Being aware of your menstrual cycle and the changes in your body that happen during this time can help you know when you are most likely to get pregnant. See how the menstrual cycle works.

The average menstrual cycle lasts 28 days. But normal cycles can vary from 21 to 35 days. The amount of time before ovulation occurs is different in every woman and even can be different from month to month in the same woman, varying from 13 to 20 days long. Learning about this part of the cycle is important because it is when ovulation and pregnancy can occur. After ovulation, every woman (unless she has a health problem that affects her periods or becomes pregnant) will have a period within 14 to 16 days.

Knowing when you're most fertile will help you plan pregnancy. There are three ways you can keep track of your fertile times. They are:

• Basal body temperature method – Basal body temperature is your temperature at rest as soon as you awake in the morning. A woman's basal body temperature rises slightly with ovulation. So by recording this temperature daily for several months, you'll be able to predict your most fertile days.

  Basal body temperature differs slightly from woman to woman. Anywhere from 96 to 98 degrees Fahrenheit orally is average before ovulation. After ovulation most women have an oral temperature between 97 and 99 degrees Fahrenheit. The rise in temperature can be a sudden jump or a gradual climb over a few days.

  Usually a woman's basal body temperature rises by only 0.4 to 0.8 degrees Fahrenheit. To detect this tiny change, women must use a basal body thermometer. These thermometers are very sensitive. Most pharmacies sell them for about $10.

  The rise in temperature doesn't show exactly when the egg is released. But almost all women have ovulated within three days after their temperatures spike. Body temperature stays at the higher level until your period starts.

  You are most fertile and most likely to get pregnant:

  • Two to three days before your temperature hits the highest point (ovulation)
    and
  • 12 to 24 hours after ovulation

  A man's sperm can live for up to three days in a woman's body. The sperm can fertilize an egg at any point during that time. So if you have unprotected sex a few days before ovulation, you could get pregnant.

  Many things can affect basal body temperature. For your chart to be useful, make sure to take your temperature every morning at about the same time. Things that can alter your temperature include:

  • Drinking alcohol the night before
  • Smoking cigarettes the night before
  • Getting a poor night's sleep
  • Having a fever
  • Doing anything in the morning before you take your temperature — including going to the bathroom and talking on the phone
    

• Calendar method – This involves recording your menstrual cycle on a calendar for eight to 12 months. The first day of your period is Day 1. Circle Day 1 on the calendar. The length of your cycle may vary from month to month. So write down the total number of days it lasts each time. Using this record, you can find the days you are most fertile in the months ahead:

  1. To find out the first day when you are most fertile, subtract 18 from the total number of days in your shortest cycle. Take this new number and count ahead that many days from the first day of your next period. Draw an X through this date on your calendar. The X marks the first day you're likely to be fertile.
  2. To find out the last day when you are most fertile, subtract 11 from the total number of days in your longest cycle. Take this new number and count ahead that many days from the first day of your next period. Draw an X through this date on your calendar. The time between the two Xs is your most fertile window.

  This method always should be used along with other fertility awareness methods, especially if your cycles are not always the same length.

• Cervical mucus method (also known as the ovulation method) – This involves being aware of the changes in your cervical mucus throughout the month. The hormones that control the menstrual cycle also change the kind and amount of mucus you have before and during ovulation. Right after your period, there are usually a few days when there is no mucus present or "dry days." As the egg starts to mature, mucus increases in the vagina, appears at the vaginal opening, and is white or yellow and cloudy and sticky. The greatest amount of mucus appears just before ovulation. During these "wet days" it becomes clear and slippery, like raw egg whites. Sometimes it can be stretched apart. This is when you are most fertile. About four days after the wet days begin the mucus changes again. There will be much less and it becomes sticky and cloudy. You might have a few more dry days before your period returns. Describe changes in your mucus on a calendar. Label the days, "Sticky," "Dry," or "Wet." You are most fertile at the first sign of wetness after your period or a day or two before wetness begins.

  The cervical mucus method is less reliable for some women. Women who are breastfeeding, taking hormonal birth control (like the pill), using feminine hygiene products, have vaginitis or sexually transmitted infections (STIs), or have had surgery on the cervix should not rely on this method.

To most accurately track your fertility, use a combination of all three methods. This is called the symptothermal method. You can also purchase over-the-counter ovulation kits or fertility monitors to help find the best time to conceive. These kits work by detecting surges in a specific hormone called luteinizing hormone, which triggers ovulation.

Some women want children but either cannot conceive or keep miscarrying. This is called infertility. Lots of couples have infertility problems. About one-third of the time, it is a female problem. In another one-third of cases, it is the man with the fertility problem. For the remaining one-third, both partners have fertility challenges or no cause is found.

Some common reasons for infertility in women include:

Age – Women generally have some decrease in fertility starting in their early 30s. And while many women in their 30s and 40s have no problems getting pregnant, fertility especially declines after age 35. As a woman ages, normal changes that occur in her ovaries and eggs make it harder to become pregnant. Even though menstrual cycles continue to be regular in a woman's 30s and 40s, the eggs that ovulate each month are of poorer quality than those from her 20s. It is harder to get pregnant when the eggs are poorer in quality. As a woman nears menopause, the ovaries may not release an egg each month, which also can make it harder to get pregnant. Also, as a woman and her eggs age, she is more likely to miscarry, as well as have a baby with genetic problems, such as Down syndrome.

Health problems – Some women have diseases or conditions that affect their hormone levels, which can cause infertility.

• Women with polycystic ovary syndrome (PCOS) rarely or never ovulate. Failure to ovulate is the most common cause of infertility in women.
• With primary ovarian insufficiency (POI), a woman's ovaries stop working normally before she is 40. It is not the same as early menopause. Some women with POI get a period now and then. But getting pregnant is hard for women with POI.
• A condition called luteal phase defect (LPD) is a failure of the uterine lining to be fully prepared for pregnancy. This can keep a fertilized egg from implanting or result in miscarriage.

Common problems with a woman's reproductive organs, like uterine fibroids, endometriosis, and pelvic inflammatory disease can worsen with age and also affect fertility. These conditions might cause the fallopian tubes to be blocked, so the egg can't travel through the tubes into the uterus.

Lifestyle factors – Certain lifestyle factors also can have a negative effect on a woman's fertility. Examples include smoking, alcohol use, weighing much more or much less than an ideal body weight, a lot of strenuous exercise, and having an eating disorder. Stress also can affect fertility.

Unlike women, some men remain fertile into their 60s and 70s. But as men age, they might begin to have problems with the shape and movement of their sperm. They also have a slightly higher risk of sperm gene defects. Or they might produce no sperm, or too few sperm. Lifestyle choices also can affect the number and quality of a man's sperm. Alcohol and drugs can temporarily reduce sperm quality. And researchers are looking at whether environmental toxins, such as pesticides and lead, also may be to blame for some cases of infertility. Men also can have health problems that affect their sexual and reproductive function. These can include sexually transmitted infections (STIs), diabetes, surgery on the prostate gland, or a severe testicle injury or problem.

You should talk to your doctor about your fertility if:

• You are younger than 35 and have not been able to conceive after one year of frequent sex without birth control.
• You are age 35 or older and have not been able to conceive after six months of frequent sex without birth control.
• You believe you or your partner might have fertility problems in the future (even before you begin trying to get pregnant).
• You or your partner has a problem with sexual function or libido.

Happily, doctors are able to help many infertile couples go on to have babies.

If you are having fertility issues, your doctor can refer you to a fertility specialist, a doctor who treats infertility. The doctor will need to test both you and your partner to find out what the problem is. Depending on the problem, your doctor might recommend treatment. About 9 in 10 cases of infertility are treated with drugs or surgery. Don't delay seeing your doctor, as age also affects the success rates of these treatments. For some couples, adoption or foster care offers a way to share their love with a child and to build a family.

Some treatments include:

• Drugs – Various fertility drugs may be used for women with ovulation problems. It is important to talk with your doctor about the drug to be used. You should understand the drug's benefits and side effects. Depending on the type of fertility drug and the dosage of the drug used, multiple births (such as twins) can occur.
• Surgery – Surgery is done to repair damage to a woman's ovaries, fallopian tubes, or uterus. Sometimes a man has an infertility problem that can be corrected by surgery.
• Intrauterine insemination (IUI), also called artificial insemination – Male sperm is injected into part of the woman's reproductive tract, such as into the uterus or fallopian tube. IUI often is used along with drugs that cause a woman to ovulate.
• Assisted reproductive technology (ART) – ART involves stimulating a woman's ovaries; removing eggs from her body; mixing them with sperm in the laboratory; and putting the embryos back into a woman's body. Success rates of ART vary and depend on many factors.
• Third party assistance – Options include donor eggs (eggs from another woman are used), donor sperm (sperm from another man are used), or surrogacy (when another woman carries a baby for you).

Finding the cause of infertility is often a long, complex, and emotional process. And treatment can be expensive. Many health insurance companies do not provide coverage for infertility or provide only limited coverage. Check your health insurance contract carefully to learn about what is covered. Some states have laws that mandate health insurance policies to provide infertility coverage.

If infertility is a problem for you, another option may be adoption. Adopting a baby or child can be one of the most rewarding experiences of your life. So many babies, children, and adolescents in the United States and around the world need a family. Some of these are healthy infants, and many are children with special needs, including physical, emotional, or mental disabilities. If you do adopt a child with special needs, there are both federal and state sources of financial assistance available to help you afford the child's care.

There are two types of adoptions:

• Open adoption – The birth mother, and possibly the birth father, know something about the adoptive parents. They might even meet and exchange names or addresses.
• Closed adoption – The birth mother and adoptive parents do not meet each other or know each others' names.

The laws of each state differ on whether, after a period of time, the files of a closed adoption can be opened later to reveal this information. State laws also differ on whether adoptions can be handled by an adoption agency or independently (such as through a doctor, lawyer, counselor or independent organization). Most adoption agencies carefully screen and study the adoptive parents.

Another option for couples who have a lot of love to share with a child is foster care. Unlike adoption, foster care is a temporary service that responds to crises in the lives of children and families. But it also can be the first step to adopting a child. Many foster children have been abused or neglected, or removed by a court order. Foster families are people who take these children into their homes to provide day-to-day care and nurturing. Children in foster care may live with unrelated foster parents, with relatives, with families who plan to adopt them, or in group homes or residential treatment centers. Even though foster care is viewed as a temporary service, many children have to stay in foster care for long periods of time.

Each child in foster care should have a plan that will let him or her grow up in a permanent family. For many children, the plan is to return to the birth parents. In these cases, foster families may work with the birth parents and the child to help them both learn the skills they need to live together again. Foster parents need to be able to love the children who live in their home, and let go of them when it is time to send them back to their parents. For other children, going back to their parents will not be possible, and the foster parents may become adoptive parents. Or they can keep other kinds of formal or informal ties with the children they parent.

Every state has its own rules about foster parenting. But, the chances are good that you can be a foster parent in your state. There are many more children in need of care than there are foster parents available. To fill this gap, states are looking for people who want to help children and can share their time and their homes. States also give foster parents many different forms of support, like training and financial assistance.

If you've been having problems getting pregnant, you know how frustrating it can feel. Not being able to get pregnant can be one of the most stressful experiences a couple has. Both counseling and support groups can help you and your partner talk about your feelings and help you meet other couples struggling with the same issues. You will learn that anger, grief, blame, guilt, and depression are all normal. Couples do survive infertility, and can become closer and stronger in the process. Ask your doctor for the names of counselors or therapists with an interest in fertility.