Ovulatory dysfunction is one of the most common causes of reproductive failure in subfertile and infertile couples. Since the first clinical trial was published in 1961, clomiphene citrate (CC) has been the front-line therapy for ovulation induction. Its use quickly expanded to other empiric indications, such as luteal phase defect and the enhancement of fecundity in unexplained infertility. Failure to respond to CC occurs in up to 20% of cases, which may then require the use of injectable gonadotropins. The drawbacks of this approach are its high cost (both for the medication and the extensive monitoring it requires), risk of the potentially life-threatening ovarian hyperstimulation syndrome (OHSS), and, perhaps most importantly, the significant risk of high-order multiple gestations. Clearly, an inexpensive yet equally efficacious oral alternative would be ideal. Recent research has focused on the successful use of aromatase inhibitors, mainly letrozole, for ovulation induction. The Rotunda medical team have begun incorporating letrozole into treatment plans for appropriately selected patients.
CC is an estrogen-receptor (ER) modulator. It binds to nuclear ER in the hypothalamus, mitigating the usual negative feedback of estrogen on GnRH during the follicular phase. This results in augmented FSH stimulation to the ovary from the pituitary as a result of changes in GnRH pulsatility and is the mechanism for ovulation induction or enhancement. Unfortunately, CC can bind nuclear ER for an extended period of time (6-8 weeks) and eventually depletes ER in other estrogen-dependent tissues, such as the endometrium and cervix. This leads to diminished endometrial development and decreased cervical mucus production. When used in the early follicular phase, letrozole inhibits estrogen synthesis, thereby causing enhanced GnRH pulsatility and consequent FSH and inhibin stimulation. This results in normal or enhanced follicular recruitment without the risk of multiple ovulation and OHSS. Letrozole has a very short half-life (~45 hours) and, therefore, is quickly cleared from the body. For this reason, it is less likely to adversely affect the endometrium and cervical mucus.
Letrozole has also been shown to improve outcome in cycles combining injectable FSH with oral ovulation induction. Recent studies report that the combination of letrozole and FSH enhances follicular recruitment while reducing the amount of FSH needed for optimal stimulation, ultimately reducing the cost of the cycle. This approach has also been useful in patients who previously responded poorly to superovulation treatment protocols.
The usual dose for letrozole ovulation induction is 2.5 mg on cycle days 3-7. Ongoing research using a single dose (10-30mg) on cycle day 3 shows similar rates of ovarian stimulation. Single doses as high as 60 mg have been administered without negative effects. Potential side effects of estrogen depletion, including hot flashes, nausea, and vomiting, have been reported in older breast cancer patients who were given the medication on a daily basis for several months. When used in a healthy population for a short time, the medication is much more tolerable. The pregnancy outcomes for letrozole ovulation induction have been very encouraging. The results of several studies show that letrozole and letrozole + FSH cycles had the highest pregnancy rates of studied regimens, and that letrozole cycles had the lowest multiple gestation rate.
Research into the role of aromatase inhibitors in fertility treatment is ongoing. As with any new course of treatment, it will be important to study long-term effects on the patient, the pregnancy and the conceived children. Due to their short half-life, it is unlikely that letrozole or other aromatase-inhibitors will be associated with any significant negative effects.
Tuesday, November 6, 2007
Monday, November 5, 2007
Antisperm Antibody Test
Antisperm antibodies (anti-spermatozoa antibodies, sperm antibodies) in the form of autoantibodies in male and alloantibodies in female patients directed against sperm antigens may prevent fertilization of the oocyte into the female genital tract and are therefore one of the major reasons for an immunologically induced infertility. Fertility disorders of unknown etiology of male as well as female patients result to a considerably amount (up to 20%) from antisperm antibodies.
An antisperm antibody test looks for special proteins (antibodies) that fight against a man's sperm in blood, vaginal fluids, or semen. The test uses a sample of sperm and adds a substance that binds only to affected sperm. Semen can cause an immune system response in either the man's or woman's body. The antibodies can damage or kill sperm. If a high number of sperm antibodies come into contact with a man's sperm, it may be hard for the sperm to fertilize an egg. The couple has a hard time becoming pregnant. This is called immunologic infertility.
A man can make sperm antibodies when his sperm comes into contact with his immune system. This can happen when the testicles are injured or after surgeries (such as a biopsy or vasectomy) or after a prostate gland infection. The testicles normally keep the sperm away from the rest of the body and the immune system. A woman can have an allergic reaction to her partner's semen and make sperm antibodies. This kind of immune response is not fully understood but may affect fertility. This is a rare cause of infertility.
The antisperm antibody test may be done if:a)A cause for infertility cannot be found. Experts disagree about the usefulness of the test because the result may not change the treatment. b)The results from another fertility test, such as the postcoital test, are not clear.
To do the test in women, a blood sample is taken from a vein in the arm. For men, a semen sample is collected after the blood samples are taken. You should not release your sperm (ejaculate) for 2 days before the test. It is important to not go longer than 5 days before the test without ejaculating.
The husband's sperm is tested for the presence of antisperm antibodies in the Direct ASAB Test. The husband should avoid ejaculation for a period of two to five days before his scheduled test. For the Indirect ASAB Test blood is drawn from the husband and/or wife and the serum is isolated from the blood. The serum is tested indirectly for the presence of antibodies to sperm by incubating it with donor sperm in the Indirect ASAB Test. If antisperm antibodies are present in the serum, they will attach to the donor sperm and cause a positive test result.
Your doctor may request the Immunobead Antisperm Antibody Test for a variety of reasons. These include a Semen Analysis which shows sperm agglutination (sticking together), a Post-Coital Test (PCT) which is abnormal, or unexplained infertility. This test is also a prerequisite for all IVF patients. Immunobeads are small beads that are treated with special proteins. If antibodies to sperm are present, these beads will attach to the sperm. One hundred motile (swimming) sperm are evaluated for bead attachment. For the male, if twenty or more of these sperm have beads attached to them (a result of 20% or greater), this is considered a positive test and indicates that antisperm antibodies may be present. For the female, a result greater than 10% is considered a positive test.
If the husband tests positive for ASAB, his semen specimen for IVF will be collected into a specimen cup containing a buffer solution that will minimize the effect of ASAB on the sperm. Normal IVF fertilization rates (fertilization of 50% or more of the mature eggs) are usually achieved with this treatment. When the female partner or both partners have tested positive for ASAB, or if the husband also has a compromised semen specimen (low count, low motility or low SPA), fertilization rates may be lower and your physician may suggest ICSI.
Sunday, November 4, 2007
Acupuncture Bad For IVF Success
Contrary to the widely held belief that acupuncture enhances a woman's chances of successfully becoming pregnant whilst undergoing IVF treatment, a study at the University of Oklahoma found that women who combine acupuncture and IVF were 37 per cent less likely to conceive than those who underwent IVF treatment alone. The new findings caused head researcher Dr LaTasha Craig, to warn that acupuncture should not be recommended until further research has been conducted to resolve the discrepancy between this study and earlier research. Previous studies had appeared to indicate a marginal increase in IVF efficacy or showed no obvious benefit, allowing some to scientifically postulate that the ancient far eastern medical practice of acupuncture might somehow affect certain muscles and glands of the nervous system to help the
lining of the uterus become more receptive to embryo implantation.
The latest study evaluated the results of 97 patients with an average age of 35 who were randomly divided into two groups. One group received acupuncture for 25 minutes before and after embryo implantation. The pregnancy rate for the IVF group without acupuncture was 69.9 per cent compared to the 43.8 per cent less successful pregnancy rate for those who
received the two-pronged acupuncture 'therapy' approach. Dr Craig suggested that other factors may have counteracted any therapeutic effect of acupuncture such as the stress from undergoing acupuncture just before IVF or from travel in traffic to external acupuncture clinics and onto IVF appointments.
Some clinics regularly offer acupuncture with its IVF services, according to Mark Bovey from the British Acupuncture Council, who was alarmed by the results. Although the number of women who undergo IVF alongside acupuncture procedures has skyrocketed, many doctors believe that the placebo effect is a likely explanation for any perceived benefit.
Saturday, November 3, 2007
Fertility Injections - A Waste of Time?
New research found that hormone injections to achieve pregnancy do not 'provide any added benefit' financially or medically in women under 40 as an alternative infertility treatment before advancing to IVF, announced head researcher Dr Richard Reindollar, from the Dartmouth-Hitchcock Medical Centre in New Hampshire, last week at the annual meeting of the American Society for Reproductive Medicine in Washington last week. The comprehensive study indicates that the thousands of Indian women each year who receive follicle-stimulating hormone (FSH) injections costing Rs 20,000 - Rs 25,000 per course for infertility treatment before resorting to IVF treatment may actually be prolonging the time it takes to become pregnant at unnecessarily increased costs and health risks than if they were to undergo IVF treatment straight away.
In the study of 503 infertile couples, those who were 'fast-tracked' to IVF treatment became pregnant three months earlier than those couples who underwent the daily injections together with artificial insemination (IUI) before, if unsuccessful, undergoing IVF treatment, which also involves ovary-stimulating injections but is coupled with the more invasive egg
extraction and embryo implantation procedures. In practice, women typically begin treatment by trying clomiphene pills together with IUI and when that is unsuccessful most Indian and many UK clinics then offer a course of injections with IUI before performing IVF as a final treatment stage. Both groups were initially unsuccessful with pills and IUI and both had a similar chance of becoming pregnant. Ultimately 78 per cent of those fast-tracked and 75 per cent of those receiving injections were successful but the fast-tracked couples had a 40 per cent increased chance to become pregnant
within the first eight months versus eleven months of treatment, and saved overall costs by an average of £5,000- reducing average payment from £35,700 to £30,750.
Women may also be placing themselves at prolonged health risk. The injections stimulate the ovaries egg production and have significant physical side-effects including headaches, abdominal pain and ovarian hyperstimulation syndrome, which in extremely rare cases can be fatal. They also increase the risk of multiple births by 20 to 30 per cent, which in turn increases the risk of birth defects and pregnancy-induced hypertension. Contrary to National Institute for Health and Clinical Excellence guidance, which recommends the NHS pay for hormone injections only for women with endometriosis, many private clinics offer them more generally often in cases of unexplained infertility, according to Mark Hamilton, chairman of
the British Fertility Society. Infertility affects one in seven British couples and Hamilton urges patients to carefully consider with their doctors the efficacy of infertility treatments before attempting treatments with lower success levels. Bill Ledger, Professor of Obstetrics and Gynaecology at the University of Sheffield felt this study adds to mounting evidence in
support of the cost-saving elimination of injections and redirection of those funds into providing cheaper IVF treatment with an equal success rate without the delay.
In the study of 503 infertile couples, those who were 'fast-tracked' to IVF treatment became pregnant three months earlier than those couples who underwent the daily injections together with artificial insemination (IUI) before, if unsuccessful, undergoing IVF treatment, which also involves ovary-stimulating injections but is coupled with the more invasive egg
extraction and embryo implantation procedures. In practice, women typically begin treatment by trying clomiphene pills together with IUI and when that is unsuccessful most Indian and many UK clinics then offer a course of injections with IUI before performing IVF as a final treatment stage. Both groups were initially unsuccessful with pills and IUI and both had a similar chance of becoming pregnant. Ultimately 78 per cent of those fast-tracked and 75 per cent of those receiving injections were successful but the fast-tracked couples had a 40 per cent increased chance to become pregnant
within the first eight months versus eleven months of treatment, and saved overall costs by an average of £5,000- reducing average payment from £35,700 to £30,750.
Women may also be placing themselves at prolonged health risk. The injections stimulate the ovaries egg production and have significant physical side-effects including headaches, abdominal pain and ovarian hyperstimulation syndrome, which in extremely rare cases can be fatal. They also increase the risk of multiple births by 20 to 30 per cent, which in turn increases the risk of birth defects and pregnancy-induced hypertension. Contrary to National Institute for Health and Clinical Excellence guidance, which recommends the NHS pay for hormone injections only for women with endometriosis, many private clinics offer them more generally often in cases of unexplained infertility, according to Mark Hamilton, chairman of
the British Fertility Society. Infertility affects one in seven British couples and Hamilton urges patients to carefully consider with their doctors the efficacy of infertility treatments before attempting treatments with lower success levels. Bill Ledger, Professor of Obstetrics and Gynaecology at the University of Sheffield felt this study adds to mounting evidence in
support of the cost-saving elimination of injections and redirection of those funds into providing cheaper IVF treatment with an equal success rate without the delay.
Friday, November 2, 2007
Investigating The Infertile Male
It is natural for the attention of the gynecologist and family practitioner to initially turn toward the female in cases of infertility. Although infertility is generally viewed a ‘female problem’, fully 45% of infertile couples have male infertility as a contributing cause. It makes sense then to begin the fertility evaluation with a basic evaluation of the male partner. Because significant male factor infertility is generally treated with in vitro fertilization, needless hysterosalpingograms, laparoscopies and clomiphene cycles can be avoided by early detection of significant dysfunction in the male partner. The savings of time and money can be tremendous. IVF with intracytoplasmic sperm injection (IVF/ICSI) has made it possible to successfully treat virtually all cases of male infertility, even with only a few moving sperm in the entire ejaculate.
The evaluation of the male partner starts with a competent semen analysis. Non-specialized laboratories, such as Ranbaxy and Metropolis, perform a World Health Organization (WHO) semen analysis. This is a crude screening test and should be replaced by the strict semen analysis (Kruger) that is done by most fertility centers. The difference between the WHO and the Kruger test is that, with the Kruger test, sperm morphology is evaluated in a very stringent manner. The results of the Kruger test predict fertilization rates in vitro and presumably in vivo as well. The WHO does not predict outcome and will frequently miss subtle but clinically significant sperm abnormalities. The cost of the Kruger test is the same or less than a WHO analysis at our center.
When male infertility is suspected and tests reveal abnormal semen parameters, the couple should be referred to a fertility physician and/or urologist for further evaluation. Conditions warranting referral for male infertility are: a sperm concentration of less than 20 million per mL, motility less than 35%, and morphology less than 5% (Kruger) or 30% (WHO).
A direct antisperm antibody test should be done in cases where the male has a history of genital trauma, genital surgery or has never initiated a pregnancy. The direct antibody test is done on a semen sample and detects whether antibodies are attached to the sperm themselves. The cutoff for a positive test varies between labs but is usually considered positive when greater than 10%-20% of sperm are bound. Couples with antisperm antibodies should be referred to a fertility physician for further evaluation and treatment.
Genetic evaluation of male infertility is indicated when there is a sperm concentration less that 5 million per milliliter. This male infertility evaluation should consist of a karyotype and a study to look for microdeletions on the long arm of the Y chromosome (Yq deletion study). An assay for DNA fragmentation in the sperm cells may also be helpful in select patients. If azoospermia is present, carrier status for one of the cystic fibrosis mutations should be ruled out. These men should, of course, be referred for a urological evaluation. If surgical treatment of the infertile male is not indicated, a fertility physician can then complete treatment.
Hormonal evaluation of the infertile male is indicated when there is a history of sexual dysfunction, azoospermia or abnormal physical findings. This workup, which consists of testosterone, FSH, LH and prolactin levels, should be accompanied by urological consultation.
Thursday, November 1, 2007
Triple Marker Test
The multiple marker test (sometimes referred to as the triple screen) can tell you if your baby is at an increased risk of having certain birth defects and genetic abnormalities. If you choose to have this test, it's important to understand that a "positive" or abnormal result doesn't necessarily mean that your baby has a problem. Infact, only about 10 percent of women with abnormal results have babies with birth defects. In general, an abnormal result means only that you may need further testing, such as ultrasound or amniocentesis, to know for sure. On the other hand, a negative or normal result is not a guarantee that your baby is healthy - but it does mean that your baby's chances of having certain birth defects are much lower. And that's why a lot of women opt to take it. Current research indicates that this test will detect 75 to 80 percent of neural tube defects (such as spina bifida and anencephaly) and 60 percent of Down syndrome in babies of women younger than 35, and 75 percent of neural tube defects and Down syndrome in babies of women 35 and older. Only about 3 to 5 percent of women will receive a positive (abnormal) result on the multiple marker - and on an average, only about 10 percent of those women will actually have a baby with a problem. That adds up to a lot of false positive results. Statistics from one of the companies that offers a multiple marker test show an even higher rate of false positives. If 1000 pregnant women take this test, only about 25 of them will show an increased risk for a baby with neural tube defects, and of those, only one or two will actually have a baby with Down syndrome. On the other hand, some women whose test results are normal will have a baby with one of these problems.
The multiple marker test measures your blood levels of three substances: alpha-fetoprotein (AFP), human chorionic gonadotropin (hCG), and unconjugated estriol (uE3). For years, women were screened for AFP alone in a test called the maternal serum AFP or MSAFP, but now most labs check for all three substances because they can tell more that way. Some hospitals screen for the hormone inhibin A as well, in what's called a quadruple screen test. When this compound is added to the test, the detection rate for Down syndrome increases to between 67 and 76 percent in women younger than 35. It's usually done between 15 and 20 weeks of pregnancy, with 16 to 18 weeks (when the hormone levels are the most consistent) being the optimum time. You'll have a blood sample taken and sent to a lab for analysis. The lab analyzes the levels of AFP, hCG and uE3 (and sometimes inhibin A) in your blood and determines whether they fall within a "normal" range for this stage of your pregnancy, based on your age, weight, race, and other factors (such as having diabetes). Having too much or too little of these substances in your blood is considered a positive, or abnormal, result. Results are generally available in one or two weeks. Your level of AFP and the other substances are considered individually and in combination to determine whether you and your baby are at risk for certain problems. The results tell you what your baby's chances are of having each kind of birth defect. For example, on average, a 35-year-old woman has a 1 in 250 to 270 chance of having a baby with Down syndrome. If the results show that your chances of having a baby with any of the defects tested for are higher than average for your age, you'll want to consider further testing. A high AFP can mean several things. Your baby produces AFP throughout your pregnancy, and a certain amount of it should cross the placenta into your bloodstream at each stage. If there's more than expected, it often means that you're carrying more than one baby or that your baby is older than your practitioner thought. But in some cases, it's a sign of an abnormal opening in the baby's spine (spina bifida), head or abdominal wall that's allowing more AFP to leak out. In rare cases, it can also signify a problem with the baby's kidneys. And in some cases, it doesn't mean any of those things. A low AFP, low estriol, and high hCG are associated with a higher risk for Down syndrome (trisomy 21). Low levels of all three mean your baby has an increased risk for trisomy 18, a more severe and less common chromosomal anomaly.
Certain results may also indicate that you yourself are at a somewhat greater risk for problems such as preeclampsia, premature birth, or miscarriage. Knowing this can allow you and your practitioner to be on the lookout for signs of trouble. If you receive an abnormal result, you'll most likely be offered a detailed (level II) ultrasound first. This test can be done right away and can give you immediate information. (If the ultrasound shows that your baby is younger or older than your practitioner thought, your results will be recalculated.) You may also want to meet with a genetic counselor at this point to discuss your risks and your options. If you have a high AFP, a level II ultrasound will confirm your baby's age and show whether you're carrying twins, and will allow your doctor to check your baby's spine and other parts for defects. If your baby is found to have spina bifida and you decide to continue the pregnancy, your medical team will be able to monitor your baby's condition during your pregnancy and prepare to do surgery once your baby's born. If you have a low AFP, the ultrasound can allow your doctor to check for several so-called "soft markers" that may suggest Down syndrome and other chromosomal disorders. These soft markers include cysts in a particular area of the brain (choroid plexus cysts), extra calcium in certain muscles of the heart (hyperechogenic intracardiac foci), a kidney problem (mild pyelectasis), a thickened nuchal fold (also called the nuchal translucency, a clear area between the back of the baby's neck and the overlying skin), an abnormally short thigh bone, and a bright-appearing (hyperechogenic) bowel.
When two or more of these markers are found, the chance that your baby has a chromosomal abnormality may be significantly higher, depending on your age and how far along you are. Also, a baby with a major structural abnormality, such as a defect in the heart or abdominal wall, has a greater chance of having a chromosomal defect. If everything looks normal on the ultrasound, it's not a guarantee that everything is okay, but it does mean that your baby has a lower risk of chromosomal defects than average for a woman your age. You may decide that this small risk is acceptable or you may decide that you'd also like to have amniocentesis to know for sure. If the ultrasound suggests your baby may have a chromosomal problem, your practitioner will usually recommend amniocentesis to determine for sure what's going on. And if the ultrasound detects certain structural defects, you may want amniocentesis to find out whether your baby has a chromosomal problem as well, which is often the case. Amniocentesis can diagnose 99 percent of chromosomal abnormalities, but it does carry a slight risk of miscarriage (one in 200 on average). This test is usually done between 15 and 20 weeks so that the parents will have the option of terminating the pregnancy before 24 weeks if they choose to. Again, you have to wait 10 to 14 days to get the results.
The main advantage of the multiple marker is that it can give you some information about your baby's risk of having certain birth defects without subjecting you to the slight risk of miscarriage associated with amniocentesis or the CVS test. If you're going to be 35 or older by your due date, your practitioner may suggest that you skip this test and go right to those more accurate tests. After you reach this age, your risk of having a baby with a chromosomal problem such as Down syndrome is higher than your risk of miscarrying because of amniocentesis. Still, if you're uncomfortable with this risk, you may choose to have the multiple marker with a detailed ultrasound instead. If the results of these are both normal, you may not want to go through with the amnio because the small chance that the baby will have a defect may now be less than the chance that an amnio would cause a miscarriage, just as it would be if you were younger than 35. Even if you know that you would never terminate a pregnancy for any reason, knowing in advance that your baby may have special needs allows you to prepare for the challenges you'll face. You might want to switch to a better-equipped hospital with specialists. Knowing what's going on with your baby will allow your medical team to monitor your pregnancy as needed and to bring a neonatologist or pediatric surgeon on board to prepare to help your baby after birth.
On the other hand, a false positive result can worry you needlessly (this is the most common complaint about the test) and make you decide to undergo amniocentesis for no reason. A false negative result could make you decide to avoid further tests that would have revealed a birth defect. Before making a decision, you'll want to discuss all of these issues with your partner, your health practitioner, and possibly a genetic counselor.
The multiple marker test measures your blood levels of three substances: alpha-fetoprotein (AFP), human chorionic gonadotropin (hCG), and unconjugated estriol (uE3). For years, women were screened for AFP alone in a test called the maternal serum AFP or MSAFP, but now most labs check for all three substances because they can tell more that way. Some hospitals screen for the hormone inhibin A as well, in what's called a quadruple screen test. When this compound is added to the test, the detection rate for Down syndrome increases to between 67 and 76 percent in women younger than 35. It's usually done between 15 and 20 weeks of pregnancy, with 16 to 18 weeks (when the hormone levels are the most consistent) being the optimum time. You'll have a blood sample taken and sent to a lab for analysis. The lab analyzes the levels of AFP, hCG and uE3 (and sometimes inhibin A) in your blood and determines whether they fall within a "normal" range for this stage of your pregnancy, based on your age, weight, race, and other factors (such as having diabetes). Having too much or too little of these substances in your blood is considered a positive, or abnormal, result. Results are generally available in one or two weeks. Your level of AFP and the other substances are considered individually and in combination to determine whether you and your baby are at risk for certain problems. The results tell you what your baby's chances are of having each kind of birth defect. For example, on average, a 35-year-old woman has a 1 in 250 to 270 chance of having a baby with Down syndrome. If the results show that your chances of having a baby with any of the defects tested for are higher than average for your age, you'll want to consider further testing. A high AFP can mean several things. Your baby produces AFP throughout your pregnancy, and a certain amount of it should cross the placenta into your bloodstream at each stage. If there's more than expected, it often means that you're carrying more than one baby or that your baby is older than your practitioner thought. But in some cases, it's a sign of an abnormal opening in the baby's spine (spina bifida), head or abdominal wall that's allowing more AFP to leak out. In rare cases, it can also signify a problem with the baby's kidneys. And in some cases, it doesn't mean any of those things. A low AFP, low estriol, and high hCG are associated with a higher risk for Down syndrome (trisomy 21). Low levels of all three mean your baby has an increased risk for trisomy 18, a more severe and less common chromosomal anomaly.
Certain results may also indicate that you yourself are at a somewhat greater risk for problems such as preeclampsia, premature birth, or miscarriage. Knowing this can allow you and your practitioner to be on the lookout for signs of trouble. If you receive an abnormal result, you'll most likely be offered a detailed (level II) ultrasound first. This test can be done right away and can give you immediate information. (If the ultrasound shows that your baby is younger or older than your practitioner thought, your results will be recalculated.) You may also want to meet with a genetic counselor at this point to discuss your risks and your options. If you have a high AFP, a level II ultrasound will confirm your baby's age and show whether you're carrying twins, and will allow your doctor to check your baby's spine and other parts for defects. If your baby is found to have spina bifida and you decide to continue the pregnancy, your medical team will be able to monitor your baby's condition during your pregnancy and prepare to do surgery once your baby's born. If you have a low AFP, the ultrasound can allow your doctor to check for several so-called "soft markers" that may suggest Down syndrome and other chromosomal disorders. These soft markers include cysts in a particular area of the brain (choroid plexus cysts), extra calcium in certain muscles of the heart (hyperechogenic intracardiac foci), a kidney problem (mild pyelectasis), a thickened nuchal fold (also called the nuchal translucency, a clear area between the back of the baby's neck and the overlying skin), an abnormally short thigh bone, and a bright-appearing (hyperechogenic) bowel.
When two or more of these markers are found, the chance that your baby has a chromosomal abnormality may be significantly higher, depending on your age and how far along you are. Also, a baby with a major structural abnormality, such as a defect in the heart or abdominal wall, has a greater chance of having a chromosomal defect. If everything looks normal on the ultrasound, it's not a guarantee that everything is okay, but it does mean that your baby has a lower risk of chromosomal defects than average for a woman your age. You may decide that this small risk is acceptable or you may decide that you'd also like to have amniocentesis to know for sure. If the ultrasound suggests your baby may have a chromosomal problem, your practitioner will usually recommend amniocentesis to determine for sure what's going on. And if the ultrasound detects certain structural defects, you may want amniocentesis to find out whether your baby has a chromosomal problem as well, which is often the case. Amniocentesis can diagnose 99 percent of chromosomal abnormalities, but it does carry a slight risk of miscarriage (one in 200 on average). This test is usually done between 15 and 20 weeks so that the parents will have the option of terminating the pregnancy before 24 weeks if they choose to. Again, you have to wait 10 to 14 days to get the results.
The main advantage of the multiple marker is that it can give you some information about your baby's risk of having certain birth defects without subjecting you to the slight risk of miscarriage associated with amniocentesis or the CVS test. If you're going to be 35 or older by your due date, your practitioner may suggest that you skip this test and go right to those more accurate tests. After you reach this age, your risk of having a baby with a chromosomal problem such as Down syndrome is higher than your risk of miscarrying because of amniocentesis. Still, if you're uncomfortable with this risk, you may choose to have the multiple marker with a detailed ultrasound instead. If the results of these are both normal, you may not want to go through with the amnio because the small chance that the baby will have a defect may now be less than the chance that an amnio would cause a miscarriage, just as it would be if you were younger than 35. Even if you know that you would never terminate a pregnancy for any reason, knowing in advance that your baby may have special needs allows you to prepare for the challenges you'll face. You might want to switch to a better-equipped hospital with specialists. Knowing what's going on with your baby will allow your medical team to monitor your pregnancy as needed and to bring a neonatologist or pediatric surgeon on board to prepare to help your baby after birth.
On the other hand, a false positive result can worry you needlessly (this is the most common complaint about the test) and make you decide to undergo amniocentesis for no reason. A false negative result could make you decide to avoid further tests that would have revealed a birth defect. Before making a decision, you'll want to discuss all of these issues with your partner, your health practitioner, and possibly a genetic counselor.
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