What is chorionic biopsy | Medical tests

Chorionic biopsy

Chorionic biopsy is a diagnostic test that involves taking a sample of placenta in order to scan it for possible genetic diseases and malformations in fetuses that have high risk for them. Its accuracy is very high, and helps parents make the decision to terminate the pregnancy if the fetus is not viable or the illness being treated that their quality of life will be diminished.
The placenta is generated throughout the first weeks of gestation from a first marriage between the embryo and the wall of the uterus. From 10 weeks of pregnancy, as a maximum, this body has already fully developed and we can distinguish different areas; one of them is the Chorion. The Chorion is the part of the placenta coming into direct contact with the wall of the uterus; It is there where is the exchange of nutrients and is the most external part.
The Chorion biopsy is performed between weeks 11 and 13 of pregnancy. You can do before, but the risk of fetal malformation or abortion is not acceptable, and later is not a cost-effective technique, since the results take time and not so advanced pregnancy can be interrupted. It may be done in two ways:

• Transabdominal: abdomen skin punctures made points to pass through the abdominal wall and reach the placenta. There are clamp or a sample of Chorion aims to analyse later under a microscope. The process is guided by ultrasound.
• Transcervical: sample collection is performed through the vagina and cervix. In this case there are punctures made points skin, but the same measures of antisepsis should be maintained to prevent infection in the placenta. Ultrasound is also used to guide the process.

This biopsy allows the study of chromosomal, genetic diseases and other malformations with great precision. The results can be inconclusive or suggest other possible disorders study. Alterations detected by this technique are very variable. Some are diagnostic of malformations and serious illnesses that will not allow the fetus to develop, so the termination of pregnancy would be recommended. Other times it will be minor alterations and interruption of pregnancy is at discretion of prospective parents and the law in force in each country.

When a chorionic biopsy is done

The chorionic biopsy is a test that is recommended to a pregnant in the following situations:
· High risk of chromosome in the embryo diseases calculated by screening that is done to all pregnant women (used ultrasound and analytical parameters).
· Study of molecular or biochemical diseases that, although they do not cause physical malformations, may compromise the life of the fetus outside the womb.
· Children or previous unborn fetuses with genetic diseases.
· Father or mother genetic disorders known.
· Confirmation of pre-implantation studies, i.e., those who perform in fertilized eggs until they are implanted in the uterus.
· Alterations in the growth or development of the foetus detected by ultrasound in the first quarter, even when screening was negative or indeterminate.
Therefore, Chorion biopsy is a diagnostic method of genetic diseases and malformations of the foetus with high accuracy. He is not recommended for use if parents have decided to continue the pregnancy regardless of the result of the test.

Preparation for chorionic biopsy

If you are performing a chorionic biopsy these are the issues that you must take into account:
· Duration: the test will last approximately 30-60 minutes. The biopsy itself lasts 10 minutes maximum, the rest consists of the preparation of the material and the biopsy area.
· Income: the chorionic biopsy can be performed on a query or an aseptic room of cures. Depending on the Center may require hospital admission or not. If your health is good you can go home soon.
· Is necessary to be accompanied?: is recommended to be accompanied. After the test you may be distressed or somewhat dizzy. He is not recommended that you drive or travel alone then.
· Drugs: don't need to take any prior medication. You should tell your doctor all the medicines taken regularly and will decide if we will suspend any. It is important to also inform of allergies to medications or other products, if you have them.
· Food: it is not necessary to remain in fasting prior to testing or after. Take a light meal and avoid taking all day coffee and other exciting substances, including also the day prior to the test. If for any reason it should go on fasting to test the doctor you warn.
· Clothes: you can go with the same clothes every day. When you get to the hospital or doctor's office it is possible that you are given a robe to change you should see fit, although often is enough to discover the part of the body that is to biopsy.
· Documents: it is important to bring with you the steering wheel which shows the performance of this test. The health insurance card is recommended. Normally you will not you any document after the test because it takes time to analyze the results.
· Pregnancy and breast-feeding: is a test that can only be performed during the first trimester of pregnancy.
· Contraindications: should not be performed in pregnancies who have had a previous abortion threat, unless there is no choice but to do. Nor is recommended before the week 11 of pregnancy or after the 13. You should discourage couples that they don't shuffle the possibility of terminating the pregnancy regardless of the result.

How the chorionic biopsy

First your doctor will study if you are a possible candidate to perform you a chorionic biopsy. It will only recommend it when the risk that the embryo has a genetic disease is high according to the screening that is done in the first trimester of pregnancy. If the risk is low is not recommended to perform this test, since it is very likely that everything goes well. To make you test will count with your consent, and will remind you that the result can be both positive and negative, and that you must face that possibility.
You will quote for you Chorion biopsy another different day. When it comes to ask you first of all that you change your clothes and views a comfortable gown for you and for the doctor that perform you the test. He then measured all your vital signs, such as blood pressure, heart rate, respiratory rate and temperature, to check that you are in optimal conditions to put you to the test.
Prepared once you will be asked you to tumbes on a stretcher in a position that facilitates the realization of the test. Normally lying face up with the legs apart, just like when make you a Pap. The first thing that will be an ultrasound done to determine where is the placenta at that time. Then proceed to perform the biopsy via transabdominal or transcervical route.
The most used technique is the transcervical; to do so, the first thing that will will be cleaning the vagina and cervix with antiseptic solutions. Thus eliminate polluting surface germs. They then inserted a very thin and long needle through the cervix to reach the Chorion and a sample. At that time, you will notice a pressure in the lower part of the abdomen (similar to the menstrual pain or discomfort of a PAP), for some women is painful, while others feel only a simple pressure intense.
Once the biopsy gynecologist will withdraw the needle. It is not usual that you bleed, but yes you can stain a little. If you are a woman with blood group Rh negative will be at that moment gamma globulin prophylaxis. Then you remain awhile in observation to check that everything went well. It will not need to wait on the results, since they need to be processed for a time and at first glance not seen no alteration.

The chorionic biopsy complications

All biopsies have risks to be evidence that invade the body organs, albeit slightly. They tend to be infrequent complications and in the majority of cases have easy solutions.
Possible complications are added to the chorionic biopsy during pregnancy, and they can appear during or after the test. Whenever they arise you should go to the emergency room. Some of the more common in chorionic biopsy complications are:
· Bleeding from the biopsy with moderate bleeding point.
· Local infection with fever.
· Abortion (< 1%).
· Uncontrollable pain .
· Drilling of other organs (very unlikely).
· Proved wrong, both positive and negative, that can be done to take attitudes wrong with the pregnancy.

Chorionic biopsy results

The results of the chorionic biopsy may take from 48 hours up to one week. The time of waiting requires patience and tranquility. You should not worry unnecessarily by the final results of the test; It is best that you don't think about it.
Histological, genetic, cellular and molecular analysis will be made on the sample biopsied. Alterations on many levels can be detected in this way. We must remember that detected alterations can be highly variable, from serious disorders that put on a serious commitment to the future baby's life, until others milder affecting deficits. Therapeutic end the doctor will recommend the indication and prospective parents must make the final decision.
All results will be interpreted by the gynecologist and geneticist, if necessary. They may as well explain what happens to the embryo and what options are available according to your experience. One cannot forget that the test is indeterminate in 2% of cases, so it may be necessary to perform more tests, or simply make decisions with the information available. The possibility of terminating the pregnancy must meditate seriously and will only be a viable option in some countries.

Published for educational purposes