How hard is it to get pregnant? The chances of conception depend on various circumstances, ranging from your menstrual cycle to your birth control. Here, experts share the scenarios where you're least likely to conceive.

By Jenn Sinrich
Updated March 02, 2021
Advertisement

Many women spend the better part of their fertile years actively trying not to get pregnant, so it might be a surprise to learn that conception isn't that easy. Indeed, there's a relatively short window during a woman's cycle (about 48 hours long) that's ideal for conceiving, whether or not she's on birth control or actively trying, says Anate Brauer, M.D., a reproductive endocrinologist at the Greenwich Fertility and IVF Centers and assistant professor of OB-GYN at NYU School of Medicine.

According to the American Pregnancy Association, a healthy 30-year-old has a 20 percent chance of pregnancy each month with frequent unprotected sex. Of course, every woman is different, and you should always use protection if you're not trying to conceive. But if you're wondering which occasions make for the least likely opportunity, check out these expert-stamped scenarios where your chances of pregnancy are lowest.

You're on Birth Control

Birth control—whether it's the pill, patch, ring, implant, IUD, or the shot (Depo-Provera)—greatly decreases your chances of conception. These methods work in various ways; for example, IUDs block sperm from reaching the egg, while hormonal contraception (like the pill, ring, and patch) prevent the recruitment of a mature egg, explains Dr. Brauer. Even if you're committed to taking your birth control, you still have to use it correctly and consistently. 

Also, if you rely on contraceptive pills, take note: Some pill packs contain four to seven days of sugar pills without any hormones. In rare ocassions, this may be long enough to allow for recruitment of a mature egg. "This is often referred to as 'escape ovulation' and is one reason for oral hormonal contraception failure," says Dr. Brauer. Missing doses of hormonal contraception could also increase the chances of accidental pregnancy. 

How hard is it to get pregnant on birth control? If you're on birth control and following all instructions, then your chances of getting pregnant are generally less than 1 percent. The effectiveness decreases with "typical use" (not using the method correctly and consistently for every sexual encounter). 

You Have Your Period

While it's not totally impossible to get pregnant while Aunt Flo is in town, your chances are pretty darn slim. If you consider what's actually happening inside your body, you can understand it a bit better: The egg that was growing inside your ovaries wasn't fertilized and, as a result, your uterine lining sheds (this is the "blood" that's released) and prepares to grow new follicles (eggs) for your next cycle. In other words, the egg that was viable for fertilization has now been flushed along with your period. 

The only way you can get pregnant on your period? Having particularly short cycles with ovulation that occurs soon after menstruation. "Sperm can live in the uterus for up to five days, so if you have intercourse towards the end of your period, sperm can still hang around long enough to fertilize an egg that is released days after your period ends," explains Dr. Brauer.

How hard is it to get pregnant while on your period? It's possible to get pregnant by having sex on your period, but the chances are extremely low. The exact risk depends upon the length of your cycle.

You Use the "Pull Out" Method

This old-school method of preventing pregnancy is a far cry from a myth. It's not foolproof and it can certainly result in pregnancy, but it does significantly decrease your chances of getting pregnant. In case you need a refresher course on the pull-out method, also known as withdrawal, it involves the male partner pulling out of the vagina before he ejaculates. The problem, however, is that pre-ejaculate or precum, the bodily fluid that's released from the penis before an actual ejaculation, very well may contain active and viable sperm.

Additionally, Mark Trolice, M.D., reproductive endocrinology and infertility specialist at My Fertility CARE: The IVF Center in Winter Park, Florida, explains that most men aren't aware of when they release this precum. "Because it's hard to predict when pre-ejaculation occurs, the withdrawal method is often fraught with peril and certainly not the most reliable method out there," he says.

How hard is it to get pregnant while using withdrawal? Withdrawal is about 96 percent effective with perfect use and 82 percent effective with typical use. If you really want to avoid pregnancy, choose a different contraceptive method (or double up with another method, such as condoms.)

You Use a Condom

When using a condom, it's vital to do so correctly. This means the condom is rolled onto the male partner's penis before there's any contact between genitals and skin (because precum could potentially lead to conception). You can make rubbers even more effective by pairing them with another form of birth control, like an IUD or the pill, or using them in combination with the pull-out method.

How hard is it to get pregnant while using a condom? Your chance of getting pregnant with condom use is about 15 percent—and that's accounting for human error. With perfect condom use every single time, those odds decrease to 2 percent, according to Planned Parenthood

You're Breastfeeding

If you haven't had a period after giving birth, especially if you're breastfeeding, it's actually unlikely that you can become pregnant. "While breastfeeding, the hormone estrogen, which is responsible for getting your period each month, is suppressed," explains Sherry Ross, M.D., OB-GYN, Women's Health Expert in Santa Monica, and author of She-ology: The Definitive Guide to Women's Intimate Health. Period. "Additionally, the hormone that stimulates breast milk production, prolactin, also prevents ovulation from occurring because it inhibits the FSH hormone that triggers your ovaries to grow and release eggs." 

How hard is it to get pregnant while breastfeeding? Without a period, you won't ovulate regularly so it's less likely to become pregnant—though it's certainly not impossible. 

You're Over 44 Years Old

Thanks to that good-old biological clock, a woman's chances of getting pregnant wane over time. Women are born with some 1 million to 2 million eggs; there's only about 300,000 left when they get their first period and 25,000 left by their late 30s. This means that a woman's chances of becoming pregnant in her early 40s are pretty slim, though it's by no means impossible. "As we get closer to 40, the ticking of our biological clock becomes louder and by 44, it can be deafening," she says. "Fertility decreases by as much as 95 percent in women between 40 and 45 years of age."

How hard is it to get pregnant over 44 years old? According to Dr. Ross, women over the age of 44 have a less than 5 percent chance of getting pregnant each month.