December 9, 2012 – 1:47 am
Non invasive and accurate DNA tests are available to help discover the sex of the baby as early as 9 weeks of pregnancy – far earlier than the 18th week ultrasound.
Pregnant and want to know the gender of your baby? Well the good news is that nowadays you no longer need to wait for your ultrasound to find out. Non invasive and accurate DNA tests are available to help discover the sex of the baby as early as 9 weeks of pregnancy – far earlier than the 18th week ultrasound pregnant mothers undergo as part of their prenatal care visits.
What DNA Tests Are Available?
Fetal DNA samples are required to determine the gender of an unborn baby. Collecting the DNA sample required is simple, painless and straightforward. There are currently two methods of sample collection available for a gender test.
The test that has been on the market the longest is a blood-based test. The test is done using a home sample collection kit as it does not actually require a medical blood draw. In fact, the blood required for this test is collected by pricking the finger with a sterile lancet (a needle like instrument) found inside the kit. Once the blood begins to drip, the expectant mother will need to allow it to drop onto a special absorbent paper provided. Once a couple of drops have collected onto the paper, the finger tip can be whipped with a small disinfecting cloth to sanitize the area.
The blood test for baby gender test offers an accuracy of 85-95%. Once in the laboratory, scientists will determine whether there is any male DNA in the sample provided. To be more precise and scientific, they seek to establish whether there are any Y chromosome-specific genetic markers in the blood sample. Any such genetic markers can only be due to a male baby as only males have Y chromosomes.
Baby Gender Testing With Urine
The most recent scientific innovation in the field of gender testing is the urine baby gender test. This DNA test is entirely non-invasive in that, as the name suggests, all that is required is a maternal urine sample. The test is viable starting at the ninth weeks of pregnancy (thus, counting from the first day of the last menstrual cycle) and is 99% accurate. To get a better understanding of how fetal DNA finds its way into the mother’s urine it would help to understand the role of the placental wall – a vital organ which envelopes the unborn baby. It is in fact, via the placenta that fetal DNA gets absorbed into the maternal blood stream.
The placenta, which is attached to the uterus of the mother, is the organ through which oxygen and nutrients are exchanged between mother and baby and where the blood supply of the baby and that of the mother also come into contact with each other. The blood passes through the circulatory system to eventually end up in the kidneys where any fetal DNA passes out along with other waste products in the mother’s urine.
For both blood and urine gender DNA tests, scientists use a DNA replication and amplification method known as polymerase chain reaction. This method allows them to work effectively with very small quantities of DNA.
Disadvantages of Each Test
The main disadvantage of the blood test for baby gender is the discomfort caused by the finger prick. Many people are also put off by the idea. The accuracy of the test is also less when compared with urine.
The disadvantage of the urine test is that it is extremely sensitive to male DNA and thus, the expectant mother is to avoid any intimate contact for at least 72 hours before testing.
Photo: lunar caustic