Pregnancy:
It is the time from conception to birth. In human beings, it is approximately 9 months and 7-10 days. The days of pregnancy are calculated from the first day of the last menstrual period or 256-270 days from the time of ovulation. Various types of extra demands are observed on the mother’s body during the period of pregnancy.
Stages of Pregnancy:
The physiological changes during pregnancy include –
Stage-1: To accommodate the growing fetus there is a marked increase in the size of the uterus takes place.
Stage-2: During the first 12-16 weeks of pregnancy, the corpus luteum enlarges. After some time, it degenerates and the placenta takes over the function.
Stage-3: In the cervix, the cervical gland increase in number, endocervix gets hypertrophied.
Stage-4: Fallopian tubes are pushed upwards due to an increase in the size of the uterus. Hyperplasia of fallopian tubes occurs.
Stage-5: During early pregnancy, under the influence of various hormones breast enlarges. Ductae and alveolar hyperplasia occur. Nipples also become longer and pigmented.
Stage-6: During this period, women gain a total of 10-12 kg of weight contributed by fetus, placenta and amniotic fluid, uterus and breast enlargement, fat deposition, Na+, H2O retention (oedema).