Tag Archives: Medical Device Design

Obesity is a risk factor for IUD Expulsions

This is National Women’s Health Week. I am trying to highlight key health-related news all week. This night’s post also comes from the latest ACOG 2017 meeting from last week.


Obesity is already a risk factor for various health conditions, such as diabetes, cardiovascular diseases and so on. For long term, reversible contraception, it is recommended that obese women opt for IUD over oral pills or patches, as the chances of venous thromboembolism is higher in obese and overweight women, than in women of normal weight. Please see referenced link below. It is an earlier paper by the same lead author/group as the current one, coming from Hawaii.

Weight classification, takes women and men from underweight to normal weight, overweight and obese. Within obesity, depending on waist size, the classification goes from Class I to Class III, representing extreme obesity. I have attached an NIH reference for your convenience.

It appears that in women with Class III obesity, IUDs can shift inside the uterus, also commonly termed IUD expulsion, at a higher rate than in women of other weight classes. This was the focus of the presentation at ACOG last week.

The current study

A retrospective cohort study, in Hawaii, with access to a diverse population including approximately a third each of Asian women and Native Pacific Islanders, has shown that obese women with Class III obesity have a risk, that is 3.06 times other women. Read other details in the paper summary and the article linked below.


The study itself was only performed, retrospectively to titrate risks. Some theories have been presented by the authors.

Placement itself might pose difficulties because of obesity.

Another risk of obesity is heavy menstrual bleeding, and therefore, IUD expulsions might be encouraged.

The authors however continue to encourage the use of IUDs in all women, regardless of body weight, as the benefits outweigh risks.


While on one end, further studies are needed, and will likelihood indicate why IUD expulsions occur at a higher rate in obese women, women should not stop opting for IUDs.

Additional studies that describe the causes for IUD expulsion might indicate that it is solely not a function of obesity, and it has already been shown that obesity is but one risk factor for expulsion.

Knowing why IUDs dislodge or move would make for better IUD design! 

Until the reasons are known and designs could be potentially improved, for the long term, women should focus on efforts that help them lose weight, in a healthy and practical manner.


  1. ACOG Presentation Summary: http://mobile.journals.lww.com/greenjournal/Abstract/2017/05001/Levonorgestrel_Intrauterine_Device_Complications.235.aspx
  2. A previous article by the same group: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4642497/
  3. The mdedge article http://www.mdedge.com/clinicalendocrinologynews/article/137744/gynecology/beware-hormonal-iud-expulsion-obese-women?channel=261&utm_source=News_CEN_eNL_051317_F&utm_medium=email&utm_content=Are%20some%20obese%20women%20having%20issues%20with%20IUDs?
  4. NIH Weight Classification: https://www.nhlbi.nih.gov/health/educational/lose_wt/BMI/bmi_dis.htm
  5. Some information on IUD Expulsion and what to do: http://www.healthline.com/health/birth-control/iud-fell-out#5
  6. Retrospective Cohort Studies: https://en.wikipedia.org/wiki/Retrospective_cohort_study
  7. Image Courtesy, Pexels: https://www.pexels.com/photo/backlit-beach-dawn-dusk-227674/

No, one pregnancy does not make Mirena or other IUDs useless

It is important to remember that the best source of advice is your Obstetrician/Gynecologist/Doctor, and regardless of all your research, you should always consult them for medical advice! 

The Backstory

Always on the look out for interesting medical device news, I came across this apparently humorous story of a baby, born through a pregnancy that occurred about 3 weeks (this is only an assumption based on what the mother herself has predicted) after the placement of a Mirena IUD.

The humor supposedly lies in the fact that the Obstetrician fished out the IUD, which was difficult to find and remove during the pregnancy, while the C-section was being performed. A nurse then put the IUD on the baby’s hand and captured an image with one of the ubiquitous smartphones, shared it, and the image then went “viral”.

What Ensued

Due to stiff competition among manufacturers and variable experiences from patients, Mirena, and IUDs in general, are discussed on and off, with their capabilities challenged. An incident such as this pregnancy always bring up questions, many fair, and many not. It is important that they be addressed, nevertheless.

I have always maintained, even in my earlier blog posts (one is linked below) on my main Medical Devices blog, that IUDs are the easiest and least invasive ways to prevent pregnancies, when compared to other devices.

Planned Parenthood appears to claim that IUDs are 99.9% effective. Now, I would be cautious even with the force of Planned Parenthood behind the statement. A pregnancy that was already initiated, hormonal imbalances or physiological oddities, improper placement, any number of things could potentially cause a pregnancy.

Even with both partners exercising birth control measures, you could still have a pregnancy!

Some Caution for Device Designers

People see the humor in the situation, but a health practitioner and a device designer/engineer should see something worrisome here. Of course, reporters (link below), don’t always know how to accurately represent information, but I find this particular sentence of concern:

The doctor was unable to remove the implant during her pregnancy, but while delivering the baby, Hellein said he found it behind her placenta.

Note: Hellein is the mother.

There are at least one of two things going on:

  1. It was simply difficult or impossible to remove the IUD during the pregnancy.
  2. It is possible that it was impossible to remove the IUD because it could not be found!

Understandably possibility no. 2 is quite worrisome. Without knowing much though, I cannot tell whether the IUD needs to have features that make it obvious during an X-Ray, Ultrasound or other imaging technique, preferably, an imaging modality whose radiation levels don’t present risks to mother or child.

Opportunities and Challenges

If the IUD is difficult to find due to anatomical challenges, whether they arise from a pregnancy or not, there is an opportunity to improve the design of IUDs. What form this might take is hard to say, and one thing to consider is, that the methods that help make the device visibility should be biocompatible and should in no way threaten the patient or any potential babies.

Further Issues

Here is something else from the article that gives me pause:

“This woman is very lucky that when the placenta grew over the IUD it did not disrupt the blood flow to the placenta,” Ghasseminia said.

She said this could lead to a miscarriage.

Laura Ghasseminia, is apparently a Planned Parenthood nurse practitioner, interviewed for the story by 10 News (link below). What she said here, gives one further pause. It is difficult to conceive, but it could be possible to design an IUD that  somehow loses flexibility or its shape once it dislodges from its location, whether due to a fertilized fetus, or due to some other reason.

All said, there are some challenges that this pregnancy and the “miracle baby” have unearthed, and this requires further consideration!


  1. The News Story Quoted Above: http://www.wtsp.com/news/exclusive-baby-born-holding-mirena-iud-mom-sets-the-record-straight/436603932
  2. An old blog post of mine: http://chaaraka.blogspot.com/2007/09/womens-health-devices-heat-upslowly.html
  3. Image courtesy, Pexels: https://www.pexels.com/photo/adorable-baby-baby-feet-beautiful-266011/