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How the Uterus Changes Size Throughout the Menstrual Cycle

How the Uterus Changes Size Throughout the Menstrual Cycle

The uterus, also known as the womb, size fluctuates throughout the menstrual cycle, responding to a complex interplay between hormonal changes and preparation for pregnancy. During the menstrual cycle the uterus can double in size and weight, which goes a long way to explaining why some people experience a heavy sensation in the pelvic area at the beginning of their menstrual cycles.

In this blog, we look at the uterus size during the different phases of the menstrual cycle, exploring the measurements and weights of the uterus at its smallest and largest points.

The Menstrual Cycle and Its Phases

The menstrual cycle typically lasts around 28 days, although it can vary from person to person. It comprises four main phases (explained below) and during each of these stages, the uterus undergoes distinct changes to create an environment suitable for potential conception.

Menstruation (Day 1-5)

The menstrual phase marks the beginning of the menstrual cycle and involves the shedding of the uterine lining, which occurs when pregnancy does not take place. On average, menstruation lasts for 3 to 5 days. During this phase, the uterus is at its smallest size and weight.

The size of the uterus during menstruation can vary between individuals but is generally around 6 to 8 centimeters in length and 4 to 5 centimeters in width. As for its weight, it may range from 30 to 50 grams. These dimensions signify the contraction and relaxation of the uterine muscles, which aid in expelling the menstrual blood from the body. However, it's important to note that these measurements are approximate and can be influenced by factors such as age and reproductive history.

Follicular Phase (Day 6-14)

The follicular phase is characterized by the development of ovarian follicles, each containing an immature egg, in preparation for ovulation. During this phase, the hormone estrogen increases, causing the uterine lining to thicken in anticipation of a potential pregnancy. This growth in the uterine lining contributes to an increase in the size and weight of the uterus.

By the end of the follicular phase, the uterus can measure approximately 7 to 9 centimeters in length and 5 to 6 centimeters in width. Its weight also increases to around 60 to 80 grams. These changes aim to create a nourishing environment for a fertilized egg to implant and develop into a pregnancy.

Ovulation (Day 14)

Around day 14 of the menstrual cycle, ovulation occurs. This is the pivotal moment when the matured egg is released from the ovary and travels through the fallopian tube, ready to be fertilized by sperm. During ovulation, the uterus reaches its largest size and weight in the entire menstrual cycle.

The uterus can grow up to 8 to 10 centimeters in length and 6 to 7 centimeters in width during ovulation. Its weight can surge to approximately 70 to 100 grams. The rise in estrogen and luteinizing hormone (LH) triggers increased blood flow to the uterus, making it more receptive to potential implantation. This enlargement is a remarkable example of the uterus's adaptability to optimize the chances of conception.

Luteal Phase (Day 15-28)

The luteal phase begins after ovulation and is characterized by the formation of the corpus luteum, a temporary endocrine structure in the ovary that produces progesterone. Progesterone helps maintain the thickened uterine lining and supports early pregnancy if fertilization occurs.

During the luteal phase, the uterus retains its enlarged dimensions from ovulation, measuring approximately 8 to 10 centimeters in length and 6 to 7 centimeters in width. Its weight remains stable at around 70 to 100 grams. The uterus stays prepared to accommodate a potential pregnancy and continues to provide a nurturing environment for a fertilized egg.

anatomical models showing uterus size changes during mensruation

Throughout the menstrual cycle, the uterus undergoes significant changes and can double in size and weight in response to hormonal fluctuations. From its smallest and lightest a the end of menstruation to its largest and heaviest during ovulation, these variations are crucial in preparing the uterus for potential pregnancy and ensuring reproductive health.

Understanding uterus size throughout the menstrual cycle helps us gain insights into our fertility and overall reproductive well-being. It's important to recognise that individual variations can exist and any concerns about menstrual cycle irregularities or reproductive health should be discussed with a qualified healthcare professional.


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Disclaimer: The information provided in this blog is for educational purposes only and should not be considered a substitute for professional medical advice. Always consult with a qualified healthcare provider for personalised guidance on your health.