Timing Intercourse to Avoid Conception

| Pro-Life Family Planning guide |

Because the effectiveness of some birth control depends on taking life after conception, we’ve put together a Pro-Life Guide for Family Planning that is meant to help couples plan when they’ll have kids while keeping their future children safe from conception onward. To see the full discussion including which methods operate after conception, take a look at the Intro to our Pro-Life Guide to Birth Control. As a foundation to this guide, we’ve written elsewhere on when life begins and what evidence we have for the significance of conception. Take a look at our scientific overview and biblical overview of these discussions there, as this guide is instead focused on the application of this truth.

On this page, we’ll be focused specifically on one of the pro-life options we have in family planning: known by some as fertility awareness based methods (FABM). At a simple level, because a couple isn’t fertile every day of a woman’s cycle, intercourse (even without a condom) does not always result in conception. We’ll talk about how to practically use this as a means of family planning and how effective it is. Bear in mind that this isn’t the only pro-life option for family planning, but it can be used also in conjunction with other methods. For example, when a couple knows when they are fertile (their fertile window), they might choose to use condoms during this part of her cycle to prevent conception. We’ll explore this more later, but first let me briefly summarize some background information on fertility.

Understanding Fertility

In our discussion on Understanding Fertility, we saw that the fertile window is generally from about 7 days before ovulation to 1 day after ovulation (the fertile window). In other words, conception can occur as a result of intercourse on any of these days. However, the chances of conception change depending on which day it is in this fertile window.

A 2019 study[1] used data from the Ovia fertility app to estimate the probability of achieving pregnancy as a result of intercourse. After reviewing 225,000 cycles from almost 100,000 women, they found that the chance of achieve pregnancy rose steadily starting 7 days before ovulation, peaked on the day before ovulation, and then dropped off more rapidly on the day of and the day after ovulation. The clear conclusion from their research is that the timing of intercourse has a big impact on the chances of conception. Here is a summary of their findings:

What this means is that if a couple can predict approximately when ovulation will occur, they can estimate their fertile window. Then, by avoiding (unprotected) intercourse on these days, they can avoid conception. Outside of that window, a couple can enjoy intercourse even without a condom without conceiving. Sounds easy, but can a couple actually do this reliably and effectively? Yes. Let’s talk about it.

Does This Actually Work?

Maybe you’ve heard of the rhythm method. If you have, you probably know it didn’t work. The rhythm method was a calendar-based guess of when a woman was fertile. Because almost all woman do not ovulate on the same day every cycle, this just didn’t work. However, things have changed. The science supporting understanding and tracking a woman’s cycle has advanced significantly. These advances change the game in terms of effectiveness. For example, you can now buy a small device that reliably tracks your cycle using a quick hormone test you do in the morning. One of these hormonal monitors (the Persona by Clearblue) is 94% effective as a method of contraception.[2]

Now, let’s get a little more specific on what methods allow a couple to time intercourse to avoid conception.

The Methods: How Do We Do This?

The chart above makes it clear that the most central part of timing intercourse is knowing when you ovulated. So, how do you know when ovulation has occurred so you’re safe to have intercourse afterwards? And how do you predict it so you know when you’re safe to have intercourse before?

Like we discussed on our page, Understanding Fertility, ovulation is part of the larger cycle. There are many different effects this cycle causes that can be monitored to predict ovulation. Here’s an overview of a few ways couples predict ovulation using these signs:

  • Hormonal Fertility Monitors: Estrogen levels climb ahead of ovulation and LH levels spike just before it occurs. Many fertility monitors track these hormones from urine tests you do at home. After doing this for a few cycles, the monitor tells you when your chances of conceiving are at their highest. Personally, we have used the Clearblue Persona for this. There are other hormonal fertility monitors that are based on this same concept. Some, like the Mira Fertility Analyzer, even integrate into apps on your phone which can provide more information and might make understanding the results easier.
  • Tracking Vital Signs: Ovulation affects a woman’s body in so many ways. Her body temperature, heartrate, and respiratory rate are all affected by her cycle in predictable ways. Tracking this information can help identify when ovulation will occur. Many apps enable you to track this information and help you predict ovulation. I know of one that is FDA cleared as a method for contraception. The Natural Cycles app comes with a thermometer and has been shown to be 93% effective with typical use (98% effective with perfect use).[3]
  • Cervical Mucus Observations: Like we discussed in Understanding Fertility, the consistency of cervical mucus changes throughout the cycle. A woman can actually notice these changes. The discharge becomes clear, “slippery” and stretchy just before ovulation. After ovulation, it becomes thicker, cloudy and less noticeable. There are apps that help you learn what you’re looking for in making these observations and help you track it. Personally, the challenge we had in using this method is that there is a learning curve in making consistent and reliable observations. However, one of the systems (FertilityCare) that uses these mucus observations has the benefit of being part of a larger approach to fertility. FertilityCare includes a network of physicians that can use the information in the app to help diagnose and treat fertility issues if needed when you are ready to conceive.

Any of these approaches takes at least a few cycles to learn how your body works specifically to accurately predict ovulation. As a result, they usually start conservative by estimating a longer fertile window to successfully prevent conception. Over time, as the method learns your cycle, they can accurately estimate a shorter window. Whether its that initial longer window or the shorter window, the reality is that all of these methods still tell you a portion of your (wife’s) cycle where intercourse can result in pregnancy. So, what does a couple do during that part of the cycle? Do they have to avoid intercourse altogether or can they just use a condom? Let’s talk about that.

Intercourse in the Fertile Window

When you use one of these methods, you know when you’re fertile. To effectively avoid conception, you cannot have unprotected intercourse (i.e., without a condom) during that portion of your cycle. As a result, some couples choose to avoid intercourse altogether during that part of the cycle. Others might simply choose to use a condom during that part of the cycle. I want to explore these two options now.

Being that this discussion is part of a pro-life guide to family planning, I want to start by clarifying that the condom is a pro-life option for avoiding conception. The condom operates before conception so whether a couple chooses to use a condom or avoid intercourse altogether during their fertile window, they can do so know there is not a risk to any children that might unintentionally be conceived in the process. Some couples do have a moral objection to using condoms for other reasons. As I discussed in the intro to this guide, this is a conviction I completely respect, just not one that I personally share. Since our focus here is protecting the life of any child conceived in the process and since the condom does not conflict with that, we do know that using a condom during the fertile portion of her cycle is pro-life.

Separate from this, what about effectiveness? Does using a condom during the fertile window significantly reduce the effectiveness of these methods? One study conducted research to address this question and found that there was not a significant difference in effectiveness when condoms were used during the fertile window.[4]

That being said, it’s helpful to remember that condoms can be very effective when used properly (98% effective), but typically only achieve about 85% effectiveness because people “cheat” some when using them. Since the chances of conception are obviously much higher during the fertile window, proper use during this part of the cycle is especially important. So, if a couple uses condoms during the fertile part of the cycle it’s prudent to be sure to use the condom correctly (e.g., for the entire duration of intercourse).

Hopefully this practical discussion has been helpful. Please check out the rest of our pro-life guide for family planning where we have also have some video discussions on other methods for family planning.

[1] Faust L, Bradley D, Landau E, et al. Findings from a mobile application-based cohort are consistent with established knowledge of the menstrual cycle, fertile window, and conception. Fertil Steril. 2019;112(3):450-457.e3. doi:10.1016/j.fertnstert.2019.05.008

[2] https://uk.clearblue.com/contraception/persona-monitor

[3] https://www.naturalcycles.com/

[4]  Frank-Herrmann P, Heil J, Gnoth C, et al. The effectiveness of a fertility awareness based method to avoid pregnancy in relation to a couple’s sexual behaviour during the fertile time: a prospective longitudinal study. Hum Reprod. 2007;22(5):1310–1319