Fertility and Menstrual Cycle Calculator | Dr. Diegomaier Nunes Neri

Calculation & Calendar

Quick guide

Cycle phases

  • Menstrual: estrogen/progesterone drop; FSH begins a new cohort.
  • Follicular: estrogen rises; mucus becomes moist → watery.
  • Ovulatory: LH peak; “egg-white” mucus; highest fertility (BMJ 2000).
  • Luteal: elevated progesterone; higher BBT; mucus tends to sticky/dry.

When to take a pregnancy test

From 12–14 DPO (days past ovulation). Variations in apps/cycles: npj Digital Medicine 2020, JMIR 2022.

Pregnancy planning

Guidelines: ASRM 2022 e ACOG — fertility awareness methods.

Frequently asked questions

How do you define the fertile and peri-ovulatory windows?

Broad fertile window ≈ −5 through the day of ovulation (some sources include up to +1 day) — see BMJ 2000. The “peri-ovulatory window (±2)” here is a educational highlight for temporal localization, not a measure of probability.

What is EDD and how is it calculated?

EDD (estimated due date) per Naegele's rule (LMP + 280 days; optional adjustment for cycle length). Technical criteria: ACOG CO#700.

Scientific references and guidelines

  1. Wilcox AJ, Dunson D, Baird DD. The timing of the “fertile window”. BMJ, 2000. PMC/BMJ
  2. Soumpasis I, Grace B, Johnson S. Real-life insights on menstrual cycles via apps. npj Digital Medicine, 2020. Nature
  3. Arévalo M, Jennings V, Sinai I. Standard Days Method. Contraception, 2002. PubMed
  4. Yu Z et al. Tracking cycles & fertile window. JMIR, 2022. JMIR
  5. ASRM Practice Committee. Optimizing natural fertility (2022). ASRM
  6. ACOG. Fertility Awareness-Based Methods. ACOG
  7. ACOG Committee Opinion No. 700: Estimating the Due Date. ACOG

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Professional information

Dr. Diegomaier Nunes Neri — CRMSC 32925 | CRMBA 39586

Email: [email protected] • Website: diegomaier.com • WhatsApp: (11) 97033-1111

Important: This content is exclusively educational and must not, under any circumstances, be used for self-diagnosis or treatment. It does not replace a consultation with a qualified health professional. Responsibility for the use of the information presented here lies entirely with the user.

I transparently declare that I have no conflict of interest with any pharmaceutical companies that may be mentioned. When I cite trade names or patented products, I do so solely to make things easier for the lay public to understand and to make medical knowledge more accessible.

All content on my website and social media is intended to inform, educate and clarify — always free of charge. No information shared here should be used as the sole criterion for evaluation, diagnosis or treatment decisions without proper professional guidance. Every person is unique and must be evaluated individually. Improper use of this information, without professional supervision, can pose serious health risks.

Last updated: September 1, 2025.

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