Running head: MSAFP AND ULTRASOUNDS FOR DIAGNOSIS OF NTD 1
Maternal Serum Alpha-Fetoprotein Screening and Ultrasound Examinations for Improved
Diagnosis of Neural Tube Defects in Infants born to Insured and Uninsured Mothers
Jennifer Hansen
Concordia University

MSAFP AND ULTRASOUNDS FOR DIAGNOSIS OF NTD 2
Background
Neural tube defects, primarily including spina bifida and anencephaly, occur early in a pregnancy, likely before a woman even knows she is pregnant. They are defects that affect the brain, spine, and/or spinal cord and are often life-threatening (Medline Plus, 2013). Spina bifida is the most common type of neural tube defect, affecting approximately 1,500 babies per year in the United States, and occurs when the bones of the spinal column do not close completely leaving part of the spinal cord exposed. Severity of spina bifida can vary widely and can sometimes be treated with surgery before or after birth. Children living with this type of defect can have paralysis of the legs and urinary and bowel incontinence (March of Dimes, 2012).
Anencephaly is a more severe form of neural tube defect and affects approximately 1,000 babies per year. Babies with this defect are born without parts of their brain and skull, a fatal condition, leaving most to live only a few hours after birth (March of Dimes, 2012). Precise causes of the defects are widely unknown at this time; however, factors such as maternal obesity or uncontrolled diabetes, taking certain anti-seizure medications, and having a family history of neural tube defects, have been found to increase a baby’s risk of being diagnosed with neural tube defects (Medline Plus, 2013; March of Dimes, 2012).
Due to the severe nature of neural tube defects and their affects on quality and quantity of life, many families prefer to know whether or not their children will or are likely to be born with these conditions. Because of this desire and the somewhat recent capability of physicians to treat neural tube defects before birth, routine prenatal screening for neural tube defects is widely becoming common practice in prenatal care. The two most common screening programs used for the detection of neural tube defects today are maternal serum alpha-fetoprotein (MSAFP)

MSAFP AND ULTRASOUNDS FOR DIAGNOSIS OF NTD 3 screening and the use of ultrasound examination. Maternal serum screening programs became available to identify pregnancies at risk for neural tube defects by detecting elevated levels of maternal serum alpha-fetoprotein, and ultrasounds are used to distinguish physical abnormalities characteristic of neural tube defect diagnosis (Driscoll & Gross, 2009). Positive results from these two types of screening programs warrants further diagnostic testing, amniocentesis, in which a sample of amniotic fluid is removed from the womb via a syringe and tested for genetic disorder markers (Amniocentesis, n.d.).
Maternal serum screening is now becoming a baseline, yet optional, procedure carried out in the second trimester of pregnancy, most often between weeks 15 and 20 (Lab Tests Online,
2013). Two commonly administered maternal serum screening tests are the triple and quad screens, both of which include testing for MSAFP. A result of “high” levels of MSAFP in the mother’s blood indicates a greater risk of the baby being diagnosed with neural tube defects.
According to Driscoll and Gross (2009), 75-90% of spina bifida cases and greater than 95% of anencephaly cases can be detected by elevated MSAFP levels with a screen positive rate of 5% of less (p. 818). In a study done with a sample of 608 pregnant working women who received the MSAFP screening during gestation weeks 16-18, the sensitivity of MSAFP for the detection of neural tube defects was 100% and specificity was 92.7% (Baghagho, et al., 2004, results section of abstract).
Ultrasound examinations are also frequently used to detect fetal neural tube defects, during the second trimester of pregnancy, typically at or around 20 weeks’ gestation. In a study with a sample size of 905 pregnancies, ultrasound scanning showed 98% sensitivity and 100% specificity for detection of neural tube defects (Morrow, McNay, & Whittle, 1991, results section

MSAFP AND ULTRASOUNDS FOR DIAGNOSIS OF NTD 4 of abstract). The same study found PV+ ultrasound diagnosis of neural tube defects was 100% and a PV- of ultrasound diagnosis was 99.9% (Morrow, et al., 1991, results section of abstract).
Screening for neural tube defects is now largely a routine prenatal procedure and typically takes place at a pregnant woman’s regularly scheduled doctor’s appointment between
15 and 20 weeks’ gestation in conjunction with screening for other fetal abnormalities, including
Down syndrome and other chromosomal disorders. According to the American Pregnancy
Association (2006), MSAFP screening is especially encouraged for pregnant women with a family history of birth defects, pregnant women who are 35 years or older, pregnant women with diabetes, and pregnant women who took potentially harmful medications or drugs during their pregnancy.
Screening leading to a diagnosis of neural tube defects or other chromosomal disorders brings about many ethical considerations, including an increased ability to provide better quality and specific pre and postnatal care for a special needs’ infant and risk of increased abortion rates.
A good ethical argument for prenatal screening indicates that the earlier physicians can detect neural tube defect abnormalities, the more specific care they can provide for the mother and potentially special needs’ fetus. However, the largest ethical issue surrounding prenatal screening for detection of neural tube defects is post-positive-screening abortion rates.
According to the California State Genetic Disease Branch, pregnancies diagnosed with a severe neural tube defect following prenatal screening had a termination rate of over 90% (Hastings
Center, 2013, para. 7). With statistics such as this, epidemiologists must be very certain their prenatal MSAFP screening programs are as sensitive and specific as possible; because, unfortunately, many little lives are affected by the results of these screening tests. Even if

MSAFP AND ULTRASOUNDS FOR DIAGNOSIS OF NTD 5 abortion is not an option for pregnant women carrying fetus diagnosed with neural tube defects, this is still devastating news for any mother and can have a large impact on the environment in which the fetus will be continuing to grow. For example, it is likely that a positive screening result could cause depression and anxiety in the pregnant woman, causing more stress on the already vulnerable fetus.
Recommendations
I would recommend both the MSAFP screening tests and ultrasound scanning for screening in my community because both have proven to be highly sensitive and specific in correctly identifying neural tube defect cases. However, I do believe that these tests should not be used alone, but in conjunction with one another. The MSAFP should be utilized widely because of its ease and cost-effective means of administration during pregnancy. However, in order to reduce false positives, I would recommend that all women who choose to undergo
MSAFP testing also have an ultrasound scheduled either before or after screening. Ultrasound scanning should be used to properly identify the gestational age of the fetus, as many MSAFP false positive screenings occur due to an inaccurate due date. This would not only reduce the occurrence of unnecessary anxiety, panic, and worry for mothers with false positive screening results, but would likely also increase the participation levels for MSAFP testing during the second trimester. If a mother receives a false positive screening during her first pregnancy because of an inaccurate due date, she is probably more than likely to forego the testing in her second pregnancy, especially if she does not believe the results of the test will affect her decision to carry the baby to term.

MSAFP AND ULTRASOUNDS FOR DIAGNOSIS OF NTD 6
Since MSAFP screening and ultrasound examinations are becoming baseline procedures in prenatal care, there is not a lot of need for increasing participation for women who seek out quality prenatal care during their pregnancies. However, encouraging women who would not otherwise seek out, or have access to, quality prenatal care to do so would also increase screening participation. Diagnoses with neural tube defects have been linked to poor quality nutrition and inadequate folic acid intake, making pregnant women who do not have access to medical and prenatal care at an even greater risk for carrying a baby with neural tube defects.
Therefore, this is the population I would like to see targeted most in attempts to increase participation in screening for neural tube defects.
In order to increase the participation rate for neural tube defect screening, public health programs should aim to increase awareness of the associated conditions and their treatments.
Providing the target population with information regarding the diagnosis and preventative treatment in the form of quality prenatal and self care, and offering emotional support for positive test results would hopefully increase willingness of women to participate in neural tube defect screening. Also offering monetary or health insurance support for those receiving positive results would help to increase participation rates because this would also increase the number of uninsured pregnant women that receive prenatal care. Government programs such as Medicaid provide a way for uninsured women to receive prenatal care and help to bring these women into clinics for routine examinations where access to screening is provided.

MSAFP AND ULTRASOUNDS FOR DIAGNOSIS OF NTD
References
7
American Pregnancy Association. (2006, July). Maternal serum alpha-fetoprotein screening
(MSAFP).
Retrieved December 18, 2013 from http://americanpregnancy.org/prenataltesting/afp.html.
Amniocentesis. (n.d.) In The Free Dictionary online. Retrieved December 16, 2013 from http://medical-dictionary.thefreedictionary.com/amniocentesis.
Baghagho, E.E., Kharboush, I.F., El-Kaffish, D.M., KarKour, T.A., Ismail, S.R., & Mortada,
M.M. (2004). Maternal serum alpha-fetoprotein among pregnant females in Alexandria
[Abstract]. The Journal of the Egyptian Public Health Association, 79 (1-2), 59-81.
Retrieved December 16, 2013 from http://www.ncbi.nlm.nih.gov/pubmed/16916050.
Driscoll, D.A.& Gross, S.J. (2009, November). Screening for fetal aneuploidy and neural tube defects. Genetics in Medicine, 11 (11), 818-821. Retrieved December 11, 2013 from https://www.acmg.net/staticcontent/ppg.
Hastings Center. (2013). Genetic testing and screening.
Retrieved December 14, 2013 from http://www.thehastingscenter.org/Publications/BriefingBook/Detail.aspx?id=2176.
Lab Tests Online. (2013, May 15). Second trimester maternal serum screening. Retrieved
December 17, 2013 from http://labtestsonline.org/understanding/analytes/triplescreen/tab/test.
March of Dimes. (2012, November). Neural tube defects.
Retrieved December 16, 2013 from http://www.marchofdimes.com/baby/neural-tube-defects.aspx.

MSAFP AND ULTRASOUNDS FOR DIAGNOSIS OF NTD 8
Medline Plus. (2013, November 25). Neural tube defects. National Institutes of Health (NIH).
Retrieved December 15, 2013 from http://www.nlm.nih.gov/medlineplus/neuraltubedefects.html.
Morrow, R.J., McNay, M.B, & Whittle, M.J. (1991, December). Ultrasound detection of neural tube defects in patients with elevated maternal serum alpha-fetoprotein [Abstract].
Obstetrical Gynecology, 78 (6), 1055-1057. Retrieved December 15, 2013 from http://www.ncbi.nlm.nih.gov/pubmed/1719459.