Handbook of Genetic Counseling/Spina Bifida

Spina Bifida

Quote Risks

• Spina bifida is usually an isolated birth defect.

Level II Ultrasound

• At 18-20 weeks, a high resolution, targeted ultrasound examination can be done to carefully and specifically examine the baby's spine.
• This is noninvasive and may provide reassurance but cannot be used as a diagnostic tool.
  • If no evidence of a NTD is seen, it cannot be guaranteed that the baby does not have a NTD.

Amniocentesis

• If the triple screen results indicate an increased risk for a NTD, one may choose to have an amniocentesis, which is a more invasive, but more diagnostic test.
• What is it?
  • Procedure used to obtain a small sample of fluid from the fluid-filled sac that surrounds the fetus
  • Performed at 15 weeks gestation or later
    • 15-18 weeks is optimal because it leaves the patient with options
    • 22 weeks is probably the latest it can be done leaving the option of elective abortion
  • Amniotic fluid contains the fetus's urine as well as other cells from the skin, throat, and digestive tract
  • Fluid is studied in the lab for abnormalities
• What can it tell me?
  • Amnio can detect certain abnormalities in the fetus.
    • Chromosome abnormalities
    • NTDs (Spina Bifida)
  • It can determine the sex of the baby.
• What can it NOT tell me?
  • Amnio cannot detect all birth defects or mental retardation.
    • For example, congenital heart defects, cleft lip & palate cannot be seen.
    • Also the severity of the defect cannot be known from amnio.
• Exactly what does the procedure involve?
  • Show figure of amniocentesis.
  • You will lie down on your back with hands behind your head.
  • Your abdomen will be cleaned with alcohol or iodine.
  • A local anesthetic may be applied to your stomach.
  • Ultrasound will be used to locate the position of the baby and the placenta and to find a safe spot for the needle.
  • A long, thin needle will be inserted through the skin, into the uterus.
  • The first few cc's of fluid will be discarded because they probably contain contamination from your cells.
  • Then a small amount (about 1-2 tablespoons) of fluid is removed and the needle is withdrawn.
  • The procedure itself usually takes ~5 minutes.
  • The baby will quickly replace the fluid that is removed.
  • The baby's heartbeat will be monitored by ultrasound.
  • Fluid will be sent to the lab and results are available in 1-2 weeks.
  • There is a small possibility of lab error or lack of cell growth
    • In this case, the procedure would have to be done again.
• What will it feel like?
  • If an anesthetic is used, you may not feel the needle enter the skin, but you will still feel it enter the uterus.
  • This is described as a sharp pain, like a menstrual cramp that usually lasts a few seconds.
  • You may also feel some cramping after the procedure.
  • You should avoid strenuous activity for 24 hours after the procedure.
  • Call your doctor immediately if you experience abdominal pain or cramps, vaginal bleeding, leakage of clear fluid from the vagina, fever, or anything else unusual.
    • Approximately 2% of women experience light bleeding or spotting.
• What are the risks?
  • The risk of miscarriage is between 1/400 and 1/200.
  • This means that the added risk for pregnancy loss attributable to the procedure is 0.5% or less.
  • There is a risk of uterine infection but this is less than 1 in 1,000
  • There is a remote chance that birth defects can be caused by the amnio (0.1%).
  • There are special considerations for mothers who are Rh negative. They need to take RhoGam after the amnio procedure.

Other Resources

• Spina Bifida Association of America

SBAA

1-800-621-3142

Review and summarize major points

www.sbhac.ca spina bifida association of Canada

Reporting of the Results

• If they are having a procedure, discuss how they would like to receive the results
  • Appointment, phone call, etc.
  • Who will contact them?
• Discuss the options: elective abortion, adoption, etc.