For some people, getting pregnant can take longer than expected. For others, pregnancy happens with one mistake in birth control.

It’s important to take care of yourself when trying to conceive. Adopt a healthy lifestyle and avoid alcohol, smoking, and recreational drugs. You might also begin taking a daily prenatal vitamin.

The timing of pregnancy for one couple can be very different from the timing with another couple. Your likelihood of conceiving depends on a few factors, including your:

  • age
  • health
  • family and personal medical history

Of course, how often you have sex also plays a role.

Most couples are able to get pregnant within six months to a year. If you’re unable to conceive after a full year of trying, it’s a good idea to consult a fertility specialist.

Sometimes there’s an obvious cause of infertility, like a physical problem with the ovaries, uterus, or testicles. In other cases, the cause is unknown.

Here’s what you need to know if you’ve been trying to get pregnant and it’s taking longer than you’d planned.

Women have the best odds of getting pregnant in their 20s. That’s when you have the largest number of healthy eggs.

Fertility naturally declines with age. The older you are, the longer it might take you to conceive.

Women are born with all the eggs they’ll ever have. As you get older, your egg supply diminishes. And the ones that remain aren’t as healthy.

By age 35, you have only a 12 percent chance of getting pregnant within any given three-month period, according to a study in PLoS One. By age 40, that number drops to 7 percent.

A man’s fertility also declines with age. An older man’s sperm is also more likely to have genetic abnormalities.

According to RESOLVE, 1 out of every 8 couples, or 12 percent of women, have trouble getting pregnant or carrying a pregnancy to term.

When should you see a doctor about infertility?

  • if you’re 35 or younger and you’ve been trying to get pregnant for a year
  • if you’re over age 35 and you’ve been trying for more than 6 months

If you know you have a health condition that affects your fertility, see your doctor sooner.

Female infertility is a factor for about one-third of couples who are trying to conceive.

The most common cause is a problem with ovulation. If you don’t ovulate, you won’t release an egg to be fertilized.

Ovulation problems can be caused by:

Blocked fallopian tubes prevent the egg from meeting the sperm. Possible causes of a blockage include:

A problem with the uterus can also make it harder to get pregnant. This may be due to an abnormal structure, or due to growths like fibroids.

Male infertility is a factor for about 8 percent of couples who are trying to conceive.

Causes of male infertility include:

  • enlarged veins on the testicles, called varicocele
  • abnormally shaped sperm
  • injury to the testes that reduces sperm production
  • heavy drinking, smoking, or drug use
  • chemotherapy or radiation to treat cancer
  • problems with the glands that produce the hormones needed to make sperm
  • more rarely, genetic disorders such as Klinefelter syndrome

In about 5 to 10 percent of couples, the cause of infertility is unexplained. It may be caused by problems with egg or sperm quality or a physical issue, but the doctor hasn’t been able to diagnose a clear reason.

Not knowing the cause can be frustrating for couples. Yet in vitro fertilization (IVF) and other fertility methods can still help you get pregnant.

Fertility specialists offer a variety of treatments, and sometimes more than one treatment is combined.

Which method your doctor recommends depends on factors like your age, health, and what caused your fertility problem.

Medicine

A few drugs are commonly used to stimulate a woman’s ovaries to release an egg:

  • clomiphene citrate (Clomid)
  • follicle-stimulating hormone (Follistim, Gonal-F)
  • letrozole (Femara)
  • human menopausal gonadotropin (Menopur, Pergonal, Repronex)
  • metformin (Glucophage)
  • bromocriptine (Parlodel)

One thing to know about these medications is that they can increase your risk of giving birth to twins or other multiples.

Medications can also help men with infertility by increasing their sperm count.

Surgery

Surgery is a treatment for both male and female infertility. In men, surgical procedures can clear up a sperm blockage, fix a varicocele, or retrieve semen from a man’s reproductive tract.

In women, surgery can be done to fix physical problems with the ovaries or uterus.

Intrauterine insemination (IUI)

This method is also called artificial insemination. The man produces a sperm sample that is then injected through a catheter into the woman’s uterus right around the time when she is ovulating. She may get medicine beforehand to help her ovulate.

Assisted reproductive technology (ART)

Assisted reproductive technology (ART) combines the sperm and eggs outside the body, and then places the embryos into the uterus. The main type of ART is in vitro fertilization (IVF).

Before IVF, the woman will get a series of injections to help her ovaries produce a lot of eggs. Once those eggs are mature, they’ll be removed using a simple surgical procedure.

The eggs are fertilized with her partner’s sperm. Fertilized eggs, known as embryos, are grown in the lab for a few days. One or two good quality embryos are then transferred into the uterus.

Other ARTs are:

  • Intracytoplasmic sperm injection (ICSI). One healthy sperm is injected into an egg.
  • Assisted hatching. The embryo cover is opened to help it implant more easily in the uterus.
  • Donor eggs or sperm. If there’s a problem with the eggs or sperm, you can get either one from a healthy donor.
  • Gestational carrier. Another woman carries your baby to term for you.

Pregnancy isn’t always the journey you expected. Sometimes it takes longer than you’d hoped to get pregnant, especially if age or physical issues are factors.

If you’ve been trying for a while with no success, see an infertility specialist for help. Or turn to an organization like RESOLVE for advice.