How can I get pregnant naturally?

By (gynecologist), (embryologist) and (psychologist).
Last Update: 12/10/2021

For a woman to become pregnant there must be vaginal ejaculation, fertilization, and implantation. For this to occur, the woman must be in her fertile days, ovulation must occur, otherwise, the egg and sperm cannot meet, so there will be no possibility of pregnancy.

In a young and healthy couple, without fertility problems, each sexual encounter in the fertile period has a pregnancy probability of 18-25%. After one year, 85% of couples seeking pregnancy are successful.

For this reason, it is recommended not to go to an assisted reproduction clinic until at least one year has passed having unprotected sex on a regular basis, or 6 months in couples in which the woman is over 37 years old since it is very possible that natural pregnancy may occur spontaneously.

Provided bellow is an index with the 6 points we are going to expand on in this article.

How and when can you get pregnant?

If the couple is using any contraceptive, the first thing to do is to stop using it, since unprotected sex is necessary to achieve pregnancy.

If you are using hormonal contraceptives, keep in mind that it may cost more, since the first cycles after stopping contraceptives may result in poor quality eggs or altered ovulation.

For a higher probability of pregnancy, intercourse should be performed on the fertile days, i.e., those close to ovulation. The woman must necessarily have free reproductive tracts, i.e., there can be no natural pregnancy with blocked tubes. These must be permeable to allow the passage of spermatozoa to the ovum so that fertilization can occur.

Nevertheless, the male must have a minimum of 15 million spermatozoa per milliliter, and of these at least 32% must have an adequate displacement, that is, good mobility. It is possible to have a natural pregnancy with lower semen quality values, but it may be more complicated.

In order to know the number of spermatozoa and to evaluate other aspects of the semen, such as whether the motility is adequate, a semen analysis must be performed. For more information on this test, see this article: What is the semen analysis and how is it performed?
There are a number of tips you can follow if you want to get pregnant fast:

  • Avoidance of harmful substances such as tobacco, alcohol and drugs
  • Eating a balanced and healthy diet
  • Reduce or avoid coffee and tea consumption
  • Exercise moderately and regularly
  • Have regular sexual relations and on your fertile days
  • Consult your physician about the possibility of taking dietary supplements such as vitamins and minerals

A healthy lifestyle benefits both male and female fertility, facilitating conception and increasing the probability of pregnancy.

How does pregnancy occur?

In the following sections, we show you step by step the three essential processes that must take place for pregnancy to occur.

Vaginal penetration and ejaculation

It is a necessary condition for a natural pregnancy to occur. The penis is introduced into the vagina and in ejaculation, the spermatozoa pass from the testicles into the penis, are surrounded by seminal fluid secreted by the glands attached to the urethra, and are deposited at the bottom of the vagina.

Arrival of spermatozoa in the tubes

Once deposited in the vagina, the spermatozoa encounter unfavorable pH conditions which they must overcome in order to pass through the cervix in search of the fallopian tubes, where the egg is located.

They must pass through the cervix, which makes their passage difficult in the non-fertile period, and easier in the days of ovulation.

The sperm cells accumulate in the hollows of the cervix and have to undergo hyperactivation, which makes them capable of fertilizing the oocyte. Then, with their swimming movement, they must actively move out of the holes and into the fallopian tubes.

If you want more information about how sperm reach the fallopian tubes you can enter here: Path of the sperm to the egg.

Egg fertilization

In the fallopian tubes, if intercourse has taken place during the fertile period, the recently ovulated egg will be waiting for the sperm to arrive, which can live for about 72 hours in the woman's reproductive system.

The egg, from the moment it leaves the ovary, can live for about 24 hours, so the fertile period is about 4 days, during which sexual intercourse is more likely to result in pregnancy.

When the egg and sperm meet, fertilization occurs, which is the fusion of both gametes to give rise to the embryo.

The complete fertilization process consists of the following phases:

  • Penetration of the corona radiata: the sperm penetrates the layer of cells surrounding the egg, called the corona radiata.
  • Penetration of the zona pellucida: the sperm penetrates the glycoprotein layer that constitutes the zona pellucida thanks to the acrosome at its end, which contains hydrolytic enzymes that dissolve this structure.
  • Membrane fusion: when the sperm membrane comes into contact with the egg membrane, they fuse, so that the head, midpiece and tail of the sperm enter the interior of the egg. This fusion of membranes induces a series of changes in the ovum that prevent the entry of more spermatozoa, in addition to the formation of the female pronucleus. The male pronucleus is formed when the sperm cell advances towards the female pronucleus, the head nucleus swells and the tail detaches from the head to degenerate.
  • Fusion of pronuclei: pronuclei are the nuclei of the gametes, which contain half as many chromosomes as the nuclei of the rest of the cells of the body thanks to meiosis. Once the male and female pronuclei are formed, the maternal and paternal chromosomes become visible and are arranged together to give rise to the zygote nucleus.

To learn more about fertilization access this link: How human fertilization occurs.

Embryo implantation

After fertilization, the fertilized egg is called a zygote. The latter divides to give rise to the embryo, which will continue to divide and make its way to the uterus so that implantation and thus pregnancy can take place.

In order for the embryo to implant, a blastocyst must be formed, which is a specific organization of the embryonic cells in which an inner cell mass is distinguished, from which the embryo originates, and an outer layer of cells, which will form the placenta.

At implantation, as seen in the image below, the outer layer of cells contacts the uterine endometrium and penetrates it so that the placental structures that will nourish the embryo and eliminate its waste can form.

For successful implantation to occur, it is important that the endometrium is in an optimal state, as Dr. Miguel Dolz explains in the interview he gave us about the importance of the layer that lines the inside of the uterus.

FAQs from users

Can I become pregnant while on my period?

By Laura Garrido B.Sc., M.Sc. (embryologist).

Even if ovulation normally takes place 14 days before the period, sometimes women ovulate at the same time of the previous period, and for this reason some pregnancies happen while you're on your period.

How many sperm cells does it take to fertilize an egg?

By Sara Salgado B.Sc., M.Sc. (embryologist).

Although only a single sperm enters the egg and gives rise to the embryo, many more are needed in the ejaculate, because they have to go through an obstacle course and get trained until they reach the egg: vagina, cervix, uterus, fallopian tube, and ampulla, which is the part of the tube where fertilization takes place.

Optimally, of the millions of sperm that are ejaculated, a few hundred thousand arrive at the correct Fallopian tube, and once close to the egg, they have to break the envelopes that surround it, thanks to a mini-pump that they have in their head called the acrosome, which pierces the layers around the egg.

Many spermatozoa are necessary to erode the layers of the ovum and they will not fertilize it until one arrives, which is not the fastest but the most opportune, which finds a freeway and connects with the internal membrane of the ovum and it is this one that enters inside the cell and fertilizes the ovum.

What are my fertile days?

By Sara Salgado B.Sc., M.Sc. (embryologist).

The day after ovulation, the day of ovulation itself and the 3 days prior to ovulation are the fertile days of the woman, i.e., days 11-15 of the cycle approximately.

Sperm can live in the female genital tract for about 3-4 days, so if they arrive before ovulation occurs, they are waiting to meet the egg.

If your periods are regular, count 14 days before you expect your next period and that is approximately the day you will ovulate. Ovulation tests measure the peak of the ovulatory hormone, LH or luteinizing hormone, which rises in levels just before ovulation, so they are a more effective way to calculate your fertile days.

In the case of irregular periods, or months without menstruation, it is advisable to consult a gynecologist if you are looking for pregnancy, because if the egg is not in the fallopian tubes waiting for the sperm, a natural pregnancy will not occur.

If I had three normal periods and the fourth is delayed, could I have fallen pregnant before the first one?

By Laura Garrido B.Sc., M.Sc. (embryologist).

Absolutely not. Every menstruation means a cycle without embryo; therefore, if you had unsafe sexual intercourse before a series of regular periods, pregnancy is unlikely the reason for the delay.

How many days does ovulation last?

By Sara Salgado B.Sc., M.Sc. (embryologist).

The ovulatory phase, that is, the period when the egg is released and ready to be fertilized, lasts about 24 hours. Ovulation occurs in the middle of the menstrual cycle, on approximately day 14. Once released, the egg has a life span of only 24 hours, so that if it is not fertilized within this time it will die and be expelled through menstruation.

Can I get pregnant without penetration?

By Laura Garrido B.Sc., M.Sc. (embryologist).

No. Neither through masturbation, neither through anal penetration, nor through vaginal frictions. Vaginal penetration is necessary for a pregnancy to take place. "And without ejaculation?" There are different opinions about the presence of sperm into the pre-seminal fluid, still the famous "pull-out method" is responsible for several unwanted pregnancies. Thus, if penetration takes place, there's no contraceptive efficacy.

If I have my period, is it possible to have become pregnant before?

By Sara Salgado B.Sc., M.Sc. (embryologist).

The period is the detachment of the endometrium from the previous cycle and occurs when there has been no implantation of an embryo, therefore, in general, if you have a period there is no pregnancy.

Is there a chance of pregnancy without ejaculation? Can I get pregnant with pre-seminal fluid?

By Sara Salgado B.Sc., M.Sc. (embryologist).

There are different opinions regarding the presence of spermatozoa in the pre-seminal fluid, but the famous "reversal" is responsible for numerous unwanted pregnancies, so if there is penetration, there is no contraceptive security.

After how long can I tell if I am pregnant?

By Sara Salgado B.Sc., M.Sc. (embryologist).

Approximately 15 days after intercourse a woman can take a pregnancy test to find out if she is pregnant. It is always recommended to wait until a delay in menstruation occurs to do the test.

For more information about embryo implantation, see this article: Embryo implantation

If you want to know what happens after the embryo implants in the mother's uterus, click here: Pregnancy month by month.

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Bellido, P. (1997). Mecanismo de fertilización. Ginecol Obstet (Perú); 43(3): 183-90.

Cerqueira Dapena MJ. (2003). Metabolismo en el embarazo. Modificaciones endocrinas. Modificaciones psíquicas. En: Cabero Roura L (Director). Tratado de Ginecología, Obstetricia y Medicina de la Reproducción. Madrid: Editorial Médica Panamericana.

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Patrat C, Serres C, Jouannet P. (2000). The acrosome reaction in human spermatozoa. Biol Cell; 92: 255-66.

Paul P, Miles DG (2002). Penetration, adhesion and fusion in mammalian sperm-egg interaction; 296/5576):2183-5.

Prof. Mary Wingfield (2017). The Fertility Handbook: Everything You Need to Know to Maximise Your Chance of Pregnancy, Gill & Macmillan Ltd, May 29, 2017

Smith, R. (2002). Biología del embrión preimplantacional. En: Beca Infante JP. (Comp.). El embrión humano. Santiago: Mediterráneo; 21-49.

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FAQs from users: 'Can I become pregnant while on my period?', 'How many sperm cells does it take to fertilize an egg?', 'Is it possible for a woman to be pregnant and still have periods?', 'What are my fertile days?', 'If I had three normal periods and the fourth is delayed, could I have fallen pregnant before the first one?', 'How many days does ovulation last?', 'Can I get pregnant without penetration?', 'If I have my period, is it possible to have become pregnant before?', 'Is there a chance of pregnancy without ejaculation? Can I get pregnant with pre-seminal fluid?' and 'After how long can I tell if I am pregnant?'.

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Authors and contributors

 Miguel Dolz Arroyo
Miguel Dolz Arroyo
M.D., Ph.D.
Bachelor's Degree in Medicine and Surgery from the Medicine Faculty of the University of Valencia (UV) and Doctor in Medicine, finished in 1988 and 1995, respectively. Physician specialized in Obstetrics & Gynecology. Expert in Reproductive Medicine, with more than 20 years' experience in the field. He is the Medical Director and founder of FIV Valencia. More information about Miguel Dolz Arroyo
License: 464614458
 Sara Salgado
Sara Salgado
B.Sc., M.Sc.
Degree in Biochemistry and Molecular Biology from the University of the Basque Country (UPV/EHU). Master's Degree in Human Assisted Reproduction from the Complutense University of Madrid (UCM). Certificate of University Expert in Genetic Diagnosis Techniques from the University of Valencia (UV). More information about Sara Salgado
Adapted into english by:
 Cristina  Algarra Goosman
Cristina Algarra Goosman
B.Sc., M.Sc.
Graduated in Psychology by the University of Valencia (UV) and specialized in Clinical Psychology by the European University Center and specific training in Infertility: Legal, Medical and Psychosocial Aspects by University of Valencia (UV) and ADEIT.
More information about Cristina Algarra Goosman
Member number: CV16874

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