Laboratory Director, NYU School of Medicine
Medical & Laboratory Director, Columbia University Medical Center
Vice Chairman of OBGYN, Mount Sinai Medical Center
In vitro fertilization, or IVF, is the most effective fertility treatment available, but it’s also the most expensive and physically taxing. For these reasons it can be hard to determine when to start IVF, when to stop, and generally what to expect from the process.
IVF is a complex process, with over 350 steps, but to oversimplify there are really just five key phases of treatment.
A woman takes injectable hormones to spur her ovaries to grow multiple follicles that contain mature eggs
A fertility doctor surgically retrieves those eggs
A fertility clinic’s laboratory uses sperm to fertilize the retrieved eggs
The same laboratory nourishes the fertilized eggs to become more stable embryos
A fertility doctor transfers an embryo into the woman’s uterus with the hope that a healthy fetus, and eventually baby develops
During the IVF process patients and doctors need to make a number of crucial decisions to increase the odds the IVF “cycle” will work. We’ll cover most of these in detail in a following lesson.
For a woman to conceive naturally, she must grow a high quality egg, ovulate it, have sex just before ovulation so that sperm is present, have a partner with a sufficient number of high quality sperm, she must have open fallopian tubes for the egg and sperm to meet, and a uterus capable of absorbing and nourishing an embryo.
For those who are unable to conceive naturally, at least one of these processes doesn’t work. Each major step of IVF is meant to help rectify one of these fundamental breakdowns.
Poor Egg Quality: If a woman has a small number of high quality eggs, stimulating the ovaries can help by making a larger number of eggs available, increasing the odds of finding a good egg. This is especially relevant to women in their late 30’s and 40’s.
Woman Does Not Ovulate (Regularly or Ever): If a woman does not ovulate an egg, it can’t be fertilized and she can’t become pregnant. IVF rectifies this through drugs that help develop eggs to the point of maturity whereby they can be surgically-retrieved from the ovary and fertilized in the laboratory. This is especially relevant to women with PCOS or hormonal imbalances.
Problematic Sperm: If a man doesn’t produce enough high quality sperm, it’s unlikely any will survive the journey from the vagina through the cervix, into the uterus and towards the fallopian tube to fertilize an egg. IVF removes all of these roadblocks. During IVF, the clinic will place a woman’s eggs in a petri dish and then surround them with sperm or inject one sperm directly into the egg. In nearly half of the cases of infertility, part of the issue resides with a man’s sperm and so this is a crucial reason IVF has higher success rates than other treatments.
Fallopian Tubes: If the fallopian tubes are blocked, natural conception is impossible because egg and sperm cannot meet for fertilization to occur. As we mentioned above, in vitro fertilization (“in vitro” means “in glass” in Latin) entails removings eggs and sperm from the body to be placed into a petri dish for fertilization. As a result, eggs and sperm can meet, which would otherwise be impossible if a woman’s fallopian tubes are blocked.
Endometrium: A woman’s uterus must be capable of absorbing and nourishing an embryo. Here IVF can be helpful to ensure “endometrial synchrony” which means the embryo arrives at the uterus when the uterus is most ready to absorb it. However, most issues within the uterus that prevent a pregnancy from occurring are structural in nature (like fibroids, polyps, or scar tissue from a D&C) and IVF does nothing to fix those. Instead, surgery (sometimes many) are required to address these structural issues.
IVF is the most successful fertility treatment but that doesn’t mean it always works. In fact the majority of IVF cycles don’t work. As a result, women who elect to do IVF often undergo multiple cycles. Two major determinants of whether an IVF cycle will work are the age of the woman being treated and the clinic at which she is being treated.
As you can see from the nationally-reported data below, IVF success rates correlate closely with age, and yet even amongst the most promising candidates (women under age 35), an IVF cycle results in a live birth less than half the time. In women over age 42, less than 5% of IVF cycles culminate in a live birth.
For this reason, as you can see from data below profiled in the the Journal of the American Medical Association, most IVF patients must undergo multiple IVF cycles before they deliver a child. You’ll also notice that the first IVF cycle is the most likely to work and each subsequent cycle is slightly less likely to work than the last cycle. This breeds the question of when someone should stop doing IVF with their own eggs, sperm, or uterus and consider using donor eggs, donor sperm, or a gestational carrier.
Generally speaking, doing an additional two to four cycles can still dramatically improve the odds of success for younger patients, but unfortunately that tends to be less true with age, as you can see below.
However, even women of similar ages can have dramatically different rates of success depending upon which clinic they go to. Let’s look at the publicly-reported success rate data for three clinics broken out by the age of the female patients. Since these clinics are all within large academic medical centers and located less than one mile from each other, presumably they see similar patients.
You’ll notice that Clinic A consistently performs better than Clinic B and both dramatically outperform Clinic C. Is there a chance Clinic C is actually more skilled than Clinic A, and some other factor is at play here? Certainly. But these same success rates unfold year-after-year and comports with what clinicians consistently tell us: going to a better clinic can improve your rate of success by up to two fold.
In the continuum of fertility treatments, IVF is the most effective, but it’s also the most costly and burdensome. To make that concrete, let’s weigh IVF versus IUI, which is also known as Intrauterine Insemination or Artificial Insemination. As you can see below in women under age 38, IVF success rates are higher (3 - 5 times) but costs considerably more (5 - 40 times).
For some fertility patients (like with those severe male factor issues or blocked tubes), IVF is the only feasible intervention to conceive. And for those who are eligible to try IUI or IVF, but who prioritize the “fastest time to pregnancy” above all else, IVF is clearly superior for every single age group as you can see below.