We talk about the generation of human eggs and sperm, the ovulatory/menstrual cycle, conception process, and fertility in both genders. One needs to be optimizing egg and sperm health for vitality and longevity, even if one does not intend to have children.
Ejaculation
Ejaculated sperm travel through the seminiferous tubules, epididymis, and vas deferens. Seminal fluid quality can be affected by lifestyle choices such as smoking and drinking. Vasectomies prevent sperm from exiting the testicle. Sperm must swim a long distance to reach the egg, and frequent ejaculation increases the concentration and quality of healthy sperm.
Fertility depends on components from both the male and female sides. Timing ovulation and intercourse is critical, with regular ovulatory cycles being ideal. The egg is available for fertilization for only 24 hours after ovulation. Ejaculation after 48–72 hours of abstinence maximizes the concentration of healthy sperm.
Ovulatory and menstruation cycle
- The ovulatory/menstrual cycle is the female reproductive cycle, which is on average 28 days long, but can range from 21-35 days
- The cycle occurs when luteinizing hormone and follicle-stimulating hormone are released
- There is no causal relationship between the lunar cycle and the menstrual cycle
Optimize fertility
About 1 in 5 couples have fertility issues due to sperm quality or a lack of sperm. DNA fragmentation analysis and sperm shape analysis can be done to determine if sperm are capable of fertilizing an egg, and hormone analysis can provide insight into underlying health issues.
To optimize fertility, it is recommended to get 6–8 hours of quality sleep per night, limit alcohol consumption to two drinks per week if not trying to conceive, and avoid smoking nicotine and cannabis when trying to conceive.
Reducing stress levels and getting enough quality sleep can also help. It is important to get an STI check if sexually active, as STI checks are crucial for fertility and avoiding miscarriages, especially for chlamydia.
The sperm economics and timelines
Urologists and OB-GYNs typically want to see 15-20 million sperm per milliliter of semen, 2–5 milliliters of semen overall, and 50–60% motile sperm to do IVF. Men should get their sperm analyzed at least once every 5 years and consider freezing their sperm if they want to conceive in the future.
Women should get their antral follicle count measured to get an indirect measure of their egg reserve. It is recommended to have a sperm analysis and AMH levels measured early to have a comparison point for future fertility.
The follicular phase and the luteal phase
- The ovulatory menstrual cycle is divided into two halves: the follicular phase and the luteal phase
- The follicular phase is marked by the maturation of follicles and the release of FSH and LH
- The luteal phase is marked by the production of progesterone from the corpus luteum, which prepares the uterine lining for potential implantation of a fertilized egg
- Inhibin, estrogen, and progesterone all play a role in regulating the cycle
- If fertilization does not occur, the uterine lining sheds and the cycle begins again
Sperm cells
- Sperm cells are germline cells, meaning the activities of an individual do not change the genetic makeup of those cells
- Sperm cells contain 23 chromosomes, 22 autosomes and one sex chromosome (X or Y)
- The job of the sperm cell is to deliver the genetic material from the father in the form of a haploid cell
- Spermatogenesis involves GnRH, FSH, and LH hormones, with the testes as the target
- It takes about 60 days for sperm to be born from their parent cells and mature to the point where they can be a good swimmer
Eggs and sperm
Fertility and fertilization is about producing offspring that contain the genetic components of both parents
- There are two types of cells in the body: somatic cells and germline cells
- Germline cells are the egg and sperm and their genetic components cannot be modified by experience
- The goal of fertilization is to bring the haploid sperm cell (23 chromosomes) and the diploid egg cell (23 pairs of chromosomes) together
- The ovulatory and menstrual cycle are about eliminating half of the chromosomal pairs in the egg cell and bringing it together with the sperm cell to create a cell with half the chromosomes from mom and half from dad
Stay away from laptops and phones!
- Males and females should understand and maximize the quality of both the egg and the sperm when trying to conceive.
- Keep testicles cool by avoiding hot tubs, saunas, and laptops on the lap.
- Reduce the amount of time spent sitting and avoid seat heaters.
- Avoid a man-spread stance if your legs are large.
- Phone use has been linked to decreased sperm quality.
Puberty Contd.
- Puberty is occurring earlier and earlier in females due to the accumulation of body fat at younger ages than in the past.
- This is not necessarily related to the obesity crisis.
- Data from various countries show that the average age of menarche has decreased significantly over the last 100 years.
- Odors from both related and non-related individuals can influence the onset of puberty.
Tracking the ovulation
There are various ways in which women can track their ovulation, including the temperature method or using apps. The regularity of the menstrual cycle duration can help predict ovulation, and a woman’s libido tends to increase prior to ovulation.
Changes in pH and vaginal secretions also occur to support sperm motility, and commercially available lubricants can be detrimental to sperm health. It is advisable to discuss lubricants with an OB-GYN or urologist for optimal fertilization.
Fertilization of the egg
For women who are 30 years old or younger, the probability of successful fertilization and pregnancy is 20% in the first month of trying. However, most couples will not conceive in the first month, and they should continue trying in subsequent months.
Typically, OB-GYNs advise couples to try for 6 months before seeking medical intervention. As a woman’s age increases, the probability of a successful conception decreases.
Testicular temprature
The testes need to be kept two degrees cooler than the body temperature for the production of healthy sperm, which is why they are located in the scrotum outside of the body.
Hot tubs, hot baths, saunas, sitting for long periods, wearing tight clothing, and using seat heaters in cars can all raise the scrotal temperature and lower the sperm count. Spermatogonia differentiate into spermatocytes, which mature into haploid sperm cells. Mitochondria are crucial for the separation of chromosomes during fertilization
Libido in women
- Libido can increase dramatically in some women in the four to five days prior to ovulation, triggered by a spike in FSH, LH, and androgens like DHEA and testosterone.
- Some women experience malaise in the mid- to second-half of the luteal phase of the ovulatory menstrual cycle that is not associated with elevated levels of estrogen.
- Estrogen in the first half of the menstrual cycle primes progesterone in the second half of the ovulatory menstrual cycle.
- Estrogen increases just prior to ovulation are responsible for increases in libido, as well as increased androgen.
Miscarriages
Miscarriages can arise from a variety of sources, including genetic defects, issues with the uterus, sperm, or egg. The egg-sperm dynamic is important in fertilization leading to pregnancy. The probability of miscarriage increases with the age of the egg, reaching 25% for women aged 35 and above and 50% for women aged 40 and above.
Chromosomal abnormalities, such as trisomies or deletions, can lead to miscarriages, even when chromosomal arrangements are normal. Age is a major factor in determining the likelihood of a successful pregnancy.
Fertility in women
To determine their basic level of fertility, women can measure the number of follicles released from the ovarian reserve each month, which can be done by ultrasound or by measuring the anti-Mullerian hormone (AMH) levels.
It is recommended that women measure their follicle count and AMH levels multiple times over a period of time to get an accurate picture of their fertility. Similarly, the quality and quantity of sperm are crucial in determining fertility. It only takes one successful sperm and one successful egg to achieve successful fertilization and pregnancy, but a lot of sperm are required to increase the probability of successful fertilization.
Puberty
- Puberty is initiated by signals from the brain and body.
- The onset of puberty is happening earlier in females than in the past.
- Puberty is actively suppressed by neurons in the hypothalamus releasing GABA and by the tonic release of melatonin.
- Low body fat stores can prevent the onset of puberty.
- Leptin, a hormone released by body fat, can trigger the onset of puberty.
