Understanding the relationship between obesity and infertility Infertility is commonly defined as not becoming pregnant after 12 months of regular, unprotected intercourse, or after 6 months if the person trying to conceive is 35 or older. Obesity is usually defined…

Why metabolism matters for fertility Fertility is not controlled by the ovaries alone. Ovulation depends on pulsatile gonadotropin-releasing hormone from the hypothalamus, follicle-stimulating hormone and luteinizing hormone from the pituitary, ovarian estrogen and progesterone production, and the ability of the…

Why the immune system matters in reproduction Reproduction is not immunologically passive. Ovulation involves controlled inflammation, sperm must survive within the reproductive tract, the embryo must implant into the endometrium, and the maternal immune system must tolerate a genetically distinct…

Understanding pelvic inflammatory disease Pelvic inflammatory disease is usually caused by microorganisms ascending from the cervix or vagina into the upper genital tract. It most often affects sexually active people of reproductive age. The organisms classically associated with PID include…

Why cervical mucus matters for conception Cervical mucus is produced by glands in the cervix under the influence of ovarian hormones. Although it may seem like ordinary discharge, it is a dynamic biologic fluid with several reproductive functions. Outside the…

Understanding uterine abnormalities The uterus develops from paired embryologic structures called the Müllerian ducts. During typical development, these ducts elongate, fuse in the midline, and the central partition between them is resorbed to create a single uterine cavity. When any…

What prolactin is and why hyperprolactinemia matters Prolactin is produced mainly by lactotroph cells in the anterior pituitary gland. Under usual circumstances, dopamine from the hypothalamus acts as a brake on prolactin secretion. When dopamine signaling is reduced, or when…

Why the thyroid matters for fertility The thyroid gland produces thyroxine, or T4, and triiodothyronine, or T3. These hormones influence metabolism in nearly every tissue, including the ovaries, endometrium, liver, and pituitary gland. In reproductive physiology, thyroid function is closely…

Progesterone’s role in the fertile cycle Progesterone is produced mainly by the corpus luteum, the temporary endocrine structure that forms in the ovary after ovulation. In the first half of the menstrual cycle, estrogen helps the endometrium grow. After ovulation,…

What is the luteal phase? The menstrual cycle is often divided into two broad halves. The follicular phase begins with menstruation and leads up to ovulation. The luteal phase begins after ovulation, when the ruptured follicle transforms into the corpus…