Understanding Fertility: How it Works, When to See Your Doctor

Getting pregnant shouldn’t be difficult. After all, it’s a natural occurrence and sometimes all it takes is paying attention to the calendar and having sex at just the right time. But, for one in five women of child-bearing age in the US, it’s not that easy 

Science defines infertility as an inability to conceive after one year (12 consecutive months) of unprotected intercourse. Because women’s fertility declines with age, most doctors evaluate their patients over 35 much sooner–usually after six consecutive unsuccessful months of trying to conceive.  

Fertility’s Perfect Storm 

For such a natural and seemingly simple endeavor, getting pregnant actually requires the “perfect storm” below: 

• A woman’s ovaries must release a viable, healthy egg 
• A man’s healthy sperm must meet and fertilize the egg along the way  
• The fertilized egg must travel through the fallopian tubes to the uterus 
• The fertilized egg must attach itself to the uterine wall where it will go through the stages of development. 

If there is an issue preventing the natural process from occurring, infertility may result. How do you know if you have fertility issues? Your doctor can evaluate your fertility once you’ve tried for the appropriate amount of time, or if you have other reasons to suspect compromised fertility. 

The Basics of Understanding Fertility 

Understanding your fertility begins with the basics, and is the first step in family planning and knowing what’s happening with your body. Knowing the basics helps you decode the “mystery” of fertility. 

A female is born with all of the eggs she will ever have in her lifetime. The ovaries, two thumb-sized organs on either side of your uterus, contain these egg cells. When a young woman reaches sexual maturity during puberty, progesterone and estrogen levels increase and her menstrual cycle begins.  

The Menstrual Cycle 

The monthly menstrual cycle is the natural process that prepares the female body for pregnancy. This cycle includes the release of a mature egg from the ovaries, a thickening of the uterine tissue lining the wall of the uterus and hormonal changes that make pregnancy possible. If the egg remains unfertilized, the body sheds the lining of the uterus.  

A normal menstrual cycle lasts 24-35 days, and a regular menstrual cycle is the best indicator your hormones are working as they should and that you’re ovulating normally. If you experience the absence of, or irregular period, and you aren’t pregnant, your doctor needs to know.  

In addition to the hormonal changes during the menstrual cycle (eg. moodiness, headaches, pelvic “twinges”), a woman may notice a slightly watery clear or white  vaginal discharge. At or around the midpoint of your cycle, the discharge may change to a thicker, slightly slippery discharge indicating ovulation.  

Your Fallopian Tubes  

When ovulation occurs, the egg travels through the fallopian tube to await fertilization. Once fertilization occurs, the fertilized egg is pushed into the uterus where iit develops into a fetus. Blockages in the fallopian tubes are a common cause of infertility.  

Sometimes a woman is born with just one fallopian tube; some women also experience blockages as a result of scarring from endometriosis, infection or surgery. The good new is if you have one healthy fallopian tube and a regular menstrual cycle, in most cases you can conceive. If you don’t have your fallopian tubes, you can still become pregnant through advanced reproductive technology such as IVF.   

The Uterus  

A pear shaped, hollow, muscular organ, the uterus sits in your pelvic cavity. During pregnancy, a fertilized egg implants in the uterus and grows and develops into a baby until birth. The uterus plays a key role in healthy fertility three ways:  

• Menstrual Cycle: The tissue and bleeding come from your uterus during your period. 
• Fertility: Your uterus must be healthy enough to support implantation of the fertilized egg for pregnancy to occur.  
• Pregnancy: A healthy uterus expands as the baby grows and contracts during the birthing process to push the baby out. 

Three separate layers make up your uterus, each with its own purpose:  

• Perimetrium is the outermost protective layer of tissue. 
• Myometrium is in the middle and provides the muscle necessary to expand and contract during pregnancy and birth. 
• Endometrium is the innermost layer made up of the tissue that supports implantation. If no fertilization occurs, the endometrium sheds during your period. 

Certain conditions of the uterus are a common cause of infertility, including irregular bleeding, pain, unusual vaginal discharge, painful urination or inability to conceive. Common conditions of the uterus that may result in infertility are:  

• Uterine Polyps: Growths in the endometrial lining of the uterus. 
• Uterine Fibroids: Small non-cancerous growths or tumors inside the uterus. 
• Uterine Cancer: Uterine sarcoma, which is rare, or the more common endometrial cancer  
• Uterine Prolapse: The uterus slips out of the normal position, most normally occurring after more than one vaginal delivery. 
• Pelvic Inflammatory Disease: An infection causing inflammation of the reproductive organs. 
• Endometriosis: Tissue related to the endometrial lining of the uterus attaches and grows outside of your uterus. 

Male Fertility 

Unlike a woman’s eggs, male sperm regenerates about every two months. For those trying to conceive, the sperm just needs to fertilize the egg. That would be fertility 101, right? Actually, there’s more to it that we’ve outlined below.  

Sperm Quantity  

The number of sperm in a single semen discharge (ejaculation) must number at least 15 million sperm per milliliter. Should the number fall below 15 million, fertilization becomes more difficult.

Sperm Motility (Movement) 

In order to reach the egg awaiting fertilization in the fallopian tube, sperm must swim through the cervix and uterus. The movement of the sperm, or motility, determines whether or not these “swimmers” reach the egg. A minimum of 40 percent of the sperm in the ejaculate must move normally for the best odds of pregnancy. Less than 40 percent may still result in pregnancy, but the more swimmers on your team the better.  

Sperm Structure 

In order for sperm to achieve the necessary motility to reach the egg there must be a normal shaped head (oval) and long tail.  

Conditions That Impair Sperm and Sperm Production 

Sperm must travel from the testes to the urethra through a network of tubes and ducts, including the vas deferens. Damage to, or absence of, the ducts results in the absence of sperm in the ejaculated fluid. This so-called sperm transport disorder may result from congenital disorders, scar tissue from an infection or disease or a surgical procedure.  

Some conditions that contribute to male fertility issues are testicular disease, hormonal disorders, and age. There are several tests that can help determine male fertility health and provide a better understanding of your overall fertility.  

Schedule a Consultation  

Now that you have more of an understanding of how fertility works, you may need to schedule an appointment with your physician to discuss any issues and have things checked out. If you suspect you have compromised fertility please contact the Reproductive Health & Wellness Center, and we’ll provide the answers you need.