Prenatal care visits are there to make sure that the unborn baby is developing healthily and to provide the mother with invaluable advice and tips to follow which will help get all the nourishment needed for her and her baby. Prenatal care is a very important aspect of pregnancy and mothers who do not receive any prenatal care are more likely to give birth to underweight babies and even more likely to die.
Although at least 50% of pregnancies are little accidents, those parents who are actually planning a child are often recommended to undergo preconception genetic health testing and a general health check. The health check is a general assessment of the mother’s state of health. Fathers-to-be will also undergo a preconception test. For men this is much simpler; their sperm count will be taken and a few questions about their medical history will be asked. For mothers-to-be DNA testing during pregnancy may involve urine testing, blood pressure, previous miscarriages, blood count check are just some of the tests she may have to undergo. The prenatal care specialist will also ask a range of questions including:
- Do have a history of any conditions in your family?
- What is your ethnic background?
- Do you take any medication or use any recreational drugs?
- Do you smoke or drink? How often?
- Have you had any operations or been involved in any accidents?
Knowing your baby is going to be born healthy
Most pregnancies are problem-free and the vast majority of children are born in perfect physical and mental health. However, there may be cases where a prenatal care visit might indicate the fetus might have a genetic condition. Some of these conditions, such as Down’s syndrome, might be indicated by an ultrasound (also called a sonogram, diagnostic sonography, and ultrasonography). Some indicators such, such as particular folds and creases in the fetus’s neck, could suggest to the health care provider that the baby might be a Down’s. Once his or her suspicion is roused, they will need to have some further testing done to confirm whether their suspicions were founded. Further testing will actually involve analysis of the fetus’s genetic makeup and thus, access to a sample of the baby’s DNA is vital.
Fetal DNA samples can be extracted in 2 ways
There are 2 main methods which enable the extraction of fetal DNA. The sample collected can be used to determine fetal genetic health or to test for paternity in pregnancy. Chorionic villus sampling is the procedure carried out earlier, feasible at around 10 weeks of pregnancy. Before this time has elapsed, there is a higher chance of injury to the baby’s fingers and toes. Chorionic villus sampling is essentially a type of biopsy (the removal of a piece of tissue) taken from a layer which lines the outer sack which envelopes the developing child and increases the surface area whereby the mother’s blood supply can come into contact. The tissue sample can be taken using either a catheter (inserted through the cervix, the opening to the womb) or by inserting a needle through the abdomen. The needles or catheter are guided into the correct place by ultrasound imagining.
Amniocentesis can be carried out between 15th and 18th of pregnancy. This procedure requires the application of a topical local anesthetic over the mother’s abdomen. To ensure the needle does not injure the baby by coming into contact with it, the OBGYN must be assisted by ultrasound imaging. Once the needle is in the womb, they will proceed to withdraw a small amount amniotic fluid.
Both amniocentesis and CVS can be used to confirm the following diseases:
- Sickle cell disease
- Cystic fibrosis
- Muscular dystrophy
- Tay-Sachs disease
The problem with both these methods of fetal DNA sampling is that they have a 1-2% probability of miscarriage. There are currently studies which are attempting to analyze the fetal DNA in the maternal blood to know the genetic health of the child with 0% risk. This type of sampling from maternal blood is being used successfully to determine the paternity of an unborn child. There is still much research to be done however, when it comes to establishing the baby’s genetic health.
Mark Rogerson is a graduate in forensic science who has received his education in both the US and the UK. Mark has currently taken a backseat in the world of academia and dedicated himself to his two kids. He currently works as a free lance writer from home during his free time. The author normally specializes in writing about genetics and forensic science. More articles by Mark Rogerson can be found by visiting homeDNAdirect South Africa.