18 Week Ultrasound

You are now on a halfway through your pregnancy. There are many changes in your baby’s development. If you didn’t have an obstetric ultrasound yet, now is the time to do it. Besides an ultrasound, you should do some of the blood tests to be sure your baby is developing healthily. Your baby’s health is not the only thing you have to care about. Your health is just as important too. So, it is the time to start with the new daily program, which includes new activities.

Your Baby’s Development

Your baby’s length is now about 14 cm from crown to rump, and his/her weight is about 190 g. The head of your baby is more in proportion with his body. His ears are establishing their function so your baby can hear your heartbeat, breath, or even recognize your voice. Your baby can also react to sounds in your environment, so you can be aware of this. His/her little eyes are still closed, but he/she can twitch the muscles around the eyes, while retina in his/her eyes becomes sensitive. The limbs are well developed and formed, therefore, your baby can kick, flex and move around and you can feel it as well. His/her nervous system is maturing. Ossification continues so the bones are getting harder. Major organs in his abdomen and chest are developed physically as well as their function. Any irregularity in the heart rates and rhythm of the heartbeat can be a sign of some malformation. In that case, your doctor will recommend some more specific tests to explore your baby’s health state. Your baby’s sleep cycle is being established which doesn’t have to be necessary congruent with yours. Sex organs of your baby are developed. Under girl´s pelvis is a womb, fallopian tubes, and vagina in place, as well as the boy´s penis, which is distinctive, while his testicles start to descend to his scrotum.

Ultrasound At 18th Week of Pregnancy

Transabdominal ultrasound is a good choice of ultrasound for this week since your baby is large enough so that your doctor can inspect his performance well through your stomach area. Your uterus is above the pelvic cavum; therefore, there are no obstacles for ultrasound waves. This is another reason for a good view via transabdominal ultrasound.

The procedure is simple. You have to drink 2 cups of water about half an hour before the examination. During the examination, you will lay on a bed and your doctor will apply a little bit of a gel on your stomach. The doctor will then move the device (transducer) crossover your stomach while explaining at the same time what is that you see on the screen of an ultrasound apparatus.

Your doctor will measure your baby’s growth. This means the length from the head to the bottom (about 15 cm), the length of baby´s femur (about 28 mm), the head circumference (about 150 mm), the abdominal circumference (about 130 mm), the baby´s weight (about 200 g) and a rate of a heartbeat (between 120-160 bpm). Ultrasound will show you the symmetry of baby´s kidneys and eyes, as well as some other steam organs and parts of the body. It also provides additional information such as:

  • Confirmation of the delivery date;
  • The appearance of the cervix;
  • The position of the placenta and amount of fluid around the fetus;
  • The number and age of fetuses.

If abnormalities are detected, you may need to have other tests.

Additional Tests


It is an aggressive procedure in which the doctor inserts a needle into the abdomen. He needs to get a small amount of amniotic fluid for analysis. Amniotic fluid contains cells and proteins from the fetus which allows us to see if there are chromosomal abnormalities such as Down syndrome. It can test the sex of the baby too. Before the procedure, the doctor may give you a local anesthetic where the needle is going to be inserted, and you can feel mild abdominal discomfort after the test. The risk of miscarriage is about 1 in every 300 women. So, if you’re having prolonged leaking of amniotic fluid after the procedure, or any kind of bleeding, you must go your doctor. Although amniocentesis isn’t a common procedure, it is recommended if your doctor estimates that you are in a risk group.  Amniocentesis is one of the most accurate tests in medicine. Its accuracy is more than 99%.

Chorionic Villous Sampling

This is a procedure also being used to test chromosomal abnormalities such as Down syndrome, as well as the sex of the baby. Chorionic villous sampling can be done at earlier stages of pregnancy. The sample can be taken through the cervix or the stomach using a needle. Your doctor prepares you for the procedure by giving some medications. It will minimize cramp or discomfort during the procedure. Chorionic villous sampling has all the beneficences as well as amniocentesis, but it has a higher risk of complications.

The Multiple Blood Markers

The period between 16th to 18th is an ideal time for blood test named The Multiple Markers Test. Using the sample of your blood doctor can detect:

  • Down syndrome,
  • Open neural tube defects,
  • Defects in the abdominal wall of the fetus,
  • Other chromosomal abnormalities.

It is also called Maternal Serum AFP (MSAFP).

Changes of Your Body

You may feel slightly off balance because your uterus lies just south of your navel and as it grows, it shifts your center of gravity. Your posture is changed by hormone relaxin, which loosens your joints so you can feel it like a load in your lower back. Ligaments are stretching to support the growing weight of your womb. Therefore, you can feel sharp pains running from the top of your uterus down to your pubic bone. There is no reason for panic since this is a normal activity during this period.

Your breasts are extended in size, so you will need a size plus of your bra. It is important to take care of your nipples, as well as the skin all over the body since now is the time when the first stretch marks can occur. If the results of the tests are fine, you can enjoy the changes in your body, because this is a sign of your baby’s well growth.

Changes to Your Daily Program

If you aren’t already working out, it isn’t too late to start. Exercise will minimize anxiety, stress load, and tone your abdominal muscles. Walking, swimming or prenatal yoga may be your best choice. But, before you start, consult your doctor first. Your weight is increasing so you will need much more rest than before, so afternoon napping will become a part of your new daily program. Your skin is stretching out; therefore, it needs more care than before. Everyday care with oil or body milk, for preventing stretch marks, will become your daily ritual. The breasts should have a special attention. You need a comfortable bra, and some lotion for the care of your nipples because your breasts are getting larger every day.  So, as you can see, the period of intensive self-caring has started.


Please enter your comment!
Please enter your name here