فيزيولوجيا الإنجاب والتخصيب

Reproductive Physiology and Fertilization

• Human reproduction involves complex interwoven genetic, biological, environmental, and behavioral processes.
• Optimal nutritional status before pregnancy enhances the chances of a healthy pregnancy and a healthy baby.
• Poor nutritional or health conditions during pregnancy increase the risks to fetal development, the mother's health, and the baby's well-being.
• Infertility, or the inability to conceive, affects approximately 9-15% of couples in developed countries.
• "Fertility" refers to the actual production of children, while "fecundity" refers to the biological capability of producing children.
• Infertility rates are commonly measured as the number of live births per 1000 women aged 15-44.
• Infertility is generally defined as the failure to conceive after one year of unprotected intercourse.
• In some cases, 40% of couples diagnosed with infertility will conceive within three years without medical assistance or technology.
• The chances of conception decrease with age and the duration of infertility.
• Healthy couples who engage in regular unprotected intercourse have a 20-25% chance of a successful pregnancy in a given menstrual cycle.
• Studies indicate that 30-50% of pregnancies are lost due to implantation failure in the first few weeks of pregnancy, and approximately 9% are lost due to miscarriage in the first 20 weeks of pregnancy.
• Common causes of miscarriage include severe fetal abnormalities. Infections, structural problems in the uterus, endocrine or immune disorders, and unexplained events.
• Multiple miscarriages and male factor infertility (such as low sperm count/density, abnormal sperm morphology, or sperm motility issues), as well as irregular ovulation cycles in females, can all contribute to reduced fertility.

Nutritional Goals During Pre-Pregnancy

• Increase the proportion of adults with healthy weight.
• Decrease the proportion of obese adults.
• Reduce iron deficiency among women of childbearing age.
• Reduce cases of spina bifida and other neural tube defects.
• Increase the proportion of women receiving pre-conception counseling.

Reproductive Physiology

• Female and male reproductive systems develop during the first few months after conception, growing in size and complexity until puberty.
• Females are born with a supply of immature eggs, and males with sperm production potential.
• Reproductive capability is established during puberty when hormonal changes cause maturation of the reproductive system over a period of 3-5 years.
• The average female cycle length is approximately 28 days.
• The first 14 days are often referred to as the follicular phase, and the last 14 days are described as the luteal phase.
• The follicular phase involves the growth and maturation of several ovarian follicles, with the ultimate release of a single egg in a process called ovulation.
• Hormonal fluctuations in the two phases (follicular and luteal) are critical for preparation and maintenance of the endometrium (lining of the uterus) for implantation.

Female Reproductive System

• The menstrual cycle prepares the egg for fertilization and implantation in the uterus.
• The cycle is a complex interaction between hormones released by the hypothalamus, pituitary gland, and ovaries.
• The first day of bleeding is defined as the first day of the menstrual cycle.
• A number of cells and structural factors assist in the preparation for egg release and support a potential pregnancy.
• Ovulation typically occurs around day 14 of a 28-day cycle.
• If fertilization doesn't occur the corpus luteum (the temporary endocrine structure formed from the follicle following ovulation) deteriorates, and the uterine lining sheds, triggering menstruation.

Male Reproductive System

• Male fertility is a continuous rather than a cyclical process.
• Fluctuations in GnRH levels trigger the release of FSH and LH, stimulating testosterone production in the testes.
• Testosterone, along with other androgens, promotes sperm maturation, which takes roughly 70-80 days.
• Mature sperm are stored in the epididymis until ejaculation.
• During ejaculation, sperm mixes with secretions from the testes, seminal vesicles, prostate, and bulbourethral glands to form semen.

Causes of Infertility

• A number of factors can disrupt the complex mechanisms of fertility, including harmful dietary sources, birth control, severe stress, infections, fallopian tube damage, and chromosomal abnormalities.
• Infertility factors can affect different aspects of the reproductive process involving ovulation, the luteal phase, sperm production, and the pathways for gamete transport.
• Sexually transmitted infections (STIs) can cause pelvic inflammatory disease (PID), potentially leading to scarring and blockage of the fallopian tubes.

يتناول هذا الاختبار الفيزيولوجيا المتعلقة بالإنجاب وعملية التخصيب. يتضمن المعلومات حول التغذية، خصوبة النساء، ومعدلات العقم. تعتبر المعرفة بهذه الجوانب ضرورية لفهم الديناميات المعقدة المتعلقة بالإنجاب.