Mention that you’re trying to get pregnant to your friend group, and suddenly everyone has advice for you. One person may sneak some herbs into your purse that she swore worked for her. Another may give you the name of her acupuncturist. The woman eavesdropping from the next table might lean over and ask if you’ve had your partner’s sperm tested.

When it comes to what actually impacts fertility—and what fertility even is, for that matter—it’s important to get your information from experienced sources and fertility specialists. Tips from friends, nosy family members, and online forums may be right or may be wrong. 

Enter: this guide. We culled through the latest research and talked to experts to bring you the ins and outs of fertility, including answers to the most commonly asked questions.

What Is Fertility and Infertility? 

Fertility is defined as a person’s ability to conceive children. And we’re not just talking about women. Men’s fertility is important for conception, too. 

On the opposite side is infertility, which means a person is unable to get pregnant due to a variety of factors, including their medical, sexual, and reproductive history; age; or physical issues. According to the American Society for Reproductive Medicine, heterosexual couples are considered to be experiencing infertility if the woman is under age 35 and they can’t get pregnant after having unprotected, consistent sex for 12 months. When the woman is older than 35, that time frame shrinks to six months.

These traditional definitions only take into account heteronormative family units. It’s important to acknowledge that single people wanting to have a baby on their own and gay couples can also experience infertility, notes Annelise Swigert, M.D., an obstetrician/gynecologist at Southdale Obgyn in Minnesota. No matter what your situation, the throughline is needing medical intervention to achieve a successful pregnancy.

How common is infertility? The World Health Organization says that 1 in 6 people globally deal with infertility in their lifetime. In the U.S., an estimated 11% of women and 9% of men of reproductive age in the U.S. have experienced fertility problems, according to the U.S. Department of Health and Human Services. But that may not capture the full scope, as this data may only relate to heterosexual couples. Which means that the number of people dealing with infertility may be considerably higher.

How Does Fertility Work?

Not to make you relive awkward sex ed memories, but let’s quickly recap what needs to happen in the body to get pregnant. For the purposes of explanation, we’ll be focusing on a heterosexual couple.

• During unprotected sex, semen is deposited in the vagina, usually close to the cervix. “Some of the sperm immediately begin swimming to the egg, while the remainder and other liquids in semen simply exit through the opening of the vagina,” says Winifred Soufi, M.D., Ph.D., an obstetrician/gynecologist in Atlanta, Georgia.
• Conception—when the egg is fertilized by the sperm—can take place as soon as three minutes after sex or up to five days later, says Dr. Soufi. Fertilization takes place in one of the fallopian tubes; they’re located between the ovaries and uterus. During fertilization, the sperm and egg unite to form a zygote, which is a fancy word for a fertilized egg. 
• After five or six days, the zygote becomes a blastocyst, or a little ball of cells. Then, it becomes an embryo, when cells start dividing. This is considered the first stage of fetal development, and lasts until the baby is born. 
• Next comes implantation. “[This is when] the fertilized egg [a.k.a. the embryo] attaches itself to the uterine wall [also called the lining],” Dr. Soufi explains. “Implantation occurs five to 10 days after fertilization—which means it can happen anywhere from five to 15 days after you had sex.” (Is your mind spinning yet?) The embryo will remain attached to the uterine lining until the end of pregnancy.

Of course, all of this assumes that the woman is not taking hormonal birth control (BC). The hormones in that type of BC can affect everything from ovulation to cervical mucus. This blocks sperm from swimming to the egg, which prevents conception.

9 Factors That Affect Fertility

When a couple can’t get pregnant, the belief often starts with: It’s the woman. But that’s only true in one-third of infertile heterosexual couples, per the U.S. Department of Health and Human Services. Another third of the time, it’s related to the man’s health. In the final third, the problem can’t be identified, or there’s an issue with both people. 

Knowing this, here are some key factors that can affect fertility:

• Age of the woman: While The American Society for Reproductive Medicine hones in on age 35, Dr. Swigert says there isn’t a dramatic shift in fertility that occurs at the 35th birthday; however, fertility begins a steady decline.
• By the mid-40s, it’s less likely that a woman will become pregnant spontaneously, she notes. There are a couple reasons why. 1) The number of eggs a woman has decreases as she ages. 2) After 40, the remaining eggs are more likely to have chromosomal abnormalities, which can increase the risk of miscarriage or the baby having potential genetic challenges.
• Age of the man: A man’s age matters for fertility, but less so than the woman’s age. “Women are born with all the eggs they will ever have, but men naturally produce new sperm [continuously],” Dr. Swigert says. Still, men do produce less sperm around age 40, which can make getting pregnant more difficult.  
• Diet and lifestyle: Generally, the healthier someone’s lifestyle, the better their fertility will be, says Dr. Swigert. “This means making healthy food choices, minimizing processed foods, and not consuming excessive amounts of sugar,” she notes. Studies also show that nicotine and alcohol can both negatively impact fertility. In fact, women who smoke are 41% more likely to experience infertility than women who don’t smoke.
• Weight: Studies show that being overweight or underweight can increase the likelihood of infertility. But remember that the scale is just one measure of health.
• Sexually transmitted infections: Women who have untreated chlamydia or gonorrhea can have a harder time getting pregnant. These sexually transmitted infections can impact the health of the fallopian tubes or cause pelvic inflammatory disease.
• Chronic health conditions: This can be in women or men, and include conditions that seem unrelated to the reproductive system, like diabetes or heart disease, explains Luisa Vera, M.D., an obstetrician/gynecologist at UNC Rex Hospital in Raleigh, North Carolina. But ovulatory disorders, such as polycystic ovary syndrome (PCOS) and endometriosis, are of particular concern. PCOS can create a hormonal imbalance that interferes with the growth and release of eggs from the ovaries. And having endometriosis can impact fertility by scarring the fallopian tubes, which can make implantation more difficult.   
• Fibroids: Between 2% and 3% of women experience infertility due to uterine fibroids, which are tumors that can develop in the uterus. “Fibroids can decrease the likelihood of getting pregnant because they can block the fallopian tubes,” Dr. Vera says. 
• Medications: Certain medications can impact sperm health, inhibit ejaculation, or affect ovulation. These include 5-alpha-reductase inhibitors (used to treat hair loss and prostate enlargement) and hormone-based skin or hair products. If you are trying to get pregnant, talk to your doctor about any meds or supplements you and your partner are taking.

3 Signs You Might Have Fertility Issues

The most obvious red flag is when you’re not getting pregnant despite trying. But there are other signs that may point toward a fertility problem.

• An irregular period: If your period is unpredictable, there may be something going on with your ovulation. Science primer: Often, wonky periods are a clue that there’s an abnormal or underactive signal from the pituitary gland in the brain. This can impact the production of two super important hormones for pregnancy: follicle-stimulating hormone (FSH) and luteinizing hormone (LH). 
  
  Here’s the relationship: FSH causes follicle growth, and follicles secrete estrogen—which is what thickens the lining of the uterus in preparation for pregnancy. And pregnancy just won’t happen without LH. 
• Super heavy periods or super light ones: Keep in mind this depends on your typical cycle. But it’s possible that either heavy bleeding or light, short periods could be a sign of an underlying health condition—one that might impact fertility.
• Unpredictable vaginal bleeding: Any vaginal bleeding that occurs outside of your period is a reason to see your doc. In this instance, it might be a clue for hormonal changes or cervical inflammation, both of which affect fertility.

How You Can Boost Your Fertility

Everywhere you turn, you’ll see all kinds of purported “cures” for getting pregnant. Be skeptical. Here’s what actually makes a difference, according to scientific research.

Lifestyle Changes That Can Help Fertility

• Having a healthy diet and lifestyle. Eating nutrient-rich foods and being generally healthy support fertility. In fact, Dr. Vera recommends taking prenatal vitamins even before you’re pregnant to ensure your body is getting all the necessary nutrients for conception.
   
• Tracking ovulation. Penciling in sex might seem unromantic, but hey, it works! Tracking ovulation tells you when your body is at its most fertile point of the month. You can do this pretty simply with ovulation tests and fertility monitoring products or apps, like Glow, Clue, and Flo.
   
• Taking prescription medication. Depending on what is impacting your fertility, certain medications can help. For example, men with low sperm count can talk to their clinician about medication to increase it, Dr. Vera shares. There are also medication options for women with PCOS or other hormonal imbalances.
   
• Working with a specialist. If you are a person with PCOS or endometriosis or have uterine fibroids, your ob/gyn might recommend a fertility specialist. Some fibroids block the fallopian tubes, which surgery can correct. Women with endometriosis may benefit from surgery or medication.  

Fertility Treatments

Getting fertility treatments is a deeply personal decision. But if you’re at the point where natural conception is likely not going to happen, a fertility specialist can go through all your options. These are a few to consider.

• Ovulation Induction: Ovulation Induction is generally a first step if a couple is having trouble trying to conceive.  This treatment will use oral or injectable medications to help improve ovulation patterns and the number of eggs released each month.  With timed intercourse this can be effective, while much less intrusive than other methods. Ovulation Induction with timed intercours has an approximate success rate of 20%.
• Intrauterine insemination (IUI): With IUI, specially prepared sperm (collected for the purpose of conception) is placed directly in the uterus. This is a common procedure for women using donor sperm from a donor insemination agency (or what we all call a sperm bank). But it can also be done with a partner’s sperm, as a way to make conception more likely if he has low sperm count. IUI has a 45% success rate after three cycles.
• In vitro fertilization (IVF): IVF can be helpful for a number of issues, including low sperm count, having a condition that makes getting pregnant more difficult (like endometriosis), or preventing the baby from developing an inherited genetic disorder. 

IVF involves injecting yourself with hormones every day for 10 to 12 days. During this time, you must also have pelvic ultrasounds and bloodwork to make sure the eggs are developing properly. Then, you have a surgical procedure where the eggs are removed. After being collected, the eggs are fertilized by sperm in a lab. A surgical procedure places the fertilized egg or eggs inside a woman’s uterus. 

The success of IVF depends on many factors, including a woman’s age. IVF has a success rate of 17% for women ages 35 to 37. For women younger than 35, it’s greater than 20%. 
 

• Egg freezing: For people facing chemotherapy or gender-affirming surgery, freezing your eggs is an option. Eggs are collected in the same way they are for IVF. The eggs are placed and kept in an embryology lab until you are ready to use them. 
• Donor eggs: In the same way donor sperm may come into play, so may donor eggs, facilitated through an egg donation agency. The person who receives the eggs may be the intended parent who can’t use her own eggs, or it might be a surrogate (someone who carries another person’s baby—more on that below). Once the eggs are fertilized, they are implanted in the recipient’s uterus. 
  Donor sperm: As mentioned above, donor sperm can be obtained from a donor

insemination agency, or sperm bank. If your partner has low sperm count,

quality, or perhaps a genetic abnormality which they do not wish to pass on to

their children this is a great option.  This is increasingly popular with

women who choose to have children on their own, as well as for

non-heteronormative families.

• Surrogacy: With surrogacy, a woman carries the baby for another couple or individual. She is impregnated through IVF using eggs from the biological mother or an egg donor, and sperm from the father or sperm donor. Since the surrogate doesn’t use her own egg, she is not biologically related to the child.

You’re probably wondering: What’s this going to cost me? Currently, 23 states plus Washington D.C. have passed fertility insurance coverage laws. However, insurance may not cover all the costs or every treatment. You’ll need to check with your insurance provider.

As you can see, fertility is complicated. There are so many variables and different ways to become pregnant. Always know you can ask your ob/gyn anything about it—there are no “dumb” questions or concerns. After all, it’s their job! Your ob/gyn will be with you every step of the way. Fertility is not a journey anyone has to do alone.