The fertile window within a woman’s menstrual cycle lasts approximately 6 days and includes the day of ovulation and the 5 days preceding ovulation. Conception rates are highest when intercourse takes place on the day of ovulation or within the 1 to 2 days preceding ovulation. Basal body temperature, changes in cervical mucus, and at-home kits designed to measure urinary luteinizing hormone (LH) can be used to predict ovulation and time intercourse appropriately.
2–4
Frequency of intercourse impacts the chance of conception. More frequent intercourse results in a higher chance for conception: Daily intercourse results in a 37% chance for conception within a cycle, and intercourse every other day results in a 33% chance for conception. Couples who have intercourse once per week have a 15% chance for conception.4
Frequent ejaculation is not associated with a decrease in male fertility. Results of a study of almost 10,000 semen specimens revealed that, in men with normal semen quality, sperm counts and motility remained normal even with daily ejaculations.5 While abstinence intervals as short as 2 days are associated with normal sperm counts, longer abstinence intervals of 10 days or more may be associated with decreasing semen parameters. It is unclear, however, if this translates into impaired sperm function.6,7
Neither coital position nor postcoital practices (such as a woman remaining supine after intercourse) affect the chance of conception.
Lubricants that do not impair sperm motility, such as canola oil, mineral oil, and hydroxyethylcellulose-base (Pre-Seed) may be helpful for some couples.8 Sexual dysfunction can be a cause of infertility or subfertility. Similarly, stress over lack of conception can impair sexual function; therefore, it is important to ask patients if they experience pain or difficulty with intercourse.
Fecundability refers to the probability of achieving pregnancy within a single menstrual cycle. Studies measuring fecundability reveal that 80% of couples attempting conception will achieve pregnancy within 6 months of attempting and 85% within 12 months. Another 7% to 8% will achieve conception over the next 3 years. The remaining couples will have a very low chance of achieving spontaneous conception.9
The probability of conception is inversely related to female age. Fecundability is decreased by approximately 50% in women who are in their late 30s compared with women in their early 20s.10,11 The chance for conception significantly decreases for women after age 35 and, while the effects of advancing age are most striking for women, some decline in fertility also occurs in men, especially after age 50.11,12
Folic acid supplementation, at least 400 μg per day, is recommended for all women attempting conception and is associated with a decreased risk of neural tube defects.13 Obese women and thin women have decreased rates of fertility. While healthy dietary practices aimed at normalizing body mass index (BMI) to normal levels may improve reproductive outcomes, there is little evidence that a particular dietary practice or regimen improves conception rates.8 Data are also lacking on the use of fertility supplements to improve ovarian reserve or aid in conception.
Smoking is unequivocally detrimental to female fertility. Women who smoke have been found to have increased rates of infertility and increased risk for miscarriage.14–16 Menopause has been found to occur 1 to 4 years earlier in smoking versus nonsmoking women.17,18
The effect of alcohol on female fertility has not been clearly established, with some studies showing an adverse impact and others showing a possible favorable effect. Based on the available evidence, higher levels of alcohol consumption (>2 drinks/day with 1 drink = 10 g of ethanol) are probably best avoided when attempting conception, but more moderate consumption may be acceptable.8 No safe level of alcohol consumption has been established during pregnancy, and alcohol consumption should be completely avoided during pregnancy.
Caffeine consumption at high levels (>500 mg or 5 cups/day) is associated with impaired fertility. While caffeine intake over 200 mg to 300 mg per day (2−3 cups per day) has been associated with a higher risk for miscarriage, moderate consumption (1−2 cups of coffee per day) has not been associated with a decrease in fertility or with adverse pregnancy outcomes.8,19–22
While the public has access to volumes of information on the Internet, it is important for patients to be educated through accurate information that is best found from professional sources, such as https://www.reproductivefacts.org, offered by the American Society for Reproductive Medicine (ASRM).
