When is most fertile

Tracking the signs of ovulation can help someone determine the precise day they ovulate each month. Some of these signs, such as basal body temperature, will continue to change after ovulation has occurred.

For this reason, a person should not use temperature to predict the fertile window. It may be helpful for someone to track the signs over a few months to get an idea of what is normal for their body. But they should keep in mind that there are several variables, and the timing of ovulation can change, month-to-month. Fertility aids measure the levels of specific hormones in the urine to determine the ovulation day each month.

Some devices also identify days of peak fertility. The following table summarizes a typical menstrual cycle and how fertile a person is likely to be at each stage:. To maximize the chances of becoming pregnant, a person should time sexual intercourse to occur during the 2 to 3 days leading up to, and including, ovulation. Sex during any of these days may provide a 20—30 percent chance of pregnancy. Some women may wish to track their fertility to prevent pregnancy.

This is known as the fertility awareness method. The Centers for Disease Control and Prevention CDC charts fertility awareness-based methods of contraception as having a 24 percent failure rate with typical use.

However, they may still become pregnant if they have ovulated early or late in their cycle, as sperm can survive in the body for several days. Ovulation and the fertile window can change from cycle-to-cycle, but they may also alter with age. Fertility naturally begins to decline in females from 35 years of age onward. Some medical conditions, such as endometriosis or polycystic ovary syndrome, also make conception more difficult. Birth control pills aim to prevent unintended pregnancy.

The pill prevents pregnancy by releasing synthetic hormones that stop ovulation from occurring and the uterus lining from thickening.

So, even if the ovaries do release an egg, a fertilized egg would be unable to implant in the wall of the uterus.

The pill also thickens cervical mucus, making it harder for sperm to reach an egg. According to the CDC , the pill is more than 99 percent effective with perfect use but only 91 percent effective with typical use. This means that, with typical use, around 9 out of women would become pregnant in a year of taking the pill. Women who track their fertile window with the aim of getting pregnant should see their doctor for preconception planning. As well as identifying barriers to conceiving, a doctor can advise on the use of folic acid or prenatal supplements to encourage a healthy pregnancy.

Women under 35 years of age should see their doctor if they do not conceive after a year of trying. Those over 35 years of age should seek medical advice after 6 months of trying to conceive. Fritz MA, Speroff L Clinical Gynecologic Endocrinology and Infertility , 8th ed. If you want to become pregnant, try to have sex every day or every other day from your first fertile day to your last fertile day.

If your periods are irregular, this calculator is not a good way to predict your ovulation dates. If you are looking for information on birth control, see the topic Birth Control.

Author: Healthwise Staff. This information does not replace the advice of a doctor. Healthwise, Incorporated disclaims any warranty or liability for your use of this information.

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Top of the page. What does this tool help you learn? What are the chances? Having sex as close as possible to the time of ovulation increases the chance of pregnancy.

If she has sex five days before she ovulates, her probability of pregnancy is about 10 percent. When does preconception health begin? How to know you are ovulating Kerry Hampton, a registered nurse and fertility specialist, discusses the importance of fertility awareness, and how to determine your fertile window to improve your chances of conceiving.

Identification and prediction of the fertile window using Natural Cycles. Self-identification of the clinical fertile window and the ovulation period. Fertility and Sterility, 5 , Optimizing natural fertility: a committee opinion. Fertility and Sterility, 1 , Revisiting the fertile window. Timing intercourse to achieve pregnancy: current evidence. Obstetrics and Gynecology, 6 , Stephenson, J. Before the beginning: nutrition and lifestyle in the preconception period and its importance for future health.

The Lancet, Pet al. Fertility and Sterility. Impact of age, clinical conditions, and lifestyle on routine semen parameters and sperm kinematics. Let al. Effects of cigarette smoking upon clinical outcomes of assisted reproduction: a meta-analysis. Hum Reprod Update, 15 1 , Zenzes, M.

Smoking and reproduction: gene damage to human gametes and embryos. Hum Reprod Update, 6 2 , Looking for more? Thinking about having a baby? Useful links: Pre-conception checklists.

Healthy conception tool.