Tag Archives: fertility

An early beta hCG test is a good predictor of an ongoing pregnancy

That first glimpse of two pink lines–is it real?–and your heart start to pound with excitement. You’re pregnant!

But after a few minutes of celebration, you descend back to earth. Okay, you’re pregnant, but for how long? Will this pregnancy stick? This is a new, more hopeful limbo than the much bemoaned two-week wait, but it is still not picnic.

These kinds of worries are inevitable. Miscarriage is very common, especially early in pregnancy. And for most women, good info about viability does not come until the first ultrasound usually performed at 8-10 weeks.

Fortunately, women undergoing fertility treatments receive information about their chances a bit earlier with a “beta”–that is, a blood test of their beta hCG (Human Chorionic Gonadotropin) levels.

What is HCG (Human Chorionic Gonadotropin)?

The embryo produces hCG as it burrows into your uterine lining. HCG passes into your bloodstream and helps to maintain the uterine lining and keep progesterone levels high in early pregnancy.

During the first trimester, blood levels of HCG rises quickly, normally doubling every 48 hours in early pregnancy, until reaching a peak around 20 weeks, after which they begin a slow decline.

Predicting ongoing pregnancy with HCG

The level of hCG in your blood predicts your chances of an ongoing pregnancy–which researchers usually define as one that lasts through the first 8-12 weeks.

The table below summarizes findings from several IVF clinic-based studies which tracked pregnancy outcomes by hCG levels. These numbers apply to singleton pregnancies. Twin pregnancies tend to have higher hCG levels.

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When comparing your test results, pay close attention to the post-retrieval or post-transfer date listed in the Day tested column. Some studies report by day from egg retrieval (post retrieval). Others report from day after blastocyst or embryo transfer (post transfer). HCG rises rapidly in early pregnancy, so whether a specific beta is a positive or negative signs depends on precisely when hCG was measured.

The hCG threshold for likely viability rises with each day. As one research team that examined hCG levels on different days post-retrieval reported “hCG samples … were taken on day 14, 15 or 16 after oocyte retrieval in 204 patients undergoing IVF or ICSI were analyzed… optimal cut-off levels to discriminate between viable and non-viable pregnancies… were found at 76, 142 and 223 IU/L for day 14, 15 and 16, respectively”

Interpreting your betas

If your betas are above the numbers listed in the table above, congratulations! Your pregnancy has a very high chance of continuing through the first trimester.

Note, however, that HCG is not as good of an indicator of a live birth as it is of avoiding a first trimester miscarriage–so you’re not completely off the worry hook yet. Your first ultrasound will provide better information than your beta about your chances of a live birth.

What if your hCG is below those in the above table? Don’t panic. In all of these studies about 40-60% of the pregnancies with values below the stated thresholds were ongoing. In other words, hCG was better at predicting a good outcome than it was at predicting  a bad outcome. Because hCG levels vary a lot from pregnancy to pregnancy, there is no strict cutoff for determining viability.

HCG Levels during the first trimester

Normal HCG levels range widely in early pregnancy.

Below are the ranges of beta hCG by week following your Last Menstrual Period (LMP), according to the American Pregnancy Association.

  • 3 weeks LMP: 5 – 50 mIU/mL
  • 4 weeks LMP: 5 – 426 mIU/mL
  • 5 weeks LMP: 18 – 7,340 mIU/mL
  • 6 weeks LMP: 1,080 – 56,500 mIU/mL
  • 7 – 8 weeks LMP: 7, 650 – 229,000 mIU/mL
  • 9 – 12 weeks LMP: 25,700 – 288,000 mIU/mL
  • 13 – 16 weeks LMP: 13,300 – 254,000 mIU/mL
  • 17 – 24 weeks LMP: 4,060 – 165,400 mIU/mL
  • 25 – 40 weeks LMP: 3,640 – 117,000 mIU/mL

Serial hCG measurements

What does often indicate an impending miscarriage, however, are hCG levels that fail to double every 48 hours or that drop over time. This nearly always indicates a failing pregnancy. It can also indicate an ectopic pregnancy–an pregnancy that has implanted somewhere other than the uterus.

One final caveat: All of the above studies involved women undergoing IVF. We cannot say whether these numbers apply to women undergoing IUI or who conceived naturally.

Special case: Frozen embryo transfers

Some but not all studies find that HCG levels are lower and less predictive of miscarriage after frozen (as opposed to fresh) embryo transfers.

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In Xue’s 2014 study, nearly 100% of pregnancies that made it past 12 weeks had day 12 hCG levels about 50 IU/L, as shown in the table below. But many miscarriages also had hCG levels above this threshold; 50 IU/L did not discriminate well between ongoing pregnancies and miscarriages.

A higher threshold of 135-147 IU/L performed better. Nearly 94% of pregnancies with hCG levels above this threshold were ongoing.

Have you had a beta? What was it and how did your pregnancy turn out?

(If you have had a first trimester ultrasound, you may wish to check out my post on miscarriage risk by week, by fetal heart rate, and by other risk factors like your age.)

References

Porat S, E. al. Early serum beta-human chorionic gonadotropin in pregnancies after in vitro fertilization: contribution of treatment variables and prediction of long-term pregnancy outcome. https://www.ncbi.nlm.nih.gov/pubmed/17307176

Kim, J. H. et al. Serum biomarkers for predicting pregnancy outcome in women undergoing IVF: human chorionic gonadotropin, progesterone, and inhibin A level at 11 days post-ET. Clin. Exp. Reprod. Med. 39, 28 (2012).

Kim, Y. J. et al. Predictive value of serum progesterone level on β-hCG check day in women with previous repeated miscarriages after in vitro fertilization. PLoS One 12, (2017).

Kumbak B, E. al. Serum oestradiol and beta-HCG measurements after day 3 or 5 embryo transfers in interpreting pregnancy outcome. https://www.ncbi.nlm.nih.gov/pubmed/17007661

Papageorgiou TC, E. al. Human chorionic gonadotropin levels after blastocyst transfer are highly predictive of pregnancy outcome. https://www.ncbi.nlm.nih.gov/pubmed/11704121

Xue Y, E. al. Effect of vitrification versus slow freezing of human day 3 embryos on β-hCG levels. https://www.ncbi.nlm.nih.gov/pubmed/24880883

Ochsenkühn R, E. al. Predictive value of early serum beta-hCG levels after single blastocyst transfer. https://www.ncbi.nlm.nih.gov/pubmed/19878087

Lambers MJ, E. al. Optimizing hCG cut-off values: a single determination on day 14 or 15 is sufficient for a reliable prediction of pregnancy outcome. https://www.ncbi.nlm.nih.gov/pubmed/16466846

Sung N, Kwak-Kim J, Koo HS, Yang KM. Serum hCG-β levels of postovulatory day 12 and 14 with the sequential application of hCG-β fold change significantly increased predictability of pregnancy outcome after IVF-ET cycle. Journal of Assisted Reproduction and Genetics. 2016;33(9):1185-1194. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5010803/

Nine Science-Backed Tips for Getting Pregnant Quickly

Back when my husband and I decided to try for a baby, I remember feeling so impatient. I basically wanted a baby right then. Today. That instant. The inevitable nine months seemed too long to wait, let alone the time it would take for us to conceive.

I am sure I am not alone in this sentiment.

So, if you too are feeling impatient to become pregnant, here are some science-based tips to help maximize your chances.

1. Have sex at the right time. Timing intercourse correctly is the most important thing you can do to conceive quickly. Continue reading Nine Science-Backed Tips for Getting Pregnant Quickly

Fertility in Your 30s and 40s: 7 Things You Need to Know

One of my former colleagues became pregnant her first shot out of the barn, the first month off the pill. Her story would hardly be noteworthy, except that she was 41 at the time.

She wanted to tell other women about her experience, she confided to me. She saw it as a sign that women can have children after age 40.

I simply nodded in response, while I privately wondered if she had not just been very lucky.

But–and this is key–how lucky?

Having a baby in your 30s and early 40s–and earlier, for that matter–is always a chance event. There will be outliers. Some women will give birth naturally at 44. Some women will suffer from early menopause at age 30. But outliers tells us little about the norm.

Anyone who wants to play the conception game, especially if they are postponing childbearing, needs to put anecdotes aside and try to grasp the actual odds. Here’s what every woman needs to know:

Continue reading Fertility in Your 30s and 40s: 7 Things You Need to Know

Does Giving Birth “Reset” a Woman’s Fertility?

Do couples have an easier time getting pregnant after they have already had a child?

I’ll confess, my interest in this topic is personal. We were one of these couples. We took over a year to conceive my son, but our second was a surprise.

Back when my first was born, as we were getting ready to head home after three long days in the hospital, with round-the-clock wake ups, I made the mistake of telling our delivery nurse that we were not planning to use birth control.

She immediately launched into a lecture that we needed birth control. “Giving birth can reset your fertility,”  she stated matter-of-factly. And then added sternly that we needed to start using birth control as soon as we resumed having sex.

Although she briefly made me feel like an errant teenager, I did not take her advice very seriously.

Various reputable sources of medical information, such as WebMd, state that the prior births do not “reset” a woman’s fertility,asserting that the notion is a myth.

Two recent studies, however, suggest there might be something to this idea after all.

Kenneth Rothman of Boston University, led a prospective study, which followed 2820 Danish couples who were trying to conceive for up to 12 cycles.

Rothman then calculated how the woman’s age affected a couple’s fecundability ratio–a statistical estimate of a couple’s ability to conceive each menstrual cycle.

Couples in which the woman had given birth before–about half of the couples in their early 30s and two-thirds of those in their mid to late 30s–had much higher fecundability throughout their 30s:

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Continue reading Does Giving Birth “Reset” a Woman’s Fertility?