overcome the Effect of Changes during the Third Trimester

1. Hemorrhoids

Hemorrhoids is a dilated, swollen veins around the rectum, a common problem for pregnant women. The enlarging uterus causes hemorrhoids by pressing on major blood vessels, which leads to pooling of blood, and ultimately makes the veins enlarge and swell. Progesterone relaxes the veins, allowing the swelling to increase. Constipation makes hemorrhoids worse. Straining and pushing hard during bowel movements puts added pressure on the blood vessels, causing them to enlarge and possibly protrude from the rectum.

You can try the following to minimize the effects as:

  • Avoid constipation
  • Exercise
  • Get off your feet when you can
  • Take warm baths two to three times a day
  • Use over-the-counter hemorrhoidal pads (such as Tucks) or witch hazel pads to clean and medicate the area.

2. Insomnia

During the last few months of pregnancy, many women find sleeping difficult. Finding a comfortable position when you’re eight months along isn’t easy. You feel a little like a beached whale. Getting up five times a night to go to the bathroom doesn’t make things any easier.

However, you may find relief in the following:

  • Drink warm milk with honey
  • Exercise during the day
  • Go to bed a little later than usual
  • Limit your liquid intake after 6 p.m
  • Invest in a body pillow
  • Take a warm, relaxing bath before going to bed

3. Swelling

Swelling (also called edema) of the hands and legs is very common in the third trimester. It most often occurs after you’ve been on your feet for a while, but it can happen throughout the day. Swelling tends to be even more common in warm weather.

For ordinary swelling, try the following:

  • Keep your legs elevated whenever possible
  • Stay in a cool environment
  • Wear supportive pantyhose or stockings that aren’t tight around your knees.
  • When in bed, don’t lie flat on your back; try to lie on your side.

4. Varicose Veins

You may notice that a small road map has suddenly appeared on your lower legs (and sometimes the vulvar area). These marks are dilated veins, referred to as varicose veins. Very often, the bluish-purple highways fade after delivery, but sometimes they don’t disappear completely. They’re most often painless, but occasionally they may be associated with discomfort, achiness, or pain.

As varicose veins are hereditary, so you can’t eliminate it because w can’t from hereditary factors. To reduce the severity of varicose veins follows these tips:

  • Avoid standing for prolonged periods of time.
  • Avoid wearing clothes that are very tight around one part of your leg, like socks with tight elastic; which has a tourniquet-like effect.
  • If you must be relatively stationary, move your legs around from time to time to stimulate circulation.
  • Keep your legs elevated whenever you can.
  • Wear support stockings or talk to your doctor about a prescription for special elastic stockings.

Changes in the Third Trimester

The mother-to-be now enters the third trimester. If the fetus is born prematurely, it is now capable of independent life and has a good chance of surviving with special care. Most development now focuses on the maturing of the brain, lungs, and digestive system.

Week 27

From now on, natural differences in the growth rate between male and female fetuses cause boys to be slightly bigger and heavier at birth than girls. This difference is not usually noticeable to the mother while the baby is still in the womb. The fetus is now regularly swallowing, yawning, and making practicebreathing movements. It starts to develop a regular pattern of resting and sleeping that alternates with periods of wakefulness and activity. The protective layer of grease (vernix) covering the skin thickens. This coincides with the kidneys maturing. They start to produce small quantities of urine that pass into the amniotic fluid, and the vernix protects the fetus’s delicate skin from irritation. The eyebrows and eyelashes are growing, and scalp hair is growing longer.


The MRI will show the uterus’s shape helps the fetus into a head-down position, but its position may change frequently.

Week 28

Despite massive fetal growth, there is still plenty of space in the uterus, and the fetus may turn somersaults, spending some time in a head-down position and some time with its head upright. As a result of all this exercise, the mother-to-be may feel kicks in several different parts of her abdomen. Skin creases are becoming visible on the fetal hands, which have taken on a chubby appearance, and the minute fingernails are perfectly formed. Within the upper and lower gums, the teeth buds have now formed separate layers of enamel and dentine. During an antenatal visit, haemoglobin levels in the mother’s blood will be checked to detect signs of anaemia. A glucose tolerance test may also be carried out in order to check for maternal gestational diabetes.


Urinalysis sticks make it easy for healthcare professionals to screen urine for glucose, hidden blood, protein, and infection.

Week 29

The surface of the fetus’s brain is becoming increasingly folded to expand its surface area in order to accommodate the many millions of nerve cells that are being formed. More nerves are
gaining the fatty myelin sheath that helps to insulate them from one another; this speeds up the development of the fetus’s movements. The amniotic sac, which envelops the fetus, and the amniotic fluid it contains are now fully developed. The two layers of the amniotic sac – the inner amnion and the outer chorion – slide over one another to reduce friction as the fetus twists and turns in the womb. Even up to the final weeks of pregnancy, when the fetus has reached its maximum size, the amniotic sac remains amazingly flexible and continues to stretch as the fetus grows.


The enlarging uterus changes the center of gravity and posture, which often leads to back strain and discomfort.

Week 30

The fetus is now beginning to look increasingly rounded, plump, and well-nourished, and over the final 10 weeks of pregnancy, it will double its weight. The fetus now has a regular sleep-wake pattern and spends approximately half the time resting quietly. Women with a Rhesus-negative blood group will receive an injection of anti-D antibodies by the 30th week of pregnancy; another dose is given shortly after the birth. This helps to neutralize an immune response if the mother is carrying a fetus with a Rhesus-positive blood group. It will reduce the chances of the mother producing her own anti-D antibodies, which might cause problems if she becomes pregnant with another Rhesus-positive fetus at some time in the future.


This woman is having her blood tested for anti-Rhesus antibodies, to avert problems in future pregnancies.

Week 31

The fetus’s skeleton has now grown almost to its birth size. As the fetus still has a lot of weight to gain, it looks rather long and thin at this stage. The skin is thickening and now looks pink rather than red because a layer of fat has been building up beneath the surface. The fetus is quite flexible, and there is still room in the amniotic sac for it to bring its feet up towards its head and even to put its toes in its mouth. Due to the cramped conditions in the uterus, the growth of multiple babies now starts to slow down compared with that of singletons, and they will also tend to be born before the due date. Even at this stage, some fetuses are already in the head-down position in preparation for birth, but others will not turn until much closer to the end of pregnancy.


A fetus can bring its feet up to its head with ease. The toes can spread and brace the foot against the uterine wall.

Week 32

The air sacs (alveoli) in the fetus’s lungs are now multiplying rapidly. Although they contain fluid, the fetus has been making practice-breathing movements for the last five months. The movements have been short bursts lasting no more than 10 seconds. Over the next few weeks, the breathing pattern becomes more regular and rhythmic as the fetus builds up towards the 40 breaths per minute it will need to make after birth. The mother-to-be may feel increasingly tired during the last trimester of pregnancy. As well as carrying the additional weight of the fetus, enlarged uterus, and amniotic fluid, her heart has to work harder to pump extra blood round her body. Lying down for regular rests during the day increases blood flow to the fetus and helps both
mother and baby.


Lying down to rest during the day has the added benefit of helping to boost the blood flow through the placenta.

 Week 33

The fetus hears many sounds from his environment. It is aware of its mother’s heartbeat, intestinal rumbles, and breathing, as well as the whoosh of blood, moving through the placenta and umbilical cord. As the brain matures, the fetus remembers and adapts to these sounds and will recognize its own mother’s voice better than anyone else’s. Loud noises may make the fetus startle, and the mother may feel the reaction as a kick. She may start to notice a regular tightening of the uterus, known as Braxton Hicks’ contractions. These practice contractions help to strengthen uterine muscles in preparation for labor. The fetal intestines have now matured to such an extent that they are capable of fully digesting and absorbing the nutrients from milk.

Week 34

The fetus starts to spend less time asleep and is awake and active much longer so that by the time it is born, it is awake for around eight hours out of every twenty-four. The fetus is becoming much more aware of itself and its immediate world, and will often touch its face, grip the umbilical cord, and suck a thumb. Its sucking reflex has become quite strong, and if it is born between now and full-term, it should be able to suckle and feed quite easily. As the fetus puts on weight and grows larger, there is less room to move around within the uterus. As fetal movements are also becoming more co-ordinated, the mother may feel them as joined-up slithers rather than individual kicks. It may feel to the mother as if the fetus is moving more now than previously.

Week 35

The fetal lungs now start to produce surfactant, a substance that allows the air sacs to open more easily. If the fetus were born now, it would be capable of breathing unaided but it will benefit from a few more weeks in the uterus to put on weight and mature fully. The hormone relaxin – produced throughout pregnancy – now has an extra function in helping relax the pubic ligaments and soften the cervix for delivery.

Week 36

The estimated date of delivery is approaching, but only 1 in 20 babies is born on the due date as calculated at the beginning of pregnancy. A birth date that is up to two weeks earlier or two weeks later than calculated is still considered normal. The placenta is becoming less efficient, and monitoring is important to ensure the fetus continues to receive all the nutrition it needs. A number of specialized tests may be offered towards the end of pregnancy, if necessary. They include tests to assess placental function, fetal growth, fetal heart rate, and fetal wellbeing. These tests may be carried out in a hospital ward or outpatient clinic. Examination of the mother’s abdomen will determine whether the fetus is in a head-down position or if a breach presentation is likely.

Week 37

At 37 weeks, fetal development is considered complete, and a singleton fetus is classed as full-term. Around 1 in 10 is born before this milestone and is recorded as premature or “preterm”; the earlier it is born, the more complex and numerous the problems. The fetus’s body now has a good layer of fat and looks healthy and plump. It is ready to be born. Most of the lanugo hair that covered it during early development has been shed into the amniotic fluid and replaced by very fine vellus hair. Fetal movements are increasingly co-ordinated, and the fetus draws its arms and legs in towards his body as space is limited. It has developed a number of primitive reflexes, such as turning towards familiar sounds and strong light that filters into the uterus.

Week 38

What exactly triggers birth when the time is right remains a mystery. Changing hormone levels may be involved but, increasingly, researchers believe the signal to start labor comes from the fetus rather than the mother. The fetus’s flat head bones are not yet fused, so they can slide over one another during birth, molding and elongating the head so it can safely pass through the birth canal. These bones spring back into shape soon after birth. The amount and length of scalp hair vary from fetus to fetus. In some it is scant, and in others profuse. Head hair can be as long as 4cm (11/2in) or more. The fetus’s skin is now thicker and more robust. It has lost most of its greasy vernix coating although some usually remain in vulnerable areas such as skin creases.

Week 39

Many mothers-to-be develop an urge to spring clean, tidy the house, and prepare the nursery. This common phenomenon is known as the nesting instinct. The mother’s breasts are preparing for lactation and have already started to produce colostrum, which is rich in energy, antibodies, and other immune-boosting substances. During the final days of pregnancy, the mother-to-be should take plenty of rest. Some parents already know the sex of their baby, but others will have decided not to find out before birth. Choosing names for the imminent arrival, and talking to him or her, helps with bonding in advance of the birth. If either parent has any outstanding concerns relating to the pregnancy or birth, advice should be sought from a midwife or doctor.

Week 40

The average pregnancy lasts 280 days (40 weeks) from the first day of the last period. Under 1 in 2 babies are still in the uterus at 40 weeks – more than half have been born. Towards the end, the cervix softens in preparation for the birth. It is common to feel backache, building pressure, and period-like pelvic cramps. Regular eating provides energy for labor, and a warm bath or lower-back massage can ease discomfort.

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