Kenophobia (Fear of Empty Spaces): Causes, Symptoms & Treatments
Tests To Reduce The Risk Of Having A Child With Down Syndrome
Diagnostic tests provide a definite diagnosis of Down syndrome The chances of having a baby with Down Syndrome increases with increasing maternal age. What can be done to reduce the risk of down syndrome in babies? Dr Anurag Gupta answers the question here.At present there is no definitive cure for Down syndrome. However, an early detection and management of the affected individual by a multidisciplinary team can help reduce symptoms and improve the quality of life. Though the life expectancy of patients with Down syndrome has improved significantly due to advances in the medical field and improvised surgical techniques for correction of congenital disabilities, prevention is always a better approach than cure, says Dr Anurag Gupta, Consultant Molecular Pathologist and Head Cytogenetics, Ampath, Hyderabad.
In an exclusive interview with TheHealthSite, Dr Gupta, talked about some tests that can reduce the risk of having a child with Down syndrome and help going to be parents make informed decisions.
First, let's understand Down SyndromeThe expert explains: Down syndrome is a genetic disorder caused by the presence of an extra copy chromosome 21. It is the most common chromosomal abnormality affecting human beings with an incidence of about 1 in every 700 to 800 births. Clinical features of Down Syndrome were first described by John Langdon Down way back in 1866 however, gain of chromosome 21 as a cause was identified in 1959 by Dr. Jerome Lejeune. Chances of Down Syndrome increases with increasing maternal age. These patients present with varying degree of growth retardation, characteristic facial features, mild to moderate intellectual disability and abnormalities affecting heart, gastrointestinal tract and other organ systems including high risk of developing leukemia.
Tests to identify if your child is at risk of Down SyndromeIf you're pregnant or planning to conceive, Dr Gupta suggests a few tests that can help identify if your child is at risk of Down syndrome.
Screening TestsScreening tests are non-invasive tests that can help identify if a foetus is at risk of Down syndrome. These tests do not provide a definite diagnosis but can indicate if further diagnostic testing is needed. All abnormal screen tests should be confirmed by diagnostic tests before a making any actionable clinical decision. The most common screening tests for Down syndrome are:
First-Trimester Combined Screening: This test is also popularly known as "Double marker test" as it involves a blood test and an ultrasound. This is performed between 11-14 weeks of pregnancy. The blood test measures the levels of two hormones namely pregnancy-associated plasma protein A (PAPP-A) and free beta-human chorionic gonadotrophin (beta-hCG). An ultrasound is done to assess the thickness of the fluid-filled space at the back of the baby's neck, "the nuchal translucency". The thickness of the nuchal translucency on ultrasound scan and hormone levels along with the maternal age are taken into consideration to calculate a risk of Down syndrome. The report of this test describes the risk as "low", "intermediate" and "high".
Second-Trimester Quad Screen aka Quadruple marker test: This test is performed in the second trimester between 15-20 weeks of pregnancy and indicates risk of Down syndrome in the developing foetus. The test measures the levels of four hormones: alpha-fetoprotein (AFP) which originates from the developing foetus, -human chorionic gonadotropin (hCG) and inhibin-A of placental origin and unconjugated estriol from both the placental and foetal liver origin. The results of these blood tests are combined with maternal age and weight, ethnic background and gestational age of the foetus, to arrive at the risk of having a foetus with Down syndrome. When Inhibin A is not done, the test is called as a triple screen or triple marker test.
Non-Invasive Prenatal Testing (NIPT): Non-Invasive Prenatal Testing (NIPT) is based on analysis of cell free foetal DNA that is present in the maternal blood. It is the most sensitive and specific screening test for the common foetal aneuploidies including Down syndrome and can detect presence of other chromosomal abnormalities. It can be performed as early as 10 weeks of gestation. NIPT is usually recommended for women who are at high risk of having a baby with Down syndrome, such as women who are over 35 years old or who have had a previous child with Down syndrome. However, as per the latest recommendations of American college of Obstetrics and Gynaecology, ACOG, prenatal testing options should be discussed and offered to all pregnant patients regardless of maternal age or risk of chromosomal abnormality. Despite being very accurate, it has the potential for false-positive and false-negative results, therefore all abnormal results should be confirmed with one of the invasive but diagnostic tests.
Diagnostic TestsDiagnostic tests provide a definite diagnosis of Down syndrome and are recommended if the screening tests indicate an increased risk of Down syndrome. These tests are invasive and are associated with relatively increased risk to the foetus as they involve obtaining tissues of foetal origin for genetic testing to look for extra copy of chromosome 21 which is diagnostic of Down Syndrome. Identification of extra copy of chromosome 21 can be done either by conventional karyotyping, a procedure that allows visualization of all the chromosomes of a cell simultaneously thereby enumerating them and characterising copy number for chromosome 21 or by Fluorescence in situ hybridization (FISH) that uses small sequences of DNA tagged with a fluorescent dye specifically targeting chromosome 21 or using Polymerase chain reaction (PCR) for chromosome 21. Though FISH/ PCR are relatively rapid compared to conventional karyotyping, analysis of the foetal genome using both karyotyping and FISH or PCR is recommended.
Diagnostic tests for Down syndrome
According to Dr Gupta, the two most common diagnostic tests for Down syndrome are:
Amniocentesis: Amniocentesis is usually performed between 15-20 weeks of pregnancy. This test involves the ultrasound guided insertion of a thin long needle through the abdomen and into the uterus to collect a sample of the amniotic fluid, a procedure called amniocentesis. The amniotic fluid is a fluid that is present all around the foetus in the amniotic sac. Besides serving as a reservoir of fluid and a source of nutrients, proteins, electrolytes, immunoglobulins, and vitamins for the developing foetus it also contains cells of foetal origin called amniocytes. These amniocytes are collected during amniocentesis and cultured to obtain and analyse baby's chromosomes. In experienced hands the risk of foetal loss after amniocentesis is around 0.11 per cent.
Chorionic Villus Sampling (CVS): CVS can be performed as early as 10-13 weeks of gestation. This test is also performed under ultrasound guidance. It involves the insertion of a needle through the abdomen or cervix to collect a sample of the chorionic villi (tiny finger-like projections on the placenta). The chorionic villi contain cells from the baby that are cultured in sterile media and are used to analyze the baby's chromosomes. Just like for amniotic fluid, the CVS sample is subjected to conventional karyotyping and FISH/ PCR to confirm or refute the diagnosis of Down syndrome. Being invasive, studies indicate a total foetal loss of 0.7 percent within 14 days using a transabdominal approach, 1.3 percent within 30 days, and 2 percent for loss anytime during pregnancy.
Risks and benefits of these testsDr Gupta says, "Screening tests carry absolutely no risk to foetal loss and can help identify risk of Down syndrome in an ongoing pregnancy, while diagnostic tests can provide a definite diagnosis. Non-Invasive Prenatal Testing (NIPT) is a relatively new test that is very safe with high sensitivity for risk of Down syndrome as well as other aneuploidies from a simple blood test."
All female during their ante-natal check-up should be offered screening tests for aneuploidy screening and it is important for couples to discuss the risks and benefits of these tests with their healthcare providers, he concludes.
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First Trimester Tests During Pregnancy
Routine tests help keep close tabs on you and your baby. That's why it's so important to keep all your prenatal appointments. Screening tests can spot potential problems early.
These tests usually include:
History and physical exam. During your first or second prenatal visit, you'll answer a lot of questions about your health and family history. This information helps the doctor know whether you have any specific risks to address, such as an inherited genetic disorder. You will also have a physical exam. Your doctor will calculate your due date based on the date of your last menstrual period.
Pelvic exam and Pap smear. Prenatal testing during the first trimester begins with a pelvic exam and Pap smear to check the health of your cervical cells. This testing screens for cervical cancer and for certain sexually transmitted diseases (STDs).
Blood tests. During one of your first visits, your doctor or midwife will identify your blood type and Rh (rhesus) factor, screen for anemia, check for immunity to rubella (German measles), and test for hepatitis B, syphilis, and HIV and other STDs.
Depending on racial, ethnic, or family background, you may be offered tests and genetic counseling to assess risks for diseases such as Tay-Sachs, cystic fibrosis, and sickle cell anemia (if these weren't done at a preconception visit). Testing for some of these diseases can also be done with saliva.
You might be tested for exposure to diseases such as toxoplasmosis and varicella (the virus that causes chickenpox. Your health care provider may also want to check your levels of hCG, a hormone secreted by the placenta, and progesterone, a hormone that helps maintain the pregnancy.
Urine tests. You will also be asked early on for a urine sample so that your doctor or midwife can look for signs of kidney infection and, if necessary, can confirm your pregnancy by measuring the hCG level. (A blood hCG test to confirm pregnancy may be used instead.) Urine samples will be collected regularly to spot glucose (a sign of diabetes) and protein, which could show preeclampsia, a pregnancy-induced disease marked by high blood pressure. This is a disease more likely to occur after 20 weeks, although protein may be present early if there is chronic kidney disease.
In the later part of the first trimester you will be offered genetic testing. Some people feel like these tests may cause them undue stress, and they prefer to make sure the baby is genetically normal after delivery. Others want all the testing they can get, realizing that these tests sometimes are not 100% accurate. Talk with your doctor or with a genetic counselor about the pros and the cons before you decide. There are different genetic testing options that involve blood tests alone or with an ultrasound that involve no risk to the fetus. If these noninvasive tests are abnormal, you might have further tests.
One first semester genetic test combines a blood test with an ultrasound to screen for Down syndrome and Trisomy 18. It may be available between 11 and 14 weeks of pregnancy. The results of a blood test that measures hCG and PAPP-A (pregnancy-associated plasma protein A) in maternal blood are used with an ultrasound measurement of the skin at the back of the fetus' neck (called nuchal translucency). The procedure may be able to spot many Down syndrome cases and other genetic conditions. However, as with all screening methods, a more invasive diagnostic technique like CVS is used if results are positive.
Noninvasive prenatal testing (NIPT). This cell-free fetal DNA test can be done as early as after 10 weeks of pregnancy. The test uses a blood sample to measure the relative amount of free fetal DNA in a mother's blood. It's thought that the test can detect 99% of all Down syndrome pregnancies. It also tests for some other chromosomal abnormalities.
Chorionic villus sampling (CVS). If you're 35 or older, have a family history of certain diseases, or have had a positive result on noninvasive genetic tests, you will be offered this invasive test, usually between 10 and 12 weeks of pregnancy. CVS can detect many genetic defects, such as Down syndrome, sickle cell anemia, cystic fibrosis, hemophilia, and muscular dystrophy. The procedure involves threading a tiny catheter through your cervix or inserting a needle into your abdomen to get a tissue sample from the placenta. The procedure carries a 1% risk of inducing miscarriage and is about 98% accurate in ruling out certain chromosomal birth defects. But, in contrast to amniocentesis, it does not help in detecting neural tube disorders, such as spina bifida and anencephaly, or abdominal wall defects. Neural tube defects can be screened for with blood work between 15-21 weeks of pregnancy.
Be sure to discuss all of your testing options with your doctor so that together you can decide on the ones that will be best for you.
If you're expecting twins, it's a high-risk pregnancy. For this reason, your doctor will want to watch you and your babies closely. You'll have all the routine tests, but expect to have some of them earlier and more often.
Your doctor may suggest that you see a perinatologist, also called a maternal fetal medicine specialist. These doctors are obstetricians who specialize in high-risk pregnancies. They may work with your regular obstetrician to manage your pregnancy and order tests.
Everything You Need To Know About Having A Baby After 35
Women over 35 who are thinking of having a baby are often anxious about their prospects of success. They've read articles in which the age of 35 is compared to a fertility cliff for females. They've been told that once they go over that edge, their egg quality will start to decline, and their chances of conceiving will plummet accordingly.
They are right to be worried. A woman's egg quality tends to hold until the age of 34 or 35 and drop thereafter," says Dr John Kennedy, medical director of Thérapie Fertility.
"At 32 years old, your chances of having a baby from a single egg are 3.5%. Your chances at 40, when your egg quality has deteriorated significantly, are 1%. Over time and with repeated trying for a baby, the difference between those two figures can be the difference between success and failure."
However, that drop in egg quality is not as precipitous as sometimes portrayed. Take for example the oft-quoted statistic that one in three women aged 35 to 39 will not be pregnant after a year of trying. What people don't realise is that it's based on data from the 1700s — a time when women's health and nutrition levels were nothing like they are today.
Modern data paints a more optimistic picture. Of the 2,820 Danish women trying to conceive in a 2013 study, 84% of those aged 20 to 35 did so within a year and so did 78% of those aged 35 to 40. That's only a 6% difference.
Conception is only the first step towards having a baby and a woman's age can have other negative consequences. "The risk of early pregnancy loss goes up," says Dr Kennedy. "It's 20 to 25% of all pregnancies in women under 30 and up to 50% in women over 40. There's also an increased risk of chromosomal abnormalities."
While these are valid concerns, figures from the Central Statistics Office show they are not deterring women from having babies in their late 30s and into their 40s. In 2021, there were 58,443 babies born in Ireland. 18,853 of these were born to women aged 35 to 39, another 4,561 to women aged 40 to 44; and 256 to women over 45. That adds up to 40.5% of all babies being born to women aged 35 and older.
There are various reasons for this. Edwina Oakes is a psychotherapist and counsellor at Cork Positive Therapy Centre and chairperson of the Irish Fertility Counsellors Association. She sees a wide range of ages in her practice. "But the majority of clients I see are in their 30s to mid-40s," she says. "The average age to marry in Ireland is the early 30s so it's only natural that those are the years the majority of people start to think about their fertility."
It's common for women today to gain third-level qualifications and to try to reach a certain level of seniority in their careers before settling down to have a family. They also have to go through a process of trial and error before finding the right partner. Years can go by, and they can easily find themselves aged over 35 by the time they are ready to have a baby.
With their chances of conceiving decreasing the older they get, it's important for women to be aware of steps they can take to mitigate against this. Getting the right nutrients in their diet is one of the most important.
Jemma Henry is a registered dietitian who specialises in fertility. She firmly believes that nutrition has a role to play in optimising the chances of conceiving.
"There are so many different factors involved in fertility, some of which can't be changed such as our age or genetics," she says. "But we know that nutrition can influence our hormones, egg quality, sperm quality and body weight. By focusing on modifiable factors like nutrition and lifestyle and by making positive changes, we can improve the likelihood of conception and pregnancy."
She recommends starting with a balanced diet. "A Mediterranean-style diet that is characterised by whole grains, fruits, vegetables, legumes, nuts, seeds, olive oil, a low amount of red meat and a moderate amount of poultry, fish, eggs and dairy is best," she says.
There is science to prove it. A 2018 Harvard study found that folic acid, vitamin B12, omega 3 fatty acids, and healthy diets such as the Mediterranean one were linked to positive effects on fertility. Trans fats, diets rich in red and processed meats, sweets and sweetened beverages were found to have negative effects.
Folic acid is crucial, according to Henry. Women are advised to take 400ug of folic acid to prevent neural tube defects," she says. "It has also been associated with promoting egg quality."
She advises taking vitamin D too. "It's thought to play a role in fertility as there are receptors found on the ovaries, sperm, and testicles," she says. "It's found in oily fish, eggs, and fortified food but as our diet isn't sufficient to support adequate intake and sunlight isn't widely available in Ireland, we should all take a 15ug supplement during the winter months."
Iodine and iron are two other critical nutrients. "Iodine is important for babies' development and iron for maintaining regular ovulation," she says. "Iodine is found in milk, yogurt, and white fish and iron in lean meat, kidney beans, chickpeas, eggs, dark leafy vegetables, and fortified cereals."
Henry also recommends that her clients eat oily fish for its omega-3 fats, lots of fruit and vegetables, and foods rich in zinc and vitamin B12. "Omega 3 has anti-inflammatory and antioxidant properties that protect female eggs from damage as they mature," she says.
"Eating an array of different coloured fruit and vegetables will provide a mix of antioxidants that will help nourish those eggs. Zinc contributes to healthy egg development and can be found in whole grains, chickpeas, lentils, and seafood while B12 is crucial for maintaining a healthy pregnancy and can be found in fish, poultry, eggs, dairy products, and fortified cereals." She discourages them from eating other foods. "I advise minimising processed foods and foods that contain high levels of sugar or trans fats as they can contribute to oxidative damage that can affect egg and sperm quality and overall fertility health," she says.
Too much coffee is off the menu. Coffee should be minimised to two cups per day as there is a link between high levels of caffeine and an elevated risk of miscarriage.
"I also tell clients to minimise their alcohol intake as it's been associated with reduced fertility in women," adds Henry.
Jemma HenryThis advice doesn't just pertain to women. Both the egg and sperm need to be optimised to make a baby, so men also have to up their game.
"A man's fertility is just as important as a woman's," says Henry. "Males are responsible for up to 30% of infertility cases and contribute to 50% of cases overall. They too should follow a nutrient-dense Mediterranean-style diet for its anti-inflammatory and antioxidative effects to protect and nourish their sperm and to promote their overall fertility."
Dr Kennedy advises women to pay attention to their BMI. "It's been shown to have a role to play in success rates," he says.
A 2018 German study implies that it may be even more important than that. Not only does it find that the higher a woman's BMI, the lower her chances of conceiving. It also finds that the higher her BMI, the higher her risk of developing complications such as gestational diabetes and preeclampsia.
Exercise can help with this and it's yet another lifestyle factor that women can control. According to this 2007 review of 17,544 American women moderation is the best approach. Thirty minutes of moderate-intensity activity five times a week boosts female fertility but too much high-intensity exercise can have a negative effect.
Stress is another factor that's often linked with failure to conceive. But Oakes isn't convinced. "The relationship between stress and infertility has been debated for years but I've seen no research evidence to suggest stress has an impact on our reproductive system," she says. "What is clear is that the inverse applies: infertility can cause stress, with women reporting elevated levels of anxiety and depression."
Dr Kennedy agrees. "Levels of stress go up as couples try to conceive and that makes the whole process so much harder," he says. "Anything that can be done to manage those stress levels is a good thing."
Oakes recommends reaching out for support. "The majority of people experiencing infertility do not share their story with family or friends," she says. "There is no need for it to be a silent struggle. There are specialist fertility counsellors to support them and talk them through their fertility journey."
While it's important that women and men know there are things they can do to enhance their fertility, it's just as important for them to remember that the older they are, the sooner they should seek fertility advice. The HSE recommends doing so after one year of trying if you are under 35 and after six months if you are older than 35.
Dr Kennedy urges them not to delay. "Getting checked doesn't have to mean getting treatment," he says. "All it means is taking control of the narrative as much as you can, arming yourself with information about your current state of fertility, and finding out about the options that are available to you."
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