Third Trimester of Pregnancy
Written by : Dr.M.D.Mazumdar, MD
The 3rd trimester of pregnancy lasts from the end of the 26th week to the end of the 40th week. By this time, all the major organs of the baby are fully formed and continue to grow and mature.
For you, it will be period where you will have a return of some of the discomforts of the Read more about stretch marks in pregnancy 1st trimester as well as an addition of some new symptoms.
Height of the Uterus
The height of the uterus continues to increase - in the beginning of the third trimester, the uterine height will be at about 1 inch above the upper margin of the bellybutton. At about the 36 week of pregnancy, it will be about 3-4 inches above the bellybutton.
The relation of the height of the uterus to the bellybutton is for a woman of average height. In taller women, the uterine height will appear to be less while in short women, the uterine height may be relatively closer to the breastbone.
But by the end of the 40th week, the height will come down - but the flanks of the abdomen will fill out. This occurs because the baby tends to descend into the pelvic cavity at this time.
The baby moves quite vigorously at the early part of the third trimester. You may feel heavy thuds as she strikes out with her limbs and hits the walls of the uterus. Some movements may be strong enough to cause you some amount of pain.
Some women complain that the movements are stronger at night and they can hardly sleep. But this is usually due to the fact that the woman herself is at rest and is more aware of the movements.
Although the fetus moves a number of times, it is important to note that it has to move a minimum of 10 times in 24 hours. Less than that, and it could signal that the baby is suffering from some amount of distress.
You may have a return of the fatigue that you had in the first trimester. The weight of the uterus and the baby increases to a great extent and you may find yourself exhausted with carrying all that weight around. This is more true if you yourself have put on too much weight or have not taken a nourishing diet or any multivitamin capsules throughout your pregnancy.
Read more about fatigue in pregnancy here ...
Your backache, if you had any may increase. You may feel a dragging sensation in your lower abdomen as the ligaments here get stretched. In women with a poor posture, the curvature of the spine increases, making her walk in the typical 'waddling gait of pregnancy'.
Use of pregnancy support belts, prenatal cradles and maternity belts and girdles will decrease your backache to a great extent.
Read more about backache in pregnancy here ...
Increased Frequency of Passing Urine
The heavy uterus presses on the bladder just in front of it and the capacity of the bladder to hold urine decreases. You may need to go to the bathroom more frequently. Sometimes the urgency may be so great that you may have to rush to the bathroom. You may even find yourself leaking a little urine occasionally, especially when you laugh or sneeze or lift any heavy weight. This is quite normal.
The fetal head also wedges into the lower part of the uterus at this stage and presses on the bladder further increasing the frequency of passing urine.
You may suffer from constipation when the heavy uterus presses back into the rectum. Progesterone can also decrease the movement of your gut, contributing to constipation. Use of soluble fibres like Psyllium Husk capsules will decrease your constipation to some extent.
Read more about constipation in pregnancy here ...
Breathlessness can occur due to pressure of the uterus against the diaphragm - a tough sheet of muscle between the abdomen adn the chest wall. This pressure decreases the space inside the chest, preventing the lungs from expanding fully. The feeling may be worse while sleeping at night. You may need to sleep propped up on pillows for comfort. Short women suffer from more breathlessness than taller women.
The breasts will continue to increase in size. In the later weeks of pregnancy, there may be leakage of a thin yellowish, sticky, fluid frrom the breasts known as colostrum. This is normal and a sign that the breasts are getting ready for feeding the baby.
Read more about sore breasts in pregnancy here ...
The feeling of fullness in your stomach may make you feel unable to eat as much as you would have liked although you feel hungry. This is because of the pressure of the uterus over the stomach.
Edema over the ankles and feet may occur due to pressure over the veins returning blood from your legs.
Varicose veins are thick tortuous veins with stagnant blood and may appear not only on the ankles and legs but also around the vulva. Hemorrhoids, which are actually varicose vains around the anus, may also occur. You may need to wear support stockings to decrease the severity of the varicose veins and oedema over your ankles and feet.
Read more about varicose veins in pregnancy here ...
Chloasma of Pregnancy
Some women develop pigmentation over their nose and upper cheeks that have a typical butterfly shaped appearance. This usually decreases after delivery but may need specialized treatments like microdermabrasion or chemical peeling of the skin for complete removal.
About 2 weeks before childbirth, you may feel your abdomen becoming lighter. This is because the head of the baby moves deeper into the pelvis and there is a decrease of the pressure symptoms in the upper abdomen. This is more true of taller women.
Your doctor will measure the height of the uterus as before. At term, she will find the uterus occupying almost the whole of the abdomen.
Stretch Marks, if any, are more silverish than purple although a few recently formed purple or pink stria may be seen. (Read more about stretch marks in pregnancy here ...)
Foetal parts and movement are felt freely. If you lie down on the bed with knees flexed, you can palpate the back of the baby on one side of the abdomen as a smooth firm oval surface. On the other side of your abdomen, you will feel a number of small knob - ike structures that move when you press on them. These are the baby's limbs.
The FHS is heard clearly over the back of the baby, on one side of the abdomen. In a cephalic presentation (when the foetus is in a head down position), the FHS can be heard on one side of the abdomen, below the umbilicus. In a breech presentation (when the baby has her head up and buttocks down), the FHS is heard to one side of the umbilicus or above it.
Regular and intermittent contractions of the uterus (Braxton Hicks Sign or contraction) occurs towards the later part of this stage of pregnancy. If you are pregnant for the first time, you may mistake these for labor contractions.
But these contractions are painless, while labour contractions are painful, and gradually increases in intensity and duration.
- Complications in Labor
- Vulvar Hematoma
- Condoms, Pills IUDs etc.
- Sexually Transmitted Disease