Oxygen consumption increases gradually in response to the needs of the growing fetus, culminating in a rise of at least 20% at term. During labour, oxygen consumption is further increased (up to and over 60%) as a result of the exaggerated cardiac and respiratory workload.

Gastro-intestinal system

The enlarging uterus causes a gradual displacement of stomach and intestines and may cause esophageal reflux resulting in mild vomiting.

Skin

Typical skin changes are :

1. Melasma or "mask of pregnancy"
The skin on the upper cheeks, forehead and upper lip, have a localised tan. Female hormones are responsible for this condition.

2. Urticaria of Pregnancy

Technically termed Pruritic urticarial papules and plaques of pregnancy (PUPPP) is a benign skin that usually arises late in the third trimester of a first pregnancy. PUPPP is the most common of the pregnancy-related skin problem and typically resolves spontaneously within one week of delivery.

Metabolism

As the fetus and placenta grow and place increasing demands on the mother, phenomenal alterations in metabolism occur. The most obvious physical changes are weight