How to Schedule Baby-Making Sex With an Ovulation Calendar

Trying to conceive? Here's how to determine your peak fertile days for baby-making sex with an ovulation calendar.

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When trying to conceive (TTC), your game plan may be to have as much sex as possible. But did you know that timing your intercourse can increase your odds of getting pregnant?

An ovulation calendar lets people track their ovulation and pinpoint the six-day window each cycle when they're most likely to conceive. Read on for everything you need to know about using an ovulation calendar to calculate your most fertile days.

What Is Ovulation?

Ovulation occurs when your ovary releases a mature egg into the fallopian tube that then moves down the fallopian tube into the uterus, says Obosa Osawe, M.D., an OB-GYN at Piedmont Physicians Obstetrics and Gynecology in Newnan, Georgia.

About 24–36 hours before ovulation, luteinizing hormone (LH) surges, triggering the egg's release. The egg survives about 12–24 hours in the reproductive tract, and if it's fertilized with sperm during this time frame, you can become pregnant. If sperm doesn't fertilize the egg, it's reabsorbed and shed with the uterine lining during your period.

Many people notice their cervical mucus becomes thinner and more slippery just before and during ovulation. This fertile-quality mucus helps sperm move more easily through the reproductive tract. While not everyone experiences symptoms of ovulation, some other signs may include:

  • Breast tenderness
  • Heightened sense of smell
  • Increased libido
  • Mild pelvic pain
  • Spotting

How Does an Ovulation Calendar Work?

Ovulation calendars offer a way to track your ovulation to determine when you are likely to be most fertile. There are a few ways you can track ovulation, including:

  • Ovulation tracker apps, which help you track and record information about your cycle
  • Ovulation predictor kits (OPKs), which detect luteinizing hormone (LH) in your urine to predict ovulation
  • Charting your cervical mucus, which can help you identify the change in texture that often signals impending ovulation
  • Charting your basal body temperature (BBT), which can help you identify a slight rise in temperature that is correlated with ovulation

All these tools essentially work by helping you identify where you are in your cycle so that you can time baby-making sex accordingly. Using two or more of these methods together can help you more accurately determine your most fertile days each cycle.

Predicting Fertility With Ovulation Calendars

Couples who are trying to conceive should plan sex around ovulation since the optimal time to try to get pregnant is when you're ovulating, says Dr. Osawe. The chances of pregnancy are highest on the day of ovulation and the 24 hours leading up to it.

But conception is still possible when sex is timed several days before ovulation since sperm can live in the fallopian tubes for three to five days, says Jingwen Hou, M.D., Ph.D., an OB-GYN at Kaiser Permanente in Hawaii. After ovulation, however, the window to conceive is short. Once the egg dissolves, within 12–24 hours of release, it can no longer lead to pregnancy.

According to the Department of Health & Human Services Office on Women's Health, a typical menstrual cycle is 28 days long. "If this is true for you, expect to ovulate about 14 days after the first day of your last period," says Dr. Osawe.

However, not everyone has a typical 28-day cycle; some people have periods that are 24 days apart, and other people's cycles are up to 38 days apart. That's why pinpointing ovulation using a calendar alone can be tricky, especially for people with irregular periods. All these variations mean you could ovulate between 11 and 21 days into your cycle.

Using an Ovulation Calendar to Conceive a Boy or Girl

Wondering if you can predict or influence fetal sex using an ovulation calendar? Some people hope to pinpoint fertile days for a baby boy or girl. There is a theory that your conception date could determine your baby's sex. This idea, called the Shettles method, was first introduced by Landrum B. Shettles in the 1960s. His book, How to Choose the Sex of Your Baby, co-authored with David Rorvik, describes the theory in more detail:

  • Fertile days for a boy: Y-sperm (which produce fetuses with XY chromosomes) supposedly travel more quickly through the reproductive system and have a shorter life span. So, the idea is sex close to ovulation is more likely to result in a boy.
  • Fertile days for a girl: X-sperm (which produces fetuses with XX chromosomes) moves more slowly and has a longer life span. So, in theory, if you have sex a couple of days before ovulation, the X-sperm will still be around when you ovulate, while the Y-sperm will die, increasing your odds of having a girl.

However, there is little scientific evidence to support this theory. In the '90s, several studies, including one from 1995 and one from 1998, found no correlation between the timing of baby-making sex and fetal sex. Additionally, a 2016 study also found no meaningful impact of timing intercourse for the purpose of conceiving a boy or girl.

Plus, if you want to get pregnant, the best method is to have sex often during your fertile window, rather than restricting it to certain days. Not only that, but keep in mind that sex is assigned at birth based on the appearance of a baby's genitalia. While sex assigned at birth often matches a person's gender (called cisgender), sometimes, for transgender, intersex, and gender nonbinary people, it does not.

Gender is a personal identity that exists on a spectrum and can change throughout a person's lifetime. More importantly, it is something that a person defines for themselves, so it's best not to get too attached to predicting a baby's gender.

Trying to Conceive: Your Ovulation Calendar

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