The female reproductive system is designed by nature to express multiple gestations during a lifetime. The different stages of fetus growth are divided into three trimesters, that are taken care of by the obstetrics surgical field. Childbirth is a natural manifestation of the female reproductive system, a development that normally takes place over 40 weeks since the last recorded menstrual period. The calculation of this period is on the assumption of a regular menstrual period cycle observed every 28 days. Gravidity or pregnancy is the result of the fusion of the ovum and sperm in the uterus. The term 'embryo' is commonly used to describe the egg's development during the first 8 weeks post-conception, while 'fetus' refers to the offspring from 2 months till birth. The three trimester periods are references to the different prenatal development stages. A common observation is that the first trimester bears the highest risk of miscarriage or the natural death of the embryo. The second trimester is characterized by the demonstrable development of the fetus, while the third trimester approximates the point of viability. The point of viability refers to the survival chances of the fetus, beyond the uterus. The Trimesters Traditionally, doctors calculate the term of pregnancy on the basis of the last recorded menstruation, ovulation, fertilization, and chemical or clinical detection. The term may be affected if the embryo gets implanted within the fallopian tubes or the cervix instead of the endometrial lining of the uterus. Morning sickness and cramping are manifestations during the first 12 weeks or the first trimester. The second trimester relates to the period between the fourth and sixth month of pregnancy. During this phase, the uterus expands up to twenty times its regular size. It is during this phase that the fetus moves and takes a recognizable shape. The third phase is calculated beyond the sixth month of gravidity. This phase is characterized by weight gain, uterus drop, regular fetus movements, a convex navel, weakened bladder control, and severe backache. During this phase, the fetus becomes stronger and displays a preparedness for ex utero viability. Labor Signs During Gravidity A woman is in 'labor' when she experiences uterine contractions, effacement, and dilation of the cervix. This takes place in the final stage of the third trimester. The distinct signs include:

• Lightening or the positioning of the fetus into the pelvis region.
• Discharge of pink, or slightly bloody mucus and the mucus plug.
• Defined and regular contractions of the cervix, in a wave-like motion, accompanied by cramps.
• Water breaking or the weeping of amniotic fluid.
• Dilation and effacement of the cervix.

It is important to differentiate between 'true' and 'false' labor pains. The Braxton Hicks contractions or 'false' labor pains sometimes manifest in the second half of the second trimester, and become increasingly common during the third trimester. This is just the body's way of aping and getting ready for delivery of the fetus or ex utero viability. 'True' labor is characterized by contractions at regular intervals, that keep getting more frequent, despite movement or position change. The most defined sign of 'true' labor is the movement of cervix dilations or contractions from the lower back to the front of the abdomen. Ideally, when the contractions are observed less than 5 minutes apart, it is the essential to seek medical assistance.