Fetal Karyotyping

Despite the advances in serum screening, fetal karyotyping continues to be gold standard in serum screening.

The detection of trisomy 18 and trisomy 21 is an important aspect of prenatal screening for chromosomal abnormalities. Trisomy 18, also known as Edwards syndrome, and trisomy 21, commonly referred to as Down syndrome, are genetic conditions that result from the presence of an extra chromosome in the affected individual. While these conditions can vary in severity, they often lead to physical and intellectual disabilities.

The triple-marker screen provides better sensitivity. The risk of fetal trisomies increases with increasing maternal age.

Sex chromosomes aneuploidies ( 47,XXY and 47,XXX ) also occur at an increased rate in women 35 years of age and older. The risk is approximately 1 in 200. At age 40 the risk is 1 in 20.

When it comes to screening for these conditions, the triple-marker screen is commonly used. This test measures the levels of three substances in the mother's blood: alpha-fetoprotein (AFP), human chorionic gonadotropin (hCG), and estriol. By analyzing these levels, the test provides information about the likelihood of a fetus having trisomy 18 or trisomy 21. The triple-marker screen is considered to be more sensitive in detecting these conditions compared to other screening methods.

It's important to note that the risk of fetal trisomies increases with increasing maternal age. At the age of 35, the risk of having a baby with a trisomy is approximately 1 in 200. This risk further increases to 1 in 20 for women who are 40 years old. This association between maternal age and trisomy risk is well-established and forms the basis for many prenatal screening programs. Additionally, sex chromosome aneuploidies, such as 47,XXY and 47,XXX, also occur more frequently in women who are 35 years of age or older.

Although the triple-marker screen provides valuable information, it is important to understand that fetal karyotyping remains the gold standard in serum screening. Fetal karyotyping involves the analysis of the fetus's chromosomes to accurately determine if there are any abnormalities, including trisomies. This diagnostic test is typically performed through procedures such as amniocentesis or chorionic villus sampling. While it is a more invasive procedure compared to serum screening, fetal karyotyping provides definitive results and allows for informed decision-making for the parents-to-be.

Prenatal Diagnosis of genetic diseases for the following patients;

1. Maternal age 35 years or above
2. Previous chromosomally abnormal child
3. Three or more spontaneous abortions
4. Patient or husband with chromosomes anomaly
5. Family history of chromosome anomaly
6. Possible female carrier of X-linked disease
7. Metabolic disease risk (previous family history)
8. NTD risk
9. Positive second-trimester maternal serum screen

Amniocentesis



Amniocentesis is carried out from 12 to 17 weeks of gestation. The underlying risk is miscarriage estimated 1 in 200.

Amniocentesis is a medical procedure that is typically carried out between 12 to 17 weeks of gestation. It involves the removal of a small amount of amniotic fluid from the sac surrounding the fetus. This fluid contains cells from the baby that can provide valuable information about its health and development. The main purpose of amniocentesis is to diagnose genetic and chromosomal disorders, such as Down syndrome, cystic fibrosis, and sickle cell anemia, among others. By analyzing the cells in the amniotic fluid, doctors can determine whether the baby is at risk of having any of these conditions. This information can help parents make informed decisions about their pregnancy and allow them to prepare for any potential challenges that may lie ahead. While amniocentesis can provide valuable information, it is important to consider the underlying risk of miscarriage. The estimated risk of miscarriage associated with amniocentesis is 1 in 200. This risk may seem small, but it is crucial for expectant parents to understand and weigh the potential benefits against the risks involved before deciding to undergo the procedure.

It is important to note that the decision to undergo amniocentesis is a personal one and should be made after careful consideration and discussion with healthcare professionals. While the procedure can provide valuable information about the baby's health, it is not without risks. Miscarriage is the most significant risk associated with amniocentesis, but it is not the only one. There is also a small risk of infection, leakage of amniotic fluid, and injury to the fetus during the procedure. It is essential for expectant parents to have a clear understanding of these risks and to feel fully informed before making a decision. Doctors will often provide detailed counseling to parents, discussing the benefits and risks of the procedure and helping them make an informed choice. It is essential for parents to ask questions, share their concerns, and ensure that they have all the information they need to make the right decision for themselves and their baby.

While the risk of miscarriage associated with amniocentesis may seem daunting, it is important to keep in mind that the majority of procedures are successful without any complications. Advances in medical technology and the expertise of healthcare professionals have greatly reduced the risk of complications over the years. Additionally, it is essential to consider the potential benefits of amniocentesis. For parents who have a higher risk of having a baby with a genetic or chromosomal disorder, the information provided by amniocentesis can be invaluable. It can help them make informed decisions about their pregnancy, seek appropriate medical care, and prepare for any challenges that may arise. Ultimately, the decision to undergo amniocentesis is a personal one, and it is essential for expectant parents to weigh the potential benefits against the risks and make a decision that feels right for them.