Whether you have been trying to conceive, experienced a contraceptive failure, or are just curious, you may be wondering just how soon you can experience pregnancy symptoms. In fact, some people have wondered if pregnancy symptoms can show up as soon as 72 hours after having sex—especially if they are feeling a little sick to their stomach or experience some breast tenderness.
But, pregnancy symptoms typically do not manifest within the first 72 hours after intercourse or conception, says Ila Dayananda, MD, MPH, a board-certified OB-GYN and chief medical officer for Oula Health. “In the earliest stages of pregnancy, the fertilized egg needs time to implant itself into the uterus lining before the body starts producing the hormones associated with pregnancy.”
This process usually takes about six to 12 days after fertilization, Dr. Dayananda says. “The earliest symptoms of pregnancy typically occur a few weeks after conception.”
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What Are the Earliest Symptoms of Pregnancy?
Missing your period is usually the first and most reliable sign that indicates a potential pregnancy, Dr. Dayananda says. “Some [people] may experience mild cramping and bloating similar to premenstrual symptoms. Tender or swollen breasts can also be one of the early signs of pregnancy.”
Other early signs of pregnancy include feeling unusually tired and making more frequent trips to the bathroom, she adds. “Nausea, with or without vomiting, also is a classic pregnancy symptom that may begin around the sixth week of pregnancy.”
Those pesky early pregnancy symptoms are due to hormone changes that occur after you miss your period, says Lauren Demosthenes, MD, an OB-GYN and senior medical director of Babyscripts, a virtual care platform for managing obstetrics. “When they occur does vary—and if they occur also varies—but all of these are signs of a healthy pregnancy. Most [people] would not feel these 72 hours after conception. And a pregnancy test would not be positive this early either.”
Keep in mind, too, that a pregnancy is not confirmed by symptoms. Those afflictions you are experiencing could be explained by other factors, including everything from sickness and stress to even premenstrual syndrome.
What’s more, many people don't feel anything, says Amy Beckley, PhD, a reproductive health and hormones expert and founder of Proov, a fertility diagnostics company. “Just because you don't have cramping, doesn't mean you are not pregnant. The only way to determine a pregnancy is by taking a pregnancy test.”
How Soon Can You Feel Pregnancy Symptoms?
Even though you may not experience pregnancy symptoms 72 hours after conception, a blood test known as quantitative beta HCG might show positive results as early as one week after ovulation. But symptoms do not show up immediately.
According to Dr. Demosthenes, most successful conception often occurs during a person's mid-cycle. “You typically ovulate and can conceive about 14 days before you would expect your next period. You can expect to have a positive pregnancy test about 10 days after conception, but you will not usually feel any symptoms this early.”
In fact, research shows that symptoms tend to become apparent around week five or six of your pregnancy. One study of pregnant people found that 72% detected their pregnancy by the sixth week after their last menstrual cycle.
That said, you may experience implantation bleeding about 10 to 14 days after conception, which might be the first sign you may be pregnant, says Dr. Demosthenes. “But remember, not all [people] have implantation bleeding.”
When to Take a Pregnancy Test
If you suspect you might be pregnant, wait until after you've missed your period before taking a home pregnancy test, advises Dr. Dayananda. “Testing too early before the hCG levels are sufficient may result in a false negative. For that reason, taking a pregnancy test around your expected period provides more accurate results.”
Also make sure you follow the instructions closely and don’t be afraid to reach out to a health care provider if you have questions. If you get a negative result but still suspect you might be pregnant, wait a few days and retest, or consult with your doctor.
Dr. Demosthenes suggests storing your test at room temperature and testing your urine first thing in the morning when it is most concentrated with the hCG hormone. Also try not to drink large quantities of fluids before you take your test. This can dilute your urine and make it harder for the test to detect the hCG, she points out.
If you are pregnant, most home pregnancy tests will be positive between seven and 10 days after conception—which might be before you miss a menstrual period, says Dr. Demosthenes. “These tests are highly accurate—97% to 99% [of the time]—and false positives are rare." However, if you are receiving injections for fertility treatment, they may give you a false positive.
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Why You Shouldn't Take a Pregnancy Test Too Early
Most experts recommend waiting until after you miss your period before taking a pregnancy test. This is because a number of different things can skew the results.
“If you take the test too soon, it could cause false negative results,” Beckley says. “Additionally, some pregnancy tests are so sensitive that they can produce false positive results with very faint lines, so testing early could get your hopes up if it doesn't turn into a real pregnancy.”
Testing too early also can cause additional stress, especially if you get a negative result when you had wanted a positive result. Plus, if you test before your missed period and it is negative, you will need to retest again in 72 hours, Dr. Demosthenes says. “Of course, you can retest daily, but this is stressful and more expensive.”
There also is the risk that the test will pick up a chemical pregnancy if you test too soon, which is a very early miscarriage, she says. “If you take a pregnancy test early and your test is positive and then you test a few days later...and it's suddenly negative, you may have experienced a chemical pregnancy where the implanted embryo started producing hCG but then stopped.”
If you had unprotected sex or a contraceptive failure, you may be worried you are pregnant. And while there is no way to know for sure until your period is late, there is an emergency contraceptive available. Known as the morning-after pill or Plan B, this contraceptive is available over-the-counter at most local pharmacies; there is also another emergency contraceptive called Ella. You do not need a prescription, but may need to request it from the pharmacist.
This pill can prevent pregnancy if taken within five days of having unprotected sex. But the sooner you take the medication, the more effective it will be. It’s also important to note that this pill prevents pregnancy; it does not cause an abortion.
When to Contact a Health Care Provider
Most experts recommend that you see a health care provider before trying to conceive. But sometimes unexpected pregnancies happen, so you should see a physician as soon as you get a positive result on a pregnancy test.
You also should see a health care provider if you experience heavy bleeding or severe abdominal pain, Beckley says. "Additionally ,if you are trying to conceive and don't conceive within 6 months, it is worth calling a health care provider to get basic fertility testing done or doing a home fertility test,” she adds.
As always, if you find yourself with lingering concerns or questions regarding trying to conceive, or potential unplanned pregnancies, be sure to reach out to an OB-GYN or health care provider for further guidance.
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