The early months of pregnancy require women to start planning for the birth of their children. It also begins a series of doctor's appointments and tests, such as prenatal tests.
Doctors use prenatal blood tests and ultrasounds to check the baby's development during the first trimester. They obtain blood samples from the mother to measure two chemicals called pregnancy-associated plasma protein A (PAPP-A) and human chorionic gonadotropin (hCG).
During the early months of pregnancy, the placenta produces a protein called PAPP-A, which rises during the first trimester. Abnormally low levels indicate an increased risk of chromosomal abnormalities in the fetus, such as Down syndrome (trisomy 21) and Edwards syndrome (trisomy 18). Typically, the baby receives two copies of each chromosome: one from the father and another from the mother. The baby has three copies of the same chromosome in these abnormalities, leading to developmental problems.
The placenta also produces another hormone, hCG. While hCG levels naturally rise during the first trimester, reaching a peak around weeks 8-10, excessively high or low levels can also indicate a potential risk for chromosomal abnormalities in the baby.
By analyzing the levels of both PAPP-A and hCG, healthcare providers can gain an initial picture of the baby's development. However, the results don't necessarily provide a final diagnosis.
The nuchal translucency (NT) scan is another important prenatal screening test. Regular ultrasounds show the whole baby, but this special ultrasound scan zooms in on the back of the baby's neck. Doctors measure the amount of fluid in this area; its thickness can indicate abnormal development.
Ideally, the measurement should fall within a specific range for the fetus's gestational age. An increased nuchal translucency thickness above the established norm serves as a marker for potential chromosomal abnormalities like Down syndrome or Edwards syndrome. Extra genetic material characterizes these conditions, which can sometimes cause fluid buildup in the nuchal translucency area.
An increased nuchal translucency thickness can also mean a higher risk for heart malformations. While not directly related to chromosomes, these defects can sometimes disrupt normal fluid flow within the fetus, leading to a thicker nuchal translucency.
Nonetheless, increased nuchal translucency thickness doesn't indicate a problem. Several factors, including maternal age and ethnicity, can influence the measurement. To determine an overall risk profile, healthcare providers will consider the NT measurement, blood test results, maternal age, and other relevant medical history.
Moreover, the first-trimester screening only provides a risk estimate for chromosomal abnormalities; an abnormal result doesn't necessarily mean a problem with the baby. However, it does warrant further investigation through diagnostic tests like chorionic villus sampling (CVS) or amniocentesis. These tests are more invasive as they involve sampling fetal tissue, so mothers need to consult their doctors before making the decision to proceed with them.
Further tests can confirm the diagnosis of chromosomal abnormalities. If medical professionals confirm chromosomal abnormality, they will recommend that the parents undergo genetic counseling. The counseling can help parents understand the implications for their baby's health and guide them in making informed decisions about the pregnancy. Knowing about potential challenges allows parents to start planning for a child with special needs. It might involve connecting with support groups and exploring available resources.
Source: scottdinesen
