The First Two Weeks of Pregnancy – Ovulation & Conception

By (embryologist) and (fertility counselor).
Last Update: 04/30/2018

If we take into account that the average length of human pregnancy is 40 weeks (280 days), during the second week of pregnancy—counting from the date of the last menstrual period (LMP)—the body is still preparing to receive the embryo. Two major events take place: proliferation of the endometrium and ovulation.

Egg fertilization and embryo implantation have not taken place yet. In other words, technically conception per se hasn't occurred. Gynecologists start counting the weeks of pregnancy from the first day of the last menstrual period, though.

For this reason, during the first and second weeks of pregnancy, the woman is not pregnant yet. Some specialists prefer to refer to them as the countdown to conception or just the weeks before conception.

Changes in the uterus & ovaries

As mentioned above, the second week of pregnancy is actually the second week of the menstrual cycle. Particularly, it is the stage at which follicle recruitment takes place, hence the name preovulatory phase.

After the beginning of the menstrual cycle, which occurs during the first week of pregnancy, the pituitary gland starts producing FSH and LH, the hormones that make the ovaries work. LH and FSH surges occur during the second week, thereby causing the following phenomena:

Follicle recruitment

The FSH surge that occurs in the first two weeks of the menstrual cycle causes the ovarian follicles to grow and migrate to the surface of the ovary. At the same time, follicle grow causes the ovary to increase the production of estradiol.

Estradiol is a sex hormone responsible for the proliferation of the uterine lining. When endometrial cells proliferate, blood vessels and uterine glands develop.

Ovarian follicles are like small "sacs" filled with fluid. Egg cell maturation occurs within each follicle.

When the second week starts, the concentration of FSH hormone levels off due to the effects of estradiol, which causes follicle recruitment to happen: just one out of all the ovarian follicles is able to interact with FSH and continue its development. The remaining follicles will degenerate, and so the eggs they contained.

Those follicles that have been able to survive continue growing until they become preovulatory follicles or Graaf follicles.


By the end of the second week of the menstrual cycle, another major hormonal change occurs: the so-called LH surge.

The LH surge causes the Graaf follicle to burst and release the egg that it contained, which travels to the Fallopian tube. This is the process that we all know as ovulation.

Finally, the follicle that has just released an egg cell becomes the corpus luteum. This endocrine structure is involved in the production of estrogen and progesterone, which have a direct effect over the endometrium (uterine lining).

Recommended for you: What Is Ovulation? – Date, Symptoms & Most Fertile Days.

Symptoms to expect

Since pregnancy has not occurred yet, there is no way for you to feel pregnancy symptoms. If any, the symptoms you are likely to have are those associated with ovulation, including:

  • Watery, egg white cervical mucus (EWCM)
  • Increased basal body temperature (at least 0.2-0.5 °C)
  • Increased sex drive
  • Pain in the lower abdomen
  • Bloating
  • Lots of gas
  • Spotting or light bleeding in the most severe cases

Broadly speaking, the discomforts and symptoms caused by ovulation are less painful than those caused by the Premenstrual Syndrome or PMS.

Recommended for you: ‘Mittelschmerz’ or Pain During Ovulation.

Ovulation predictor kits (OPKs)

Those women who are trying to conceive (TTC) and have trouble identifying their fertile days because they lack ovulation symptoms can use an ovulation predictor kit or OPK to find them out.

OPKs can be purchased at pharmacies and work by detecting the LH surge in urine. Thanks to them, you can learn about your most fertile days easily and quickly.

Sexual intercourse during the second week of the menstrual cycle increases the chances of getting pregnant, as the woman is in her fertile days (fertile window).

Dos and don'ts

Those who are trying to get pregnant should start following healthy lifestyle habits in order to have a healthy pregnancy.

In women who have fallen pregnant unexpectedly, it is common that they pick up healthy habits once they learn about the pregnancy and not earlier.

To sum up, when a couple is TTC, following healthy habits is crucial. Here are some useful tips for you to follow from this moment on:

  • Visit your OB/GYN: If you are trying to get pregnant, you should tell your doctor about your plans in order to make sure that everything's fine with you.
  • Foods to eat: Although there are no foods to avoid, you should include those that are reach in proteins, folic acid, calcium, etc. Moreover, you can add vitamin supplements to your diet to stay healthier.
  • Caffeine, tobacco and alcohol: You should quit these unhealthy habits as soon as possible if you want to have a healthy pregnancy from the very beginning. Caffeine, nicotine, and alcoholic drinks are toxic substances that may damage the baby and increase the miscarriage risk.
  • Antibiotics: You can take antibiotics during this second week, especially if there in cases of urinary tract infections (UTIs). Drinking plenty of water is strongly recommended as well.

Additionally, specialists do recommend that women who are trying to become pregnant get informed about good health habits to pick up before and during pregnancy. Learning about the habits to avoid is essential, too.

FAQs from users

Why are you considered two weeks pregnant at conception?

By Zaira Salvador B.Sc., M.Sc. (embryologist).

Because the weeks of pregnancy are counted from the first day of the woman's last menstrual period. Keeping this in mind, technically the woman is not pregnant during the first two weeks of pregnancy. However, fetal development doesn't start until conception, which occurs about two weeks later (week 4 of pregnancy).

Related post: When Does Week 1 of Pregnancy Start? – Symptoms & Key Facts.

Can you see a 2 week pregnancy on ultrasound?

By Zaira Salvador B.Sc., M.Sc. (embryologist).

No, it's not possible. You have to wait until at least the fifth week of pregnancy to have a real chance to see anything on an endovaginal ultrasound. In fact, sometimes the gestational sac can be seen as early as on week 5, but you have to wait until week 7 to see the embryo.

Learn more: Ultrasound Scans in Pregnancy.

Can you get a positive pregnancy test at 2 weeks?

By Zaira Salvador B.Sc., M.Sc. (embryologist).

Keeping in mind that conception has not taken place at week 2, the answer is no. However, if you take a pregnancy test two weeks after conception, you are likely to get a positive result if embryo implantation has occurred.

Recommended for you: When to Do a Pregnancy Test? – How to Use, Results & Accuracy.

How big is your baby at 2 weeks?

By Zaira Salvador B.Sc., M.Sc. (embryologist).

Two weeks after conception, the size of an embryo is often said to be that of a poppy seed. At week 5, it resembles an apple seed, and by week 7 it is as big as a blueberry.

Suggested for you

It is during the second week when couples should start having intercourse every two days approximately in order to increase the chances for egg fertilization and embryo implantation. Learn more: How Does Natural Conception Occur?

If everything goes as expected and fertilization occurs, embryo development will start next week. Find out what happens next here: 3 Weeks Pregnant – Symptoms & Size of the Fetus.

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 Zaira Salvador
Zaira Salvador
B.Sc., M.Sc.
Bachelor's Degree in Biotechnology from the Technical University of Valencia (UPV). Biotechnology Degree from the National University of Ireland en Galway (NUIG) and embryologist specializing in Assisted Reproduction, with a Master's Degree in Biotechnology of Human Reproduction from the University of Valencia (UV) and the Valencian Infertility Institute (IVI) More information about Zaira Salvador
License: 3185-CV
Adapted into english by:
 Sandra Fernández
Sandra Fernández
B.A., M.A.
Fertility Counselor
Bachelor of Arts in Translation and Interpreting (English, Spanish, Catalan, German) from the University of Valencia (UV) and Heriot-Watt University, Riccarton Campus (Edinburgh, UK). Postgraduate Course in Legal Translation from the University of Valencia. Specialist in Medical Translation, with several years of experience in the field of Assisted Reproduction. More information about Sandra Fernández

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