Reproductive medicine is a medical specialty focused on diagnosing and treating conditions that affect the reproductive system, fertility, and the ability to have children. It covers everything from hormonal disorders and structural problems to advanced laboratory techniques like in vitro fertilization. The field serves women, men, and couples, and it extends well beyond infertility into areas like fertility preservation, genetic screening of embryos, and third-party reproduction using donors or gestational carriers.
Who Reproductive Medicine Serves
About 1 in 6 adults worldwide experience infertility at some point, according to a 2023 World Health Organization report. That rate is remarkably consistent across income levels: 17.8% in high-income countries and 16.5% in low- and middle-income countries. Infertility is typically defined as the inability to conceive after one year of regular unprotected sex, or after six months if the woman is over 35.
But reproductive medicine isn’t only for people struggling to conceive. The field also treats hormonal conditions like polycystic ovary syndrome (PCOS), which affects roughly 1 in 10 women of childbearing age, as well as endometriosis, uterine fibroids, recurrent pregnancy loss, and menopause-related concerns. On the male side, it addresses low sperm counts, hormonal imbalances, erectile dysfunction, and structural problems like varicoceles or blocked sperm-carrying tubes.
The Specialists Behind the Field
The physicians at the center of reproductive medicine are reproductive endocrinology and infertility (REI) specialists. Their training path is long: after medical school, they complete a full residency in obstetrics and gynecology, followed by a three-year fellowship specifically in reproductive endocrinology. During that fellowship, they must complete and defend a research thesis before becoming board-eligible. This gives them deep expertise in the endocrine, genetic, anatomical, and molecular causes of reproductive problems.
REI specialists don’t work alone. Reproductive medicine clinics typically involve embryologists who handle eggs and sperm in the lab, reproductive urologists who treat male-factor issues, genetic counselors, and mental health professionals who support patients through what can be an emotionally demanding process.
How a Fertility Workup Works
When someone seeks help, testing usually begins for both partners at the same time. For men, the starting point is a semen analysis. The World Health Organization’s most recent reference values (from 2021) set the lower normal thresholds at 39 million sperm per ejaculate, 42% total motility, 30% progressive motility (sperm swimming forward), and 4% normal forms. Falling below these numbers doesn’t guarantee infertility, but it signals that something may need closer attention. If semen fructose levels are low, that can point to a blockage in the reproductive tract.
For women, a key early test is anti-Müllerian hormone (AMH), a blood marker that estimates ovarian reserve, meaning roughly how many eggs remain available. AMH can be drawn on any day of the menstrual cycle, which makes it convenient. Low levels suggest the ovaries may not respond well to fertility medications. Doctors also evaluate the uterus and fallopian tubes, often with imaging, to check for structural problems like blocked tubes, fibroids, or other abnormalities.
Common Treatments
Treatment depends entirely on the cause. Hormonal imbalances in either partner may respond to medication. Structural issues, like a varicocele in a man or fibroids in a woman, can sometimes be corrected surgically. When the problem is unexplained or doesn’t respond to simpler approaches, the next step is usually one of the assisted reproductive technologies.
Intrauterine Insemination (IUI)
IUI is a relatively straightforward procedure. Sperm are concentrated in a lab and then placed directly into the uterus through a thin tube, bypassing the cervix. It’s often a first-line option for mild male-factor infertility, unexplained infertility, or when donor sperm is being used.
In Vitro Fertilization (IVF)
IVF is more involved. The ovaries are stimulated with hormones to produce multiple eggs, which are then retrieved and combined with sperm in a laboratory dish. If fertilization succeeds, one or more embryos are transferred to the uterus. About 60% of IVF cycles in the United States now use a technique called intracytoplasmic sperm injection (ICSI), where a single sperm is injected directly into an egg. This is especially useful when sperm quality is poor or when standard fertilization in a dish hasn’t worked.
Success rates vary significantly by age. The CDC publishes clinic-specific data each year, and the most recent available figures cover 2022. Rates are broken down by patient age group and by whether the patient used her own eggs or donor eggs. As a general pattern, success rates are highest for women under 35 and decline with each subsequent age group, which is why age is the single most important factor in fertility treatment outcomes.
Genetic Testing of Embryos
One of the more significant advances in reproductive medicine is the ability to test embryos before they’re transferred to the uterus. There are three main types of preimplantation genetic testing.
- PGT-A (aneuploidy screening) checks whether an embryo has the correct number of chromosomes. Extra or missing chromosomes are the most common cause of failed implantation, miscarriage, and conditions like Down syndrome. This test helps select embryos with the best chance of a healthy pregnancy.
- PGT-M (monogenic disorders) screens for a specific inherited disease when one or both parents are known carriers. It can be used for any hereditary condition where the responsible gene has been identified, such as cystic fibrosis, sickle cell disease, or Huntington’s disease. In rare cases, PGT-M is also used to select an embryo that is a tissue match for a sick sibling who needs a stem cell transplant.
- PGT-SR (structural rearrangements) is for parents who carry chromosomal rearrangements like translocations, inversions, or deletions. These rearrangements can lead to miscarriage or genetic conditions in offspring, and PGT-SR helps identify embryos that didn’t inherit the problem.
Fertility Preservation
Reproductive medicine also focuses on protecting future fertility. Egg freezing (oocyte cryopreservation) involves stimulating the ovaries, retrieving mature eggs, and flash-freezing them using a technique called vitrification. The first successful pregnancy from a frozen egg happened in 1986, and the technology has improved dramatically since then.
There are two broad reasons people freeze eggs or embryos. The first is medical: patients facing chemotherapy, pelvic radiation, or other treatments that damage the ovaries can preserve eggs beforehand. Despite this option being available, only about 1 to 2% of women of reproductive age diagnosed with cancer ultimately go through any type of fertility preservation, partly because many never receive counseling about it.
The second reason is elective, sometimes called “social” egg freezing. People choose this to buy time when they haven’t found a partner, aren’t financially ready, or simply want more flexibility around when to have children. The American Society for Reproductive Medicine removed the experimental label from egg freezing for medical patients in 2013 and deemed elective freezing ethically permissible in 2018. Sperm freezing and embryo cryopreservation are also widely available and follow a similar logic.
Third-Party Reproduction
When a person or couple can’t conceive using their own eggs, sperm, or uterus, reproductive medicine offers third-party options. Donor sperm can be used in IUI or IVF. Donor eggs are fertilized through IVF and the resulting embryo is transferred to the intended parent or a gestational carrier. Embryo donation is also possible, where a previously created embryo from another couple is transferred. Gestational surrogacy involves a carrier who becomes pregnant through embryo transfer but has no genetic connection to the child. These paths allow single individuals, same-sex couples, and people with medical conditions that prevent pregnancy to build families they otherwise couldn’t.