By Zaira Salvador BSc, MSc (embryologist).
Last Update: 02/28/2018

From the moment of embryo implantation on, the hormones released by the pregnant woman and the embryo itself will be responsible for the first pre-pregnancy signs, as well as for the preparation of the woman’s body to bear the pregnancy. At the very beginning, during which the woman is still unaware that she is pregnant, it is not uncommon that no symptoms appear. Typically, women find out they are pregnant before they miss their period, which is why it is considered the earliest pregnancy symptom.

When do symptoms start?

There are women who begin to notice the first pregnancy symptoms a few days after the embryo has implanted itself into the uterus, while for others it might take longer for them to feel some kind of sign. Some women might not present any symptoms at all. In short, the vast majority of women begin to feel the symptoms of pregnancy on day 7 through day 14 after conception.

If only one symptom is felt, the probability of being pregnant is lower. However, noticing several symptoms at the same time helps many women get used to the idea that they are pregnant even before pregnancy is confirmed.

The very early symptoms of pregnancy are actually quite similar to those of the PMS (premenstrual syndrome). Given that they often appear before you miss your period, it is often quite hard to tell any difference between them.

It should be noted, however, that not feeling any symptom does not automatically mean that you are not pregnant, or that something goes wrong. As explained earlier, it depends on each woman, and while some feel these symptoms with a greater level of intensity, others do not feel any remarkable changes.

Symptoms to look out for

The very first pregnancy symptoms are very similar to those of the premenstrual syndrome (PMS). They are hard to distinguish, nevertheless, because they usually occur before the date when the woman’s period is supposed to show up. Some of the earliest signs of pregnancy are detailed below:

  1. Breast changes: In addition to becoming particularly sensitive and bigger, pregnancy may cause your areolas to darken and small rashes to appear all around them.
  2. Vaginal changes: It is not uncommon for a light bleeding to appear between day 7 through day 10 post fertilization. This happens because of the implantation of the fertilized egg into the uterine lining.
  3. Fatigue: It is normal to experience some minor discomfort during the first days of pregnancy due to: a rise in the basal body temperature and the heart rate, low blood pressure and an increased sense of being sleepy.
  4. Changes in olfactory perception and aversion to certain foods: The sense of smell becomes more sensitive, and some smells which had previously gone unnoticed will now be perceived.
  5. Nausea and vomiting: You may not feel nausea until at least one month after conception. However, there are women who never feel it, and also others who start noticing it too early. The good news is that most women stop feeling dizziness from the second trimester of pregnancy onwards.

After the first 15 days post embryo implantation, the woman is more likely to start suspecting that she may be pregnant, mainly because pregnancy symptoms become more obvious. The following are typically the earliest pregnancy symptoms in the first month:

  1. Abdominal bloating: Due to hormonal changes, it is not uncommon for the abdominal area to become swollen, since estrogen causes fluid retention.
  2. Frequent urination: During the early stages of pregnancy, estrogen and progesterone levels increase. The hCG hormone, which is used to detect pregnancy, is also responsible for increasing the blood flow to the pelvic region and, thus, for the constant urge to urinate during early pregnancy. Later, during the last trimester of pregnancy, it will be caused by the size of the uterus, which puts pressure on the bladder.
  3. A rise in the basal body temperature: During pregnancy, the basal body temperature increases by at least one degree.
  4. Mood swings: Due to hormonal changes, mood swings are usual.
  5. Food cravings: The hCG hormone is responsible for sensory changes which cause food appealing or, conversely, aversion to certain foods.

Most of the symptoms mentioned earlier may occur before your menstruation. However, the most obvious ones are two: a missed period and a positive home pregnancy test.

FAQs from users

Does missed period always mean pregnancy?

By Zaira Salvador BSc, MSc (embryologist).

Actually, a missed period is one of the most important early signs of pregnancy, yet your period being late does not always translate into you being pregnant. It might be caused by hormonal imbalances, which influence your menstrual cycle by preventing ovulation and subsequently menstruation.

A woman whose period is late can take a pregnant test. If you get a negative result, our advice is that you take another one after 4 to 5 days. If it is negative again, it means that you are not pregnant.

Should your period be missing the following month too, it is strongly recommendable to visit your gynecologist, so that you can have your hormonal levels evaluated with a blood test. If the presence of hormonal alterations is confirmed, your doctor will decide what is the best treatment to regulate your cycles.

Can a virgin get pregnant without penetration?

By Zaira Salvador BSc, MSc (embryologist).

Pregnancy is not possible without vaginal penetration. Thus, if a woman notices some kind of body change, general nuisance, pain, or any other pregnancy-like symptom, it is likely related to your period, hormonal imbalances, or an illness.

Can you be pregnant with only a few symptoms?

By Zaira Salvador BSc, MSc (embryologist).

No, having a few pregnancy symptoms does not mean you are pregnant by default. As we explained earlier, the most typical pregnancy signs are akin to those of the PMS. The only way a woman can be sure if she is pregnant or not is by taking a pregnancy test, which measures her hCG levels. Keep in mind that hCG is only present in your body if you are pregnant.

When do common pregnancy symptoms start before BFP?

By Zaira Salvador BSc, MSc (embryologist).

Considering that the clearest sign is a missed period, we can say that normal pregnancy symptoms start at week 4, as women usually get their next period about 4 weeks from the beginning of their last period. However, some women are able to notice some symptoms right after conception.

It should be noted, however, that if you are feeling something at 2 weeks, it is likely caused by your usual menstrual cycle, as at this point you are ovulating and about to conceive, but fertilization has not happened yet. At 3 weeks, most women notice what we know as implantation spotting, or start feeling fatigue, food aversions, frequent urination, etc.

Which hormones are secreted during pregnancy?

By Zaira Salvador BSc, MSc (embryologist).

Although many hormone levels are affected in the body when a woman becomes pregnant, the following are the most common hormones and their functions:

hCG (human chorionic gonadotropin
This is the one that causes the nausea often associated with pregnancy, and is produced only during pregnancy.
Progesterone
It is released by the ovaries and the placenta. It stimulates the thickening of the endometrial lining to prepare for embryo implantation.
Estrogen
It is produced by the placenta and helps maintain a healthy pregnancy.
hPL (human placental lactogen)
Produced by the placenta, provides nutrition to the fetus and stimulates milk glands in the breasts.

When do hormones in pregnancy level off?

By Zaira Salvador BSc, MSc (embryologist).

Normally, the levels of pregnancy hormones kick in 8 days after ovulation, peak at 60-90 days, and then decrease slightly. Although it varies from woman to woman, they usually level off for the remainder of pregnancy.

When does pregnancy sense of smell start?

By Zaira Salvador BSc, MSc (embryologist).

Along with the list of symptoms listed above, having a heightened sense of smell is an early pregnancy symptom that may appear as early as 15 days post ovulation.

Why do women have an increased sense of smell during early pregnancy?

By Zaira Salvador BSc, MSc (embryologist).

A woman may be sensitive to smells all of a sudden due to the rise in the levels of hCG. This is the reason why many scientists have related it to morning sickness and nausea, two of the most typical pregnancy signs.

Will pregnancy increase my breast size?

By Zaira Salvador BSc, MSc (embryologist).

Yes, all pregnant women experience a significant change in their bra size. Breasts become swollen and enlarged as early as during the first trimester because of an increase in the levels of estrogen and progesterone. The growth normally continues throughout your entire pregnancy.

What does progesterone do in early pregnancy?

By Zaira Salvador BSc, MSc (embryologist).

To give you a more detailed explanation about the role of progesterone in early pregnancy, let me tell you about its function after ovulation, as well as before and during pregnancy:

After ovulation
the ovaries start to produce it, which is needed by the uterus.
Before pregnancy
prepares the uterus for pregnancy.
During pregnancy
it helps prepare a supportive environment in the womb for an embryo.

Suggested for you

The ones mentioned here are only the earliest pregnancy signs as reported by the majority of pregnant women. However, if you want to check a timeline with the whole list of pregnancy symptoms, visit the following post: Most common pregnancy symptoms.

If you are here it is because you already discovered that you are pregnant or because you suspect so. Then, you might be interested in learning what is waiting for you during the 1st month by clicking here: First month of pregnancy.

Have you already taken a pregnancy test and got a positive result? Then you might want to learn more about the terminology used to refer to each stage of embryo development. Learn more here: Differences between zygote, embryo and fetus.

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Authors and contributors

 Zaira Salvador
BSc, MSc
Embryologist
Bachelor's Degree in Biotechnology from the Polytechnic University of Valencia (UPV). Embryologist specializing in Assisted Procreation, with a Master's Degree in Biotechnology of Human Assisted Reproduction from the University of Valencia (UV) and the Valencian Infertility Institute (IVI). More information
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3 comments

  1. Featured
    Lucy Mulligan

    Hello,I did a FET and dr said my chances of becoming pregnant were very high… I took a test on day 8 post transfer and it says negative… do you think it is because hCG is still low? What do you recommend? Should I repeat it? Pls, help!

    • Mscross

      Hello lucy, i think day 8 is still early to take a test and that you still have chances for it to be a bfp! you should definitely repeat it 😉

      • Sandra FernándezBA, MA

        Indeed, as mscross said, day 8 is still a bit too early for your hCG levels to be detectable yet, so my advice is that you repeat the test in a few days or wait till you have your blood test done to get more accurate results.

        I hope this helps,

        Best