In-Depth Study Notes on the Female Reproductive System and Related Pharmacology

Hormones of the Female Reproductive System

• Key Hormones:
  • Gonadotropin-Releasing Hormone (GnRH): Released by the hypothalamus; stimulates the pituitary gland.
  • Follicle-Stimulating Hormone (FSH): Stimulates ovarian follicle development.
  • Luteinizing Hormone (LH): Triggers ovulation and formation of the corpus luteum.
• Estrogen and Progesterone:
  • Produced by developing follicles; regulate menstrual cycle and secondary sexual characteristics.
  • High levels inhibit FSH and LH release.
• Ovulation:
  • Triggered by a surge in LH leading to oocyte release. Upon fertilization, the corpus luteum forms, secreting progesterone to maintain pregnancy.

Ovarian and Uterine Cycles

• Phases of the Cycle:
  • Follicular Phase (Day 1 menses - ovulation): FSH levels rise; follicles mature releasing estrogen.
  • Luteal Phase (Post-ovulation): Presence of corpus luteum; progesterone prepares the endometrium.
  • Menstruation: Shedding of the endometrial lining when fertilization does not occur.

Hormonal Feedback Mechanism

• Negative Feedback Loop:
  • High estrogen/progesterone levels suppress FSH and LH production to regulate hormone balance.

Functions of Luteinizing Hormone:

• Induces ovulation and promotes progesterone production from the corpus luteum.

Estrogen and its Effects

• Types of Estrogen: Estradiol, Estrone, Estriol.
• Physiologic Effects:
  • Maturation of reproductive organs and development of secondary sexual characteristics.
  • Cardiovascular protection (lowers LDL, increases HDL, strengthens bones).
  • Increases thromboembolic risks and can stimulate estrogen-sensitive tumors.

Progesterone and its Functions

• Supports endometrial development and breast tissue; crucial during pregnancy.
• Can be used for contraception and in the management of certain menstrual disorders.

Hormonal Contraceptives

• Mechanism of Action: Low doses of estrogen and progesterone prevent ovulation by inhibiting FSH/LH.
• Types of Birth Control Pills:
  • Monophasic, Biphasic, Triphasic, Quadriphasic: Variations in hormone dosing.
• Non-oral delivery: Vaginal rings, patches, and long-acting methods (IUDs).

Risks and Benefits of Hormonal Contraceptives

• Risks: Breast cancer, thromboembolic events, hypertension, gallbladder disease.
• Benefits: Lower ovarian cancer risk, regulated menstrual cycles, reduced dysmenorrhea.
• Common Side Effects: Nausea, breast tenderness, weight changes,
  • Serious Events: Thromboembolic disorders, hypertension.

Progestin-Only Contraceptives

• Options such as pills (Micronor), IM injections (Depo-Provera), IUDs (Mirena).
• Suitable for women contraindicated for estrogen; side effects may include irregular bleeding and mood changes.

Emergency Contraception

• Purpose: To prevent pregnancy following unprotected intercourse; most effective within 72 hours.
• Options: Levonorgestrel (Plan B) and ulipristal (Ella); both may cause nausea.

Medical Abortion

• Drugs Used: Mifepristone (blocks progesterone) often combined with misoprostol (prostaglandin to induce contractions).
• Side Effects: Nausea, vomiting; risks include uterine rupture and retained products of conception.

Menopause Management

• Symptoms: Hot flashes, insomnia, mood shifts, vaginal atrophy, increased cardiovascular and dementia risks.
• Hormone Replacement Therapy (HRT): Use with caution due to risk of cancer and thromboembolic disorders.
• Forms of HRT: Estrogens (estradiol, conjugated estrogen), typically combined with progestins if the woman has a uterus.

Dysfunctional Uterine Bleeding (DUB)

• Defined as abnormal uterine bleeding; causes vary widely.
• Terminology includes amenorrhea, menorrhagia, and oligomenorrhea.

Fertility Treatments and Endometriosis Management

• Fertility Drugs: Clomiphene for ovulation induction; others include FSH/LH enhancers.
• Endometriosis Management: Primarily through oral contraceptives or medications that suppress FSH such as leuprolide.

Female Hypoactive Sexual Desire Disorder (HSDD)

• Approved Drugs: Flibanserin (Addyi) and Bremelanotide (Vyleesi) with associated risks for syncope and hypertension.