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Калкулатор за Овулация с Кломид и Летрозол

Calculate your personalized medicated cycle schedule: pill days, follicular scan windows, 36-hour trigger shot ovulation clock, and timed intercourse protocol.

Quick Summary: Medicated Ovulation Kinetics

Clomid (clomiphene) and Letrozole (femara) stimulate follicular development when taken on Cycle Days 3–7 or 5–9. Ovulation occurs 5 to 10 days after the last pill, or precisely 36 to 40 hours after an hCG trigger shot (Ovidrel/Pregnyl) is administered.

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Доказателствено Базиран Изчислителен Модел • Одитиран: Октомври 2026

Прегледано от: Екип по клинични изследвания и изчислителна методология на Free Ovulation Tracker

Основа от научна литература: Wilcox et al. (NEJM, 1995 & 1999) • Практически бюлетини на ACOG • Стандарти на СЗО за репродуктивно здраве

Архитектура на поверителност: 100% Локално изпълнение в браузъра на клиента (Нулево съхранение на сървъри)

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Medicated Ovulation & Trigger Shot Timeline Calculator

Precision clinical timelines for Clomid, Letrozole (Femara), and Ovidrel/Pregnyl timed intercourse (TIC) & IUI protocols.

Select Your Medicated Cycle Protocol

Cycle Day 1 (First Day of Full Flow Menses)

Medication Window (CD3–CD7)пн – птFollow your prescribing physician's exact dosing schedule (commonly taken at a consistent hour daily).

Follicular Ultrasound Scan WindowCD10–CD12 (пн)Transvaginal sonogram to measure lead follicle diameter (target ≥18–20mm before trigger) and endometrial lining thickness (≥7mm).

Predicted Ovulation Windowвт – сбTypically 5–10 days following last Clomid tablet, or 4–8 days following last Letrozole tablet.

Prescription Supervision Notice

Clomiphene citrate, Letrozole, and hCG trigger shots are prescription medications requiring direct OB-GYN or Reproductive Endocrinologist ultrasound monitoring. Seek prompt medical attention if you experience severe pelvic bloating, rapid weight gain, nausea, or shortness of breath (signs of Ovarian Hyperstimulation Syndrome / OHSS).

Clinical Reproductive Pharmacology: Letrozole (Femara) — Days 3 to 7 (First-Line for PCOS)

Letrozole temporarily suppresses estrogen synthesis without depleting estrogen receptors in the cervix or endometrium. It is the gold standard for PCOS (Legro et al., NEJM), resulting in thicker endometrial lining and higher live birth rates.

The "Testing Out the Trigger" Protocol

Ovidrel (choriogonadotropin alfa 250 mcg) introduces approximately 300–500 mIU/mL of exogenous hCG into your circulation. Because hCG has a biological elimination half-life of 29–36 hours, it takes 10 to 14 full days to clear below the 10–25 mIU/mL threshold of home pregnancy tests. If you test daily starting at 7 DPO, the test line will lighten until almost invisible (negative), then darken again if endogenous pregnancy hCG takes over.

Track Unmedicated Natural Cycles Between Treatment Rounds

Between medicated cycles or when taking a rest month, monitor your natural baseline fertile window with our free online ovulation tracker.

Free Online Ovulation Tracker

Clinical Methodology

Mechanism of Action: Clomiphene vs. Letrozole vs. Ovidrel Trigger

Clomiphene citrate functions as a selective estrogen receptor modulator (SERM) that blocks hypothalamic estrogen receptors, triggering an increase in pituitary FSH. Letrozole inhibits aromatase, temporarily lowering estrogen without depleting cervical receptors.

The recombinant hCG trigger shot binds directly to ovarian LH receptors, initiating final meiotic maturation and follicle rupture in a reliable 36 to 40 hour window.

Frequently Asked Questions About Medicated Fertility Cycles

Audited under our Clinical Methodology & Citations.

Why does ovulation happen exactly 36 hours after an hCG trigger shot?

Recombinant hCG binds LH receptors on granulosa cells with high affinity, initiating prostaglandin and collagenase synthesis that systematically breaks down the ovarian wall within 36 to 40 hours.

Can Clomid cause false-positive ovulation predictor kits (OPKs)?

Yes. Clomid stimulates rapid endogenous LH surges while the medication is active. Starting OPKs too early (before CD10) often yields misleading false positives.

What is "testing out the trigger shot"?

Ovidrel contains exogenous hCG that takes 10 to 14 days to metabolize. Taking daily pregnancy tests until negative confirms that any subsequent darkening line represents a true new pregnancy.

What is the ideal timed intercourse schedule with a trigger shot?

Physicians recommend intercourse on the evening of trigger administration, 24 to 36 hours post-trigger, and again the following morning.

Primary Fertility Hub

Plan Your Full Menstrual Cycle on Our Free Ovulation Tracker

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📖 Companion Clinical Guide

Read Full Clinical Guide →

Ovulation on Clomid, Letrozole & Ovidrel Trigger Shots: Timing Guide

Groundbreaking physiological analysis based on NEJM, ACOG, and WHO clinical standards.

Explore Guide →

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📚 Additional Evidence-Based Reading

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PCOS & Ovulation Tracking: Why 28-Day Calculators & OPKs Fail

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