Obstetrics and Gynaecology
Introduction and Reproductive Anatomy
Maternal and perinatal mortality definitions and female reproductive anatomy for MBBS, including uterine support, blood supply and pelvic relations, mapped to NMC codes OG1 and OG2.
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Introduction and Reproductive Anatomy
Maternal and perinatal mortality definitions and female reproductive anatomy for MBBS, including uterine support, blood supply and pelvic relations, mapped to NMC codes OG1 and OG2.
This opening chapter frames obstetrics and gynaecology with the vital statistics used to measure maternal and perinatal health and lays down the reproductive anatomy that every later topic depends on. It defines maternal and perinatal mortality, stillbirth and abortion, then walks through the uterus, tubes, ovaries, blood supply and pelvic support.
High-yield: Introduction and Reproductive Anatomy
- The maternal mortality ratio is deaths per 100,000 live births; India's figure has fallen steadily but haemorrhage, hypertensive disease and sepsis remain the leading causes.
- A maternal death is defined as death during pregnancy or within 42 days of its termination from any cause related to or aggravated by the pregnancy, excluding accidental causes.
- Perinatal mortality counts stillbirths plus early neonatal deaths in the first seven days per 1,000 total births.
- A stillbirth is foetal death at or after 28 weeks of gestation or a birthweight of 1,000 grams or more in the Indian definition.
- Abortion is the expulsion of the products of conception before 20 weeks or below a foetal weight of 500 grams.
- The uterus is a pear-shaped organ that is normally anteverted and anteflexed, lying over the bladder.
- The main support of the uterus comes from the cardinal (transverse cervical) and uterosacral ligaments, not the broad or round ligaments.
- The ureter passes below the uterine artery near the cervix, giving the surgical adage water under the bridge, a key landmark in hysterectomy.
- The blood supply of the uterus is chiefly the uterine artery, a branch of the anterior division of the internal iliac artery.
- The ovary is supplied by the ovarian artery, a direct branch of the abdominal aorta at the level of L2.
- The pouch of Douglas (recto-uterine pouch) is the most dependent part of the peritoneal cavity and a common site for collection of blood or pus.
- The fallopian tube has four parts: interstitial, isthmus, ampulla and infundibulum; fertilisation normally occurs in the ampulla.
- The pelvic floor is formed mainly by the levator ani, whose puborectalis and pubococcygeus components are key to continence and support.
- Maternal morbidity and near-miss audit help identify preventable factors and improve the quality of obstetric care.
Key maternal and perinatal definitions
- **Maternal mortality ratio:** Maternal deaths per 100,000 live births. Leading Indian causes: haemorrhage, hypertensive disorders, sepsis.
- **Stillbirth:** Foetal death at or after 28 weeks or birthweight 1,000 grams or more (Indian definition).
- **Perinatal mortality:** Stillbirths plus early neonatal deaths (first 7 days) per 1,000 total births.
- **Abortion:** Loss of pregnancy before 20 weeks or foetal weight below 500 grams.
NMC competencies in this chapter
- **OG1.1:** Birth rate, maternal mortality and maternal morbidity
- **OG1.2:** Perinatal mortality and morbidity, including neonatal mortality and audit
- **OG1.3:** Stillbirth and abortion: definitions and significance
- **OG2.1:** Development and anatomy of the female reproductive tract, pelvic relations and physiology of conception
Frequently Asked Questions
What is the difference between maternal mortality ratio and rate?
The maternal mortality ratio is deaths per 100,000 live births, while the rate uses women of reproductive age as the denominator. The ratio is the figure quoted for programme monitoring in India.
Where does the ureter cross the uterine artery, and why does it matter?
The ureter passes below the uterine artery near the cervix, the water under the bridge relation. Knowing it prevents ureteric injury during hysterectomy and pelvic surgery.
Why is the pouch of Douglas clinically important?
It is the most dependent part of the peritoneal cavity, so blood from a ruptured ectopic or pus from pelvic infection collects there and can be reached on vaginal examination or culdocentesis.
How does this chapter help in NEET-PG?
The vital statistics definitions and the uterine and ovarian blood supply and support are recurring one-mark facts, and the anatomy underpins later obstetric and surgical questions.
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