Super-fertility – a justification for recurrent miscarriages

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Miscarriages are an emotionally and physically uncomfortable experience for a woman to go through. A recurrent miscarriage is defined as losing three or more pregnancies in a row and unfortunately there is a self-assigned negativity related to females with this tragic fate. Normally, a miscarriage is detected at the formal 6-week scan in which a biochemical pregnancy is confirmed or rejected.

Having casually worked in a fertility practice, I have experienced the devastation associated with patients that are ecstatic about their positive pregnancy test, only to receive news that it was a miscarriage or the horribly put alternative, ‘missed abortion’.

Many affected women feel guilty that they are simply rejecting their pregnancy, said Prof Nick Macklon, a fertility consultant in the UK.

But there is an alternative explanation to this devastating occurrence. This is super-fertility. A recent study conducted by a team of UK and Dutch scientists have discovered that one explanation for recurrent miscarriages is not due to the ‘rejection’ of a fertilized embryo. It could be due to these women being super-fertile.

Super-fertility is the notion that some women have wombs that allow poor quality embryos to implant when they should be rejected. The scientists that published these findings carried out experiments of high and low quality embryos against womb cells. The cells of women with normal fertility grew out towards the high quality embryo whereas the cells of women with recurrent miscarriages grew out towards both embryos. This displayed that the womb cells of women with super-fertility did not discriminate between high and low quality embryos – offering an explanation to recurrent miscarriages.

The current method in place to combat this is in-vitro fertilization (IVF) with pre-implantation genetic diagnosis (PGD). This provides these women with a greater chance of a successful pregnancy.

The following steps explain IVF with PGD.

  • Retrieval of ova (eggs) from a female’s ovaries
  • Fertilization of eggs with collected sperm
  • Growth of embryo to the 8-cell stage (see picture above)
  • Removal of one of these cells for genetic testing
  • Re-implantation of high quality ‘normal’ embryos into the female’s uterus

By testing each embryo for genetic abnormalities and quality, healthy embryos are transferred back into the female patient for conception.

This study gives great hope for fertility specialists and women alike as it removes the negative associations of miscarriage. It also offers an explanation for women that have experienced an ‘unexplained’ miscarriage. Researchers are now focusing on whether super-fertility can be tested for, and if the cells of the womb can be altered to only favour high-quality embryos.

7 Responses to “Super-fertility – a justification for recurrent miscarriages”

  1. Sila says:

    Thats right Harriet.

    Seeing as females release one egg per month, we have one chance to conceive per menstrual cycle. If the embryo is low quality, it should be rejected.

    For a woman with normal fertility it might take a few months of ‘trying’ before they get pregnant. Super-fertile women can get pregnant more easily, but unfortunately this failure of embryo selection can lead to more failed pregnancies.

  2. Harriet Dashnow says:

    Thanks for the post, Sila. It’s a great way of changing perspective after a miscarriage.
    Is the logic something like, a woman with normal fertility would never have become pregnant with that specific embryo? So the super-fertile women are having more pregnancies per cycle over all?

  3. Sila says:

    Thanks Neha,

    You make a great point. Since the embryos used for surrogate mothers are tested for quality, there shouldn’t be an issue of miscarriage due to ‘low quality’.

    The thing is, it takes about a year or two of medical and personal background checks to be qualified as a surrogate, so I am sure these women are perfectly fertile themselves! In any case, the best thing to come out of this is the positive message it sends to women who suffer from miscarriages.


  4. Neha Patil says:

    This is a super super good post. Samantha asked my question and Sila anwered it offcourse. I wonder if these super fertile women make fantastic surrogate mothers cause they wont really have a problem of rejection of the embryos, would they?

  5. Sila says:

    Thanks for your comments guys!

    Samantha – studies have suggested that the normal regulation of embryo selection may have evolved as a response to the pressure of the high percentage of chromosomally abnormal embryos present in fertile women. Super-fertility is a result of this ‘natural selection failure’.

    Peter, sadly I have come across many women who have had anywhere from two up to eight miscarriages in their reproductive lives. IVF can get quite expensive and with PGD, it is double the cost. It is not 100% successful as there is only so much a doctor can do before the embryo is transferred back into the patient. After this point, it is the females womb which will govern if the embryo will implant or not.

    I definitely think the most important thing is to stay positive and this study will definitely help women in that respect. Also, having a caring physician that guides the patient through such an emotional experience is very important (I can recommend a few fantastic specialists if you like).

    The full paper can be access (for free!) on the following link, for those of you who would like to read about the full study.

  6. Peter says:

    Great post Sila!
    I have a friend that recently had a 2nd miscarriage – she and her husband were pretty devastated but they’re trying again with IVF.
    The main drawback with IVF is that it’s pretty expensive from what I’ve heard, and it’s not 100% successful, right?

  7. Samantha Walker says:

    Ooh super interesting. Are there any theories in circulation about what may be the cause of this ‘super fertility’?