hCG Calculator
ObGyn Intelligence
HCGCALCULATOR.COM

Ectopic Pregnancy and hCG

What the numbers can tell you, what they can't, and the symptoms that outrank every number.

READ THIS FIRST IF YOU HAVE SYMPTOMS

If you are pregnant (or might be) and have severe or one-sided abdominal pain, shoulder-tip pain, dizziness or fainting, or heavy bleeding: this page can wait. Emergency care cannot. A ruptured ectopic pregnancy is life-threatening and treatable — the treatable part depends on being seen in time.

WHAT AN ECTOPIC PREGNANCY IS

An ectopic pregnancy is one implanted outside the uterine cavity — over 90% in a fallopian tube. About 1-2% of pregnancies are ectopic. The tube cannot host a growing pregnancy; as it stretches it can rupture and bleed internally. This is why early pregnancy protocols take location so seriously, and why hCG patterns get watched so closely before ultrasound can settle the question.

WHAT HCG CAN TELL YOU — AND WHAT IT CANNOT
• There is no hCG level that diagnoses ectopic pregnancy. None. Low, normal, and high values all occur.
• The classic ectopic pattern is an hCG that rises too slowly - below the minimum viable-pregnancy thresholds (slow-rising hCG) - or plateaus.
• But 21% of ectopics rise exactly like a healthy pregnancy, and 8% fall like a miscarriage (Silva 2006). The pattern raises or lowers suspicion; it never closes the question.
• The question closes with transvaginal ultrasound: a pregnancy seen inside the uterus (with rare exceptions in fertility treatment) effectively excludes ectopic.
• When hCG is above roughly 3,500 mIU/mL and ultrasound sees nothing in the uterus, concern rises substantially - that threshold is set deliberately high so viable pregnancies are not treated by mistake (ACOG PB 193; see the discriminatory zone).
PREGNANCY OF UNKNOWN LOCATION (PUL)

Often the first visit ends without an answer: positive hCG, nothing yet visible either way. This is a pregnancy of unknown location — a category, not a diagnosis, and most PULs turn out to be normal early pregnancies that were simply too early to see. The protocol is serial hCG (usually 48 hours apart — our calculator interprets exactly these draws), repeat ultrasound, and low threshold for return if symptoms change. Frustrating as the wait is, this watchful protocol is what protects both your safety and a wanted pregnancy from premature treatment.

RISK FACTORS AND ONE MYTH

Risk is higher after a previous ectopic, tubal surgery, pelvic infection, or with an IUD in place (IUDs prevent pregnancy overall; the rare pregnancies that occur are more often ectopic) — but half of ectopics occur with no risk factor at all, which is why symptoms always outrank statistics. And the myth: a positive home test with an ectopic is common — ectopics make hCG too. A negative test is possible when levels are very low, but never count on a strip to exclude an ectopic when symptoms say otherwise.

KEY SOURCES
1. Tubal ectopic pregnancy. ACOG Practice Bulletin No. 193. American College of Obstetricians and Gynecologists. Obstet Gynecol. 2018;131(3):e91-e103.
2. Silva C, Sammel MD, Zhou L, Gracia C, Hummel AC, Barnhart K. Human chorionic gonadotropin profile for women with ectopic pregnancy. Obstet Gynecol. 2006;107(3):605-610.
3. Barnhart KT, Guo W, Cary MS, et al. Differences in serum human chorionic gonadotropin rise in early pregnancy by race and value at presentation. Obstet Gynecol. 2016;128(3):504-511.
4. National Institute for Health and Care Excellence. Ectopic pregnancy and miscarriage: diagnosis and initial management. NICE guideline NG126. 2019 (updated 2023).
5. Schreiber CA, Sonalkar S. Tubal ectopic pregnancy. N Engl J Med. 2025;392(8):798-805.
Try the hCG Calculator →