Pregnancy - identifying fertile days


Definition

Fertile days are the days a woman is most likely to get pregnant.

Infertility is a related topic.

Alternative Names

Basal body temperature; Infertility - fertile days

Information

When trying to become pregnant, many couples plan intercourse between days 11 to 14 of the woman's 28-day cycle. This is when ovulation occurs.

However, it is hard to know exactly when ovulation will happen. Health care providers recommend that couples who are trying to have a baby have sex between days 7 and 20 of a woman's menstrual cycle. In order to become pregnant, having sex every other day or every third day works just as well as having sex every day.

Ovulation

Watch this video about:
Ovulation

If you have an irregular menstrual cycle, an ovulation predictor kit can help you know when you are ovulating. These kits check for luteinizing hormone (LH) in the urine. You can buy them without a prescription at most drug stores.

There are various other methods to help detect when you are most likely to be able to conceive a baby.

Note: Some lubricants can interfere with conception. If you are trying to get pregnant, you should avoid all douches and lubricants (including saliva), except those specifically designed to not interfere with fertility (such as Pre-seed). Lubricants should never be used as a method of birth control.

EVALUATING YOUR CERVICAL FLUID

Cervical fluid protects the sperm and helps it move toward the uterus and fallopian tubes. Cervical fluid changes occur when the woman's body is getting ready to release an egg. There are clear differences in how it looks and feels during the woman's monthly menstrual cycle.

You can use your fingers to see how your cervical fluid feels.

TAKING YOUR BASAL BODY TEMPERATURE

After you ovulate, your body temperature will rise and stay at a higher level for the rest of your ovulation cycle. At the end of your cycle, it falls again. The difference between the 2 phases is most often less than 1 degree.

If your temperature is between 2 marks, record the lower number. Try to take your temperature at the same time every day, if possible.

Create a chart and write down your temperature every day. If you look at a complete cycle, you will probably notice a point at which the temperatures become higher than in the first part of your cycle. The rise is about 0.2 degrees or more above the previous 6 days.

Temperature is a useful indicator of fertility. After checking for several cycles, you may be able to see a pattern and identify your most fertile days.

References

Jensen JT. Mishell DR. Family planning: contraception, sterilization, and pregnancy termination. In: Lentz GM, Lobo RA, Gershenson DM, Katz VL, eds. Comprehensive Gynecology. 6th ed. Philadelphia, PA: Elsevier Mosby; 2012:chap 13.

Lobo RA. Infertility: etiology, diagnostic evaluation, management, prognosis. In: Lentz GM, Lobo RA, Gershenson DM, Katz VL, eds. Comprehensive Gynecology. 6th ed. Philadelphia, PA: Elsevier Mosby; 2012:chap 41.

Rebar RW, Catherino WH. Reproductive endocrinology and infertility. In: Goldman L, Schafer AI, eds. Goldman's Cecil Medicine. 25th ed. Philadelphia, PA: Elsevier Saunders; 2016:chap 236.

A.D.A.M. content is best viewed in IE9 or above, Firefox and Google Chrome browser.