The patient usually makes the diagnosis of pregnancy before consulting her doctor and in most instances, confirmation is quite easy. However, in early pregnancy, a definite diagnosis may be difficult to make and it is often when this decision is of considerable importance that it is hardest to be sure.
Pregnancy is a continuous process where an insult in early-stage to the mother and the fetus can affect the outcome. The following points highlight the importance of early diagnosis:
– To protect the fetus from teratogenic agents such as alcohol, smoking, drugs, X-rays.
– For early identification and proper management of high-risk pregnancies. For example medical disorders complicating pregnancy such as diabetes mellitus and hypertension.
– To provide nutrition supplements (folic acid, calcium, ferrous sulfate) to improve maternal nutrition level thus ensuring adequate fetal nutrition.
– To take measures to prevent fetal and neonatal complications by early detection and treatment of maternal infections and by giving tetanus toxoid to prevent neonatal tetanus.
– For early therapeutic termination of pregnancy with less physical and psychological trauma in cases where pregnancy is absolutely contraindicated such as primary pulmonary hypertension.
– Calculation of the expected date of delivery is easier and more accurate if the pregnancy is diagnosed early. This is important in assessing the maturity of the fetus.
Early diagnosis also allows you to verify the correct composition of amniotic fluid to identify serious malformations.
The amniotic fluid is of mixed origin or heterogeneous. In early fetal life, the osmolality and the electrolyte content of the amniotic fluid are similar to that of the serum. Therefore, it is considered an ultrafiltrate of the maternal serum.
1. Almost 99% of the amniotic fluid is made up of water.
2. Also, it contains the cell and cell debris such as:
– fetal epithelial cells;
– amniotic cells;
– dermal fibroblasts;
– red blood cells (in case of placental abruption).
3. Proteins also contribute to its composition. Alpha-fetoprotein (AFP) is such an important protein and the level of which is elevated in open neural tube defects and reduced in Downs syndrome. Therefore, it is used as a marker for the antenatal diagnosis of these disorders.
4. Pigments and stains such as bilirubin and meconium can be found in amniotic fluid. The level of bilirubin in the amniotic fluid is measured in cases of rhesus isoimmunization between the mother and the fetus to determine the extent of fetal involvement.
5. Electrolytes and metabolites such as Sodium (Na+), urea, creatinine, hormones, and enzymes are also a part of amniotic fluid.
6. Also and sebaceous material can be found in amniotic fluid.
Confirmation of the diagnosis of the pregnancy can be achieved by investigating.
Radio receptor assay
Most commonly used test for the diagnosis of pregnancy is agglutination inhibition test to detect hCG in urine. The patient should be told not to drink excessive water on the previous day. Early morning first voided samples should be collected. The test becomes positive from 6-7 days after conception to the 12th week of pregnancy. Knowing the level of hCG is also important to get an idea of pathologies associated with pregnancy such as ectopic pregnancy, Hydatidiform mole, missed miscarriage.