Ep 142: Infertility in a Couple of Reproductive Age
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This is Katarina Heidhausen, Executive Editor of Harrison's Principles of Internal Medicine. Harrison's Pod Class is brought to you by McGraw-Hills Access Medicine, the online medical resource that delivers the latest content from the best minds in medicine. And now, on to the episode. Hi, everyone. Welcome back to Harrison's Pod Class. We're your co-hosts. I'm Dr. Kathy Handy. And I'm Dr. Charlie Wiener, and we're joining you from the Johns Hopkins School of Medicine. Today's episode is about a couple of reproductive age.

Hey, Kathy. So today we're seeing a couple who comes to clinic because they've not been able to conceive a child despite nine months of unprotected intercourse. They're asking for your advice, and this topic today is going to be on infertility.

The WHO actually categorizes infertility as a disease of the reproductive system. It's very common. It affects over 48 million couples worldwide, and it's defined as the inability to achieve a pregnancy over 12 months of unprotected intercourse. One measure that's talked about when we're talking about infertility is the fecundability rate. So that's the ability to achieve a pregnancy within one menstrual cycle.

That's the highest in the first three months of attempting and declines over the next nine months. Approximately 85% of couples will achieve pregnancy after 12 months and 95% will achieve pregnancy after 24 months. Well, let me tell you more about this couple. They're both 35 years old and they've been married for a year. They've been trying to conceive for the last six to nine months.

The man has never had a steady partner with whom he's had unprotected sex. The woman had an IUD for contraception, but had it removed seven months ago. Her menses have always been regular. Neither of them report having prior sexually transmitted infections, and neither have a family history of infertility. Okay, you touched on a number of really important factors there to try to get to the potential causes of infertility. Well, let's get right into the question.

The question says, which of the following statements regarding infertility is true? Option A says greater than 85% of causes relate to an issue with the woman. Option B is if the female partner's age is greater than 35 years, it is recommended to initiate evaluation after one year of attempting pregnancy. Option C is obesity is a risk factor for infertility only in women.

Option D is semen analysis should be included in the initial evaluation of infertility. And option E is the probability of achieving pregnancy declines with age for men and women less than 50 years old. Okay, let's start with A. So that's false. The causes for infertility are generally classified as female causes, male causes, or unexplained.

Overall, female factors are present in about 30 to 40% of couples with infertility. Male factors are present in about 40 to 50%. And then both male and female factors are identified in about 20 to 30%. Unexplained infertility refers to the absence of any identified abnormality after completing the infertility workup, and that occurs in about 10 to 15% of couples. So male causes are more or at least equally common than female causes. What are the common male causes?

So there are four main categories. One is anatomic, so that would be if someone had a vasectomy or absence of the vas. There are endocrine factors. This includes hypogonadism or hypothyroidism, for example. Obesity and medications can also contribute to these endocrine factors. And then there are sexual factors like erectile dysfunction. And lastly, there are genetic factors that can lead to primary testicular dysfunction. How about the most common female causes?

So I will group those into four categories too. So there are tubal factors such as pelvic inflammatory disease or salpingitis, endometriosis or prior surgeries would fall into that category. There are uterine causes such as congenital malformations or fibroids or uterine scarring. And then there's ovulatory dysfunction, polycystic ovarian syndrome would fall into that category, diminished ovarian reserve or even premature ovarian insufficiency.

And lastly, endocrine dysfunction. Again, hypothyroidism or even hyperprolactinemia can be in that category. You mentioned obesity for both sexes. So does that mean that option C is false also? Yes. In men, morbid obesity is associated with infertility. But in women, either extreme of BMI, either high or low body mass index, is associated with infertility. Options B and E both mention age. Let's discuss those.

Age is more important in women than men. So compared to women aged 30 to 31 years old, fecundability, remember that's the ability to get pregnant within one menstrual cycle, that's reduced by 14% in women aged 34 to 35. It's 19% in women aged 36 to 37 years old, 53% in women aged 40 to 41 years old, and then 59% in women aged 42 to 44 years.

So an infertility evaluation is recommended after six months of trying in women over the age of 35. So option B is false. Okay, what about men? Option E says the probability of achieving pregnancy also decreases for men up to 50 years old. That's not true. Although the probability of achieving a pregnancy decreases after the age of 35 in women, primarily due to chromosomal abnormalities in the oocyte during meiosis, a similar decline has not been observed in men under the age of 50.

Okay, well that leaves us with option D, which addresses the initial evaluation. Yes, the initial evaluation of a couple for infertility should include a detailed medical history, laboratory testing, and preconception counseling for both partners, and that will include a semen analysis. And that's largely because of the first point that almost half of cases of infertility have an etiology that relates to the male.

What's included with the semen analysis? The semen sample is collected after two to seven days of abstinence, and it provides an assessment of the sperm count, the motility, the morphology, the volume, and the pH. Although there is significant overlap between semen parameters of fertile and infertile men, those with abnormal sperm parameters should undergo further endocrine and genetic evaluation. And further testing for the woman?

Yeah, that will be decided after the initial history, the physical in labs, but it could include tests such as additional endocrine evaluation and ultrasound, ovulation and reserve evaluation, a hysterosalpingogram, and also a genetic evaluation. Great. So to summarize, today's teaching points are that infertility is a couple's issue and is not specific to one sex.

A comprehensive history and physical examination, as well as basic screening of both partners, should be included in the initial evaluation. The treatment and the likelihood of success will depend on all of these factors, which is why counseling should be an important component of the care of the couple. This question and other questions like it can be found in the Harrison Self-Review Book and online, and you can read more about this in the chapter on infertility and contraception.

Visit the show notes for links to helpful resources, including related chapters and review questions from Harrison's, available exclusively on Access Medicine. If you enjoyed this episode, please leave us a review so we can reach more listeners just like you. Thanks so much for listening.