Additional Testing & the Maternal Fetal Medicine (MFM) Consult
MFMs are the super-specialists of the obstetric world. In some areas, the MFMs are so busy taking care of very complicated pregnancies that they don’t do deliveries at all. They are a great resource to get to the bottom of complications and take a deeper look at uncertain situations.
However, they work in a world that is so super focused on complications in a department that is vulnerable to lawsuits. At least in some areas, it seems easy to get stuck in the MFM visit sequence with no common sense way out. Tunnel vision regarding complications and the fear of liability can result in one MFM visit leading to another and another with further testing at each appointment. For some parents this may be exactly what they want, and that’s great if so.
First know that your provider (midwife or OB) will follow the standard of care and offer an MFM consult once your anatomy scan shows your baby may have club foot. The reason is that there are other syndromes or conditions associated with club foot that your baby may or may not have. What are these? How common are they and what are the tests for them?
Distal Arthrogryposis - is a term used to describe a number of rare conditions characterized by stiff joints and abnormally developed muscles in hands and feet. This is not diagnosable via ultrasound or any prenatal testing.
Congenital Myotonic Dystrophy - is rare-occurring in only 1/8000 pregnancies. It is usually passed on by the mother, though she may not know she has it. It can be diagnosed prenatally through amniocentesis or non-invasive prenatal testing (NIPT).
Meningomyelocele - the most severe form of Spina Bifida in which part of the spinal cord and nerves form outside of the body, in a sac. It is very rare, occurring in 1/15000 births. It can be detected in the Quad Screen blood work (see links on tests below) but is most accurately diagnosed via ultrasound.
Amniotic Band Sequence (ABS) - a problem with the amnion (part of the amniotic sac) causes baby to be entangled by bands of tissue. It can be mild or severe and is very rare, affecting anywhere between 1 in 1200 to 1 in 15,000 live births. Ultrasound is the only way it can be detected. It is not genetic so genetic testing does not apply to this condition.
Trisomy 18 - in which a baby has an extra Chromosome 18. This condition most often means baby won’t live to delivery or will live just a little while after (a couple of week, though some little humans with Trisomy 18 do live past a year). Trisomy 18 can be detected on ultrasound and NIPT. It occurs in 1/2500-1/2600 of pregnancies.
22q Deletion Syndrome - a rare syndrome in which a very tiny part of the 22 chromosome occurring in 1 in 4000 people. Prenatal testing is not recommended for babies who have a club foot diagnosis from ultrasound that do not also have a heart defect or two or more associated anomalies and family history. NIPT is not diagnostic but can provide screening for this syndrome. Amniocentesis is diagnostic.
Most women will have an anatomy scan and are offered NIPT, which can be done by their provider (they don’t have to go to an MFM for these). You can do the NIPT at any point in pregnancy. In addition, the midwife, OB, or MFM may offer additional ultrasounds.
While ultrasounds are very common, they’ve not necessarily been proven safe. The benefits very often outweighs the risks, as far as we understand risk of ultrasound at this time, but please research to see how you feel about the safety before agreeing to more ultrasounds than you’re comfortable with. Once your baby is diagnosed via ultrasound with CF, you do not necessarily have to follow up to see if the feet are still abnormal later in pregnancy, unless you want to. An anatomy scan already looks for soft markers for other conditions that may also include CF so it is not mandatory that you have another scan by an MFM, unless this is your preference.
Let’s stop here and talk about what the NIPT is. Non invasive means it is not invasive like the amniocentesis is. NIPT is a blood test done on mom. Amniocentesis is a needle inserted into the abdomen used to extract amniotic fluid. It has a miscarriage risk of .25-.50% (one fourth or one half of a percent chance). NIPT is quite accurate but is misnamed “test” as it’s just a screening. Screenings are not diagnostic. It’s like scanning the room for your mom, where as amniocentesis is looking at each person closely to find her.
Some families will choose to stop at the ultrasound. They are comfortable with the very low likelihood of another condition being present since the rest of the anatomy scan was normal. It may be common for some providers to push for more testing at this point but as long as the parents are informed of their options, it can be reasonable to decline further testing.
Some families will request the NIPT blood test be done on mom after an ultrasound shows clubfoot. If there are no other signs of other conditions, the family may opt to stop here. They may also stop here if they are not comfortable with the risk of miscarriage, even if there may be other signs of a condition. Some families may want more information about their baby’s condition so they can prepare themselves for what may be ahead, both emotionally and logistically-for instance if they live in a rural area, they may decide to deliver in a hospital of a larger city nearby so they have access to a higher level of NICU. Knowing this information ahead of time is a pro of testing.
Cons of testing with NIPT: Since it’s just a screening, it can provide false results. The remedy to this is further testing with amniocentesis, which carries a low miscarriage risk, or waiting out the pregnancy with anxiety. Some families will choose neither test for this reason while others will find peace with further testing. There is no wrong answer, the decision is yours.
Ultimately, the question you need to ask yourself is, “What will I do with this information?” Will it help me or cause more anxiety?
Some other helpful information to consider is that you know your baby may have CF ahead of time, though sometimes parents don’t know until birth. There are many conditions not seen until birth or the weeks after birth and hospital and doctors are used to diagnosing and treating these unexpected conditions. Rural communities have protocols for flying or moving babies via ambulance to higher level NICUs. Larger hospitals treat very sick babies all the time. It may help you to discuss how this would work in your place of birth (even birth centers and home birth midwives have protocols to move sick babies to hospitals but a club foot diagnosis should not change your place of birth if you plan to birth outside of the hospital).
As you research and consider what is best for your family, know that you are allowed to accept or refuse every referral you’re given (ever-not just now). Additionally, you’re allowed to ask questions until you’re satisfied with your answers, including getting second opinions.
https://www.ortho.wustl.edu/content/Patient-Care/8...
https://www.ajog.org/article/S0002-9378(19)31127-5...
https://www.nationwidechildrens.org/conditions/22q...
https://www.gimjournal.org/article/S1098-3600(21)0...
Tests: Quad screen vs NIPT: https://my.clevelandclinic.org/health/diagnostics/...
https://www.hopkinsmedicine.org/health/treatment-t...
https://chriskresser.com/natural-childbirth-iib-ul...
https://sarahbuckley.com/ultrasound-scans-cause-fo...
https://obgyn.onlinelibrary.wiley.com/doi/full/10....
https://wfumb.info/2019/04/15/echoes-2-2-2-2-2-2-2-2-2-2-2-2-2-2-2-2-2-2-2-2-2-2/
https://pubmed.ncbi.nlm.nih.gov/11476919/