Female and Male Fertility

Question 1

Periodontal disease and fertility (mother)

Answer 1

Periodontal disease and fertility (mother) ― periodontal disease
can lengthen the time to conceive by approx. 2 months:
* It can prevent ovulation— increases inflammatory
markers (IL-1). IL-1 inhibits GnRH production.
* Metabolic waste products from oral bacteria and
inflammatory markers can cross the placenta and affect the foetus.
* Fusobacterium nucleatum has been isolated from the
amniotic fluid and placenta of women delivering prematurely.

Question 2

Periodontal disease and fertility (father)

Answer 2

Causal links exist between oral infections and infertility. Treatment
of oral infections = 20% improvement in spermatic parameters

Question 3

The seminal microbiome (SMB)

Answer 3

semen = the fluid that sperm swim in
* Semen has its own microbiome that is thought to come from the GIT, mouth, vagina (sexual partner and mother!).
* The SMB is thought to aid conception, support health
of the offspring and modulate immune responses.
* The SMB is more diverse but has lower bacterial concentrations
than the vagina. This diversity is thought to help expose and train
the VMB and immune system to aid pregnancy and conception.
* The SMB should be lactobacillus dominant (like the VMB) — it has
been shown that these bacteria prevent sperm damage by ROS.
* A meta-analysis found that sex during IVF increases implantation
by 23%; the semen (with the SMB) prompts the cervix to release
immune signalling molecules such as regulatory T-cells.
* The SMB is negatively impacted by antibiotics,
antifungals, STIs, prostatitis, lubricants, smoking,
alcohol, obesity and poor penile hygiene practices.
* Ureaplasma urealyticum is a frequent causes of male infertility.
* Low quality semen is also associated with E.coli, prevotella,
chlamydia, gonorrhoea, bacteroidetes and firmicutes.
These can generate oxidative stress and sperm damage.

Question 4

The vaginal microbiome (VMB)

Answer 4

A healthy fertile VMB is normally
associated with a dominance of the lactobacilli species, with a low
diversity of other species. Lactobacilli create an acidic, inhospitable
environment which prevents the overgrowth of potential pathogens.
* Lactobacillus crispatus (a commensal of the healthy vagina)
is associated with a higher implantation rate in women
undergoing IVF if it is in high abundance in the vagina.
* The presence of bacterial vaginosis, such as
ureaplasma and gardnerella, when coupled with low lactobacilli
species and a higher pH, can increase the chance of miscarriage.
* Mycoplasma, ureaplasma and chlamydia trachomatis are examples
of bacteria that have been negatively associated with fertility.
* The vaginal microbiota can be negatively impacted by
STIs, alcohol, smoking, poor vaginal or oral
hygiene, increased blood glucose levels, copper
IUD coil, a low vitamin A, D, C and E status etc.
* A low oestrogen environment can impact the
growth of the VM. Cervical fluid is important as a
fuel source to feed lactobacilli as it is rich in glycogen.
* You can positively impact the vaginal microbiota by reducing
infections, improving blood glucose levels, improving oestrogen
levels, and supporting lactobacilli growth with pre and probiotics.

Question 5

Exercises and fertility

Answer 5

Moderate exercise improves circulation and insulin resistance
which increases the likelihood of conception:
* Intensive exercise is deleterious for fertility,
as it raises cortisol production = ↓ progesterone.
* Excessive secretion of endorphins interferes
with the normal production of FSH and LH, in turn
inducing ovulatory disorders and luteal phase
dysfunction, which accounts for lack of embryo
implantation and first-trimester miscarriages.
* In males, excessive exercise has been
associated with oligospermia (oligo = ‘few’).

Question 6

Effect of stress on fertility

Answer 6

The release of cortisol, adrenaline and noradrenaline
can inhibit the release of GnRH (gonadotropin releasing hormone)
→ responsible for the release of the sex hormones LH and FSH:
* Under stress, the body will prioritise
the production of cortisol, leading to
reduced progesterone production.
* Stress influences sex hormones via
downregulation of LH and FSH, and
modulates steroidogenesis in the testes
/ ovaries. It disrupts gonadal function and
ultimately reduces sperm parameters.

Question 7

Age is a contributing factor to lowered fertility

Answer 7

• Women are born with all the oocytes they will ever have. Oocyte
  numbers / quality diminish with age esp. if not living a healthy lifestyle.
• Chromosomal abnormalities, poor
  embryonic development, implantation
  failure and miscarriage risk increase
  with age. Abnormalities: 1:500 aged
  20; 1:400 aged 30; 1:60 aged 40+.
• Men can father children at an
  advanced age, but sperm morphology
  and motility tend to decline with age.

Question 8

Assisted reproductive technologies

Answer 8

• In vitro fertilisation (IVF): Stimulation of ovaries,
  egg retrieval, fertilised in vitro with sperm,
  fertilised embryos transferred into uterus.
• Intracytoplasmic sperm injection (ICSI):
  Sperm is injected into egg in vitro (if fertility
  issue is due to sperm abnormalities).
• Intrauterine insemination (IUI)— sperm is placed inside
  uterus around ovulation to facilitate fertilisation.
• Sperm, oocyte, or embryo cryopreservation