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Medical Factors

What causes infertility?

There are many causes of infertility. For a successful pregnancy to occur: A healthy egg needs to be meet healthy sperm, fertilize, develop and find a good place to grow (a receptive uterus).

Problems at any of these steps can cause difficulties in getting pregnant:

  1. A woman’s body might not release an egg each month due to hormone imbalances.
  2. The man’s body might not produce enough sperm for successful fertilization.
  3. The fallopian tubes can be blocked or non-functional (for example, as a result of scarring from previous infections or inflammatory conditions like endometriosis). This would prevent the egg and sperm from meeting.
  4. It’s also possible that the uterus might not be receptive to implantation due to abnormal conditions like polyps, fibroids or infections.

It’s important to note that 30-40% of infertility cases are due to male factors. We need enough motile, swimming sperm to fertilize an egg. A “normal” ejaculate has over 18 million motile (swimming) sperm. Some men produce fewer or no sperm. Other men produce plenty of sperm but have obstructions in their tubes (the vas deferens), preventing sperm from being released. Just because a semen sample appears normal, doesn’t mean that there are sufficient numbers of sperm inside. We need to check with a microscope.

How do you determine ovarian reserve?

A woman’s ovarian reserve is directly related to age and potential to produce multiple eggs with ovarian stimulation. Ovarian reserve, or egg supply, begins to gradually decline beginning at the age of 30. The amount of medication required to stimulate the ovaries will increase and the number of follicles and eggs produced from the ovaries declines. These factors lower a woman’s chances of pregnancy with our best treatments. Several tests are used to determine a woman’s fertility potential, including blood tests such as Anti-Mullerian Hormone (AMH), FSH and Estradiol and a pelvic ultrasound to evaluate Antral Follicle Count.

What do the hormone tests indicate?

Normal ovulation requires a well-choreographed interplay of numerous hormonal events involving the brain, pituitary gland and ovaries. Stress, medical conditions and other events can throw these off and cause hormone imbalances that affect ovulation. If you are not ovulating every month, we will need to screen for conditions like Polycystic Ovarian Syndrome (PCOS), Hyperprolactinemia, Thyroid Problems, as well as other less common conditions. In order to evaluate your case, we may test for additional hormones.


How many eggs do we need?

The long answer is that the optimal number to ensure a single healthy pregnancy varies by age, reproductive history (have you been pregnant before?), and other factors that could make it easier or harder to get pregnant in the future.

The short answer: we recommend having at least 20 mature eggs frozen before your 37th birthday. Why? The largest study to date looking at the average number of mature eggs needed per live birth in patients using IVF suggested that 20 eggs were needed, up until age 37. Beyond age 37 the number was higher (about 40 eggs per baby at age 40 and 60 eggs by age 42). These numbers correlate very well with the national IVF success rates in the United States, as reported by the CDC.



What is a “mature” egg?

A mature egg (a.k.a. an “M2 oocyte”) is an egg that has completed the first stage of meiosis (reducing its DNA by half to prepare for fertilization with sperm). Not every egg that is retrieved is mature and therefore not every egg can be used. An egg must be “mature” to fertilize successfully.

How do you evaluate uterine conditions?

Although there are several molecular tests of uterine receptiveness, most current tests are not very predictive. The most important tool right now is to make sure the uterus is free of any lesions like polyps or fibroids. This is best done by either a Sonohysterogram, also known as a Saline Infusion Sonogram (SIS) or hysteroscopy. Occasionally, an endometrial biopsy can be performed to rule out chronic infections, or to perform experimental molecular testing.

How do you evaluate a male partner?

For men, the evaluation is even simpler. We perform a Semen Analysis to see if there are enough motile (swimming) sperm to reach and fertilize an egg. Low or absent sperm counts can be due to problems producing sperm or in a blockage preventing the sperm from being released. Appearing to ejaculate normally does not mean there are enough quality sperm being emitted.

The basic male evaluation can be addressed with two key questions:

Do you produce a sufficient number of “swimming” sperm to total sperm?
Fertile men typically produce tens of millions of sperm per ejaculate. It’s not enough to produce sperm; the job isn’t done until they reach the egg and fertilize it. Unfortunately, it’s a long journey, and therefore nature provides millions of sperm in the hope that one is able to make it to the egg, attach and fertilize.

Are the sperm able to leave your body?
Just as women have tubes that can be blocked (the fallopian tubes), the same is also true with men. The vas deferens is the tube that carries sperm from the testes to the penis. Sometimes these tubes can be blocked or congenitally absent. With an obstructed vas deferens, a man’s ejaculation may appear normal but lack sperm.

We evaluate sperm with a Semen Analysis, which tests the percent motility, or the number of sperm per ejaculation. We also examine direction and speed, shape, and other factors that can give your doctors insight into your ability to conceive without assistance.

When will we know what’s keeping us from getting pregnant?

The typical fertility assessment of both partners can be completed within a month (or one menstrual cycle) of an initial consult.

With Spring Fertility, you can know what’s happening in just one day. With our Same Day 360° Comprehensive Evaluation & Action Plan, you and your partner can come in to complete an initial consult, evaluation, and review of treatment options in a single day. By the end of the day, you’ll know your options and probability for success. You’ll leave equipped with a personalized roadmap and treatment plan.

How can we do that? We are one of only a handful of clinics across the country to offer everything onsite, including HSG, AMH testing, and semen analysis. Doing so allows us to shorten your wait for results. We know your time is important, so we’ve designed our workflow around your needs.


What is the IVF process like?

The IVF process is a series of steps that we’ll help you understand so you know exactly what to expect. Typically, the first 8-12 days encompass ovarian stimulation leading up to the egg retrieval. The egg retrieval coincides with preparing sperm for fertilization.

Then, depending on your situation, we’ll decide on what’s best for next steps:

Fertilization: Conventional IVF or ICSI?
When to plan your transfer: How long should we care for your embryos before transferring or freezing them? 2-3 or 5-6 days?
Embryo Transfer: Fresh or frozen? If frozen, do we transfer them in the future using a controlled or natural cycle?
Genetic testing: Do we test your embryos before transferring them?

We can help you decide what to do for each step based on your unique case and requirements.


How many embryos do we need?

A pregnancy requires one healthy embryo to be delicately transferred to a receptive uterus at the optimal time. Unfortunately, most embryos are not able to implant successfully, even under the best circumstances.

Here’s what we know: A healthy embryo (called a “euploid embryo”) has 46 chromosomes. Too many or too few and it’s unlikely to implant or might implant and miscarry.

“Euploid” embryos have approximately 50% chance of implanting and developing into a healthy baby. So on average, we need two euploid embryos to have a successful pregnancy.

But how many embryos do I need to get two euploid embryos?

Women under 35 have a 2 in 3 chance of having chromosomally normal blastocyst, so would need about 3 blastocyst stage embryos (on average) per live birth. As women age, the chances of having a chromosomally normal blastocyst decline.

At 40, women have a 1 in 3 chance of having a chromosomally normal embryo at the blastocyst stage, so would need about 6 blastocysts for a successful pregnancy. At 42, women have a 1 in 4 chance of having a chromosomally normal blastocyst, so might need about 8 blastocyst stage embryos (on average) per live birth. Women over 42 years have a 1 in 5-6 chance of finding a chromosomally normal embryo. This is why many women over 42 are using donor eggs, unless they froze their own eggs earlier.

For women using donor eggs, the chances of a successful pregnancy depends on the age of the donor. Since most donors are in their 20’s, far fewer embryos will be required per live birth.

Please don’t despair! Although the numbers above may seem discouraging, everyone is an individual and we have patients that beat the odds and have successful outcomes with a 2% chance. The above numbers are to give you a sense of overall probability. Please discuss your case with your doctor to get more individualized answers.

Should I transfer every embryo?

You do not need to transfer every embryo. After you transfer your desired and recommended embryo(s) we can cryopreserve any additional embryos with the potential for implanting. These are saved for a future pregnancy or if this attempt isn’t successful. Embryologists have been cryopreserving embryos since the 1980s. Today, embryo survival is better than 98% and many studies have shown the outcomes with frozen embryo transfers to be as good or better than with fresh embryos. See how we prepare your embryo for transfer:


What is elective cryopreservation: Are Frozen Embryos better than Fresh?

Several recent studies have been published that suggest frozen embryos may have higher pregnancy and live birth rates and may even have better live birth outcomes. Our interpretation: For some patients a frozen embryo transfer is going to be safer and result in a higher pregnancy rate. However, not all patients benefit from this approach so we do not recommend freezing all embryos to every patient. We believe we can identify the patients who will benefit from a “freeze all” approach and frozen embryo transfer during their monitoring. In these cases, we recommend cryopreserving all of your embryos without transferring them in order to increase your chance of a successful and healthy pregnancy.

Reasons we might cryopreserve without transferring an embryo:

Elevated early progesterone. The uterus has a “window of receptivity” when it will allow a good embryo to implant. Before and after that window, even a good embryo won’t be successful. Sometimes, the elevated hormone levels seen with ovarian stimulation can “confuse” the uterus into thinking the embryo will be arriving before it is ready. By the time the embryos arrive, the uterus is not receptive to implantation. So, instead of transferring a good embryo into a uterus that is no longer “receptive,” we’ll wait and use a frozen embryo when the timing is better.

New concerns about the uterine lining. Rarely, we detect a new polyp or bleeding that was missed before starting the IVF process.

Ovarian hyperstimulation syndrome. In patients who produce many eggs and embryos, ovaries can become hyperstimulated and need time to ‘cool down’ to allow for successful implantation. This is quite rare, and although it’s disappointing to experience an unplanned delay, it usually means there’s a good chance at a successful pregnancy the next month with a frozen embryo transfer.

Patient choice.
 One of the most common reasons is that a patient or couple wants to create embryos to transfer later, either for medical or personal reasons.

How long can my embryos be frozen?

Embryo freezing has been performed since the 1980s. Sperm cryopreservation has been successfully performed since the 1970s. We have seen many births from embryos cryopreserved for over 10 years and even some births from sperm cryopreserved for as long as 19 years. Animal studies suggest that cryopreservation is possible for even longer without detectable consequences but beyond 10-15 years, our experience is limited.

For frozen transfers, why might someone do a “controlled” (medicated) versus “natural” transfer cycle?

One decision we’ll consider together is whether you’ll want to do a natural or controlled (medicated) frozen embryo transfer.

If you’ve decided to get genetic testing or are otherwise using frozen embryos, then we’ll work with you to time your transfer. Compared to a “fresh” IVF cycle with ovarian stimulation, a frozen embryo transfer is much easier. Depending on your preferences for timing and your medical history, we can do a controlled cycle or a natural cycle.

  • Controlled Cycle: We give you medications to prevent your body from ovulating. We provide all the estrogen and progesterone you need for about 10 weeks.
    • Advantages: You can schedule the transfer to your convenience and have more control over the process.
    • Disadvantages: Cost and inconvenience of taking medications for 10 weeks.
  • Natural Cycle: We allow your body to ovulate on its own. As a result, you produce your own estrogen and progesterone and require minimal additional medication.
    • Advantages: Lower cost of medication.
    • Disadvantages: There is more initial monitoring to make sure we know when you ovulate and as such, it’s more unpredictable. We cannot control the exact date of the embryo transfer, since your body will ultimately determine when we need to transfer the embryo. We are also unable to give supplemental estradiol before you ovulate, so patients with thin lining may do better with a controlled cycle to supplement endometrial growth.

How common is miscarriage? What are my chances once I’m pregnant?

Unfortunately, miscarriages are very common and related to the age of the woman whose eggs are being used. While only 10-15% of pregnancies in your 20’s will end in miscarriage, this risk increases substantially during your mid to late 30’s. For women over 40 years of age over half of pregnancies will end in miscarriage. By age 45, nearly 75% of pregnancies will end in miscarriage.

Can I prevent a miscarriage?

While IVF alone cannot prevent a miscarriage, it does allow for embryo testing, which can minimize the risk of miscarriage after embryo transfer. After embryo sampling and PGS, the subsequent miscarriage rate is very low (3-8%) if the embryo has been tested and shown to be euploid.

When should I begin considering an egg donor?

At Spring, we counsel patients who are planning for an egg retrieval when they are 45 or older that we suggest that they consider using donor eggs. We have had successful live births from women ages 44, 45 and 46 with their own eggs, and successful pregnancies have been reported above age 46. However, these chances are low and we transparently counsel and educate patients to make decisions that are right for them. We recognize that the decision to use an egg donor requires careful consideration and we are here to support you. Our primary goal is to help our patients in their journey to have a family, and we strongly believe that DNA is only one component of parenthood. An embryo must implant, develop, and spend 9 months in your womb before you deliver your baby and devote a lifetime of care. The primary determining factor of the health and happiness of your future child is your parenting 😊

Endometrial Biopsy Testing Options

If you are struggling with infertility, you may have heard of endometrial testing options, such as the ERA (endometrial receptivity analysis), CD138 for chronic subclinical endometritis, or Receptiva Dx which claims to diagnose patients with endometriosis. All these tests boast strong claims of significantly improving patients’ chances of carrying a successful pregnancy. Please know that your Spring providers will always recommend any test or intervention that they think will help you be successful. While we are our patients’ strongest advocates, we are also data-driven scientists. For a full breakdown on how these tests work, the validity of their claims, and to learn more about specific cases in which we may recommend, you can read more here.

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