So sorry you are going through this stress. I am five weeks pregnant with my first child myself and am wracked with worry. I can’t imagine how difficult it must be for you to hear the word “Edwards Syndrome” (or any “syndrome”) without having confirmation that this even the case.
“Too much amniotic fluid” is known medically as polyhydramnios, which occurs in ~0.5-2.0% of all pregnancies. It is caused by any condition that causes the fetus to have an increase in urine production or decrease in fetal swallowing.
There are many degrees of polyhydramnios: mild, moderate or severe. Not surprisingly, mild is better than severe.
Polyhydramnios is usually first discovered subjectively (i.e., the sonogram technician says, “wow, there’s a mild, moderate, or severe amount of extra amniotic fluid... that looks like it could be polyhydramnios”) and is then followed up by more precise measurements that can give you the OFFICIAL diagnosis. Because there can be some component of human error (some will see mild polyhydramnios when others will see a normal amount of fluid), many physicians like to perform a second follow-up scan (as it sounds like your physician is doing) before officially giving you the diagnosis.
From the patient’s perspective, however, it’s not that straightforward. Usually, after that first scan where polyhydramnios might be seen, doctors tell their patients that they may have “polyhydramnios” and suggest all the possibilities it could be… Which is terrifying to hear. So please, unless you heard the words “moderate or severe polyhydramnios” at that first scan… please (try) to relax until this is confirmed on your second scan.
There are many causes—and they usually differ based on severity (mild, moderate, or severe).
- Mild polyhydramnios is most caused by idiopathic factors 40% of the time (i.e., nobody knows why it happens). In these cases, about 75% of these babies will not be diagnosed with an abnormality at birth (only 25% will). Another 25% of mild cases are caused by the mom of the fetus having diabetes mellitus (do you have diabetes?), and then a smaller percentage of mild cases are caused by having twins (which doesn’t sound like your case).
- Severe polyhydramnios is usually caused by a genetic abnormality or syndromes like Edwards Syndrome. These cases, of course, are the most concerning to physicians and patients.
Edwards Syndrome, or trisomy 18, is also associated with many different sonographic “markers” such as limb abnormalities, nuchal thickening, neural tube defects, facial/cardiovascular/gastrointestinal defects, etc. These abnormalities are found in two-thirds of Edwards Syndrome fetuses between 17 and 24 weeks. Overall, 90% of trisomy 18 cases are diagnosed pre-natally by seeing these sonographic “markers” PLUS seeing abnormal screens (in the 1st trimester: VERY LOW beta-hCG and PAPP-A levels; 2nd trimester: LOW levels of alpha-fetoprotein, unconjugated estriol, and human chorionic gonadotropin). That means about 10% of cases are not detected through the sonogram + screen combination… So that is certainly not the majority.
It sounds like you had a normal result in your first trimester screen, and aside from the polyhydramnios, you didn’t have any of the “markers” of Edwards syndrome at your 20-week scan—which is reassuring.
I hope your scan on January 2 went well. If you had polyhydramnios at that time, your doctor can offer you more definitive testing (cfDNA) that is 97.7% accurate at detecting Edwards Syndrome. So if there is still a suspicion of Edwards syndrome, hopefully this newer test can give you some clarity.
I hope the polyhydramnios was a fluke. But if not, please know that it is better that you know in advance so that you can work with your doctor to decide what’s the next best step for you and your family. I cannot imagine how stressful/terrifying this must be for you, but please know you have done EVERYTHING RIGHT. If this turns out to be Edwards Syndrome, it is in NOT your fault in any way.
Stay strong—you can handle anything that comes your way. Just take this one step at time… Try to be present in the moment and know that the answers will come soon.
Wishing you all the best,
M.O.
Sources:
Palomaki, G.E., Messerlian, G.M., Halliday, J.V. (2017). Prenatal screening for common aneuploidies using cell-free DNA. In V.A. Barss (Ed.), UpToDate. Retrieved January 18, 2018, from www.uptodate.com/contents/prenatal-screening-for-common-aneuploidies-using-cell-free-dna.
Beloosesky, R, and Ross, M.G. (2018). Polyhydramnios. In V.A. Barss (Ed.), UpToDate. Retrieved January 18, 2018, www.uptodate.com/contents/polyhydramnios.
Abele H, Starz S, Hoopmann M, et al. Idiopathic polyhydramnios and postnatal abnormalities. Fetal Diagn Ther 2012; 32:251.
Dorleijn DM, Cohen-Overbeek TE, Groenendaal F, et al. Idiopathic polyhydramnios and postnatal findings. J Matern Fetal Neonatal Med 2009; 22:315.
Touboul C, Boileau P, Picone O, et al. Outcome of children born out of pregnancies complicated by unexplained polyhydramnios. BJOG 2007; 114:489.