Female fertility can be defined as the ability of a woman to conceive and carry a pregnancy for 9 months, which is called full-term pregnancy.
In this sense, and for a woman to be considered fertile, she has to meet two basic requirements:
- Her ovaries are able to produce good-quality eggs in order for the sperm to be able to penetrate and fertilize them.
- Her uterus is able to bear a pregnancy to term, that is, from fertilization to labor.
In women, fertility is regulated by both the female reproductive system and the endocrine system, which have to be properly regulated and coordinated in order for all the steps involved in the process to be successful.
Female reproductive system
The anatomy of the female reproductive system can be classified into two groups depending on whether we are talking about the external or the internal organs.
The whole set of external female genitalia is known as vulva. It includes the following parts:
- Mons pubis or mons Venus
- It is a rounded mass of fatty tissue that covers the pubic bone, and at the same time is covered by pubic hair and skin. Its function is to protect the internal organs by absorbing shocks.
- Labia majora
- It consists of two cutaneous folds that protect the vulva. They work by preventing the entrance of bacteria into the female reproductive system.
- Labia minora
- It is made of two flaps of skin which function is to protect the opening of the vagina and keep the internal organs under the adequate temperature.
- Vulval vestibule
- This part of the external organs includes the urethral orifice, the opening of the vagina, the hymen, the Bartholin’s glands, and the Skene’s glands (a.k.a. periurethral or paraurethral glands).
- It is a cylindrical, button-like, and erectile organ that is made of multiple sensory nerve endings that make it very sensitive to sexual stimulation.
The perineum is the region where the pelvic floor muscles are located. It is composed of muscles that surround and protect both the vulva and the anus.
Conversely, the breasts or mammary glands are also considered to be external female reproductive organs. Their function is to secrete milk and feed infants after childbirth.
The urethra is not a part of the female reproductive system: it it just the external opening of the urethra, from which females eject urine during urination. However, the G-spot is believed to be located here.
The female internal reproductive organs are the ones responsible for human reproduction and are located within the woman’s abdominal cavity. Each one of them is listed below:
- It is a muscular and tubular part of the female reproductive system which function is to connect the uterus with the exterior. It allows for the entrance of the penis during sexual intercourse, and acts as the birth canal to deliver a newborn.
- Cervix uteri
- The cervix is the lower part of the uterus and connects it with the vagina.
- Uterus or womb
- It consists mostly of smooth muscle (i.e. myometrium), and is the place where pregnancy and fetal development occur. Its inner layer or endometrium thickens on a monthly basis to receive the embryo, and shreds in the form of menstrual flow if embryo implantation does not take place.
In English language, uterus is the medical term to refer to this internal organ, and is mostly used in medical and related contexts, while womb is more commonly used in everyday language.
- Fallopian tubes
- These tubes, which length is about 10 mm, connect the ovaries with the womb. The sperm meets the egg here when fertilization occurs.
- They are the female gonads and can be found in pairs alongside the lateral wall of the uterus. Their function is to produce egg cells and release one during the fertile days of the woman’s menstrual cycle. They are responsible for the production of female sex hormones, too.
Should an alteration that prevents the woman from conceiving appear, she will be diagnosed with female sterility or infertility. Nevertheless, and thanks to the progress made in the field of assisted reproductive technology (ART) to date, today it is possible for childless women to get pregnant in spite of infertility.
How do organs shift during pregnancy?
The internal organs described above keep on changing significantly during the approximately 40 weeks of pregnancy. Obviously, these changes are caused by the fetus growing inside, thereby occupying more space inside the mother’s body.
The internal organs of the woman are also put under a great amount of pressure, being this the reason why pregnant women experience pain, aches, and general discomforts like abdominal or round ligament pain, among others. In short, the impact of pregnancy requires the woman to adjust both physically and mentally.
It is not until the third trimester when the woman’s internal organs become really squashed:
- The lungs become cramped and move upwards
- The intestines move out of the way
- The stomach pushes up against the lungs
- The uterus puts pressure on the bladder, causing it to be considerably squashed
At birth, the organs are squeezed, the heart pumps harder and the baby presses upon the bladder, which is the cause of the huge discomfort that women feel during labor.
When do girls hit puberty?
For a woman to be fertile, all her reproductive organs should work properly. This can be achieved thanks to the anatomy of the woman and the right functioning of her endocrine system, which function is to release the appropriate hormones.
During childhood, the reproductive system does not release sex hormones, and the body works exactly the same for boys and girls. The only thing that allows us to distinguish between them are their primary sexual characteristics, that is, their sex organs.
When girls start puberty, which usually occurs at age 11 or 12, their ovaries start working as a consequence of the releasing of FSH and LH by the pituitary gland, two hormones that cause the female reproductive organs to develop.
From that moment on, the ovaries start segregating the typical female hormones by default: estrogens and progesterone. Moreover, the secondary sexual characteristics of females start developing:
- Growth of breasts
- Development of the skeleton: the pelvis is adapted for pregnancy and childbirth
- Pubic hair
- First period and ovulation
- Voice changes
The regulation of the menstrual cycle should occur with normality for a woman to be considered fertile. The length of a typical cycle is 28 days approximately, and the fertile window, which is the moment when ovulation takes place, occurs halfway through the cycle. It is during the woman’s fertile window when she is recommended to try to conceive, as her chances for becoming pregnant will be considerably higher.
Recommended for you: What Is Ovulation? – Date, Symptoms & Most Fertile Days.
Fertility signs in females
There is no natural or at-home method to tell whether a woman is infertile or not. However, we can spot common physical signs in women throughout their menstrual cycle that can help us to determine when is the best moment for conceiving.
Paying attention to the cervical mucus is one of the best ways to tell whether a woman is fertile or not. It is a fluid secreted by the cervix that keeps on changing throughout the woman’s monthly cycle. During ovulation, it becomes translucent and slippery to pave the way for the sperms.
Another way through which women can monitor their fertility is by tracking their basal body temperature (BBT). During the first part of the menstrual cycle, it is relatively low, but it will experience a rise on the day of ovulation and stay at an elevated level until right before the beginning of menstruation.
Mittelschmerz or ovulation pain is another natural fertility sign. Some women experience ovulation pain when their body is releasing an egg. Normally, it appears only on the side that they are ovulating on. Those who are able to feel it can predict when to have sex should they wish to become pregnant.
Also, when a woman is ovulating, her body releases LH hormone into urine. An increase in LH can be tested with ovulation predictors (OPKs), which work by testing on strips. Ideally, women using these devices should test twice a day, preferably at 10 am and again at 8 pm.
You can keep track of all the natural fertility signs you notice over the cycle by writing them down on a chart or calendar. There exist even fertility-charting applications (apps) for smartphones that will enable you to collect data.
Age and female fertility rates
Women are born with a limited egg supply, which means that they already have all the eggs they will ever have. The truth is, as a woman ages, her egg cells age with her, that is, both quality and quantity diminish. This means that, the later the woman tries to conceive, the longer it will take for her to achieve pregnancy.
Yet, and while the chances of getting pregnant decrease, the risk of miscarriage increases at the same time, which means that both rates are inversely proportional. On average, the likelihood of becoming pregnant starts decreasing at about age 32, a decline that speeds up from age 35.
So you can have an idea, while the chance of conceiving each month is about 20% at 30, it is around 5% at 40. In short, we can say that, by age 40, female fertility has fallen by half. At this point, there are more risks of birth complications such as birth defects or genetic abnormalities.
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FAQs from users
Can alterations in the cervical mucus lead to female infertility?
Yes, alterations in the cervical mucus can are a common cause of female infertility. The cervical mucus is a secretion produced before ovulation and it disappears after the woman ovulates. It has a sticky texture, and its mission is to pave the way for sperms toward the tubes. It is, in fact, a good indicator of female fertility.
When do girls stop growing in height?
Giving an exact number is difficult, but generally it occurs when they get their first period, which takes place around 11-12 1⁄2 years of age on average. Girls can continue to grow in height, but not significantly. Normally, they reach their full adult height by age 14-15.
When do women ovulate?
In women with a normal 28-day menstrual period, the most fertile period, that is, ovulation occurs 14 days after the first day of the last menstruation. Nonetheless, the days before and after this date are considered to be fertile, which means that the woman could get pregnant as well.
What age do girls get their period?
First and foremost, it should be clear that there is no right age for the first period to show up. Although most girls start to menstruate between ages 10 and 15 years, one should keep in mind that every girl’s body has its own schedule. A common sign that a girl is going to get her first menstrual period is vaginal discharge fluid, which usually begins 6-12 months before it appears.
What age do girls get pubic hair?
Pubic hair goes hand in hand with other signs that occur during puberty, including breast growth, first period, etc. However, a few children may have pubic and armpit hair long before they show other signs of puberty. It is known as precocious puberty and might occur even before age 8.
What age do women peak sexually?
It is different for every adult. However, it depends on estrogen to a large extent, which reaches its apex around the mid- to late-20s, being in line with female fertility. Although some say that it is different for men and women, the truth is that both reach their sexual peak when they are most comfortable with their own sexuality.
When do women go through menopause?
Menopause is the end of a woman’s fertility and usually starts around age 51, provided that it occurs naturally. Nevertheless, it can happen earlier, which is known as premature menopause or early menopause. Once it starts, it should stop completely within about 4 years, as it involves three phases: perimenopause, menopause, and postmenopause.
Does smoking affect fertility in females?
Yes, smoking affects the different stages of the reproductive process, including egg cell maturation, hormone releasing, the environment of the womb, etc. It can even damage the DNA of the egg cell. In fact, women who are smokers and are trying to conceive with no luck are recommended to quit smoking. The good news is that its effects can be reversed within a year.
Does caffeine affect fertility in females?
Normally, studies suggest that caffeine consumption increases the risk of miscarriage during pregnancy. However, caffeine intake may also impact a woman’s ability to conceive in terms of length of time.
Suggested for you
Alterations or disorders of the female reproductive system can make it difficult or impossible for a woman to get pregnant. You can learn more about them in the following article: Diseases that Cause Female Infertility.
Are you TTC and would like to start using OPKs or ovulation calculators? It will be a piece of cake after reading this guide: How Do Ovulation Calculators Work?
A woman’s ovarian reserve or egg supply is composed of the total amount of eggs contained within her ovaries, which diminishes with age. If you want to delve deeper into it, do not miss this post: What Is the Ovarian Reserve?
National Health Service (NHS) (UK) (2009). The Pregnancy Book. Your complete guide to: A healthy pregnancy, Labour and childbirth, The first weeks with your new baby. Crown copyright 2009. Produced by COI for the Department of Health.
Prof. Mary Wingfield (2017). The Fertility Handbook: Everything You Need to Know to Maximise Your Chance of Pregnancy, Gill & Macmillan Ltd, May 29, 2017.
The American College of Obstetricians and Gynecologists (2011). Frequently Asked Questions (FAQ156). Pregnancy.
The National Women’s Health Information Center, U.S. Department of Health and Human Services, Office of Women’s Health (2006, April). Prenatal Care. Retrieved November 9, 2007
Wilcox AJ, Weinberg CR, Baird DB. Timing of intercourse in relation to ovulation: effects on the probability of conception, survival of the pregnancy and sex of the baby. N Engl J Med 1995;333:1517– 1521.