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A study of girls in Istanbul, Turkey, in 2011 found the median age at menarche to be 12.7 years. [ better source needed ] [ 9 ] In the United States, an analysis of 10,590 women aged 15–44 taken from the 2013–2017 round of the CDC's National Survey of Family Growth found a median age of 11.9 years (down from 12.1 in 1995), with a mean of 12 ...
The normal level of hemoglobin (an oxygen-transport protein found in red blood cells) for women is 12.0 to 15.5 g/dL (for men, 13.5 to 17.5 g/dL). [ 51 ] [ 52 ] [ 53 ] Women's hearts have finer-grained textures in the muscle compared to men's hearts, and the heart muscle 's overall shape and surface area also differs to men's when controlling ...
Menstrual cycle The menstrual cycle is a series of natural changes in hormone production and the structures of the uterus and ovaries of the female reproductive system that makes pregnancy possible. The ovarian cycle controls the production and release of eggs and the cyclic release of estrogen and progesterone. The uterine cycle governs the preparation and maintenance of the lining of the ...
The term vagina is from Latin vāgīna, meaning "sheath" or "scabbard". [1] The vagina may also be referred to as the birth canal in the context of pregnancy and childbirth. [2] [3] Although by its dictionary and anatomical definitions, the term vagina refers exclusively to the specific internal structure, it is colloquially used to refer to the vulva or to both the vagina and vulva.
Primary amenorrhea is defined as an absence of secondary sexual characteristics by age 13 with no menarche or normal secondary sexual characteristics but no menarche by 15 years of age. [3] It may be caused by developmental problems, such as the congenital absence of the uterus, failure of the ovary to receive or maintain egg cells , or delay ...
The third dredge-up occurs after a star enters the asymptotic giant branch, after a flash occurs in a helium-burning shell. The third dredge-up brings helium, carbon, and the s-process products to the surface, increasing the abundance of carbon relative to oxygen; in some larger stars this is the process that turns the star into a carbon star. [3]
One cause of hypomenorrhea is Asherman's syndrome (intrauterine adhesions), of which hypomenorrhea (or amenorrhea) may be the only apparent sign. The degree of menstrual deficiency is closely correlated to the extent of the adhesions.
Diagram showing the relationship between the zenith, the nadir, and different types of horizon.Note that the zenith is opposite the nadir. The nadir [a] [b] is the direction pointing directly below a particular location; that is, it is one of two vertical directions at a specified location, orthogonal to a horizontal flat surface.