External Factors That Affect Conception

Factors Affect Conception

About 12% of women in the U.S., ages 15 to 44, have difficulty becoming pregnant or carrying a pregnancy to term. While difficulty in conceiving is often caused by internal physical problems, in both men and women, there are also lifestyle choices and external factors to consider.

Physical problems

Any physical condition that prevents an egg from being produced, being fertilized by sperm or successfully attaching to the uterus can affect a woman’s fertility:

  • Polycystic ovary syndrome (PCOS), which causes women to ovulate in an irregular way or not at all.
  • A diminished egg count, which can be the result of medical or surgical causes
  • Improper functioning of the the hypothalamus or pituitary glands, which produce the hormones needed to keep ovaries functioning
  • Fibroids, which are benign tumors that develop on the uterus wall
  • Endometriosis or the growth of uterine tissue outside of the uterus can prevent the fertilized egg from adhering to the uterine wall. Endometriosis causes 30 percent of all treated cases of infertility.
  • Obstruction in the fallopian tubes due to a pelvic infection or abdominal surgery. About 20 percent of all treated cases of infertility are the result of such obstruction.
  • Autoimmune diseases such as lupus, diabetes, thyroid disease, and rheumatoid arthritis may interfere with fertility.
  • Premature menopause, occurring before the age of 40.

If a woman is having difficulty conceiving, her doctor will attempt to rule out any of these causes.

Age definitely plays an important a part in conception. While the average age of menopause is 50, fertility begins to decline around age 35. Even in vitro fertilization (IVF ) is less successful after the age of 43. The span of a woman’s fertile years may be determined by genetics.

External factors

Lifestyle factors and external influence play a role in fertility. Making healthy lifestyle choices and avoiding chemical exposure may improve the odds of conception.

  • Studies suggest that smoking affects fertility, since it affects hormone production. Smoking is also suspected of playing a part in ectopic pregnancy, a serious condition in which the fertilized egg fails to move to the uterus and instead become attached to the fallopian tube.
  • Heavy drinking is associated with ovarian problems.
  • Being overweight. Studies have shown that being overweight or obese can decrease your chances of becoming pregnant. Getting down to a healthy weight may improve your odds of conceiving.
  • Being underweight—due to excessive exercise, malnutrition or anorexia—can also contribute to infertility since low body fat levels will affect the reproductive system.
  • Many medications leave your system quickly but a few can affect reproductive health and ability for months. For example, a contraceptive injection could reduce fertility for up to 10 months, while chemotherapy drugs should be stopped at least three months before you plan to get pregnant. Discuss any medication, use with your doctor. That includes herbal remedies too, since some affect hormones. The list of prescription medications that can affect fertility include steroids, antiepileptics, antipsychotics, painkillers and thyroid medications.
  • Environmental hazards. Research suggests that environmental contaminants, such as phthalates, polychlorinated biphenyls (PCBs), dioxin, and pesticides, can affect ovulation. Hormone disrupting chemicals have also been shown to affect female fertility and are suspected of affecting sperm rates and health in men. A 2012 study by the National Institutes of Health showed that couples with high levels of certain chemicals in their bodies took about 20 percent longer to conceive compared with those with lower exposures.
  • Other negative factors include high temperatures, radiation exposure or extreme mental stress.

Male infertility

Sometimes the issue is male infertility. At least a third of fertility problems may be attributed to the father. While a man’s fertility can also be affected by health conditions, some of the reasons for decreased fertility are due to lifestyle factors.

Some physical conditions that affect male fertility include:

  • Prostatitis or a genital infection that swells or inflames the prostate
  • Mumps after puberty can in some cases reduce fertility
  • Undescended testicles that are not brought into the scrotum from a young age will not produce sperm
  • Hernia surgery may injure the vas deferens, the tube carrying sperm from the testicles to the urethra.

External factors

Lifestyle factors can also cause fertility problems in men. Making healthier choices can improve the odds of conception.

  • Smoking can affect sperm motility.
  • Drinking heavily can affect both the quality and quantity of sperm.
  • Using illegal drugs, such as cocaine, can temporarily reduce the quantity of sperm.
  • Prescription medications such as antibiotics or colchicine, which is used to treat gout, and sulfasalazine, which is used to treat ulcerative colitis, can also affect fertility. Prospective fathers should discuss medication use with a doctor.
  • X-rays can reduce sperm count. So, can exposure to environmental pollutants and pesticides.
  • Using saunas, steam rooms and hot tubs may reduce sperm count.
  • Chemicals and pesticides can damage the male reproductive system by killing or damaging cells;  including sperm cells.

It’s important to consider and discuss all of these factors with your doctor if you are having a difficult time conceiving.

Joan MacDonald
Joan Vos MacDonald has written about health and fitness for newspapers, magazines and websites. She is a member of the National Association of Science Writers and the author of two books on health-related topics, "Tobacco and Nicotine Dangers," for young adults, and "High Fit Home," a design book about fitness and architecture. She lives in upstate New York near her children and grandchildren.

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