How to Differentiate Menstruation from Miscarriage

Throughout pregnancy, every expectant parent hopes for the healthy development of the fetus. However, various complications may still arise during gestation—among the more serious is miscarriage. Notably, symptoms of threatened miscarriage can closely resemble those of menstruation, leading to frequent confusion. So, how can one distinguish between normal menstruation and miscarriage? Below, we address this question.

How to Differentiate Between Menstruation and Miscarriage

Menstruation refers to the regular, cyclical vaginal bleeding experienced by women approximately once per month. In healthy women, the typical menstrual cycle lasts 28 days, with bleeding lasting 3–5 days and total blood loss averaging 20–50 mL. In contrast, spontaneous miscarriage involves not only vaginal bleeding but also the passage of tissue-like material and is often accompanied by severe abdominal cramping. Such symptoms are generally absent during normal menstruation. Although causes of miscarriage are complex and multifactorial, couples actively trying to conceive should prioritize preconception health checkups. These evaluations can help prevent many avoidable complications and reduce both physical and psychological harm associated with miscarriage.

Knowledge Extension: What Are the Causes of Miscarriage?

1. Embryonic Factors

Chromosomal abnormalities in the embryo constitute the leading cause of miscarriage. Chromosomal anomalies are detected in 50%–60% of embryos lost during early pregnancy. Either parent’s chromosomal abnormality—whether numerical (e.g., aneuploidy) or structural (e.g., translocations, deletions)—can be transmitted to the offspring, resulting in miscarriage. Beyond genetic factors, maternal infections or exposure to certain medications or environmental toxins may also induce embryonic chromosomal abnormalities, most commonly leading to miscarriage before 12 weeks’ gestation.

2. Maternal Factors

Uterine anatomical abnormalities—including uterine hypoplasia, unicornuate uterus, didelphys uterus, uterine septum, intrauterine adhesions (Asherman syndrome), or submucosal/intramural fibroids—can impair blastocyst implantation and subsequent embryonic development, thereby increasing miscarriage risk. Severe cervical lacerations, cervical insufficiency (incompetent internal os), or markedly shortened cervix may predispose to premature rupture of membranes and subsequent miscarriage. Additionally, luteal phase deficiency (LPD), hypothyroidism, and poorly controlled severe diabetes mellitus are all recognized contributors to early pregnancy loss.

The above outlines key distinctions between menstruation and miscarriage. We hope this information proves helpful to you.