Obstetrics: medical disorders in pregnancy — diabetes, heart disease, anemia is a core MBBS — Clinical (Phase 3 Part 2) concept in MBBS. This guide explains what it is, walks through a fully worked example, and lists the key equations you need — with a short quiz to test yourself.

Key equations and worked example

At a resting rate of 72 bpm, each cardiac cycle lasts 60/72 ≈ 0.83 s. In one day the heart beats about 72×60×24 ≈ 100,000 times, pumping roughly 7,500 litres of blood — enough to fill a small tanker truck every week. During exercise at 150 bpm the cycle shortens to 0.4 s, mostly by cutting the resting (diastole) phase.

• <code>Cardiac output = heart rate × stroke volume</code>
• <code>Cycle duration = 60 / (heart rate in bpm) seconds</code>
• <code>Typical stroke volume ≈ 70 mL; resting output ≈ 5 L/min</code>
• <code>Blood pressure ≈ 120/80 mmHg (systolic/diastolic)</code>

Obstetrics: medical disorders in pregnancy — diabetes, heart disease, anemia in detail

Obstetrics: medical disorders in pregnancy — diabetes, heart disease, anemia is one of the central ideas in MBBS — Clinical (Phase 3 Part 2), and it appears in MBBS curricula under Obstetrics and Gynecology. It is worth learning deeply because it connects to so many other topics in this section.

The heart is a double pump: the right side sends deoxygenated blood to the lungs, the left side sends oxygenated blood to the body. The left ventricle has the thickest wall because it works against the highest pressure. The aorta — the body&#39;s largest artery — carries each stroke volume out to the systemic circulation. One-way valves (mitral, aortic, tricuspid, pulmonary) keep blood flowing forward; the &#39;lub-dub&#39; sounds are these valves snapping shut.

For exams, the pattern is predictable: first a definition or statement of the result, then a direct numerical application of one of the equations above, then a "why" question — why the formula takes that form, or what changes when a variable is doubled or halved. The worked example and quiz below cover exactly that progression.

Quick self-check:

• Q: Which chamber has the thickest muscular wall, and why?<br />A: The left ventricle — it must generate enough pressure to push blood through the entire body.
• Q: What causes the &#39;lub-dub&#39; heart sounds?<br />A: &#39;Lub&#39; is the mitral and tricuspid valves closing at the start of systole; &#39;dub&#39; is the aortic and pulmonary valves closing at the start of diastole.
• Q: What is the aorta?<br />A: The largest artery in the body — it carries oxygenated blood from the left ventricle out to the systemic circulation.
• Q: How is cardiac output calculated?<br />A: Cardiac output = heart rate × stroke volume (≈ 72 bpm × 70 mL ≈ 5 L/min at rest).