Duration
of Pregnancy - It is calculated by clinicians as 10 lunar
months or 9 calendar months and 7 days or 280 days or 40 weeks
calculated from first day of the last menstrual period. This is called
menstrual or gestational age.As fertilization occurs 14 days prior to the expected missed period and in previously normal cycle of 28 days duration, it is about 14 days after the first day of the period. Thus the true gestation period is to be calculated by substracting 14 days from 280 days i.e. 266 days. This is called fertilization or ovulatory age.
SIGN & SYMPROMS OF PREGNANCY
Pregnancy is divided into three trimesters
First trimester (0-12 weeks)
Second trimester (13-28 weeks)
Third trimester/last trimester (29-40 weeks)
First Trimester - Presumptive/subjective symptoms of early months of pregnancy are :
- Amenorrhea - Cessation of menstruation during
the reproductive period in an otherwise healthy individual having
previous normal periods is due to pregnancy unless proved otherwise.
- Morning sickness - It is present in 50% of
cases and is more pronounced in first pregnancy. It appears
following the missed period till the end of first trimester. It can
be in form of nausea on rising from the bed or vomiting and loss of
appetite.
- Frequency of micturition (increased frequency of
urination) - It is more during 8-12th week and symptoms
disappear after the 12th week.
- Breast discomfort - Feeding of fullness and
pricking sensation is present from 6-8th week.
- Easy fatigability is a frequent symptom.
Objective Signs
- Breast Changes - Breast signs are valuable only
in primigravidae (in first pregnancy) changes are evident from 6-8
weeks. There is enlargement of breast and delicate veins visible
under the skin.
Nipple and areola became more pigmented especially in dark women. Thick yellowish secretion can be expressed from nipple as early as 12th week.
- Pelvic changes - Uterus remains a pelvic organ
till 12th week. These changes may help in the diagnosis of
pregnancy.
Vaginal Sign - Copious non-irritative mucoid discharge from the vagina.
Uterine Sign - Pregnant uterus feels soft and elastic and is enlarged in size. Regular and rhythmic uterine contractions can be elicited during bimanual examination by 4th week.
The symptoms of nausea & vomiting and frequency of micturition usually subside. The new features that appears are:
- Quickening: It denotes the perception of active
fetal movement by the women. It is felt about 16-18th week. It can
be a useful guide to calculate the expected date of delivery.
- Progressive enlargement of the lower abdomen.
- Appearance of secondary areola in breast at about 20th week
- Chloasma: pigmentation on the forehead and cheek may appear at about 24th week.
Signs
The symptoms of nausea & vomiting and frequency of micturition usually subside. The new features that appears are:
- Linea nigra - A linear pigmented line appears
on abdomen below umbilicus in midline and can be seen from 20th
week.
- Striae (both pink and white) are visible on
the lower abdomen.
- Uterus is further enlarged till above the umbilicus and is ovoid
in shape.
- Imegular spasmodic infrequent and painless contraction can be
felt on the uterus - Braxton Hicks contractions.
- Active foetal movement can be felt by 20th week.
- 5. Foetal heart sounds can be hard with a stethoscope by 18-20 weeks. It is the most conclusive clinical sign of pregnancy.
Third Trimester
Symptoms
- Amenorrhoea Persists.
- Enlargement of the abdomen is progressive which produces
mechanical discomfort to the patient such as palpitation or dyspnoea
following exertion.
- Lightening - At about 38th week a sense of relief of the pressure
symptoms is obtained due to descent of the head of the fetus into
pelvis.
- Frequency of micturition reappears.
- Foetal movements are more pronounced.
Signs
- Cutaneous changes - Increase in pigmentation and striae.
- Uterine shape becomes spherical from cylindrical beyond 36th
week.
- Braxton Hicks contractions are more evident.
- Palpation of the foetal parts become much easier
- Foetal heart sound is heard distinctly
- Radiology or sonography gives conclusive evidence of pregnancy.

