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Калкулатор за Удвояване на Бета ЧХГ (hCG)

Q: Why does doubling slow down after 6,000 mIU/mL?

This is normal placental physiology. As trophoblast volume expands, kinetics shift from rapid doubling to a plateau, and ultrasound becomes the primary clinical diagnostic tool.

Q: At what hCG level should a gestational sac be visible on ultrasound?

The discriminatory zone is 1,500 to 2,000 mIU/mL, at which point a high-resolution transvaginal ultrasound should clearly visualize an intrauterine gestational sac.

Check early pregnancy viability kinetics: calculate exact doubling time in hours, 48-hour percentage increase, and DPO benchmark ranges from serial blood draws.

Quick Summary: hCG Doubling Kinetics

In viable early intrauterine pregnancies, serum beta-hCG levels double every 48 to 72 hours when below 1,200 mIU/mL. Between 1,200 and 6,000 mIU/mL, doubling naturally slows to 72–96 hours, and exceeds 96 hours above 6,000 mIU/mL.

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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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Beta hCG Doubling Time Calculator & DPO Benchmarks

Calculate your exact quantitative serum hCG doubling velocity, 48-hour percentage increase, and physiological benchmarks.

1st hCG Draw (mIU/mL)

2nd hCG Draw (mIU/mL)

Hours Between Blood Draws

Hours

Estimated DPO (Optional)

DPO

hCG Doubling Time35.8 HoursEquivalent to 1.5 Days

Standardized 48-Hour Increase+153.3%Actual change over 48h: +153.3%

Statistical Model SummaryNormal Expected Doubling (<1,200 mIU/mL)

Your hCG is doubling every 35.8 hours (153% every 48h). In viable intrauterine gestations below 1,200 mIU/mL, titers typically double every 48 to 72 hours (minimum conservative 35% to 53% 48-hour rise).

⚠️ Urgent Medical Safety Notice (Ectopic Pregnancy Warning)

An online beta-hCG calculator is for informational tracking only and cannot confirm an intrauterine pregnancy or rule out an ectopic pregnancy. Seek immediate emergency medical care if you experience severe one-sided pelvic or abdominal pain, vaginal bleeding or spotting, shoulder-tip pain, dizziness, lightheadedness, or fainting—even if your hCG doubling time appears within normal ranges. Always review serial blood draws with your OB-GYN.

Normal Beta-hCG Reference Ranges (DPO & Gestational Age)

American Pregnancy Association Benchmarks

Median Beta-hCG levels and reference ranges by days past ovulation (DPO)
Days Past Ovulation (DPO)	Median Level	Normal Physiological Range
10 DPO	12 mIU/mL	5 – 30 mIU/mL
12 DPO	48 mIU/mL	17 – 119 mIU/mL
14 DPO (Period Due)	137 mIU/mL	48 – 426 mIU/mL
16 DPO	350 mIU/mL	111 – 1,100 mIU/mL
18 DPO	800 mIU/mL	260 – 2,400 mIU/mL
21 DPO (5 Weeks LMP)	2,500 mIU/mL	750 – 7,500 mIU/mL

Expected Beta-hCG doubling times and serum ranges by gestational age
Gestational Age (LMP)	Expected Doubling Time	Serum hCG Range
3 Weeks (7–14 DPO)	36 – 48 Hours	5 – 50 mIU/mL
4 Weeks (Period Due)	48 – 72 Hours	10 – 425 mIU/mL
5 Weeks (Gestational Sac)	48 – 72 Hours	19 – 7,340 mIU/mL
6 Weeks (Yolk Sac / Fetal Pole)	72 – 96 Hours	1,080 – 56,500 mIU/mL
7–8 Weeks (Cardiac Activity)	>96 Hours	7,650 – 229,000 mIU/mL
9–12 Weeks (Peak Level)	Plateau / Decline	25,700 – 288,000 mIU/mL

Calculate Exact DPO from Ovulation Date

Knowing your exact Day Past Ovulation (DPO) is critical when evaluating early beta-hCG values. Pinpoint your ovulation date using our Free Ovulation Tracker.

Free Ovulation Tracker

Clinical Methodology

The Endocrinology of Human Chorionic Gonadotropin (hCG)

Following blastocyst implantation (8–10 DPO), the syncytiotrophoblast secretes hCG into maternal circulation to rescue the corpus luteum from degradation, sustaining critical progesterone production.

hCG exhibits rapid exponential doubling during early gestation, peaking between weeks 9 and 11 before declining to a steady plateau for the remainder of pregnancy.

Frequently Asked Questions: Beta hCG Doubling Time

Audited under our Clinical Methodology & Citations.

What is a normal hCG doubling time?

Below 1,200 mIU/mL, a doubling time of 48 to 72 hours (minimum 35% to 53% increase in 48 hours) is expected in healthy intrauterine pregnancies.

Does slow-rising hCG always mean miscarriage or ectopic pregnancy?

Not necessarily. While slow doubling (<35% in 48 hours) increases suspicion of non-viable or ectopic pregnancy, roughly 15% of normal intrauterine gestations exhibit slower rises.

Why does doubling slow down after 6,000 mIU/mL?

This is normal placental physiology. As trophoblast volume expands, kinetics shift from rapid doubling to a plateau, and ultrasound becomes the primary clinical diagnostic tool.

At what hCG level should a gestational sac be visible on ultrasound?

The discriminatory zone is 1,500 to 2,000 mIU/mL, at which point a high-resolution transvaginal ultrasound should clearly visualize an intrauterine gestational sac.

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