Trying to conceive? Understanding fertile windows, fertility risk factors, and when to seek medical guidance will help you feel confident during the preconception journey.


By Dr. Nazaneen Homaifar

The whole getting pregnant process can be a lot to take on. It can feel like you’re doing a home science project on your body. If you don’t succeed, you’re left wondering if you’ve done something wrong or if there’s something wrong with your body. That’s where we come in—we’re here to help you get your bearings and walk you through your cycle.

Let’s go back to the basics. Before you started trying to get pregnant, you probably just thought of your cycle as your period once a month-ish. In actuality, your body is doing a lot more than just shedding your uterine lining. About two weeks before your period, you ovulate—your ovaries release an egg, and it travels down your fallopian tubes, where it hangs out, waiting to be fertilized. If you’re trying to get pregnant, you’ll want to have sex right before and during ovulation. This is called your fertile window, the time when you’re most likely to conceive. 

It’s super helpful to figure out exactly when your fertile window is during your cycle. On that, you’re in luck! We made a helpful ovulation tracker that you can use to stay on top of your cycle, decode your body’s signals, and pinpoint when you’re most fertile. 

We’ve also written about some ways to tell if you’re ovulating—there are a few types of tests that you can use, which we’ve described here. As a quick refresher, the main methods are ovulation tests (a urine-based test similar to a pregnancy test), basal temperature tracking (your body’s temperature changes in response to ovulation), and cervical mucus tracking (your cervical mucus changes in texture and color during your fertile time of the month). To learn how to use these three different methods, read our guide here

What if it’s not working?

It can take a long time to conceive without medical assistance—about 80% of couples get pregnant during the first six months of trying, but that’s definitely not everyone. Outside of timing sex, a lot of the advice around how to increase your chances of getting pregnant has to do with lifestyle choices and self-care—eat right, maintain a healthy body weight, get enough sleep, avoid excessive drug and alcohol use, etc. Even if you’re making a big effort to do those things, human biology is mysterious and sometimes out of our control. All we can do is try the best we can to make the adjustments that facilitate getting pregnant.

With that said, there are also some factors that may be making it harder for you to conceive. There are a few indicators that can help you know if some of the common barriers to fertility might apply to you:

  1. If you have an irregular period or infrequent periods. Irregular periods mean infrequent, irregular, or cycles without ovulation. If you don’t know when you’re ovulating or aren’t ovulating at all, you don’t know when you are fertile to time sex, making it pretty hard to get pregnant.  If this is you, you should tell your doctor and discuss your options.
  2. If your weight is outside of a healthy range. Bodyweight either above or below the healthy range for your height can disrupt your menstrual cycle. That doesn’t mean you’re infertile, but it could interfere with ovulation, making it harder for you to conceive.
  3. If you’ve had an untreated sexually transmitted infection (STI). Some STIs can lead to scarring in the uterus and fallopian tubes, making it difficult for a fertilized embryo to journey down the fallopian tubes to implant in the uterus. This underscores the importance of testing regularly for STIs; it can be easy to miss unchecked infections resulting from STIs, so now is a good time to get tested, for both your health and your future baby’s health.
  4. If you’re a cigarette smoker. Women who smoke experience infertility 54% more often than women who do not. Smoking generates reactive oxygen species, which damage a woman’s fixed lifetime supply of eggs and increase the risk of miscarriage.

Should I get my hormones tested? In most cases, no. 

You may have heard of people having their hormones tested to see if they’re “fertile enough” before they try to conceive or make decisions to defer pregnancy. These tests involve blood draws that check your thyroid stimulating hormone (TSH), prolactin, luteinizing hormone (LH), follicle stimulating hormone (FSH), anti-Mullerian hormone (AMH), and estradiol. We don’t recommend routine testing of these hormones unless an infertility workup is indicated under the guidance of your doctor. 

TSH, prolactin, LH, and FSH are hormones that can affect your menstrual regularity. When patients haven’t had a period in three or more months, these are part of the routine hormones we check in order to determine why periods may have been disrupted. That being said, if you have regular cycles, we can be pretty confident that these hormones are within a normal range, without the need for testing. 

AMH and FSH levels can be used to estimate the size of your primordial follicle pool or the number of eggs you have left before you hit menopause. Women with known infertility (evaluated by a reproductive endocrinologist and infertility or REI specialist), cancer patients, and patients who have had a significant injury to their ovary from radiation or surgery usually have lower than expected AMH levels. 

AMH is used to predict success rates (number of potential eggs retrieved) and calculate medication dosages for in-vitro fertilization (IVF). AMH is not accurate in predicting your chance of carrying a baby to term and shouldn’t be used to determine your chances of getting pregnant spontaneously

We recommend talking to your doctor at your preconception visit; based on your medical history they can advise if hormone testing is indicated. 

The bottom line

If you and your partner have been trying for a while to conceive (one year if you’re under 35 or six months if you’re over 35), and it’s just not happening, it’s helpful to see your doctor. You can talk through various risk factors, lifestyle choices, and options for moving forward. 

There’s no need for immediate concerns about infertility. Often, trying to get pregnant is one of the first times we are forced to surrender to a process that is outside of our hands. That surrender of control can feel destabilizing and frustrating. If you have any red flags mentioned in this article, or things are taking longer than the suggested wait times for your age, talk to your doctor or provider, who can help you sort through those emotions, and work with you to come up with concrete steps to move forward.


Image by Robert Mapplethorpe.