The first test that they offer is called the Integrated Prenatal Screening (IPS), at 11, 13 and 15-18 weeks gestation. The IPS gives you a statistic probability that your child will have a genetic problem such as Down Syndrome, but also spina bifida.
The IPS test uses measurements from 2 different blood tests and one ultrasound, as well as looks at mother age to give a statistical probability of different problems.
The IPS screen measures the level of a protein called alpha-fetoprotein (AFP), which is made naturally by the fetus and placenta. During pregnancy, a small amount of AFP normally crosses the placenta and enters the mother’s bloodstream. But if abnormally high levels of this protein appear in the mother’s bloodstream it may indicate that the fetus has a neural tube defect. [Diagnosing Spina Bifida in Infants - I don't actually like the article - but the definition is good]
Of every woman who takes this test 2-3% will have a positive result - but most of these women will have a false positive and everything is fine. A false negative is rare - it would mean that there is not a high level of AFP in the mothers blood system. But it is possible to still have spina bifida (as we found out)
Statistics are a funny thing. When I was pregnant with my daughter Katheryn we had a false positive (1 in 7 chance of having a child with trisomy-18). With Nickolas we had a false negative, I later found out that our probability of having a child with spina bifida was 1 in 800, higher than the average of 1 in 1200 (in Canada) but definitely below the limits of a positive result (1 in 100).
Well, we were that 1 person in 800.
There is current research suggesting that early prenatal ultrasound measurements at 11-13 weeks could be used as an early detection of spina bifida.
The second round of normal prenatal testing is usually around 18-20 weeks and is another ultrasound. This is usually the one everyone is so excited about because you can sometimes find out the sex of the baby. But they do alot more than just look at the sex.
Different measurements of the head and face as well as the body can be made - it is called an anatomy scan.
In the case of spina bifida the back lesion (missing vertebrae) may not be seen in ultrasound, but other markers (clues) can be seen on this 20 week ultrasound. Ultrasound findings of a lemon sign (lemon shaped head), banana sign (cerebellum shaped like a banana) or absent cerebellum (or not visualized - doesn't mean it is actually missing) all suggest that spina bifida is present.
All of the regular prenatal testing is meant to clue in the doctor/midwife that there could be a problem. Additional testing would then be done to follow up with the initial findings.
The first, least invasive test is a second level ultrasound (level 2). Often a mother must travel to an unfamiliar medical centre for this test with doctors that she doesn't know.
This additional ultrasound is more targeted to look more closely at the specific markers that came up in the regular anatomy scan. The ultrasound is usually done by a specialist who understands high risk pregnancies.
For the mother, it is not any different from all the other ultrasounds. It might take longer and more turning, moving for an accurate picture.
In my experience, my second level ultrasound lasted over 1 hour and there was lots of flipping and flopping to get the right measurements. The ultrasound technician is not allowed to tell you anything. But when an ultrasound takes over an hour it is not a good sign.
I was lucky that a doctor was able to talk to me that day, and that I didn't have to wait to hear the words... spina bifida.
Additional testing was offered to try to get more information.
This additional testing is more invasive and does come with a risk.
An amniocentesis is when they take a small sample of amniotic fluid (20mL) to examine the fetal DNA. An ultrasound is used to help to guide the needle. It takes only a couple of minutes to take the fluid, most of the time is waiting and getting into the right position.
The needle poke is not much worse than getting blood taken (not nearly as much pain as you have in your head you would feel if someone stuck a needle into you belly). It mostly just feels weird. I thought you would need a bandaid or something. But it just leaves a tiny red mark.
The puncture site heals over in 24-48 hours and you are supposed to take it easy. An amniocentesis does come with a risk of miscarriage and infection. Some parents do not believe that the risk of an amniocentesis outweighs the benefit of reaffirming a spina bifida diagnosis and ensuring there is no other chromosomal problems.
To reaffirm the spina bifida diagnosis, the amniotic fluid will show increased AFP levels. It takes about 48-72 hours for a FISH study. This is just a quick chromosome count and will rule out a trisomy chromosome (where there is 3, instead of 2). It also counts the X and Y and will tell you girl or boy.
Another test in the prenatal arsenal is an MRI.
The MRI uses a magnet and radio frequency to show internal structures. It allows you to look at soft tissues easily and does not expose mother or child to radiation.
It takes about 45-60 minutes of staying still in a very enclosed space with loud noises moving around you.
Personally I sang the words of the Phantom of the Opera in my head, with my eyes tightly shut. I got through Act I.
You get a cool picture at the end of it.
You can actually SEE the spina lesion at the base of the spine - see the white line - that's the spinal cord, and see how it's open to the skin?
The results should be reviewed by a doctor who actually knows about spina bifida. Our genetics doctor was our go-to person at the high risk pregnancy clinic, and he had valuable, up-to-date information about what spina bifida is.
Our MRI results were reviewed and explained to us by a pediatric neurosurgeon, and who was the same doctor who would eventually do the surgery. We also talked about plan of care and what to expect with the developmental pediatrician at the local spina bifida clinic.
All of the information that is relayed to parents (and family) by medical professionals should also be screened by WHO is telling you. A family doctor, regular OB, midwife deals with normal pregnancies. This is a pregnancy that has become different. The family doctor, OB, midwife may never have seen an infant or child with spina bifida and their information may be coming from textbooks that are decades old.
To get true, valuable information about the results of what you are dealing with, you need to go to doctors who do this. Doctors who know what spina bifida looks like.