When will pregnant women be tested for Rh antibodies?

The article was consulted professionally by Dr. Trinh Thi Thanh Huyen – Obstetrician and Gynecologist – Obstetrics and Gynecology Department – Share99 Hai Phong International Health Hub

All pregnant women should be tested for Rh antibodies. This is one of the first and most important tests in pregnancy to determine whether the body carries the Rh protein in the blood.

1. What are Rh antibodies?

Rhesus (Rh) is a genetic protein found on the surface of red blood cells. If the blood has protein, i.e. rh is positive. If the blood is low in protein, i.e. rh is negative.

Rh yang is the most common blood type in blood groups, about 85% of people have Rh yang, the rest is Rh yin. People with Rhymemia are not a medical condition and it usually does not affect health. However, it can affect pregnancy. Pregnant women with Rh negative need special care and if the fetal Rh case is positive it means that rh incompation between the mother and the baby is also known as blood type disagreement. A baby can inherit the Rh factor from a parent.

If the body has a negative Rh, the blood will be tested for Rh antibodies between the 28th and 29th weeks of pregnancy. If the body does not have Rh antibodies, then immunoglobulin Rh will be injected. This injection is intended to prevent the body from creating antibodies for the rest of the pregnancy.


During pregnancy, if Rh between the mother and the baby is incompated, it will lead to blood type disagreements

2. Why rh antibody tests should be performed during pregnancy

During pregnancy, if Rh between the mother and the baby is incompated, it will lead to blood type disagreements , the mother's blood and the blood of the fetus do not get along during pregnancy. During childbirth or if the pregnant woman has bleeding or abdominal injuries, a small amount of the baby's blood may come into contact with the mother's blood, and the mother's body will produce Rh antibodies after contact with the baby's red blood cells.

The fact that antibodies are produced does not occur only during the first pregnancy, but will likely occur at the next pregnancy. If at the next pregnancy the baby has Rh positive, then these Rh antibodies can pass through the placenta and damage the baby's red blood cells. This can lead to anemia that even causes pregnancy to stop growing, since red blood cells are destroyed faster than the mechanism of change in the baby's body. Red blood cells are important factors for carrying oxygen throughout the body.

If the woman has a negative RH blood type during pregnancy, it is necessary to conduct other blood tests during the first tri tri month of pregnancy, in the 28th week of pregnancy and at birth. If the body of the pregnant woman has not started producing Rh antibodies, it may be necessary to inject a blood product called immunoglobulin Rh. Immunoglobulins work to prevent the body from producing Rh antibodies during pregnancy.

Where the baby is born with rh negative, no additional treatment is required. But if the baby is born with Rh positive then another injection will be needed immediately after birth. If Rh between the mother and the baby is incompative, then the medical staff may recommend an rh immunoglobulin injection because the blood of the mother's body will likely come into contact with the baby's blood in cases such as:

  • abort
  • abort
  • Extra-intracular pregnancy – when fertilized eggs nest somewhere outside the uterus, usually in the ovulation tube
  • Surgical removal of a benign tumor that develops in the uterus
  • Amniotic fluid puncture – a pre-production test in which a sample of fluid that surrounds and protects the baby in the uterus (amniotic fluid) is removed for testing or treatment
  • Spool velvet hair sampling – a pre-production test in which a sample of the wise projections that produce most of the placenta (padded velvet hair) is removed for testing
  • Pre-birth diagnostic test in which a sample of the baby's blood is removed from the umbilical cord for testing
  • Bleeding during pregnancy
  • Abdominal injuries during pregnancy
  • The baby's external manual rotation in the butt position – such as the buttocks before labor
  • Labor

4. Rh antibody tests and interventions based on test results

The Rh antibody test is a blood test during pregnancy and does not harm the fetus as well as the mother's body. It is performed only once and blood samples are usually taken during the first pregnancy examination and sent to the laboratory for analysis.


Rh antibody test does not harm both mother and child

If the pregnant woman is Rh positive, there is no need to conduct any interventions. Since the drug will not work, but instead the doctor will monitor the health of the baby closely because the baby may need a blood transfusion after birth or sometimes even the stage in the womb.

If the Blood Type Rh is negative and the fetus is Rh positive, the pregnant body is capable of creating antibodies that can be harmful during the next pregnancy. If the pregnant woman has vaginal bleeding at any time during pregnancy, contact the medical facility for immediate care. In addition, the pregnant woman should be injected with immunoglobulin Rh around the 28th week of pregnancy and will likely receive one more shot after birth. It should be noted further that the pregnant woman needs to inform the medical staff about rh's condition before labor in order to have timely and accurate interventions.

At Share99 International Health Hub, there is a full maternity service as a solution to help pregnant mothers feel secure because there is a team of doctors throughout the pregnancy. When choosing a full-service maternity, a pregnant woman can:

  • The process of pregnancy is monitored by a team of specialists
  • Regular examination, early detection of abnormalities
  • Package maternity for the convenience of childbirth
  • Infants receive comprehensive care

For direct advice, please click hotline number or register online HERE. In addition, you can register for remote consultation HERE

Source reference: mayoclinic.org, acog.org

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About: Minh Quynh

b1ffdb54307529964874ff53a5c5de33?s=90&d=identicon&r=gI am the author of Share99.net. I had been working in Vinmec International General Hospital for over 10 years. I dedicate my passion on every post in this site.


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