Pregnancy lasts approximately 280 days or 9 months and occurs in 3 stages or trimesters. It begins with fertilization of an egg by sperm in the fallopian tubes. The fertilized egg then implants in the uterus and develops into an embryo and later a fetus, receiving oxygen and nutrients from the placenta via the umbilical cord. Each trimester involves specific developmental stages for the fetus and physiological changes in the mother's body to support fetal growth. The due date is estimated based on the first day of the woman's last menstrual period.

2. Pregnancy
• It is the period from fertilization to birth.
• It starts when a male’s sperm fertilizes a female’s egg (ovum)
in the woman's fallopian tube, making a (Zygote) with 46
chromosomes.
• The zygote starts to divide, and after five to seven days of
dividing and growing, it attaches itself to the wall of the uterus.
The moment it is implanted in the wall of the uterus it becomes
an (Embryo) and the placenta starts to develop.
• After 8 weeks, the developing embryo called (Fetus).
• The placenta give the embryo/fetus the oxygen and nutrition,
and removes the waste through the umbilical cord.

3. Implantation
in uterus
(Embryo)
Ovum
How the pregnancy happens?
Sperm

4. Implantation
in uterus
(Embryo)
Ovum
How the pregnancy happens?
Sperm
The normal pregnancy
lasts about
> 280 days
or > 9 months
or > 40 weeks
or > 3 trimesters
Normal delivery could be
from 38 – 42 weeks.

5. 1- Presumptive Signs:
(physiological changes noticed by the woman herself)
- Absence of menstruation (Amenorrhea)
- Nausea and vomiting (morning sickness): common from week
2–12.
- Breast tenderness, and swollen.
- Urination frequency.
- Fatigue and sleepiness.
Signs of pregnancy

6. 2- Probable Signs:
(physiological and anatomical changes that can be perceived by
the health care provider)
- Chadwick’s sign: darkness of the vulva.
- Goodell’s sign: softening of the cervix and vagina with
increased in discharge.
- Hegar’s sign: Softening of the lower uterine segment.
- Growth of uterus and abdomen.
- Skin hyperpigmentation: brownish pigmentation in the face, darkness
of nipples, linea nigra (pigmentation of the midline of abdominal skin).
- Positive pregnancy test results: detection of human chorionic
gonadatropin (hCG) in maternal urine or blood. The tests are
accurate, but not 100%.

7. 3- Positive Signs:
(Objective signs of pregnancy noted by the examiner by positive
examination of the embryo)
- Sonographic visualization of the embryo: Cardiac movement
noted at 4–8 weeks.
- Fetal heart beat: by using a Doppler in the10–12 weeks.
- Fetal movement: felt by the examiner after about 20 weeks.

8. Physiologic maternal changes
Pregnancy causes physiologic changes in all maternal organ systems; most return to
normal after delivery.
- Increased blood supply to breasts and uterus.
- Increased levels of estrogen and progesterone.
- Changes in senses of taste and smell, and increase in saliva.
- Softening of joints, and increased mobility of the sacroiliac and symphysis pubis.
- Increased in blood flow.
- Increased need for glucose, H2O, iron, and folic acid due to developing fetus.
- Heart rate increases from the normal 70 to as high as 90 beats/min.
- Decrease in blood pressure in first and second trimesters and became normal at
the third trimester.
- Increased breathing rate.
- increase in kidney and bladder size.
- High pigmentation of the skin.

10. Stages of pregnancy
1- First trimester (week 1-week 12)
- During the first trimester hormonal changes affect almost every organ system
in body.
- The baby develop rapidly. The major organs develop in this trimester.
- The menstruation stopped.
- Pregnant symptoms and signs (Mood swings, headache, morning sickness).
The weeks are grouped into three trimesters:

11. 1- First trimester in the baby
- The baby’s brain, heart and spinal cord have begun to form.
- Baby's heart starts to beat in the 8th week.
- The sex organs begin to form.
- The face starts to form.
- At the end of eight weeks, the baby is a fetus and looks more like a human, and about 2.5 cm.
- At 12 weeks we can see if he is a boy or girl. And the baby can make a fist.

12. 2- Second trimester (week 13-week 28)
- Most of the early pregnancy symptoms will gradually disappear.
- Other symptoms appears such as: backache, leg swollen, and heartburn.
- Stretch marks on the abdomen and breasts.
- The uterus will grow rapidly in size
- Fetus move at about 18 to 22 weeks.
- Increase of heart rate and blood flow to accommodate the needs of the
fetus.

13. 2- Second trimester in the baby
- Muscle tissue and bone continue to form.
- Skin begins to form in the 16th week.
- The baby can hear and swallow at the 20th week.
- Real hair begins to grow on your baby's head at 24th week. The lungs are formed, but do not
work.
- At the end of the trimester, the baby now about 30 cm.

14. 3- Third trimester (week 29-week 40)
- During this final trimester, your fetus grows larger and the body organs
mature. The fetus moves frequently, especially between the 27th and 32nd
weeks.
- A fetus usually set into a head-down position in the uterus.
- Shortness of the mother breath.
- Belly button of the mother may stick out.
- The breasts begin to produce colostrum (yellowish rich milk).

15. 3- Third trimester in the baby
- The baby’s bones are fully formed at 34th week.
- The eyes can open and close and sense changes in light.
- By the end of 37 weeks, the baby is considered full term and the organs are ready to function on
their own.
- Near the due date, the baby may turn into a head-down position for birth.

16. Due Date of delivery
Expected date of delivery / confinement (EDD/EDC) can be calculated
easily by Naegele's rule by:
1- adding one year,
2- subtracting three months, and
3- adding seven days to the first day of a woman's last menstrual period
(LMP).
*example
LMP = 8 May 2009
+1 year = 8 May 2010
−3 months = 8 February 2010
+7 days = 15 February 2010
Another method is by adding 9 months and 7 days to the first day of the
last menstrual period.