Case of Elevated Inhibin with a Midtrimester Maternal Serum Screen

I have spent most of my free time this week, the little I seem to have anymore, catching up with all of the readers' comments that accumulated while I took my vacation. One thing that seems to be a constant in medicine is that you can turn off your computer, pager, and cell phone for a few days, but it will all be waiting for you and you WILL pay for it in the end! Not complaining, just a statement of fact. I REALLY do love what I do! Anyway, there were several excellent questions raised by our readers in their comments and I thought that I would share several with you over the next couple of days.

Mon Feb 18, 03:40:00 PM 2008 Kate said...

To Dr. T,
I have been reading everyone's comments and leared a lot. I have also abnormal quadruple screen 1:27 risk for Down syndrome (trisomy 21). I am 32 years old. I had two ultrasounds after that and both were normal. I was just diagnosed with a dermoid tumor in my ovary in this pregancy. From my quadruple screen, the inhibin was elevated at 2.24 multiples of the median (MoM). Everything else was close to 1 MoM. I wanted to see if you know of a case with dermoid causing abnormal quadruple screen. Is there anything associated with high inhibin during pregnancy.
Thanks!

Fri Feb 29, 07:32:00 PM 2008 Kenneth F. Trofatter, Jr., MD, PhD said...

To Kate Feb 18: Inhibin is one of the 'serum markers' that is included in the maternal serum 'quad screen (alpha-fetoprotein (AFP); hCG (the 'pregnancy hormone'); estriol; and inhibin)' performed in midtrimester to screen for certain birth defects, particularly those that involve defects in the body wall (especially, neural tube defects and abdominal wall defects) and also used to reassess risk for certain chromosomal abnormalities (especially trisomy 21 (Down syndrome) and trisomy 18). The primary advantage of including 'inhibin' in the test is that it can help to reduce the 'false-positive' rate of the screening.

Although inhibin is made by multiple tissues in the genital tract, there is not a lot of literature on elevated levels associated with ovarian tumors. I did stumble on one article, however, that described high levels of inhibin in an ovarian teratoma (like a dermoid) in an older woman (Itoh, et al., Pathol Int 2004;54:279-83). More often, high inhibin levels have been associated with hypertensive disorders (preeclampsia) during pregnancy (Sartori, et al., J Thromb Haemost 2008;6:352-8). There is some suggestion that certain patients have these elevated levels as early in midtrimester as the maternal serum screening is done (16-20 weeks) (Kim, et al., J Korean Med Sci 2006;21:452-6). I hope that's all this is and not an indication that your baby has a chromosomal abnormality. I always learn from extraordinary questions like yours, so PLEASE let me know how things turn out. Many of our readers will appreciate your feedback as well. Thank you for reading and so much for writing.
Dr T

Fri Feb 29, 07:32:00 PM 2008

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