Trying to conceive and wondering how often you should have sex? Read our detailed guide and determine when you are most fertile.
At this point, you’re well acquainted with the basics of heterosexual sex: the man ejaculates, then his sperm swim up through the woman’s vagina and cervix with the hopes of making it all the way to the fallopian tubes. Then, perhaps, one triumphant little sperm unites with an egg. The newly fertilized egg burrows into the uterine wall and develops into an embryo. Nine months later, you’ve got a baby. And that’s that, right? Well, it’s unfortunately not quite that simple, but a little light reading might just help you nail your understanding of exactly what’s going on, so you can time sex to your advantage.
It seems like having lots of unprotected sex should lead straight to pregnancy and a baby. But, for many women, the road to conception is much more complicated.
Know Your Cycle
Let’s begin with the basics of menstruation because you can’t time sex if you’re not tracking your menstrual cycle accurately (and that’s an easy thing to stumble over). The end game here is to figure out your fertile window—the days of the month when you’re most likely to conceive. After years of suffering through insatiable cravings, painful cramps and feeling bloated, you can finally appreciate your cycle for its innate purpose: to make a baby.
Cycle length varies from woman to woman, and it does so pretty widely with the normal range being anywhere from 21-34 days and the average duration being about 28-32 days. Your menstrual cycle is a two-act show: you first have the follicular phase followed by the luteal phase. Day 1, the first day of the follicular phase, is when you get your period and start bleeding. About midway through your cycle, a hormone in the brain called follicle stimulating hormone (FSH) signals to your ovaries that it’s time to prepare an egg for fertilization. You’re born with a lifetime inventory of eggs—around two million! But most of them will never be viable for fertilization, so although this is an awe-inspiring number, it’s not the same as having two million chances to get pregnant. All of your eggs are stored in small, fluid-filled sacs in your ovaries called follicles. Several of these follicles are recruited each month to prepare an egg; however, only one of those follicles will make it to maturity—this follicle promotes its own growth and suppresses the maturation of the other ovarian follicles thus becoming the dominant follicle. I bet you didn’t know your ovaries are a battlefield each month, right?
For the egg that does mature: this happens around day eight of your cycle, when your body’s estrogen levels skyrocket. This signals the beginning of your “fertile window”—a six-day period before you ovulate.
Experts recommend having sex daily or every other day during the fertile window, but especially the three days (sperm lifespan) right before you ovulate. This is when your chances of conceiving are at their highest. And while it’s definitely still possible to get pregnant in the 1-2 days after ovulation (that’s the egg’s lifespan), the chances of success decline steadily from the day of ovulation onwards.
A quick rise in luteinizing hormone (LH) is what prompts your ovaries to release an egg every month. This is called the LH surge and usually occurs in the 12-36 hours leading up to ovulation.
The intrepid egg then ventures down the fallopian tube and into the uterus, where it awaits fertilization by sperm.
Sperm can also be impressively resilient and can survive for up to five days inside the woman’s reproductive tract—that’s why, even though ovulation lasts only about 12-24 hours, the fertile window is usually about six days.
Lastly, beginning right after ovulation ends, the luteal phase of your menstrual cycle lasts about two weeks for most women. Progesterone and estrogen levels in your body increase. The uterine lining thickens to prepare to support a possible pregnancy.
Although ovulation can get all the attention, your luteal phase is important for conception, too! Some research shows that a shortened luteal phase can make it tougher to conceive.
If no pregnancy occurs this time around, then the uterine lining sheds, leading to the oh-so-fun process of bleeding. Then, the cycle begins anew.
How long does it take to get pregnant after having sex?
The actual biological process of conception is pretty miraculous when you think about it, but let’s clear up one misconception: pregnancy does not happen instantaneously—it can often take a few days after sex for the egg and sperm to meet up.
Even after these cells unite, the newly fertilized egg must take root in the uterine wall — this is called implantation. This can be a tricky process. Research shows that about two thirds of lost pregnancies happen due to implantation failure.
Normal implantation can be an asymptomatic process or it can be accompanied by light bleeding (for more information on that, check out our article Is this Spotting My Period or am I Pregnant?).
After the embryo is comfortably situated, certain hormones are released that signal the beginning of your pregnancy.
Finding the fertile window
Having sex within the fertile window certainly boosts your chances of conceiving, but finding these special few days can be tough, especially for those of us who have erratic cycles.
Here are a few simple ways you can figure out your fertile window:
- Cervical Mucus
Look out for “fertile-quality” cervical mucus. This is vaginal discharge that is stretchy and translucent and is often compared to egg whites.
To test your cervical mucus, gently insert a (freshly washed) finger into your vagina and try to gauge the consistency and quantity of the discharge. An abundance of the egg white-like mucus is a good sign that you’re in your fertile window.
Note, your body is always creating cervical mucus to protect against infections and lubricate during sex. You produce the least amount of mucus right after your period. In general, normal vaginal discharge is yellow or cloudy white and has a sticky texture.
- Ovulation Test Kits
There are many ovulation kits on the market nowadays. Many of them work by measuring LH levels in your urine. As previously mentioned, the LH surge is what prompts your ovaries to release an egg.
Once you see a positive ovulation test—indicating the LH surge has taken place—you can time your sex accordingly.
Of course, these commercial tests aren’t always accurate for everyone. Conditions like polycystic ovary syndrome (PCOS) can affect LH test results and can also make it harder for you to conceive.
- Trackers and Calendars
There are several trackers and calendars available both online and as apps on your phone. We've even put together an Ovulation Tracker for you here!
- Basal Body Temperature
Your basal body temperature (BBT) actually rises a bit after you ovulate, so you can use daily temperature measurements to track your cycle. A woman’s BBT generally stays in the range of 97-98 degrees fahrenheit. After ovulation, the secretion of progesterone by the corpus luteum leads to a rise in the BBT of about 0.5–1 degree fahrenheit.
As a result, this can be a useful method but only retrospectively—since the temperature rise occurs after ovulation, you need to record your BBT for several cycles. Some women find it helpful to develop a temperature chart over a few cycles that helps them predict ovulation.
How much time to spend in the bedroom?
You’re probably wondering if more sex means faster pregnancy, shouldn’t we be doing it as often as possible? At this point though, the science isn’t totally conclusive about how often you should be having sex. When you’re having sex seems to be far more important than how often you’re doing the deed.
Although having to pencil sex into your calendar might make it feel just like another household chore, research shows that sex during your fertile window significantly increases your likelihood of getting pregnant. Therefore, having a keen sense of when your fertile window is should be what really helps you conceive more quickly.
A study published in the New England Journal of Medicine found that nearly all of the pregnancies within their study sample were attributed to sex that ocurred during the fertile window. The frequency of intercourse did not make a significant difference.
Does sex position matter?
There are no specific sex positions that can increase your chances of conceiving. Reclining back with your legs elevated might be a nice relaxation pose, but it won’t do all that much to hurry sperm along unfortunately.
As far as position goes, it’s best to go with whatever you and your partner are most comfortable with. At the end of the day, sex should still be enjoyable for both of you!
What about sperm?
For the men out there, no need to fear—there isn’t sound evidence that frequent ejaculation decreases fertility. A man’s ejaculate has hundreds of millions of sperm and only one of these is necessary for fertilization. If you’re at all concerned though and want to save up your swimmers, you can try staying abstinent during the days leading up to the fertile window but not much longer than that—abstinence intervals of five days or more are associated with a drop in sperm counts.
Although these odds seem good, a man can have a tougher time making a baby if he has low sperm motility or concentration, or his sperm cells are misshapen. Going back to basics, healthy sperm come from a healthy lifestyle! Eating a nutritious diet, maintaining a healthy weight, cutting down on the booze and eliminating cigarettes from your life all promote sperm health. In fact, all of the above is true for women, too. Simple lifestyle improvements can improve your chances of conceiving.
For the TLDR crowd, what’s the take away with all of this? When it comes to sex, timing is key. The research supports having sex daily or every other day during your fertile window, which is the six days preceding ovulation. While there are several ways to detect ovulation, it’s important that you find the most reliable and comfortable method for you.
And as with all things in medicine, you and your partner should make sure to incorporate healthy lifestyle practices as you move forward including decreasing alcohol use, stopping smoking, eating a well-balanced diet, and maintaining a healthy weight. Read our Five Things to Do Before Getting Pregnant article for more!