Elements that can affect fertility include:
Egg quality and quantity can decrease with age, beginning in the mid 30s - and declining in the late 30s and early 40s. This has a direct impact on the chances of conception and embryo quality after fertilization.
Irrespective of whether it is the female or male partner who smokes, smoking makes it more difficult to conceive. Smoking also reduces the chances that fertility treatment will be successful. Once a smoker stops, both the chances of conceiving naturally and fertility treatment success improve.
Nicotine affects the production of hormones necessary for pregnancy and smoking also impedes the transportation of the egg through the fallopian tubes to the uterus; it is also toxic to sperm. Smoking can cause a woman’s eggs to be more inclined to genetic problems as well.
Some research suggests that smoking may even negatively affect the embryo's ability to implant in the uterus. Some studies show that women who have never smoked have had up to twice the rate of success when trying to conceive than women who have smoked. The successful conception rate drops further the longer the woman has smoked, according to other studies.
For a couple in which the woman smokes, even if the couple conceives, they have a greater risk of losing the baby that couples with non-smoking mothers. Studies show that smoking during pregnancy increases the risk of miscarriage, or of the baby passing away shortly after birth.
Even though the exact relationship between stress and fertility is not yet known, medicine believes that hormones play a key role, specifically, cortisol or epinephrine, whose levels rise and can remain high during times of chronic stress.
Alcoholism or excessive alcohol consumption is associated with a number of ovulatory dysfunctions that can dramatically impact fertility. Scientific evidence indicates that women should refrain from drinking alcohol if they are trying to conceive because conception rates are lower in couples where the woman consumes alcoholic beverages. Alcohol consumption during pregnancy increases miscarriage rates and may also cause fetal alcohol syndrome (FAS) in newborns. Babies with FAS have a range of learning and behavioral problems and characteristic physical features, including: small heads, small eyelids, a flat mid-face, and a low nasal ridge.
Studies show that being significantly over- or under-weight can reduce fertility. A change of just 15% (plus or minus) in BMI can alter period patterns or even create problems with fertility.
Medical studies show that women need at least a minimum level of body fat in order to have menstrual cycles. A very low BMI, which is below 19, may affect women's fertility, including:
High BMI may directly cause infertility or may complicate a woman's other existing causes of infertility. It can also cause difficulties in fertility treatment, including: