Pregnancy is the period during which a baby develops in the womb of a female. It starts with conception, which is when a sperm fertilizes an egg and this fertilized egg attaches to the inner lining of the womb. This then develops into the placenta and embryo, and by the eighth week, into a foetus. When a woman is carrying more than one baby, such as twins, or triplets or more, her pregnancy is labeled as a multiple pregnancy. A full term pregnancy is about 37 to 42 weeks since conception. A baby born sooner is called pre-term, and a baby born later is called post-term.
Pregnancy is divided into three phases or trimesters:
The first trimester is from 0 to 12 weeks and is a period of rapid changes for both the baby and the mother. During this period, the baby develops its brain, spinal cord and other organs, and its heart starts beating. Its toes and fingers start taking shape. This period is critical and carries the highest risk of miscarriage, which is the natural death of an embryo or fetus.
The second trimester is from 13 to 28 weeks, during which the baby develops further and starts to move and hear. Its heartbeat can be heard through a stethoscope during this period.
The third trimester is from 29 to 40 weeks. During this time, the baby gains weight, and its movements are more pronounced as it positions itself lower in the mother’s belly for delivery.
Pregnancy leads to many changes in the mother’s body as well, as it adapts to its new responsibility of nourishing and supporting a baby. Changes may include fatigue, mood swings, nausea, changes in breast and skin, frequent urination, constipation, weight gain, swelling and body aches ealong with other changes.