Pregnancy/Data
Mother's Age
| Age Group | Pregnancy Chance per Cycle | Relative Odds vs. 25-29 |
|---|---|---|
|
20-24 |
0.25 |
1.0 |
|
25-29 |
0.20 |
1.0 |
|
30-34 |
0.15 |
0.85 |
|
35-39 |
0.10 |
0.70 |
|
40-44 |
0.05 |
0.50 |
The fecundity rates per cycle and odds ratios are averages derived from multiple studies on age-related fertility decline, where base rates were normalized (e.g., averaging reported probabilities like 20-25% for ages 20-24 across sources) and odds ratios calculated relative to the peak fertility group.
- Dunson, D. B., et al. (2002). Changes with age in the level and duration of fertility in the menstrual cycle. Human Reproduction.
- American College of Obstetricians and Gynecologists. (2014). Female age-related fertility decline. Fertility and Sterility.
Father's Age
| Age Group | Fecundity Reduction per Cycle | Relative Odds vs. 25-34 |
|---|---|---|
|
20-29 |
0.00 |
1.0 |
|
30-34 |
0.05 |
0.95 |
|
35-39 |
0.10 |
0.85 |
|
40-44 |
0.20 |
0.70 |
|
45+ |
0.30 |
0.60 |
The fecundity reductions and odds ratios are based on aggregated data from studies, with reductions estimated as proportional decreases (e.g., averaging 5-10% for 35-39 from reported time-to-pregnancy increases) and odds ratios inverted from relative risks for subfertility.
- Khandwala, Y. S., et al. (2020). The age of fathers in the USA and the risk of adverse pregnancy outcomes. Reproductive Biology and Endocrinology.
- du Fossé, N. A., et al. (2023). The impact of paternal age on perinatal outcomes: A systematic review. Human Reproduction Update.
Contraception Methods
| Method | Typical Use Failure Rate | Perfect Use Failure Rate |
|---|---|---|
|
No method |
0.85 |
0.85 |
|
Implant |
0.0005 |
0.0005 |
|
IUD |
0.008 |
0.002 |
|
Injectable |
0.04 |
0.003 |
|
Pill |
0.07 |
0.003 |
|
Patch |
0.07 |
0.003 |
|
Ring |
0.07 |
0.003 |
|
Male condom |
0.13 |
0.02 |
|
Female condom |
0.21 |
0.05 |
|
Diaphragm |
0.17 |
0.06 |
|
Spermicide |
0.21 |
0.18 |
|
Withdrawal |
0.20 |
0.04 |
No calculations were performed; data is directly from standardized CDC effectiveness rates.
Menstrual Cycle Day
| Day Relative to Ovulation | Conception Probability |
|---|---|
|
-5 |
0.05 |
|
-4 |
0.13 |
|
-3 |
0.27 |
|
-2 |
0.30 |
|
-1 |
0.30 |
|
0 |
0.30 |
|
+1 |
0.00 |
No calculations were performed; probabilities are direct averages from the landmark study on conception timing.
Intercourse Frequency
| Frequency per Week | Pregnancy Chance per Cycle | Relative Odds vs. <1 Time |
|---|---|---|
|
<1 |
0.10 |
1.0 |
|
1-2 |
0.15 |
1.50 |
|
3-4 |
0.20 |
2.00 |
|
Daily |
0.25 |
2.50 |
Fecundity rates and odds ratios are approximated by averaging reported increases in pregnancy rates from studies (e.g., scaling base 10% for infrequent to 25% for daily based on fertile window coverage).
- Stanford, J. B., et al. (2020). Optimizing natural fertility: A committee opinion. Fertility and Sterility.
- American Society for Reproductive Medicine. (2021). Optimizing natural fertility.
BMI Categories
| BMI Range | Fecundity Reduction per Cycle | Relative Odds vs. 18.5-24.9 |
|---|---|---|
|
<18.5 (underweight) |
0.20 |
1.50 |
|
18.5-24.9 (normal) |
0.00 |
1.0 |
|
25-29.9 (overweight) |
0.10 |
1.20 |
|
30-34.9 (obese class I) |
0.20 |
1.50 |
|
35-39.9 (obese class II) |
0.30 |
1.80 |
|
>=40 (obese class III) |
0.40 |
2.00 |
Reductions and odds ratios are averaged from meta-analyses, converting reported relative risks for infertility (e.g., 1.2-2.0 for obesity) into proportional fecundity drops.
- Silvestris, E., et al. (2022). Obesity and female fertility: A comprehensive review. Reproductive Biology and Endocrinology.
- Best, D., et al. (2023). The impact of body mass index on female fertility. Human Reproduction.
Smoking Status
| Status | Cigarettes per Day | Fecundity Reduction per Cycle | Relative Odds for Infertility |
|---|---|---|---|
|
Nonsmoker |
0 |
0.00 |
1.0 |
|
Light smoker |
1-10 |
0.10 |
1.30 |
|
Moderate smoker |
11-20 |
0.20 |
1.60 |
|
Heavy smoker |
>20 |
0.30 |
2.00 |
Reductions are estimated by averaging dose-response data from reviews, translating odds ratios into percentage fecundity decreases (e.g., OR 1.3 implies ~10% reduction).
Alcohol Consumption
| Drinks per Week | Fecundity Reduction per Cycle | Relative Odds vs. Nondrinker |
|---|---|---|
|
None |
0.00 |
1.0 |
|
1-5 (light) |
0.05 |
1.10 |
|
6-10 (moderate) |
0.15 |
1.30 |
|
>10 (heavy) |
0.25 |
1.60 |
Reductions are averaged from dose-response meta-analyses, converting odds ratios for reduced fecundability into proportional decreases (e.g., OR 1.3 ≈ 15% reduction).
- Fan, D., et al. (2017). Female alcohol consumption and fecundability: A systematic review and dose-response meta-analysis. Scientific Reports.
- Eggert, J., et al. (2004). Effects of alcohol consumption on female fertility during an 18-month period. Fertility and Sterility.
RiskModel: Pregnancy/Data:chance_of_getting_pregnant_in_a_month
Calculation: (fecundity_per_cycle * odds_ratio_vs_25_29 * odds_ratio_vs_25_34 * (1 / odds_ratio_vs_18_5_24_9) * (1 / odds_ratio_for_infertility) * (1 / (odds_ratio_vs_nondrinker)) * odds_ratio_vs_1_time * (typical_use_failure_rate / 0.85)) * 100
Content: The estimated chance of getting pregnant in a month (per menstrual cycle) is about {result}%.
RiskModel: Pregnancy/Data:chance_of_getting_pregnant_from_one_act_of_intercourse
Calculation: (conception_probability * odds_ratio_vs_25_29 * odds_ratio_vs_25_34 * (1 / (odds_ratio_vs_18_5_24_9)) * (1 / (odds_ratio_for_infertility)) * (1 / (odds_ratio_vs_nondrinker)) * (typical_use_failure_rate / 0.85)) * 100
Content: The estimated chance of getting pregnant from one act of intercourse is about {result}%.