Can New Pregnancy Test Be Used To Watch For Early Miscarriage?

This article is more than 7 years old.
A new pregnancy test also tells you how far along you are. (Carey Goldberg/WBUR)
A new pregnancy test also tells you how far along you are. (Carey Goldberg/WBUR)

"Your hCG levels aren't rising the way we'd like."

That was the official beginning of my miscarriage. I was 40 and childless and wanted a baby more than anything in the world. I'd gotten pregnant quickly, but after several weeks, something seemed wrong. I wasn't feeling pregnant. My doctor suggested a second blood test for hCG — Human Chorionic Gonadotropin, the telltale pregnancy hormone that rises rapidly as an early pregnancy progresses.

My numbers did not look good. A few dread-filled days later, I started to bleed. I joined the great multitudes of women who miscarry; it's estimated that from one-fifth to one-third of early pregnancies end spontaneously.

So you'll understand my response to the news that Clearblue, a popular brand of fertility monitors and pregnancy tests, has just begun to offer a novel test in the United States that measures a woman's hCG levels. For me, it instantly raised the question: So if you can now track your hCG at home, does that mean you can pick up early chemical signals of a possible miscarriage? And if so, is that good, or just potentially more crazymaking?

2013-09-05 10.03.50

Called the "Clearblue Advanced Pregnancy Test with Weeks Estimator," the new test hit store and online shelves this month at between $7 and $9 each, and takes a sophisticated technological step past the simple "+" or "-" on urine test sticks. It tells you, with an estimated 93 percent accuracy, how far along you are, whether "1-2 weeks" after conception, "2-3 weeks" or "3+ weeks."

The "weeks estimator" is not meant to replace the current gold standard for pregnancy dating: ultrasound scans and a calendar look at a woman's last menstrual period. But Time Magazine says the new test can offer welcome information to women who hunger for it, and could help bring in patients who need early prenatal care.

I contacted Clearblue, a subsidiary of Procter and Gamble, and they put me in touch with a member of their advisory board, Dr. Michael Zinaman, a professor at Tufts University Medical School and chairman of the Department of Obstetrics and Gynecology at St. Elizabeth’s Medical Center in Boston.


Dr. Zinaman's short answer to my chemical question is: Yes, the new test works basically just like the hCG blood test my doctor used years ago to pick up signals of my miscarriage: it measures levels of the hormone. In effect, he said, the ability to "read" and measure hCG has gone "from big table top machines into little hand-held disposable test strips."

But first, some major caveats: The new test is not meant to be used to watch for signs of miscarriage, he said. It was not approved for that usage. It is not marketed for that. (In fact, there's a very clear warning on the Clearblue product page: "This test cannot be used to determine the duration of pregnancy or to monitor the progression of pregnancy.")

Still, in answer to my questions and scenarios involving women who, say, test repeatedly and do not see their "weeks estimator" rising from 1ish to 2ish to 3+, Dr. Zinaman said: "It is giving much more information than women had had before, and of course what women do with that information, God knows, we’ll find out as the test is available on the market. It is certainly not indicated for the things that you mentioned, but women will get good information about the progression of their pregnancy, because it is geared to tell you that [your] hormone level is at a certain level, or range of levels, and whether that is a rising level or a falling level."

In Europe, where the hCG tests have been on the market since 2008, it seems many women quickly figured out they could use it to try to monitor an early pregnancy's progress.

In a 2011 post, The Alpha Parent blog notes that "a lot of women use the test as a reassurance tool to indicate that their pregnancy is progressing as it should be." (It also warns that the test results "can be worrying, particularly for women with previous miscarriage," and are not meant to measure multiple pregnancies.)

It concludes:

In short, dating a pregnancy is best left to a professional, not a money-making gimmick. To quote, if you are concerned or wish to monitor the advancement of your pregnancy, please do it properly - under a physician's supervision, with a blood test at a lab - not at home with a pee-stick.

Conservative advice, but is it realistic? When I was seeking to have children, I was an information maximalist, even resorting to the pricey Clearblue fertility monitor to determine my most fertile time of the month. It was then about $200, plus about $50 a month for test sticks, and I swore by it, giving it credit (true, not all the credit) for the two healthy pregnancies that followed my miscarriage.

A miscarriage is a loss of innocence. Never again does a positive pregnancy test promise a baby; it merely promises a possible baby on the far side of many rocky shoals. So if I were trying to have a baby now, I think I'd spring for repeat hCG tests even though I'd know full well they were not definitive.

I would never act on what the tests said without medical confirmation — never, for example, give up a pregnancy for lost and go drink away my sorrows. But if a pregnancy was going wrong again, I would still want to get a hint of that as soon as possible.

Dr. Zinaman expects there will be many women like me. "I think women will be calling and saying, 'It’s not rising. I want to see the doctor,'" he said. "And the nurse will say 'Ah, you’re too early, don’t worry about it.'  'No, I used a real test, this new one.' And the nurses will say, 'No, don’t worry about it.' {But] That woman is going to be right, every time."

Another warning from Dr. Zinaman: Normal pregnancies tend to follow a very tight curve on hCG charts early on, he said, but some abnormal pregnancies follow that curve as well, and "then can fall off the curve at nine or ten weeks."  So even if the hCG seems to progress normally, "it's not a slam-dunk that you're going the right way."

And a note from my sad experience: Whatever tests they order, there's generally nothing a doctor can do to save an early pregnancy that does not "take." The hCG test simply gives some potential early warning.

Dr. Alison Zimon, a reproductive endocrinologist at Boston IVF who was not involved with the hCG test, said that patients do need to understand that it is potentially not entirely accurate -- even blood tests for hCG are notoriously variable

But enabling patients to do more testing at home is progress, she said, whether it's fertility-related hormones or pregnancy hormones. Boston IVF has recently developed a test that allows infertility patients to test their estrogen levels in their saliva at home, she said, saving them a half-dozen office visits and blood draws per cycle.

"I support such innovations in reproductive testing," she said, "because I believe such technology empowers patients, it gives them more options, more information, and alleviates stress and anxiety by reducing the need for multiple doctor's visits."

Readers, what do you think? Would you buy the new tests, and how would you use them?

This program aired on September 6, 2013. The audio for this program is not available.

Carey Goldberg Twitter Editor, CommonHealth
Carey Goldberg is the editor of WBUR's CommonHealth section.